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Spring Rate Questions

Bicyclist

Turbo Monkey
Apr 4, 2004
10,152
2
SB
Hey, so I need a few suggestions as far as spring rate goes.

First of all, I weigh 140-145 naked and I'm running a 450# spring on a DHX on a 2005 Demo 8. I want to match my X-soft Boxxer spring on an 06 Team. I'm debating a 350 and a 400. TF Tuned says 342 for 33% sag and 363 for a firmer feel. I'm worried that if I go to a 350 it'll be too big of a change and wallowy feeling in the back compared to the front.

Second, my friend is on a Demo 9 with a Swinger and a 350# spring and there's way way too much sag. He weighs 170 naked. I think a 450 would probably be appropriate. Again, TF Tuned recommends around a 350 for firm FR, but that thing is WAY too much sag as is.

Third, another friend is on a 2005 Enduro Expert running a DHX coil to be just like an SX Trail. He's running a 450 spring currently and is also thinking about downsizing to a 400. He weighs 130.

Any suggestions for these 3 bikes? Thanks a lot in advance.
 

Netguy

Monkey
Nov 8, 2004
609
0
Whistler
Don't know if this helps, however I am 210, and have all 3 of those bikes, and have played with different setups. Here is what I found perfect for me, for Whistler DH riding.

1. Demo9 - Swinger - 550lb
2. Demo8 - Swinger - 600lb, DHX - 600lb. Roco - 550lb
3. SX Trail2 - DHX = 450lb
 

dhkid

Turbo Monkey
Mar 10, 2005
3,358
0
Malaysia
HERE is a good spring rate calculator.

what you can do is back check, measure how much sag you are getting with the recommended spring rate. if its in the 30% range then its spot on and you just need to get used to that wallowy feeling. do keep in mind that the true spring rate of a spring may vary quite a bit. old springs tend to be soft too.
 

Erci

Chimp
Sep 10, 2001
93
0
NJ
HERE is a good spring rate calculator.

what you can do is back check, measure how much sag you are getting with the recommended spring rate. if its in the 30% range then its spot on and you just need to get used to that wallowy feeling. do keep in mind that the true spring rate of a spring may vary quite a bit. old springs tend to be soft too.
Cool calculator! What does "RELEVANT SHARE OF BIKE WEIGHT" stand for?
 

dhkid

Turbo Monkey
Mar 10, 2005
3,358
0
Malaysia
oh.. sorry cant help you there. my best guess is the percentage of the bike that is sprung weight.