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Edthorne
5/20/2022 10:59am
5/20/2022 10:59am
Edited Date/Time
6/28/2022 11:56am
I figure this is a hot topic, and may as well have a little thread of it's own.
Personally I own a Range and love it, but for the broader market I could see brands going to a sort of mid-pivot design, with an idler being used mainly to get rid of pedal kick back.
Personally I own a Range and love it, but for the broader market I could see brands going to a sort of mid-pivot design, with an idler being used mainly to get rid of pedal kick back.
I have also heard they don’t jump as well. I could see this being a major draw back for some people but personally don’t see this as an issue. I like bikes that have a stuck to the ground feel. Anyone have feed back on that?
The idler doesn't present any drag that I've noticed while riding, unless its not maintained. More maintenance is required, but once you get your head around that and keep everything clean and greased it's no problem at all. Upper pully does look like it's wearing out pretty quickly so it'll be interesting to see how long it lasts.
I've not noticed any issues with getting the bike airborne, it's playful and it eats rough terrain a lot better than my previous ride (Sentinel with a Cascade link).
High pivots are an interesting concept, and the Druid in my opinion proves it's a valid configuration for shorter travel bikes.
If high pivots had been the norm for years and all of a sudden low pivots came about, people would be saying the low pivots "didn't jump as well". People are just set in their ways and don't like to change what they've been doing.
Cons- Same Bro's are all about the 6-bar next.Keep up luddite.
I typically ride all mountain/enduro-lite bikes in the 150-ish travel realm. I like long rides with gnar and there is often some heinous climbing involved.
The benefits of a high-pivot bike are well-documented in the DH realm and are obviously catching on for a enduro bikes. I’m curious to see how far that technology trickles down from there. My guess is it would be reserved for gravity racing / riding.
The idea of an idler adding any drag, however minimal, on my all-mountain bike isn’t appealing no matter how good the suspension feels.
The benefit of the stability, corner speed and taking square edge hits (repeatedly) is well worth it for me. I am running an EXT Storia coil which makes this little bike a beast, maybe the most capable 130mm bike.
So I ended up with single high pivot about a centimeter or two above the chain line to put the power down to the ground and that sweet, sweet brake bar to stop the brake jack and make all of that well earned speed usable.
In summation... Yes high pivot, but brake jack is more important than pedal kick back.
The only effect of the idler size on everything is chain positioning for the antisquat (with the same mounting bolt a larger ring will move the chain higher) and for the losses (a larger idler ring will cause less chain articulation and cause less losses in the drivetrain).
The gear ratio is defined by the number of pedal rotations vs. the number of rear wheel rotations. And that is defined by the number of front chainring teeth vs. the number of teeth of the gear you are in on the cassette. The idler has no effect on that, just like the derailleur pulleys don't.
If you have a layshaft scenario (Cannondale Fulcrum, Starling's 5-speed proto), then you have to take into account all the branches of the drivetrain. WIth idlers you can just ignore said idler.
What idler bikes don't work with is oval chainrings, as the idler puts them out of time for the oval ring.
The main point though is that you need to take care of the clocking on your own as it depends on the position of the idler relative to the BB - if its directly above it, rotating it by 90° is a safe bet. If its further back (ala Supreme v5), it takes some more thought and care.
The don't work claim was a generalisation, mainly used to prevent people from blindly mounting oval rings on idler bikes without giving it a thought. People that know the catch will see through my claim anyway. QED, you.
EDIT: how long before we get high pivot or even bike model specific oval chainring that work with shimano and Sram cranks and a Re clocked correctly?
He basically feels that the high pivot is way more planted (duh). At first he felt like he wasn't able to throw it around as well, but as he's gotten more accustomed to the bike (and he's also grown and gotten stronger), he's not really complaining about it not jumping as well or being as jibby as the Status. Some of that difference also likely comes from moving from the mullet to full 29er as well as a huge difference in geometry (rear chain stay) on the two bikes.
Climbing seems fine. Idler pulley definitely can add a bit of noise to the drivetrain when you get into wet/gritty conditions.
Cons: Some Enduro Pro riders think they aren't "enduro" enough
I wasn't very interested in idler bikes before this since my local trails aren't very rocky, but my experience with the O-Chain leads me to think that a mid-height idler design could be really incredible on a trail bike (~140-150mm). Not so high as to cause the rear end to grow a ton and make the bike feel like a barge in berms and tight corners, but still decoupling the pedal kick. A good idler design would still be key for me though - I hate noisy bikes, and if the idler sounded like it was grinding all the time it'd drive me nuts.
The inevitable update to the Druid (the geometry is quite dated at this point) should be really interesting.
I rarely see chainline discussed with high pivot idler bikes. The bike's chainline is going to have an impact on how draggy and loud the idler is. On the Kavenz I'm running a 50.5mm chainline with the idler spaced accordingly and the idler is silent in the main climbing gears. There is no noticeable drag compared to traditional bikes. There is mild idler noise in the highest gears but I don't care about that since I only use them descending anyway.
If you're running a boost chainline which is about 53mm I can see why the idler may be be noisy or feel draggy.
I've noticed many high pivot bikes have fairly long chainstays. Then as the bike compresses they grow even longer. The Kavenz has a 425mm chainstay which grows to a max of 440mm. This is much shorter than the Range which is 442 in size L and the Dreadnaught at 450mm in size L. I don't know how much those two bikes grow but probably at least 15mm or more. This dramatic chainstay difference is probably one of the contributing factors for why the Kavenz feels like such a playful and maneuverable bike despite its high pivot. The Forbidden and Norco are probably going to feel more ground hugging in comparison.
-The idler drag is noticeable, but it isn't extreme. I've heard people say the idler reduces the efficiency of the drivetrain by around 2%, and I'd believe that. Years ago, I had some Hammerschmidt cranks (with the internal planetary gear), and supposedly those things added about 9% inefficiency. I couldn't deal with the Hammerschmidts - they were too draggy, but the idler doesn't bother me that much. I still wouldn't want an idler on a lighter weight bike that was more oriented towards climbing, but it's fine on an enduro sled.
-The high pivots jump just fine off of actual jumps. What they don't do as well is pop off of little roots or rocks. Jumping off of something that's at least as long as the bike's wheelbase feels essentially the same as jumping on a non-HP bike. But tagging a little bump with the rear wheel to get some pop doesn't work quite as well - the wheel moves backwards and out of the way (which is the whole point of the high pivot), and that robs you of some of your pop. It's not impossible or anything, but it's a little more work than on a non-HP bike.
-Manualing a high pivot bike is harder.
-My old Jedi cornered weird. As you pressed into a corner and the suspension compressed, the wheelbase stayed roughly the same (whereas on a non-HP bike, the wheelbase gets shorter; the front wheel moves backwards at the angle of the headtube, and the rear wheel moves forward-ish around the main pivot). If you were used to a "normal" bike, this made the Jedi feel long and cumbersome in corners, and it took some getting used to. I haven't had that same need for adjustment with the Norco - from my first ride on it, I actually felt like it cornered really nicely and very intuitively. I mostly chalk that up to the Norco having less rearward travel than the Jedi, and the Norco's geometry suiting my personal front / rear weight preferences.
-I haven't had any noteworthy maintenance issues with my idlers, but I know others that have. This probably depends on the specific bike, the specific bearings, and the weather you're riding in.
The potential issue is that pressing into the travel the weight distribution front-rear changes going through the travel. It doesn't change as much on a normal bike with a more forward axle path.
The Jedi had a pretty short rear end though.- 422mm stays vs. 442.5 on the Range (the Jedi was also 27.5"). But of course, both of those bikes effectively have longer stays once sagged.
But yeah, like you said, it really just comes down to front-rear weight distribution in the corner. I don't feel like I need to do anything different on the Range, But I definitely had to adjust my body position / riding style on the Jedi.
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