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

PB Forum :: Mechanics' Lounge
Suspension SETUP, a 'how to' guide...
Author Message
flag dmadness
Posted: Mar 13, 2015 at 20:58 Quote
Itz all math.. you can do the ratio if you know the compressio on a given spring and you also need to know the leverage ratio for the suspensio design. Hit the text book or just loom online for the pdf for the spring.
flag ibishreddin
Posted: Mar 13, 2015 at 21:36 Quote
Would adding 50lbs to my weight be the same as a 300lb spring at normal body weight?
flag staike
Posted: Mar 14, 2015 at 4:27 Quote
No. But honestly, I would say you would get pretty close or spot on the 33% sag with a 300lb spring if you have 26% now. Based on experience. A steel spring is cheap anyways so it's not like you're gonna go bankrupt if you decide to get a 275 or 325 spring later on.
flag shawnmcgr
O+
Posted: Mar 14, 2015 at 6:25 Quote
ibishreddin wrote:
Is there a way to calculate how Much sag a lighter spring will give me? I'm on mojo HD with 350lb spring and get 17mm (26%) currently. Want to get 33%. Tried spring calc but find them to be inaccurate as they don't take into account suspension design. Any help or your experience when going down in spring weight would be helpful. BTW I'm 143lbs

350×17÷25.4=234lbs. That's the force your current spring is exerting.

234/300×25.4=19.8mm=displacement under new 300 spring.

234/275×25.4=21.6

This is a reasonable approximation for small changes as the geometry of your suspension will be changing by very small amounts so can be ignored. You are also going to face tolerances in spring rates (how close to 300lbs/in is the new spring). So getting more precise than that for a total change of 4.6mm is a waste of time, IMHO.
flag Nobble
Posted: Mar 14, 2015 at 8:23 Quote
i'd probably go down one springrate.


or start saving for a decent air shock.
flag bikerboywill
Posted: Mar 14, 2015 at 13:36 Quote
MrDuck wrote:
cheeverbrent wrote:
Just purchased a 2014 lyrik rc2dh solo air 170mm. Fork was purchased new and put on my 2013 specialized enduro evo. I am having a hard time getting a 20% sag. If I use recommended psi from manufacturer it seems way too stiff and I'm getting like 10% sag. I weigh 200 geared up which they recommend setting at 85 psi. To get 20% sag I have to drop it Down to 65 psi which is the recommended pressure for someone weighing 160 Lbs. This seems like a pretty big difference and just wanted to get some advice. Also it feels like there is a lot of stiction too, will that go away when I break the fork in? Any feed back would be greatly appreciated! Thanks!
The recommended pressures can often be far off, I wouldn't worry about it excessively. Just try to go with 20% sag and bring your shock pump for first few rides and go from there.

The stiction could be caused by the fork being dry. Just about the biggest flaw with rockshox forks is they often come hardly lubed at all from the factory, so you may want to pull the lowers and put the proper amount of fluid in there, it's a super simple 5 minute job, and I'd recommend doing it with every new RockShox. Apart from that yes, the fork might have more friction in the lowers when it's new, it will definitely diminish to some extent, but it's unlikely to turn it from terrible to awesome, so whether it's an issue really depends mostly on how bad it is to start with.

Also I think I've read putting pike seals in lyriks is a pretty good upgrade. Might be worth doing if your gonna take the lowers off anyway
flag ibishreddin
Posted: Mar 14, 2015 at 23:49 Quote
shawnmcgr wrote:
ibishreddin wrote:
Is there a way to calculate how Much sag a lighter spring will give me? I'm on mojo HD with 350lb spring and get 17mm (26%) currently. Want to get 33%. Tried spring calc but find them to be inaccurate as they don't take into account suspension design. Any help or your experience when going down in spring weight would be helpful. BTW I'm 143lbs

350×17÷25.4=234lbs. That's the force your current spring is exerting.

234/300×25.4=19.8mm=displacement under new 300 spring.

234/275×25.4=21.6

This is a reasonable approximation for small changes as the geometry of your suspension will be changing by very small amounts so can be ignored. You are also going to face tolerances in spring rates (how close to 300lbs/in is the new spring). So getting more precise than that for a total change of 4.6mm is a waste of time, IMHO.

Thanks, that's what I was looking for. But 7mm sag is a big difference, no?
flag NotDannyHart
Posted: Mar 15, 2015 at 15:53 Quote
Is it difficult to add bottomless tokens to the new Rockshox forks?
flag scrippsranchDJ
Posted: Mar 15, 2015 at 19:41 Quote
NotDannyHart wrote:
Is it difficult to add bottomless tokens to the new Rockshox forks?

Very easy. Let all the air out, unscrew the top cap on the air side, screw token(s) onto the underside of the top cap, reinstall top cap. Check the manual for torque specs on the topcap.
flag NotDannyHart
Posted: Mar 16, 2015 at 1:15 Quote
scrippsranchDJ wrote:
NotDannyHart wrote:
Is it difficult to add bottomless tokens to the new Rockshox forks?

Very easy. Let all the air out, unscrew the top cap on the air side, screw token(s) onto the underside of the top cap, reinstall top cap. Check the manual for torque specs on the topcap.
Thanks!
flag hawkins4242
Posted: Mar 19, 2015 at 10:41 Quote
so i recently bought a new dh bike and on it came a set of 2014 boxxer r2c2 forks. since new the low and high speed compression has made no difference what so ever. i have used them for 3 rides in total and have just put new oil in them as i heard sometimes they dont come with the right amount of oil in them but it is still no better with the correct amount of oil. has anyone else had the same problem? and how much harder should the forks feel when the compression is on hard compared to soft? hope someone can help! thanks
flag Nobble
Posted: Mar 19, 2015 at 10:43 Quote
hawkins4242 wrote:
so i recently bought a new dh bike and on it came a set of 2014 boxxer r2c2 forks. since new the low and high speed compression has made no difference what so ever. i have used them for 3 rides in total and have just put new oil in them as i heard sometimes they dont come with the right amount of oil in them but it is still no better with the correct amount of oil. has anyone else had the same problem? and how much harder should the forks feel when the compression is on hard compared to soft? hope someone can help! thanks
adding compression isn't going to affect how "hard" the suspension is. Try turning low speed compression off, riding around and grabbing the front brake to slow down. Then turn it all the way up and do the same thing.

The fork should dive into travel when LSC is minimized and stay high in the travel when it's maxed.
flag bikerboywill
Posted: Mar 19, 2015 at 13:54 Quote
Well low speed does make them feel harder. The sag will be the same but they won't move as easily, therefore harder. You should notice a massive difference from fully open and fully closed. I'd get them changed
flag chriskneeland
O+
Posted: Mar 19, 2015 at 14:00 Quote
bikerboywill wrote:
Well low speed does make them feel harder. The sag will be the same but they won't move as easily, therefore harder. You should notice a massive difference from fully open and fully closed. I'd get them changed

Nah, I have the same fork. You don't really notice until you ride. Mostly braking and diving into corners. Up the low speed and you'll notice it doesn't dive as much. If you're using all of your travel, up the highspeed until you like how it feels.

There was about 40ml less oil from the factory than the recommended amount. I don't notice any difference using the reccommended amount. I think the only way you would be able to increase the damping is to up the weight of the oil. Not sure how comfortable that would be on long days of downhilling.
flag gabriel-mission9
Posted: Mar 19, 2015 at 14:13 Quote
cmkneeland wrote:
bikerboywill wrote:
Well low speed does make them feel harder. The sag will be the same but they won't move as easily, therefore harder. You should notice a massive difference from fully open and fully closed. I'd get them changed

Nah, I have the same fork. You don't really notice until you ride. Mostly braking and diving into corners. Up the low speed and you'll notice it doesn't dive as much. If you're using all of your travel, up the highspeed until you like how it feels.

There was about 40ml less oil from the factory than the recommended amount. I don't notice any difference using the reccommended amount. I think the only way you would be able to increase the damping is to up the weight of the oil. Not sure how comfortable that would be on long days of downhilling.

Upping the weight of the oil will basically only affect the low speed damping.
Imo the adjustments on the R2C2 cartridge are pretty subtle. Very hard to tell the difference in standard car park test.

 


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