Suspension SETUP, a 'how to' guide...

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Suspension SETUP, a 'how to' guide...
Author Message
flag yourrealdad
Posted: Aug 28, 2020 at 12:46 Quote
Rdlynch2 wrote:
I got a question...

I understand setting sag. But is setting sag and leaving it more important or do you set the shock pressure so you utilize all available travel?

Sag should just be a starting point. When you say set sag and leaving it, do you mean never adjusting it?

Like RMR said only look for full travel use "appropriately". You should have a little travel left after most rides unless you went big or messed up. If you have an air shock and you know you are going big then put some more pressure in or volume spacers. Worry less about what travel you are getting and more about what the bike feels like.

If using a coil then you have to find the right spring rate so that you achieve close to recommended sag and again appropriate travel use. Sag will be adjusted by the rate and preload. If you have to turn the preload adjuster more than 2 turns to get the coil solid and achieve sag, you might possibly want to think about a different spring. Same if you are bottoming harshly and often.
flag Granda
Posted: Aug 29, 2020 at 6:50 Quote
Rdlynch2 wrote:
I got a question...

I understand setting sag. But is setting sag and leaving it more important or do you set the shock pressure so you utilize all available travel?

IMO - yes. Leave sag and adjust compression
flag liamhutch89
Posted: Sep 14, 2020 at 6:46 Quote
Hi all, i'm on a 2021 Commencal Clash and so far haven't been able to dial in my rear shock's settings (super deluxe ultimate with 3 tokens factory fitted).

I'm running 210 psi which gets me to the recommended 30% sag and i'm using full travel on most DH / freeride runs. I don't feel it get to the end of the travel but the rubber band shows that I have. All good so far, however i'm finding on steep dirt jumps the bike is being unpredictable, with a sensation of being stuck in the air (aka dead sailor), or being thrown forwards sometimes. I typically have good jump technique and can whip/flip/etc so I don't think it is that. My rebound is to the slower end of normal and i'm running my fork on the firmer side.

I'm thinking it could perhaps be due to the high progression of 3 tokens combined with a progressive linkage, and I pump take offs HARD due to a long bmx background. I've noticed if I actively try not to pump hard to boost things the bike is more predictable.

My previous bike was a capra with a coil shock and I didn't have this issue. Other differing factors are my new bike is shorter, it has 27.5 wheels (vs 29) and the front end is lower - its still high-ish but my Capras was very high. Whilst geometry could be part of the problem I feel that this would not give the unpredictability that i'm getting.

I'm worried that if I try reducing tokens i will blow through the travel too easily. Could it be anything else?
flag JohnyBoy
Posted: Sep 14, 2020 at 6:50 Quote
Maybe try a little less rebound on the back
flag bikerboywill
Posted: Sep 14, 2020 at 7:50 Quote
I’d take a token out of the shock and run less sag, 30% is a lot for a modern bike, especially a free ride bike being used for jumps. I used to ride 15% on my demo that I just used for bike parks
flag liamhutch89
Posted: Sep 14, 2020 at 8:24 Quote
bikerboywill wrote:
I’d take a token out of the shock and run less sag, 30% is a lot for a modern bike, especially a free ride bike being used for jumps. I used to ride 15% on my demo that I just used for bike parks

Interesting. I might go to the extreme first then and take out all the tokens and run around 20% sag so I can easily feel what it's doing and then experiment with inbetween settings!

Contrary to most people I hate a poppy bike for jumps and freeride, I prefer 'dead' and stable so I can pull off a lip by myself in the way I want to!
flag R-M-R
Posted: Sep 14, 2020 at 8:38 Quote
bikerboywill wrote:
I’d take a token out of the shock and run less sag, 30% is a lot for a modern bike,

Disagree.


bikerboywill wrote:
especially a free ride bike being used for jumps.

Okay, that's fair.


bikerboywill wrote:
I used to ride 15% on my demo that I just used for bike parks

Maybe a bike with less travel would've been better, rather than trying to turn a DH bike into something else. It's difficult to imagine using full travel at twice the recommended spring rate, unless you used a lot of preload, in which case the suspension performance would've been compromised.


liamhutch89 wrote:
I might go to the extreme first then and take out all the tokens and run around 20% sag so I can easily feel what it's doing and then experiment with inbetween settings!

That's sensible and it doesn't cost anything to try.


liamhutch89 wrote:
Contrary to most people I hate a poppy bike for jumps and freeride, I prefer 'dead' and stable so I can pull off a lip by myself in the way I want to!

Fair enough; everyone's preferences are different. You may get the stability you want via damping, i.e. try a little slower low-speed compression and rebound.
flag wellbastardfast
O+
Posted: Sep 14, 2020 at 10:07 Quote
Fox dhx2 coil do i need a new damper shaft if i reduce the stroke length of it from 65mm to 60mm.

Thoughts ?????
flag gabriel-mission9
Posted: Sep 14, 2020 at 11:52 Quote
wellbastardfast wrote:
Fox dhx2 coil do i need a new damper shaft if i reduce the stroke length of it from 65mm to 60mm.

Thoughts ?????

No. If its the newest 2021 spec you just add a couple of shims to the end of the shock body. 2020 and earlier you need a travel reducer puck to be fitted under the bottom out bumper by a service center. Unless you have the correct sized shaft clamps
flag wellbastardfast
O+
Posted: Sep 14, 2020 at 12:49 Quote
gabriel-mission9 wrote:
wellbastardfast wrote:
Fox dhx2 coil do i need a new damper shaft if i reduce the stroke length of it from 65mm to 60mm.

Thoughts ?????

No. If its the newest 2021 spec you just add a couple of shims to the end of the shock body. 2020 and earlier you need a travel reducer puck to be fitted under the bottom out bumper by a service center. Unless you have the correct sized shaft clamps

It's 2020 one so just a 5mm spacer behind the bump stomp basically
flag bikerboywill
Posted: Sep 14, 2020 at 14:00 Quote
R-M-R wrote:
bikerboywill wrote:
I’d take a token out of the shock and run less sag, 30% is a lot for a modern bike,

Disagree.

Modern air dh suspension at 30%? The negative springs are so large now that I feel at 30% sag you have no support and not enough ramp up

bikerboywill wrote:
especially a free ride bike being used for jumps.

Okay, that's fair.


bikerboywill wrote:
I used to ride 15% on my demo that I just used for bike parks

Maybe a bike with less travel would've been better, rather than trying to turn a DH bike into something else. It's difficult to imagine using full travel at twice the recommended spring rate, unless you used a lot of preload, in which case the suspension performance would've been compromised.

It was on air both front and rear so didn’t have any preload, I also was rarely riding anything rough that needed sag for the negative travel to maintain grip, just a lot of suspension support for landing impacts

liamhutch89 wrote:
I might go to the extreme first then and take out all the tokens and run around 20% sag so I can easily feel what it's doing and then experiment with inbetween settings!

That's sensible and it doesn't cost anything to try.


liamhutch89 wrote:
Contrary to most people I hate a poppy bike for jumps and freeride, I prefer 'dead' and stable so I can pull off a lip by myself in the way I want to!

Fair enough; everyone's preferences are different. You may get the stability you want via damping, i.e. try a little slower low-speed compression and rebound.
flag gabriel-mission9
Posted: Sep 14, 2020 at 15:32 Quote
wellbastardfast wrote:
gabriel-mission9 wrote:
wellbastardfast wrote:
Fox dhx2 coil do i need a new damper shaft if i reduce the stroke length of it from 65mm to 60mm.

Thoughts ?????

No. If its the newest 2021 spec you just add a couple of shims to the end of the shock body. 2020 and earlier you need a travel reducer puck to be fitted under the bottom out bumper by a service center. Unless you have the correct sized shaft clamps

It's 2020 one so just a 5mm spacer behind the bump stomp basically

Ya
flag R-M-R
Posted: Sep 14, 2020 at 16:00 Quote
bikerboywill wrote:
Modern air dh suspension at 30%? The negative springs are so large now that I feel at 30% sag you have no support and not enough ramp up.

Depends on the bike, but yes, I feel 25% - 35% works. That's measured at the wheel, mind you, which works out to a little less at the shock.
flag gspottickles918
Posted: Sep 14, 2020 at 21:08 Quote
R-M-R wrote:
bikerboywill wrote:
Modern air dh suspension at 30%? The negative springs are so large now that I feel at 30% sag you have no support and not enough ramp up.

Depends on the bike, but yes, I feel 25% - 35% works. That's measured at the wheel, mind you, which works out to a little less at the shock.

How do you measure sag at the wheel? Say I wanted to know exactly how much rear suspension travel my bike has?
flag R-M-R
Posted: Sep 14, 2020 at 22:25 Quote
Pandora's box ...

First, we would need to establish how to measure the travel. In descending order of reasonableness:

1. Vertical, with the pitch of the frame remaining constant
2. Straight line between the endpoints of the axle path
3. Aligned along the arc of the travel

Note that Trust used method #3, which is where their "arc travel" came from. Disingenuous way to pad their numbers, if you ask me. Anyway ...

The easiest way to do it is to model the bike in Linkage. That's how I generated the sag tables I provided to you. The accuracy will depend on the quality of the images used for the model and whether you interpolate the central plane of the bike.

There's also a question of how to incorporate other sources of "travel", such as:

• Tire compression, which is about a third to half the linkage travel
• Wheel flex
• Frame flex, which is more than you may expect

 


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