Ask the experts

[carlh]

104 bcd 30t hyperglide plus chainring is not made. The Shimano cassette has a 45t second cog instead of the 42 in a sram so my using cog 2 as my primary climbing gear should still work with the 32 and my bailout is just a touch taller but I think I can deal.

[mmmm...pow!]

On second look, the oneup is not for use with shimano 12 speed. I've used them with shimano 10 speed with no issues, and the switch system with shimano 12 speed, so not sure why it won't work.

[XXX-er]

I had a 28T absolute black on an Affect crank which came on my Yeti 5.5 , it was possible cuz its a splined mount so there was no need for a spider mount that might get in the way of going small, i thot the Affect was a good product

[Whiteroom_Guardian]

Ok so I've come to the conclusion that I just don't really like the Gnarvana rear suspension design. It seems at really high speeds it works quite well, but at medium and slower speed it is very harsh. Even with a properly tuned Push coil on the back.

I've never been much of a geometry nerd, but I will say the short(?) 444mm reach seems to work well for my short arms. 63.6 head angle is important I guess. 450mm chainstay seems to really help the bike whip around. I rode some nice dirt yesterday and the bike was turning SOOOO nice, but the rear end is just......rough......and it has a tendency to want to feel a little wild/unpredictable when hitting jumps. I've tinkered with slowing down/speeding up the rear shock a bit and it's still just weird.

Is there a site where I can put in some geo numbers and find what bike is similar but with different/more proven rear suspension design? Is the "Freedom Linkage" that different from other Horst bikes?

I definitely want a good pedaling but capable enduro race bike. If I didn't race I would be looking at 130-140mm bikes for sure. 160-180mm rear is definitely needed.

[toast2266]

Ok so I've come to the conclusion that I just don't really like the Gnarvana rear suspension design. It seems at really high speeds it works quite well, but at medium and slower speed it is very harsh. Even with a properly tuned Push coil on the back.

I've never been much of a geometry nerd, but I will say the short(?) 444mm reach seems to work well for my short arms. 63.6 head angle is important I guess. 450mm chainstay seems to really help the bike whip around. I rode some nice dirt yesterday and the bike was turning SOOOO nice, but the rear end is just......rough......and it has a tendency to want to feel a little wild/unpredictable when hitting jumps. I've tinkered with slowing down/speeding up the rear shock a bit and it's still just weird.

Is there a site where I can put in some geo numbers and find what bike is similar but with different/more proven rear suspension design? Is the "Freedom Linkage" that different from other Horst bikes?

I definitely want a good pedaling but capable enduro race bike. If I didn't race I would be looking at 130-140mm bikes for sure. 160-180mm rear is definitely needed.

Try a different shock first. I ran a push on my enduro briefly and it *really* prioritized support over plushness. That thing was amazing on big square edged hits, but it was maybe the least supple coil shock on small bumps that I've ever ridden.

Like, even if you can just find someone with the same shock size that'll let you borrow their shock for the day. It might be the wrong tune for the gnarvana, but it'll at least give you some idea if a different shock will get you anywhere on your concerns.

[Andeh]

Ok so I've come to the conclusion that I just don't really like the Gnarvana rear suspension design. It seems at really high speeds it works quite well, but at medium and slower speed it is very harsh. Even with a properly tuned Push coil on the back.

I've never been much of a geometry nerd, but I will say the short(?) 444mm reach seems to work well for my short arms. 63.6 head angle is important I guess. 450mm chainstay seems to really help the bike whip around. I rode some nice dirt yesterday and the bike was turning SOOOO nice, but the rear end is just......rough......and it has a tendency to want to feel a little wild/unpredictable when hitting jumps. I've tinkered with slowing down/speeding up the rear shock a bit and it's still just weird.

Is there a site where I can put in some geo numbers and find what bike is similar but with different/more proven rear suspension design? Is the "Freedom Linkage" that different from other Horst bikes?

I definitely want a good pedaling but capable enduro race bike. If I didn't race I would be looking at 130-140mm bikes for sure. 160-180mm rear is definitely needed.

I felt the same way about my Megatrail's suspension. I could never pin it down. If you look at the kinematic charts (https://linkagedesign.blogspot.com/2...l-29-2020.html - ignore page name, that's for Gnarvana), it's kind of middle of the road. Nothing crazy. My guess is that it's only moderately progressive (~20%) so if you want bottom out support on a coil you've got to run a bit higher spring rate and HSC. So it never felt great on ledgy chunk or brake bumps. I even put an O-Chain on mine, which helped some but never really fixed it. In comparison, my Nomad 6, which is much more progressive feels awesome all around, even without the O-Chain.

Like what Toast is saying, try it with an air shock.

The one kinematic it has that stands out to me is pretty high anti-rise, so you definitely want to run the rebound fast. It's going to want to sit down into it's suspension when braking, which will make it firm up / pack up. Edit: in comparison, my Levo has like 65% AR, and the newer SC VPP bikes have AR that drops down rapidly to around 70% mid-travel.

[Whiteroom_Guardian]

Ok cool. Yeah running rebound really fast....basically wide open....makes it not pack up and handle braking bumps better, but then it also makes it wild/kicky on jumps.

My only "modern" comparison really is my old SB150 which I ran with both an X2 and with a Push. Overall that bike just seemed to handle chunk/braking bumps/etc much better in the rear.

I suppose I could find an air shock to try, and if it felt better on the bike I could sell the Push and try to find an airshock that is good but doesn't blow up all the time. Are X2s better now?

[smmokan]

I probably don't ride as hard as you, but I *really* liked the CC Kitsuma Air on my Gnarvana last year.

[carlh]

Anyone vacuum bag tubes that live on the bike? My last spare had a big crack in it when I pulled it off for a buddy this week and I want to avoid a repeat. I’m thinking the water and oxygen are the killers and having it pouches up would extend life.

[John_B]

Is there a site where I can put in some geo numbers and find what bike is similar but with different/more proven rear suspension design? Is the "Freedom Linkage" that different from other Horst bikes?

www.geometrygeeks.bike let's you compare geometry of different bikes but as far as I know you can't configure it to offer recommendations.

[Whiteroom_Guardian]

www.geometrygeeks.bike let's you compare geometry of different bikes but as far as I know you can't configure it to offer recommendations.

Looks like an option for "You can now search the database by numbers." on the main page. Last time I looked at that site they didn't have that function. BUT you gotta pay for it. Damn.

[Andeh]

Ok cool. Yeah running rebound really fast....basically wide open....makes it not pack up and handle braking bumps better, but then it also makes it wild/kicky on jumps.

My only "modern" comparison really is my old SB150 which I ran with both an X2 and with a Push. Overall that bike just seemed to handle chunk/braking bumps/etc much better in the rear.

I suppose I could find an air shock to try, and if it felt better on the bike I could sell the Push and try to find an airshock that is good but doesn't blow up all the time. Are X2s better now?

If rear feels kicky on jumps but you know you need it that fast, speed up fork to balance. I went through a whole rabbit hole a month ago for same thing.

X2s right now have a really bad rep for issues. Basically last couple model years are ???. But I'm sure there's a ton on PB lol.

[Whiteroom_Guardian]

^^^ So with my fork sped up (Zeb Performance Elite or whatever....if sucks) the bike becomes an unwieldy scary pogo stick.

Yeah my old X2 I blew up twice. Nice shock when it's working.

[toast2266]

I think running the suspension fast to combat higher anti rise isn't going to solve your problem. Speeding up your rebound will keep your suspension from packing up, but the bike isn't packing up, it's squatting. Messing with the rebound isn't going to change that - it's just going to make the return from a brake induced squat less controlled.

The solution to anti-rise induced harshness is obviously to just not use the brakes.

[Whiteroom_Guardian]

Ok so how much of pedal kickback is related to the rear hub if at all? I can pick up and drop the rear end from 12-16" in the air and get the crankset to kickback quite a lot. Is that suspension design or somehow my rear hub has some issue? Its an I9 hydra that seems perfectly fine.

[Andeh]

That's a long and controversial topic. I'd suggest to go read the Blister review of the O-Chain for an explanation of the mechanics of pedal kickback and what affects it.

[Whiteroom_Guardian]

Pretty good explanation I found. Even when not touching the brakes my bike is rough as fuck.

[toast2266]

Ok so how much of pedal kickback is related to the rear hub if at all? I can pick up and drop the rear end from 12-16" in the air and get the crankset to kickback quite a lot. Is that suspension design or somehow my rear hub has some issue? Its an I9 hydra that seems perfectly fine.

Pedal kickback on the gnarvana is almost identical to most other bikes in that class (some high pivot bikes with idlers being an exception). The only way you're going to substantially change that is to mount an ochain. A lower engagement hub would help a little bit, but it's not enough of a difference to be worth spending money on it.

Also, observing kickback by dropping a stationary bike doesn't really provide an accurate view of the situation.

[XtrPickels]

Ok cool. Yeah running rebound really fast....basically wide open....makes it not pack up and handle braking bumps better, but then it also makes it wild/kicky on jumps.

I didn't see what such you are running, but do you have high speed and low speed rebound?

Keep it quick for low speed and slowing down high speed may keep things more balanced between the needs.

[Andeh]

I think your biggest issue is the older gen Zeb Select fork, since it's an obvious pig and there's no quick and easy fix for it besides replacing it. It's really tough to get your bike's suspension to feel good and balanced if one of the 2 pieces sucks. If you're likely to always do a frame-up build for your bikes, I'd start by replacing the fork and see if the bike as a whole feels better with a fork up front that's more supportive and you can run the rebound faster to balance out the rear. If you're likely to a do a complete bike, I'd just suck it up and write the current setup as a learning experience. You know you like the geometry, but you don't like the suspension and kinematics.

[toast2266]

^^^ Agreed with that.

I think it's 75% the fork, and 25% that it's just spring time, we're all out of shape from the winter, and everything feels rougher when we're not up to speed yet and riding properly. Or maybe that last part is just me, but I'm fat and weak and out of shape.

[rideit]

Ok, So I ran this by a friend who happens to be the engineer of the GG designs.
He said:

That sounds like a setup issue, there is nothing in the suspension kinematics that make it harsh at slow to medium speed. Everything about the kinematics is smooth and predictable, it's not like it has to be ridden at full speed for it to work, at least when setup well.

Wild/unpredictable on jumps suggests the damping setup is odd, and/or a lot of spring preload. An odd balance of high/low speed damping can make a bike unpredictable, or excessive spring preload can do the same, as either can make substantial changes in forces at the wheel with small input changes.
Tires and tire pressure can also make a bike feel harsh at slow to medium speed as well. This is partly why I run EXO with CushCore.

Have him post his measured shock setup:
Accurate measured sag (not: 30-35% I think)
Spring rate, rider weight
Spring preload
LSC
HSC

[Dantheman]

FWIW, I assume the Gnarvana kinematics are basically the same as my Megatrail, which I find to be very composed on jumps. The answer here is that you clearly need to swap the suspension for a Mezzer Pro and Mara Pro

[Whiteroom_Guardian]

Ok, So I ran this by a friend who happens to be the engineer of the GG designs.
He said:

That sounds like a setup issue, there is nothing in the suspension kinematics that make it harsh at slow to medium speed. Everything about the kinematics is smooth and predictable, it's not like it has to be ridden at full speed for it to work, at least when setup well.

Wild/unpredictable on jumps suggests the damping setup is odd, and/or a lot of spring preload. An odd balance of high/low speed damping can make a bike unpredictable, or excessive spring preload can do the same, as either can make substantial changes in forces at the wheel with small input changes.
Tires and tire pressure can also make a bike feel harsh at slow to medium speed as well. This is partly why I run EXO with CushCore.

Have him post his measured shock setup:
Accurate measured sag (not: 30-35% I think)
Spring rate, rider weight
Spring preload
LSC
HSC

Accurate measured sag (not: 30-35% I think) = Shock eye to eye is 230mm. Sagged i'm only getting like 210mm. Thats very little.
Spring rate, rider weight = 400lb spring and I'm 175 kitted up.
Spring preload = the least amount. So just enough that the spring isn't loose.
Both on the "Open/DH" valve of Push 11-6 coil:
LSC = 14 out from full closed (I have run the factory recco which is 16)
HSC = 15 out from full closed (I have run the factory recco which is 14)
Rebound = 17 out from closed/slowest....(I have run at factory recco of 13)

I run DD casings with Cush core pro in the back and XC in the front. 21psi in the rear and 19 in the front. Pretty soft. Impossible to run Exos in Big Sky unless you like killing tires every single day. If I had two wheelsets I would have one with lighter casings and XC cush only for regular riding and keep the heavy meats for park only.

[jamal]

That info is kinda not useful without shock stroke and total number of clicks from open to closed.

Personally I am liking the re-tune to a digressive valving on my bike, seems i can run more pressure, have more pedaling support, and it's still smooth over rougher stuff. IE there is more LSC and less HSC. But it's more of an xc bike sooo maybe not comparable and my "rougher stuff" is pretty tame.