Hello Vital MTB Visitor,
We’re conducting a survey and would appreciate your input. Your answers will help Vital and the MTB industry better understand what riders like you want. Survey results will be used to recognize top brands. Make your voice heard!
Five lucky people will be selected at random to win a Vital MTB t-shirt.
Thanks in advance,
The Vital MTB Crew
I know we spent thousands of dollars on precision ground sizers, go/no-go gauges and had countless sets of lowers sized, CMM measured, tested, inspected, dyno'ed etc and STILL had a lot to learn about bushing sizing.
BUT sizing the bushings bigger almost always makes the fork feel better, so if a shop does that and cleans/services your fork at the same time- it might be a nice improvement. It's just a company like RS can't gamble with over-sizing bushings. You'd have thousands of warranty forks to deal with. If a shop over-sizes a few customer's lowers not a big deal.
Also- if you can live with a little bushing play- the fork is probably going to be smoother.
Looking at some tech randoms on some random site, I see the rotor does have engraving on the outer side while being installed this way. As you'd expect on a correctly installed rotor.
I understand Brembo has quite a bit more history in designing brakes than I do, but I'd love to hear from the designer of this rotor. Last time I checked, physics applied to us all the same and the usual way to mount a rotor has a very good reason behind it.
110% on target. Pal had a spoke pop midway thru a 25mi ride and it went through the sealing tape. Bummer, but a tube held up for the rest of the loop. Week later on my way home same damn thing happened to me on my commuter. Got hip to the idea of the Gorilla Tape over sealing tape from another website. It does stop the puncture and the sealing tape is a treat to remove as compared to year old and sealant logged Gorilla Tape. Added bonus, it creates a better seal in the tire drop zone, so even well used and stretched out tires pop up with a floor pump.
I do a layer of rim tape I don't remember the exact width I got. It fits in the rim bed and covers the spoke holes. Then do a another layer over top with rim tape that covers the entire inner width.
I honestly think Rockshox doesn't get enough credit for their attention to friction - everyone loves to talk about the latest dampers but those come well after the friction and the spring in terms of what actually matters. I noticed things like increasing the bushing length and carefully choosing bath oil viscosity (not too thick in most forks, but the short travel skinny leg forks get heavier oil) along with good alignment and clearances in the new forks. Fox still use very short bushings in all their models, plus I'm positive the oil channels they added in the lowers do more to let the oil drain down and around the bushings than to actually keep oil on them!
And I do agree its pretty much impossible for manufacturers to produce forks with "perfect" bushing clearance since a certain percentage will be big enough to make noticeable play which only leads to a huge number of complaints - especially when that fork has been sitting in a box for a month or 2 and the oil hasn't properly circulated again. The stack up of parts from the crown to lowers then hub spacing means it is a very fine balance but generally most forks are put together quite well in the last couple of years. While I personally prefer slightly more clearance I understand its not realistic for production and having been the warranty guy for a suspension brand in the past I know all too well how that goes
Fox forks were way too tight about 10-15 years ago and no one really called it out (apart from the damping being described as "supportive"...lol). They just blamed the kashima coating once that wore out when really it was because the air spring sucked all the bath oil and left a tight bushing running dry on the stanchion. But if bushings are the tiniest bit too loose then its called out IMMEDIATELY
I have run my sizing tools through pretty much every fork I've worked on in the last 6 years - but I spent a lot of time testing different sizes and understanding the clearances needed so I'm not overdoing it. With a lot of new forks now it basically just a clearance test if the tool goes through easily then I can be sure they are good enough and not going to cause issues for people. There are definitely a lot of sizing tools out there (a lot of the commercially available ones too....) which come in crazy big sizes like +0.15mm and thats a real concern if used in the wrong hands!
Found on REI's website - available 5/28 - is this a new XT Di2?
https://www.rei.com/product/215401/shimano-deore-xt-12-speed-rear-derailleur
aren't you finding plenty of RS non ultimate to be tight in the bushing? Every time i'm hopping on a new bike or a demo bike everything that is not the older series still with the charger 2.1 feels like a stick, even with the damper fully opened, it just feels it doesn't move freely, While every fox always feels good, factory or performance it feels free to move and with better tolerances, am i just really unlucky or is that what you have experienced working on many forks?
That is the Shimano STEPS eBike only Di2 derailleur, been around for quite a while but not much media on it
The first generations of Fox forks (both the OG coil 40s and 36s) were famous for excessive bushing play. They rattled like snakes, and Fox said they needed to be that way for them to have that buttery smooth sliding. A couple generations after they had to tighten the tolerances to quiet the rattling complains.
Was this mentioned here? SR Suntour are working with Rogue Racing to develop an electronically actuated shock. Pictures are from the pink website. Apparently the actuator is controlled by a software that reads the terrains and it acts on the normal compression circuit. The shock can be locked out too.
![]()
I don't know, chassis is pretty big part of the fork that is staying stock 🤷🏻
I have used pretty much this setup to both minimize chances of the first tape being lifted of the rim when doing tire change and also to make it more durable/ less prone to rolling tire of the rim. And to be honest, it does that to such an extent, that once I wanted to remove the tire, there was just no way in hell it's coming of, three other people tried to peel the sidewall by standing on deflated tire on the ground, it just didnt budge. In the end 1 managed to peel it off using massive pliers (50cm). Needless to say, I'm running the same setup still, knowing I won't rip the tire of the rim in berms even if I get a slow puncture and loose some pressure is nice and worth the hassle once the tire change time comes. Some of you might remember Marschy using silicone sealant to glue sidewalks to the rim of Greg's wheels. This is more elegant and less time consuming I would say with result being pretty much the same. If I had to change tire few times during the weekend I would be less pleased though.
+0.15mm oversize would take some serious time and a lot of elbow grease to make I through the bushing that is in typical size range. I use + 0.1mm head on my boxxer, the lowers weren't too bad from the factory, but I still got decent workout from it don't it in the sunny afternoon lol. I don't think I would be even able to start the burnishing process with +0.15
Having some experience with burnishing in series production it's not something to do by hand... Using some kind of press to push the tool through and a fixture to ensure alignment should be the basis of it all.
This guy makes makes burnishing tools and he recently showed his new helical self feeding option. Just hold the drill and let the tool do the work.
why don’t you do it like intend does? too much manual labor?
I would be surprised if your typical Taiwanese worker doesn't fully assemble the fork in the same time as it takes to manually burnish the bushings.
Simple answer, volume... Look at how many forks Rock Shox has as OEM spec.. Their lowest volume high end fork is still more units than Intend does in a year..
RS probably flows 5x more free product to bros than Intend sells in a year. Scale not even on the same planet.
I scooped a camelbak insulation cover for my 3L bladder for super cheap, then throw either the bladder or the whole pack into the fridge overnight. Works great for AR summers.
Can you specify? I don’t know what intend does.
But yeah I believe RS is making thousands of forks per day (a lot of volume comes from the lower end stuff you guys don’t think much about- eg Judy). Or at least was during the Covid peak. Tact time is a real issue.
I’d worry about those rotating burnish tools scraping/burning material off the bushings. Fill the lower leg with bushing dust. The factory sizing method is different and that is what is tested and validated by engineering team. YMMV.
One longevity trick is to wash your lowers when you do a service. Get a long bottle brush, dish soap and scrub the lowers out, flush with a garden hose, let it dry overnight then finish rebuilding. I think dust and grit gets in the lowers and unless you actually scrub it out it just stays in there and causes more issues.
takes about a minute for both legs:
https://www.youtube.com/watch?v=HlCWHTxueaY
min 1:00 to about 2:00, a capable engineer should be able to automate this step with a robot...
see post above
That’s more or less what is done by a series of machines. Then go/no-go gage tested and sent down the line.
I don’t think you get it Dave. We are going to revolutionize fork manufacturing on this forum without ever having visited a factory or even talking to a designer or engineer about the myriad of factors that affect the design and manufacture of said forks.
Holy mother of God!!! I would not want that thing anywhere near my bushings (fork or otherwise)!!
For real, as @Dave_Camp said this thing will do all kinds of nasty stuff to the bushings besides burnish it to size.
This is what is recommended by GGB for their DP4 bushing (steel backed, sintered bronze and teflon coated, looks very much like the stuff that is used in shock eyelets, probably very different to what is used in fork lowers):
https://www.ggbearings.com/en/our-products/metal-polymer-bearings/dp4
That last sentence seems important…
Most current lyriks and Zeb's seem to have a pretty good tolerance where everything is nicely aligned and don't bind but with minimal clearance. So while I prefer slightly more clearance, I wouldn't call them tight and it's probably a combination of forks sitting around for a while and getting dry/sticky that makes them feel less than ideal.
It's interesting, it often feels like Fox forks have 4 bushings with fractionally different sizes, but maybe the average clearance is larger so combined with the thick oil used in the spring leg (and lots of oil in the damper side) it makes them feel OK in the parking lot but it isn't technically the "best" overall for friction at all speeds and forces. While RS forks feel like they have very tight (as in good) tolerances and everything is consistently aligned through the travel but its probably less forgiving when there isn't enough oil coating the bushings.
Interestingly, the most recent time I have seen binding problems from RS was one of the years/batches of Charger 2.1 Zeb around 2021 - They seemed to pinch inwards and got noticeably better once the hub was installed!
Oliver is a smart guy! He made my original handle which I still use, as well as my steerer pressing gear. I think that new design just uses very fine machining on the surface to gradually draw it through the bushing and wouldn't be removing any material. It's probably a lot better than the technique of trying to mash an oversized tool through the bushing with brute force as I know for a fact that can tear the material away from the steel backing. So if you need an extra large burnishing tool this is possibly a good way to do it, but it would be unusual to need that in the first place.
I have had other heads made over the years though and I find a design like what you posted there works really well in my workshop
It is crazy how much gunk builds up in the bottom of the lowers and under the bottom out pads! This $4 bottle brush from bunnings is my favourite cleaning tool and I make sure they are spotless. I remember working in shops if we had a customer with filthy lowers and you just sprayed it with cleaner and wiped with a rag, you could open that fork back up a month later and would look filthy again! You really need to put some work in it, I don't think I've hosed out lowers before but it probably works great! Filling a tub with warm soapy water would do the trick, just make sure its 100% dry before putitng it back together
The Peaty's bottle brush is also quite nice with the mop-end but the handle was too short so I need to make a longer one and it might end up replacing the trusty bunnings brush!