the blades on Shimano are as strong as the lip on a can of beer, crash once and they're fatigued, crash twice and you need a...
the blades on Shimano are as strong as the lip on a can of beer, crash once and they're fatigued, crash twice and you need a new one, on magura the sort of carbotecture master is more of an issue, it not ranting, it makes sense, both options, especially when paired together are a worse combo bang for buck in the long run than say Hope as you miss both companies warranties and get both levers and calipers that are officially un serviceable
Hello brake nerds! I have a very annoying issue with my Dominon A4s that has me scratching my head. I bought the set for my fat bike and have been using it a lot this year. When it is freshly bled, the lever free throw is a decent 10-15mm and bite point is crisp. Over the course of a month the free throw grows to a whopping 35+mm where they are nearly touching the bar. The bite is still pretty crisp. I adjust the lever reach as a bandaid fix but eventually the bite keeps going closer and close to the bar. It can't be air trapped in the system otherwise the bite would be spongey right? Could there be a leak somewhere in the system? I noticed two drops of DOT fluid escape the reservoir cap when I was pressurizing them during the last bleed. What the heck is going on with these? It happens to both front and rear at different rates. I am using the SRAM pro bleed kit and the fittings don't leak either.
Hello brake nerds! I have a very annoying issue with my Dominon A4s that has me scratching my head. I bought the set for my fat...
Hello brake nerds! I have a very annoying issue with my Dominon A4s that has me scratching my head. I bought the set for my fat bike and have been using it a lot this year. When it is freshly bled, the lever free throw is a decent 10-15mm and bite point is crisp. Over the course of a month the free throw grows to a whopping 35+mm where they are nearly touching the bar. The bite is still pretty crisp. I adjust the lever reach as a bandaid fix but eventually the bite keeps going closer and close to the bar. It can't be air trapped in the system otherwise the bite would be spongey right? Could there be a leak somewhere in the system? I noticed two drops of DOT fluid escape the reservoir cap when I was pressurizing them during the last bleed. What the heck is going on with these? It happens to both front and rear at different rates. I am using the SRAM pro bleed kit and the fittings don't leak either.
Heya, let's dig in. Set the lever up so the reservoir is at 12 o'clock on the handlebar. ideally so the reservoir cover screws are perpendicular to the floor. Pump the brake lever a number of times and see if it firms up (a little or a lot). If so, culprit is air in the MC. Culprit could be bleed issue or it could be that the drops of brake fluid you're seeing by the reservoir are indicating a res leak, likely from the bladder. I'd remove the cover and inspect the bladder. It should be free from tears. Dependiong on how heavy handed you were pushing n pulling on your syringes, you may have popped the bladder from its grooves or tore it. Haven't seen that with the Doms(yet) but have seen it with other makes/models.
Hello brake nerds! I have a very annoying issue with my Dominon A4s that has me scratching my head. I bought the set for my fat...
Hello brake nerds! I have a very annoying issue with my Dominon A4s that has me scratching my head. I bought the set for my fat bike and have been using it a lot this year. When it is freshly bled, the lever free throw is a decent 10-15mm and bite point is crisp. Over the course of a month the free throw grows to a whopping 35+mm where they are nearly touching the bar. The bite is still pretty crisp. I adjust the lever reach as a bandaid fix but eventually the bite keeps going closer and close to the bar. It can't be air trapped in the system otherwise the bite would be spongey right? Could there be a leak somewhere in the system? I noticed two drops of DOT fluid escape the reservoir cap when I was pressurizing them during the last bleed. What the heck is going on with these? It happens to both front and rear at different rates. I am using the SRAM pro bleed kit and the fittings don't leak either.
From your description, it was unclear if the lever throw grows simply when the bike sits for a while, or if it is only through hours of use that it grows. If it is directly related to hours of use, is it possible that you have sticky caliper pistons which aren't advancing through the seals to compensate for pad wear?
The different rate at which the throw increases on front and rear would fit with that, especially if the rear increases faster than the front, as people typically use the rear brake more and go through pads faster.
Checking to see if the pad/rotor gap is staying consistent or, as the pads wear, is it growing in relation to the lever throw would be another way to verify this. If they do seem sticky, then cleaning and lubing the pistons should be an easy fix.
If the pad gap is staying consistent though, that should indicate the pistons are advancing as they should, and, as HexonJuan pointed out, there may be insufficient fluid supply to continue activating them as more and more of the reservoir fluid is called in to fill the increased volume as the pistons advance. I would think the feel would get mushy in that instance though, whereas it sounded like you still get a firm bite point, but it just moves over time.
Thanks, I just did that pump up test and there was no noticeable firm up. The bite point gets a tiny little sharper after a few pulls but that's pretty normal. There is about a month of fat biking left so I will open up the MC after that OR if the lever runs out of adjustment. I am a bit of a gorilla when it comes to pushing and pulling so I might have ruptured the bladder like I did on my Maximas. Really need to curb that habit I built bleeding SRAM brakes.
Hello brake nerds! I have a very annoying issue with my Dominon A4s that has me scratching my head. I bought the set for my fat...
Hello brake nerds! I have a very annoying issue with my Dominon A4s that has me scratching my head. I bought the set for my fat bike and have been using it a lot this year. When it is freshly bled, the lever free throw is a decent 10-15mm and bite point is crisp. Over the course of a month the free throw grows to a whopping 35+mm where they are nearly touching the bar. The bite is still pretty crisp. I adjust the lever reach as a bandaid fix but eventually the bite keeps going closer and close to the bar. It can't be air trapped in the system otherwise the bite would be spongey right? Could there be a leak somewhere in the system? I noticed two drops of DOT fluid escape the reservoir cap when I was pressurizing them during the last bleed. What the heck is going on with these? It happens to both front and rear at different rates. I am using the SRAM pro bleed kit and the fittings don't leak either.
From your description, it was unclear if the lever throw grows simply when the bike sits for a while, or if it is only through hours...
From your description, it was unclear if the lever throw grows simply when the bike sits for a while, or if it is only through hours of use that it grows. If it is directly related to hours of use, is it possible that you have sticky caliper pistons which aren't advancing through the seals to compensate for pad wear?
The different rate at which the throw increases on front and rear would fit with that, especially if the rear increases faster than the front, as people typically use the rear brake more and go through pads faster.
Checking to see if the pad/rotor gap is staying consistent or, as the pads wear, is it growing in relation to the lever throw would be another way to verify this. If they do seem sticky, then cleaning and lubing the pistons should be an easy fix.
If the pad gap is staying consistent though, that should indicate the pistons are advancing as they should, and, as HexonJuan pointed out, there may be insufficient fluid supply to continue activating them as more and more of the reservoir fluid is called in to fill the increased volume as the pistons advance. I would think the feel would get mushy in that instance though, whereas it sounded like you still get a firm bite point, but it just moves over time.
I ride pretty regularly and have high volume so the bike doesn't sit around for too long. Regardless, I just did a piston advance/lube procedure yesterday and it hasn't helped. As for pad/rotor wear I just installed new Sinter Green pads a few rides ago on a rotor that is pretty fresh so it can't be that. Funny enough the "growth" is pretty random. Sometimes it is the front that gives out faster and sometimes it is the rear. These observations were after around 800 km/ 40,000M+ vert of fat biking in the last 5 months.
I ride pretty regularly and have high volume so the bike doesn't sit around for too long. Regardless, I just did a piston advance/lube procedure yesterday...
I ride pretty regularly and have high volume so the bike doesn't sit around for too long. Regardless, I just did a piston advance/lube procedure yesterday and it hasn't helped. As for pad/rotor wear I just installed new Sinter Green pads a few rides ago on a rotor that is pretty fresh so it can't be that. Funny enough the "growth" is pretty random. Sometimes it is the front that gives out faster and sometimes it is the rear. These observations were after around 800 km/ 40,000M+ vert of fat biking in the last 5 months.
Wow, that is mysterious! I look forward to hearing what the culprit was when you finally figure it out. It certainly sounds like you're doing a good and thorough job with the troubleshooting.👍
I ride pretty regularly and have high volume so the bike doesn't sit around for too long. Regardless, I just did a piston advance/lube procedure yesterday...
I ride pretty regularly and have high volume so the bike doesn't sit around for too long. Regardless, I just did a piston advance/lube procedure yesterday and it hasn't helped. As for pad/rotor wear I just installed new Sinter Green pads a few rides ago on a rotor that is pretty fresh so it can't be that. Funny enough the "growth" is pretty random. Sometimes it is the front that gives out faster and sometimes it is the rear. These observations were after around 800 km/ 40,000M+ vert of fat biking in the last 5 months.
When I had Dominions, I noticed there was a pretty big change after the first couple rides on free stroke, following new pads. With fresh pads, the free stroke is really short, but it pretty rapidly grows to whatever the nominal rollback is. It was more pronounced running aftermarket pads (like Galfer) instead of the Hayes ones, as the Galfer total backer+pad thickness is greater. I'd always end up with different feeling front/rear since the pads wore at different rates.
I ride pretty regularly and have high volume so the bike doesn't sit around for too long. Regardless, I just did a piston advance/lube procedure yesterday...
I ride pretty regularly and have high volume so the bike doesn't sit around for too long. Regardless, I just did a piston advance/lube procedure yesterday and it hasn't helped. As for pad/rotor wear I just installed new Sinter Green pads a few rides ago on a rotor that is pretty fresh so it can't be that. Funny enough the "growth" is pretty random. Sometimes it is the front that gives out faster and sometimes it is the rear. These observations were after around 800 km/ 40,000M+ vert of fat biking in the last 5 months.
When I had Dominions, I noticed there was a pretty big change after the first couple rides on free stroke, following new pads. With fresh pads...
When I had Dominions, I noticed there was a pretty big change after the first couple rides on free stroke, following new pads. With fresh pads, the free stroke is really short, but it pretty rapidly grows to whatever the nominal rollback is. It was more pronounced running aftermarket pads (like Galfer) instead of the Hayes ones, as the Galfer total backer+pad thickness is greater. I'd always end up with different feeling front/rear since the pads wore at different rates.
Yup this sounds like something related to roll-back, as in the seals are able to pull the pistons back along way. One thing you can do is lubricate the pistons with proper brake grease as that reduces how much the sqaure seal can grip the piston. So they will be able to advance closer to the piston, as that design relies on the surface finish and friction between the seal and piston
Got these in the mail the other day from the UK. Heard some rumblings about the looks on here, they do look decidedly old school but I’m excited to see another player in the game. Will report back once I finally get them mounted.
When I had Dominions, I noticed there was a pretty big change after the first couple rides on free stroke, following new pads. With fresh pads...
When I had Dominions, I noticed there was a pretty big change after the first couple rides on free stroke, following new pads. With fresh pads, the free stroke is really short, but it pretty rapidly grows to whatever the nominal rollback is. It was more pronounced running aftermarket pads (like Galfer) instead of the Hayes ones, as the Galfer total backer+pad thickness is greater. I'd always end up with different feeling front/rear since the pads wore at different rates.
I have been through 3 sets of pads (OEM organic, OEM metallic and now Sinter) and you are right about the changing feel between them. I ended up bleeding the brakes every time I changed the pads which is pretty annoying.
Hello brake nerds! I have a very annoying issue with my Dominon A4s that has me scratching my head. I bought the set for my fat...
Hello brake nerds! I have a very annoying issue with my Dominon A4s that has me scratching my head. I bought the set for my fat bike and have been using it a lot this year. When it is freshly bled, the lever free throw is a decent 10-15mm and bite point is crisp. Over the course of a month the free throw grows to a whopping 35+mm where they are nearly touching the bar. The bite is still pretty crisp. I adjust the lever reach as a bandaid fix but eventually the bite keeps going closer and close to the bar. It can't be air trapped in the system otherwise the bite would be spongey right? Could there be a leak somewhere in the system? I noticed two drops of DOT fluid escape the reservoir cap when I was pressurizing them during the last bleed. What the heck is going on with these? It happens to both front and rear at different rates. I am using the SRAM pro bleed kit and the fittings don't leak either.
Hey, I don't know if you have checke this yet, but take a look at how the olive is sitting on the hose at the lever. When I first got my Hayes, I had a shop set them up for me and who ever did the install got the barb and olive on the hose crooked. That allowed dot fluid to get into the fiberglass insulation in the hose and bassically would drain the master cylinder over time. I cut the old barb and olive off and properly set a new one in and I've never had issues since
Hello brake nerds! I have a very annoying issue with my Dominon A4s that has me scratching my head. I bought the set for my fat...
Hello brake nerds! I have a very annoying issue with my Dominon A4s that has me scratching my head. I bought the set for my fat bike and have been using it a lot this year. When it is freshly bled, the lever free throw is a decent 10-15mm and bite point is crisp. Over the course of a month the free throw grows to a whopping 35+mm where they are nearly touching the bar. The bite is still pretty crisp. I adjust the lever reach as a bandaid fix but eventually the bite keeps going closer and close to the bar. It can't be air trapped in the system otherwise the bite would be spongey right? Could there be a leak somewhere in the system? I noticed two drops of DOT fluid escape the reservoir cap when I was pressurizing them during the last bleed. What the heck is going on with these? It happens to both front and rear at different rates. I am using the SRAM pro bleed kit and the fittings don't leak either.
Hey, I don't know if you have checke this yet, but take a look at how the olive is sitting on the hose at the lever...
Hey, I don't know if you have checke this yet, but take a look at how the olive is sitting on the hose at the lever. When I first got my Hayes, I had a shop set them up for me and who ever did the install got the barb and olive on the hose crooked. That allowed dot fluid to get into the fiberglass insulation in the hose and bassically would drain the master cylinder over time. I cut the old barb and olive off and properly set a new one in and I've never had issues since
Great point! I have a few spare olives and enough hose so I will install fresh ones on the next bleed. I've experienced that once on SRAM when I kinked my hose.
Hey All, this is borderline brake tech... more of a brake question then anything.
For all the TRP DHR Evo users (The previous generation, not the new Evo X) what are you doing for dropper post remote mounting? I previously had a wt light action remote, with a discrete 22mm clamp that played ok with the dhr evo levers. This last weekend, I went to move a wt remote pro over to the bike with the DHR Evo's and there is virtually no way to get them to play together ergonomically. I emailed WT components and they pointed out that while TRP claims that their levers are I Spec-II compatible, that TRP altered their version of I-spec and not directly compatible with WT (and sounds like most other) ispec clamp designs.
So... what dropper levers are people using with this brakes, and how do you have them mounted?
Orbital sander + 120 grit pad 20-30 seconds on each side x2 using medium pressure. This is how I prep my rotors when changing pad compounds/brands...
Orbital sander + 120 grit pad 20-30 seconds on each side x2 using medium pressure. This is how I prep my rotors when changing pad compounds/brands. I even do this when changing pads to fresh ones. Never let me down.
Going to circle back here. Just got an orbital sander to breath new life into some of the "dead" rotors I've accumulated.
Holy smokes did it work super well, a bit of 150 grit to 220 and they look brand new.
You don't even need to use an orbital sander. I just take a sheet of 150 grit, spin the wheel on the frame and hold the sandpaper against the rotor one side at a time. You don't need much pressure or time - just trying to clean off the surface deposit of pad compound.
Orbital sander + 120 grit pad 20-30 seconds on each side x2 using medium pressure. This is how I prep my rotors when changing pad compounds/brands...
Orbital sander + 120 grit pad 20-30 seconds on each side x2 using medium pressure. This is how I prep my rotors when changing pad compounds/brands. I even do this when changing pads to fresh ones. Never let me down.
You don't even need to use an orbital sander. I just take a sheet of 150 grit, spin the wheel on the frame and hold the...
You don't even need to use an orbital sander. I just take a sheet of 150 grit, spin the wheel on the frame and hold the sandpaper against the rotor one side at a time. You don't need much pressure or time - just trying to clean off the surface deposit of pad compound.
Yeah, but an orbital sander is way easier in my opinion. Granted you might scuff up some of the pant/markings off the brake surface itself, but it was a price I was willing to pay.
I've tried the sandpaper to rotor on the bike for years and never got it to work.
Hey All, this is borderline brake tech... more of a brake question then anything.For all the TRP DHR Evo users (The previous generation, not the new...
Hey All, this is borderline brake tech... more of a brake question then anything.
For all the TRP DHR Evo users (The previous generation, not the new Evo X) what are you doing for dropper post remote mounting? I previously had a wt light action remote, with a discrete 22mm clamp that played ok with the dhr evo levers. This last weekend, I went to move a wt remote pro over to the bike with the DHR Evo's and there is virtually no way to get them to play together ergonomically. I emailed WT components and they pointed out that while TRP claims that their levers are I Spec-II compatible, that TRP altered their version of I-spec and not directly compatible with WT (and sounds like most other) ispec clamp designs.
So... what dropper levers are people using with this brakes, and how do you have them mounted?
Most I-Spec II adapter have a lip at the end, I just cut that lip and it worked well for the time I had my set of DHR Evo and wolftooth dropper / sram shifter.
Hey All, this is borderline brake tech... more of a brake question then anything.For all the TRP DHR Evo users (The previous generation, not the new...
Hey All, this is borderline brake tech... more of a brake question then anything.
For all the TRP DHR Evo users (The previous generation, not the new Evo X) what are you doing for dropper post remote mounting? I previously had a wt light action remote, with a discrete 22mm clamp that played ok with the dhr evo levers. This last weekend, I went to move a wt remote pro over to the bike with the DHR Evo's and there is virtually no way to get them to play together ergonomically. I emailed WT components and they pointed out that while TRP claims that their levers are I Spec-II compatible, that TRP altered their version of I-spec and not directly compatible with WT (and sounds like most other) ispec clamp designs.
So... what dropper levers are people using with this brakes, and how do you have them mounted?
Most I-Spec II adapter have a lip at the end, I just cut that lip and it worked well for the time I had my set...
Most I-Spec II adapter have a lip at the end, I just cut that lip and it worked well for the time I had my set of DHR Evo and wolftooth dropper / sram shifter.
Thanks for the reply. Not to be overly needy about this... but did that setup work with the remote pro? the remote pro has a few extra lateral bolt hole/mounting options that seemingly make the integration with the trp brakes a pita... at least for 22mm clamps.
If this solution does work for the remote pro, I could kiss you.
I'm a bit disappointed in the life of the Galfer "ebike" (purple) pads. After 2 months on the rear of my midpower ebike, they were already down to 3.3mm thickness (SRAM says replace Maven pads at 3.0; fresh pads seem to vary a bit between 3.9-4.0mm). And that was during the offseason so in that time there were definitely weeks where I rode less than I do in the summer because it was too rainy, or I was out skiing. Feel-wise, they were somewhere in between SRAM black & copper, but lasted much less than either. I know the Galfer green pads are super short lived, but I would have expected their "ebike" pads to be designed for more use.
I might give the MTX golds a try. I've used them years ago with Codes and liked them. Or just stick with SRAM metallics - they're not noisy like the old Code/Guide ones, and last a long time.
You don't even need to use an orbital sander. I just take a sheet of 150 grit, spin the wheel on the frame and hold the...
You don't even need to use an orbital sander. I just take a sheet of 150 grit, spin the wheel on the frame and hold the sandpaper against the rotor one side at a time. You don't need much pressure or time - just trying to clean off the surface deposit of pad compound.
Yeah, but an orbital sander is way easier in my opinion. Granted you might scuff up some of the pant/markings off the brake surface itself, but...
Yeah, but an orbital sander is way easier in my opinion. Granted you might scuff up some of the pant/markings off the brake surface itself, but it was a price I was willing to pay.
I've tried the sandpaper to rotor on the bike for years and never got it to work.
Yeah the orbital sander seems like a good solution to me - I'll give that a go some time! There are simimlar methods with a mill or drill press which are much more involved to set up so I think thats a good middle ground. Just between you fingers would only have a superficial effect - you ideally want to reset the surface and remove any old material deposits or grooves worn by the old pads.
Also how do people go with cleaning oil contaminated pads and rotors? Isopropyl alcohol is often recommended but its actually not very good at dissolving mineral oil. Acetone is much better (following by a rinse with IPA) for that purpose if you are trying to revive a set of brakes.
Yeah the orbital sander seems like a good solution to me - I'll give that a go some time! There are simimlar methods with a mill...
Yeah the orbital sander seems like a good solution to me - I'll give that a go some time! There are simimlar methods with a mill or drill press which are much more involved to set up so I think thats a good middle ground. Just between you fingers would only have a superficial effect - you ideally want to reset the surface and remove any old material deposits or grooves worn by the old pads.
Also how do people go with cleaning oil contaminated pads and rotors? Isopropyl alcohol is often recommended but its actually not very good at dissolving mineral oil. Acetone is much better (following by a rinse with IPA) for that purpose if you are trying to revive a set of brakes.
This is a great follow up question, and I was wondering the same thing. My go-to for old pads is to spray with isopropyl, a little scuff with 100 grit sandpaper, and then spray again with isopropyl, and that's typically worked okay-ish. For pads and/or that I know are contaminated, I've put those in the oven on broil to boil the oil out of them, which I've heard mixed things about.
Would love to hear other people's tips for reviving old pads that still have lots of material but for whatever reason are still not getting it done in the stopping department.
I've never been able to resuscitate pads contaminated by mineral oil. If that stuff gets down into the pad compound, it's there to stay. No combination of iso, brake cleaner, fire, and sanding has been able to save them when I've tried. With DOT or general trail/road gunk, a couple rounds of iso & sanding usually works. If the contamination caused the pad to get particularly deeply glazed, then I've good success with doing a quick pass on the rotor with a Dremel tool to really roughen up the surface and help reset the pad.
Thanks for the reply. Not to be overly needy about this... but did that setup work with the remote pro? the remote pro has a few...
Thanks for the reply. Not to be overly needy about this... but did that setup work with the remote pro? the remote pro has a few extra lateral bolt hole/mounting options that seemingly make the integration with the trp brakes a pita... at least for 22mm clamps.
If this solution does work for the remote pro, I could kiss you.
Can't help you as I was running that DHR setup before the remote pro was launched.
Edit: I checked Wolftooth website to see how the remote pro I-Spec II adapter is and I think just cutting the outside lip should still work. Maybe the position closest to the clamp might not work but the middle and furthest out should still work.
You don't even need to use an orbital sander. I just take a sheet of 150 grit, spin the wheel on the frame and hold the...
You don't even need to use an orbital sander. I just take a sheet of 150 grit, spin the wheel on the frame and hold the sandpaper against the rotor one side at a time. You don't need much pressure or time - just trying to clean off the surface deposit of pad compound.
Yeah, but an orbital sander is way easier in my opinion. Granted you might scuff up some of the pant/markings off the brake surface itself, but...
Yeah, but an orbital sander is way easier in my opinion. Granted you might scuff up some of the pant/markings off the brake surface itself, but it was a price I was willing to pay.
I've tried the sandpaper to rotor on the bike for years and never got it to work.
Yeah the orbital sander seems like a good solution to me - I'll give that a go some time! There are simimlar methods with a mill...
Yeah the orbital sander seems like a good solution to me - I'll give that a go some time! There are simimlar methods with a mill or drill press which are much more involved to set up so I think thats a good middle ground. Just between you fingers would only have a superficial effect - you ideally want to reset the surface and remove any old material deposits or grooves worn by the old pads.
Also how do people go with cleaning oil contaminated pads and rotors? Isopropyl alcohol is often recommended but its actually not very good at dissolving mineral oil. Acetone is much better (following by a rinse with IPA) for that purpose if you are trying to revive a set of brakes.
Got some Maven's and they're my first set of mineral oil brakes in a long, long time. Holy crap that stuff is hard to get off anything. As far as wiping down the master cylinder, bars, etc. and cleaning off tools, would you use acetone followed by IPA or would you be worried about the finish to components and bars?
And thanks for all the great info you offer up in these forums.
Yeah, but an orbital sander is way easier in my opinion. Granted you might scuff up some of the pant/markings off the brake surface itself, but...
Yeah, but an orbital sander is way easier in my opinion. Granted you might scuff up some of the pant/markings off the brake surface itself, but it was a price I was willing to pay.
I've tried the sandpaper to rotor on the bike for years and never got it to work.
Yeah the orbital sander seems like a good solution to me - I'll give that a go some time! There are simimlar methods with a mill...
Yeah the orbital sander seems like a good solution to me - I'll give that a go some time! There are simimlar methods with a mill or drill press which are much more involved to set up so I think thats a good middle ground. Just between you fingers would only have a superficial effect - you ideally want to reset the surface and remove any old material deposits or grooves worn by the old pads.
Also how do people go with cleaning oil contaminated pads and rotors? Isopropyl alcohol is often recommended but its actually not very good at dissolving mineral oil. Acetone is much better (following by a rinse with IPA) for that purpose if you are trying to revive a set of brakes.
Got some Maven's and they're my first set of mineral oil brakes in a long, long time. Holy crap that stuff is hard to get off...
Got some Maven's and they're my first set of mineral oil brakes in a long, long time. Holy crap that stuff is hard to get off anything. As far as wiping down the master cylinder, bars, etc. and cleaning off tools, would you use acetone followed by IPA or would you be worried about the finish to components and bars?
And thanks for all the great info you offer up in these forums.
No worries! Yeah mineral oi is tough to fully clean up - the thin viscositiy allows it to hide in all the gaps of the parts too. I probably wouldn't wipe down the cockpit with acetone - it can really destroy paintwork and some plastics and rubber so you do have to be careful with it. For mineral brakes (and suspension) I normally just use bike wash or simple green to clean the exterior after a job, then rinse with IPA to get any degreaser residue off later if needed
Yep, I'd much rather a replaceable part fail in a game of lawn darts rather than the MC body.
Hello brake nerds! I have a very annoying issue with my Dominon A4s that has me scratching my head. I bought the set for my fat bike and have been using it a lot this year. When it is freshly bled, the lever free throw is a decent 10-15mm and bite point is crisp. Over the course of a month the free throw grows to a whopping 35+mm where they are nearly touching the bar. The bite is still pretty crisp. I adjust the lever reach as a bandaid fix but eventually the bite keeps going closer and close to the bar. It can't be air trapped in the system otherwise the bite would be spongey right? Could there be a leak somewhere in the system? I noticed two drops of DOT fluid escape the reservoir cap when I was pressurizing them during the last bleed. What the heck is going on with these? It happens to both front and rear at different rates. I am using the SRAM pro bleed kit and the fittings don't leak either.
Heya, let's dig in. Set the lever up so the reservoir is at 12 o'clock on the handlebar. ideally so the reservoir cover screws are perpendicular to the floor. Pump the brake lever a number of times and see if it firms up (a little or a lot). If so, culprit is air in the MC. Culprit could be bleed issue or it could be that the drops of brake fluid you're seeing by the reservoir are indicating a res leak, likely from the bladder. I'd remove the cover and inspect the bladder. It should be free from tears. Dependiong on how heavy handed you were pushing n pulling on your syringes, you may have popped the bladder from its grooves or tore it. Haven't seen that with the Doms(yet) but have seen it with other makes/models.
From your description, it was unclear if the lever throw grows simply when the bike sits for a while, or if it is only through hours of use that it grows. If it is directly related to hours of use, is it possible that you have sticky caliper pistons which aren't advancing through the seals to compensate for pad wear?
The different rate at which the throw increases on front and rear would fit with that, especially if the rear increases faster than the front, as people typically use the rear brake more and go through pads faster.
Checking to see if the pad/rotor gap is staying consistent or, as the pads wear, is it growing in relation to the lever throw would be another way to verify this. If they do seem sticky, then cleaning and lubing the pistons should be an easy fix.
If the pad gap is staying consistent though, that should indicate the pistons are advancing as they should, and, as HexonJuan pointed out, there may be insufficient fluid supply to continue activating them as more and more of the reservoir fluid is called in to fill the increased volume as the pistons advance. I would think the feel would get mushy in that instance though, whereas it sounded like you still get a firm bite point, but it just moves over time.
Thanks, I just did that pump up test and there was no noticeable firm up. The bite point gets a tiny little sharper after a few pulls but that's pretty normal. There is about a month of fat biking left so I will open up the MC after that OR if the lever runs out of adjustment. I am a bit of a gorilla when it comes to pushing and pulling so I might have ruptured the bladder like I did on my Maximas. Really need to curb that habit I built bleeding SRAM brakes.
I ride pretty regularly and have high volume so the bike doesn't sit around for too long. Regardless, I just did a piston advance/lube procedure yesterday and it hasn't helped. As for pad/rotor wear I just installed new Sinter Green pads a few rides ago on a rotor that is pretty fresh so it can't be that. Funny enough the "growth" is pretty random. Sometimes it is the front that gives out faster and sometimes it is the rear. These observations were after around 800 km/ 40,000M+ vert of fat biking in the last 5 months.
Wow, that is mysterious! I look forward to hearing what the culprit was when you finally figure it out. It certainly sounds like you're doing a good and thorough job with the troubleshooting.👍
When I had Dominions, I noticed there was a pretty big change after the first couple rides on free stroke, following new pads. With fresh pads, the free stroke is really short, but it pretty rapidly grows to whatever the nominal rollback is. It was more pronounced running aftermarket pads (like Galfer) instead of the Hayes ones, as the Galfer total backer+pad thickness is greater. I'd always end up with different feeling front/rear since the pads wore at different rates.
Yup this sounds like something related to roll-back, as in the seals are able to pull the pistons back along way. One thing you can do is lubricate the pistons with proper brake grease as that reduces how much the sqaure seal can grip the piston. So they will be able to advance closer to the piston, as that design relies on the surface finish and friction between the seal and piston
Got these in the mail the other day from the UK. Heard some rumblings about the looks on here, they do look decidedly old school but I’m excited to see another player in the game. Will report back once I finally get them mounted.
I have been through 3 sets of pads (OEM organic, OEM metallic and now Sinter) and you are right about the changing feel between them. I ended up bleeding the brakes every time I changed the pads which is pretty annoying.
Hey, I don't know if you have checke this yet, but take a look at how the olive is sitting on the hose at the lever. When I first got my Hayes, I had a shop set them up for me and who ever did the install got the barb and olive on the hose crooked. That allowed dot fluid to get into the fiberglass insulation in the hose and bassically would drain the master cylinder over time. I cut the old barb and olive off and properly set a new one in and I've never had issues since
Great point! I have a few spare olives and enough hose so I will install fresh ones on the next bleed. I've experienced that once on SRAM when I kinked my hose.
Hey All, this is borderline brake tech... more of a brake question then anything.
For all the TRP DHR Evo users (The previous generation, not the new Evo X) what are you doing for dropper post remote mounting? I previously had a wt light action remote, with a discrete 22mm clamp that played ok with the dhr evo levers. This last weekend, I went to move a wt remote pro over to the bike with the DHR Evo's and there is virtually no way to get them to play together ergonomically. I emailed WT components and they pointed out that while TRP claims that their levers are I Spec-II compatible, that TRP altered their version of I-spec and not directly compatible with WT (and sounds like most other) ispec clamp designs.
So... what dropper levers are people using with this brakes, and how do you have them mounted?
Going to circle back here. Just got an orbital sander to breath new life into some of the "dead" rotors I've accumulated.
Holy smokes did it work super well, a bit of 150 grit to 220 and they look brand new.
You don't even need to use an orbital sander. I just take a sheet of 150 grit, spin the wheel on the frame and hold the sandpaper against the rotor one side at a time. You don't need much pressure or time - just trying to clean off the surface deposit of pad compound.
Awesome! Glad you tried it out. Switching between pad compounds has never been easier.
This is a great tip. I already have an random orbital sander chilling in my closet. Easy to do.
Yeah, but an orbital sander is way easier in my opinion. Granted you might scuff up some of the pant/markings off the brake surface itself, but it was a price I was willing to pay.
I've tried the sandpaper to rotor on the bike for years and never got it to work.
Most I-Spec II adapter have a lip at the end, I just cut that lip and it worked well for the time I had my set of DHR Evo and wolftooth dropper / sram shifter.
Anyone try MTX's with their Mavens after metallic and organic? How do they compare?
Thanks for the reply. Not to be overly needy about this... but did that setup work with the remote pro? the remote pro has a few extra lateral bolt hole/mounting options that seemingly make the integration with the trp brakes a pita... at least for 22mm clamps.
If this solution does work for the remote pro, I could kiss you.
I'm a bit disappointed in the life of the Galfer "ebike" (purple) pads. After 2 months on the rear of my midpower ebike, they were already down to 3.3mm thickness (SRAM says replace Maven pads at 3.0; fresh pads seem to vary a bit between 3.9-4.0mm). And that was during the offseason so in that time there were definitely weeks where I rode less than I do in the summer because it was too rainy, or I was out skiing. Feel-wise, they were somewhere in between SRAM black & copper, but lasted much less than either. I know the Galfer green pads are super short lived, but I would have expected their "ebike" pads to be designed for more use.
I might give the MTX golds a try. I've used them years ago with Codes and liked them. Or just stick with SRAM metallics - they're not noisy like the old Code/Guide ones, and last a long time.
Yeah the orbital sander seems like a good solution to me - I'll give that a go some time! There are simimlar methods with a mill or drill press which are much more involved to set up so I think thats a good middle ground. Just between you fingers would only have a superficial effect - you ideally want to reset the surface and remove any old material deposits or grooves worn by the old pads.
Also how do people go with cleaning oil contaminated pads and rotors? Isopropyl alcohol is often recommended but its actually not very good at dissolving mineral oil. Acetone is much better (following by a rinse with IPA) for that purpose if you are trying to revive a set of brakes.
This is a great follow up question, and I was wondering the same thing. My go-to for old pads is to spray with isopropyl, a little scuff with 100 grit sandpaper, and then spray again with isopropyl, and that's typically worked okay-ish. For pads and/or that I know are contaminated, I've put those in the oven on broil to boil the oil out of them, which I've heard mixed things about.
Would love to hear other people's tips for reviving old pads that still have lots of material but for whatever reason are still not getting it done in the stopping department.
I've never been able to resuscitate pads contaminated by mineral oil. If that stuff gets down into the pad compound, it's there to stay. No combination of iso, brake cleaner, fire, and sanding has been able to save them when I've tried. With DOT or general trail/road gunk, a couple rounds of iso & sanding usually works. If the contamination caused the pad to get particularly deeply glazed, then I've good success with doing a quick pass on the rotor with a Dremel tool to really roughen up the surface and help reset the pad.
Can't help you as I was running that DHR setup before the remote pro was launched.
Edit: I checked Wolftooth website to see how the remote pro I-Spec II adapter is and I think just cutting the outside lip should still work. Maybe the position closest to the clamp might not work but the middle and furthest out should still work.
Got some Maven's and they're my first set of mineral oil brakes in a long, long time. Holy crap that stuff is hard to get off anything. As far as wiping down the master cylinder, bars, etc. and cleaning off tools, would you use acetone followed by IPA or would you be worried about the finish to components and bars?
And thanks for all the great info you offer up in these forums.
No worries! Yeah mineral oi is tough to fully clean up - the thin viscositiy allows it to hide in all the gaps of the parts too. I probably wouldn't wipe down the cockpit with acetone - it can really destroy paintwork and some plastics and rubber so you do have to be careful with it. For mineral brakes (and suspension) I normally just use bike wash or simple green to clean the exterior after a job, then rinse with IPA to get any degreaser residue off later if needed
God you all need to stop wasting your beers cleaning up brake fluid. IPAs supposed to make the brake jobs more enjoyable.
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