[Steve M]

After some fairly basic, standardised info from some of you guys regarding the spring rates you run on your DH bikes, front and rear. If you could fill out the following template for me that would be much appreciated:

Rider weight (lbs or kg):
Rider height (ft/in or m):
Bike (brand/model/year):
Rear travel (in):
Shock stroke (in):
Shock model:
Shock spring rate (lbs/in):
Fork model:
Fork spring:
Class you race:

Only fill out that last one IF you race obviously, I'm not trying to judge anyone, just see if there are any trends in setup. For the fork springs please just use the manufacturer's typical method of spring identification, eg for Fox forks, green/blue/purple/whatever, RS have red/yellow/etc. If you happen to know the actual spring RATE of the fork in lbs/in that saves me looking it up but doesn't bother me to do so.

As an example, my own setup from a little while back:
Rider weight (lbs or kg): 200lbs/90kg
Rider height (ft/in or cm): 6'2", 188cm
Bike (brand/model/year): IH Sunday, 2009
Rear travel (in): 8.0
Shock stroke (in): 3.0
Shock model: Elka Stage 5
Shock spring rate (lbs/in): 350
Fork model and year: RS Boxxer 2008
Fork spring: Yellow
Class you race: Elite

Thanks guys.

Edit - please only reply if you have coil springs front and rear, I don't have the available info on chamber volumes and piston diameters etc to calculate the effective spring rates from air pressures.

 

[ridiculous]

Rider weight (lbs or kg): 161 lbs
Rider height (ft/in or m): 70 in
Bike (brand/model/year): Intense M6 08
Rear travel (in):9.5
Shock stroke (in):3.5
Shock model: Revox Intrinsic
Shock spring rate (lbs/in): 350
Fork model: 40
Fork spring: blue
Class you race:

 

[Commencal-guy]

Rider weight (lbs or kg): 160
Rider height (ft/in or cm): 5'8",
Bike (brand/model/year): Commencal DH 2010
Rear travel (in): 8.0
Shock stroke (in): 3.0
Shock model: Elka Stage 5
Shock spring rate (lbs/in): 350
Fork model and year: RS Boxxer 2010
Fork spring: Yellow
Class you race:

 

[sethimus]

Rider weight (lbs or kg): 95kg
Rider height (ft/in or cm): 184cm
Bike (brand/model/year): Specialized SX-Trail '08
Rear travel (in): 6.7
Shock stroke (in): 2.75
Shock model: Bos Stoy
Shock spring rate (lbs/in): 375
Fork model and year: Bos N'dee '09
Fork spring: purple? (extra hard)
Class you race: i don't race

 

[RedOne]

Rider weight (lbs or kg): 190lbs, 87kg
Rider height (ft/in or m): 6'1", 185cm
Bike (brand/model/year): Morewood Izimu 2008, Large
Rear travel (in): 8.2", 210mm
Shock stroke (in): 3", 76mm
Shock model: Marzocchi Roco WC, Push Race Tune
Shock spring rate (lbs/in): 400
Fork model: Boxxer, Push Rebound Kit, Shimmed Manitou Compression Piston
Fork spring: Standard, yellow
Class you race:

 

[IH8Rice]

Rider weight (lbs or kg):220
Rider height (ft/in or m):6'2"
Bike (brand/model/year):Foes DHS 2:1 Mono 2007.5
Rear travel (in):10"
Shock stroke (in):4.5"
Shock model: Curnutt XTD coil
Shock spring rate (lbs/in):175lbs
Fork model:2008 888 ATA
Fork spring: air
Class you race:expert/cat 1

Rider weight (lbs or kg):220lbs
Rider height (ft/in or m):6'2"
Bike (brand/model/year):Evil Revolt 2009
Rear travel (in):8"
Shock stroke (in):3.5"
Shock model: RC4/CCDB
Shock spring rate (lbs/in): 450
Fork model: 2010 888 Evo Ti
Fork spring:-200lb
Class you race:expert/cat 1

 

[Viv92]

Rider weight (lbs or kg): 80kg ~175lbs
Rider height (ft/in or m): 1.85m ~6'1"
Bike (brand/model/year): 2007 Morewood Izimu
Rear travel (in): 8.2"
Shock stroke (in): 3"
Shock model: BOS Stoy
Shock spring rate (lbs/in): 350lb/in or 400lb/in
Fork model: 2008 Boxxer Team
Fork spring: Silver - soft
Class you race: U/19

 

[Jase76]

Rider weight (lbs or kg): 85Kg
Rider height (ft/in or m): 1.75m
Bike (brand/model/year): 08 Rotec RL9
Rear travel (in): 9
Shock stroke (in): 3
Shock model: RS Vivid
Shock spring rate (lbs/in): 425
Fork model: 2009 RS Boxxer WC with BOS Cartrige
Fork spring: AIR-110 psi
Class you race: Expert / B grade

 

[rollertoaster]

Rider weight (lbs or kg):205lbs
Rider height (ft/in or m):6'2"
Bike (brand/model/year):2008 chumba f5
Rear travel (in):8.5"
Shock stroke (in):3.0"
Shock model:vivid
Shock spring rate (lbs/in):400
Fork model:boxxer wc '08
Fork spring:120-130psi
Class you race:cat 2 (petitioning for cat 1 for 2010 season)

 

[The Breaker Man]

Rider weight (lbs or kg):187
Rider height (ft/in or m):6'2
Bike (brand/model/year):SantaCruz V10 2010
Rear travel (in):10
Shock stroke (in):2.75
Shock model:Cane Creek Double Barrel
Shock spring rate (lbs/in):450
Fork model:2010 Boxxer WC
Fork spring:75psi

 

[thom9719]

Rider weight (lbs or kg): 200lbs
Rider height (ft/in or m): 6'3
Bike (brand/model/year): Evil Revolt
Rear travel (in): 8"
Shock stroke (in): 3"
Shock model: RC4
Shock spring rate (lbs/in): 500
Fork model: 2010 fox 40
Fork spring: undecided
Class you race: Pro

-KT

 

[jeremy_2640]

Rider weight (lbs or kg): 77kg
Rider height (ft/in or m): 180cm
Bike (brand/model/year): Giant Glory DH 2006
Rear travel (in): ~8"
Shock stroke (in): 70mm
Shock model: Kenny TeKin Special (Fox DHX 4)
Shock spring rate (lbs/in): 400 Ti
Fork model: Fox 40
Fork spring: Purple
Class you race: Expert

 

[Trekrules]

Rider weight (lbs or kg): 119lbs
Rider height (ft/in or m): 5'5
Bike (brand/model/year): Trek Session 10 2007
Rear travel (in): 10
Shock stroke (in): 3.50
Shock model: Rock Shox Vivid
Shock spring rate (lbs/in): 250lbs
Fork model: Rock Shox Boxxer World Cup 2010
Fork spring: Air with 95-110psi(depending on which track)

 

[Jeremy R]

Rider weight (lbs or kg): 180lbs
Rider height (ft/in or m): 5'10
Bike (brand/model/year): 08 Morewood Izimu
Rear travel (in): 8.2
Shock stroke (in): 3.0
Shock model: Cane Creek Double Barrel
Shock spring rate (lbs/in): 300 (borderline too soft)
Fork model: 08 Boxxer team
Fork spring: standard
Class you race: semi-pro

 

[Biffff]

Rider weight: 200 pounds
Rider height: 6,1"
Bike: 2008 Specialized Demo
Rear travel: 8.25"s
Shock stroke: 2.75
Shock model: Cane Creek Double Barrel
Shock Spring rate: 450 ti
Fork Model: 2010 Fox 40 RC2
Fork Spring: Blue at the moment. Thinking about putting the green in.
Class you race: Elite

If anybody wants to elaborate on what spring they're are running in there 40, and how thats working for them it would be appreciated.

 

[freeridefool]

Rider weight (lbs or kg):165
Rider height (ft/in or m):5'10"
Bike (brand/model/year):2003 Giant dh comp
Rear travel (in):8ish
Shock stroke (in):2.75
Shock model: Pushed Fox dhx
Shock spring rate (lbs/in):400
Fork model:05 Dorado
Fork spring:Stiff
Class you race:expert

 

[William42]

Rider weight (lbs or kg): 180
Rider height (ft/in or m): 6'2"
Bike (brand/model/year): Canfield Lucky 2007
Rear travel (in): 203mm
Shock stroke (in): 8.75x2.75
Shock model: Elka stage 5
Shock spring rate (lbs/in): 400lbs
Fork model: Boxxer WC
Fork spring: 115PSI
Class you race: Sport/Expert

 

[cableguy]

Rider weight (lbs or kg): 185lb
Rider height (ft/in or m): 5'10"
Bike (brand/model/year): Canfield Jedi 2009
Rear travel (in): 7.75"
Shock stroke (in): 2.75"
Shock model: Bos Stoy
Shock spring rate (lbs/in): 350lb
Fork model: Bos Idylle
Fork spring: Yellow

 

[bullcrew]

Rider weight (lbs or kg): 235
Rider height (ft/in or m): 6'3"
Bike (brand/model/year): Canfield jedi
Rear travel (in): 7.75
Shock stroke (in): 8.75x2.75
Shock model: roco wc air / vivid 5.1
Shock spring rate (lbs/in): 200;150/400 for fast rocky 450 for big hits
Fork model: 2010 Boxxer WC
Fork spring: Dont know just lowered PSI so it would ride low
Class you race: 4th grade caucasions and asians

 

[Brian HCM#1]

Rider weight (lbs or kg): 200lbs
Rider height (ft/in or m): 6'
Bike (brand/model/year): Karpiel Disco Volante 2009
Rear travel (in): 8.25"-9.5"
Shock stroke (in): 3"
Shock model: Elka Stage 5
Shock spring rate (lbs/in): 400lbs
Fork model: Fox 40
Fork spring: Green
Class you race: I have no class

 

[cjcrashesalot]

Rider weight (lbs or kg): 180lbs
Rider height (ft/in or m): 70"
Bike (brand/model/year): 2008 Giant Glory DH
Rear travel (in): 8.8"
Shock stroke (in): 3"
Shock model: DHX5
Shock spring rate (lbs/in): 450
Fork model: 2008 Fox 40
Fork spring: Green? (firm, stock one)
Class you race: Cat 1

 

[JudgeDH]

Rider weight (lbs or kg): 210lbs
Rider height (ft/in or m): 6'2"
Bike (brand/model/year): Trek Session 88
Rear travel (in): 8"
Shock stroke (in): 2.75"
Shock model: 2009 CCDB
Shock spring rate (lbs/in): 450
Fork model: 2009 Fox 40RC2
Fork spring: Blue on 2009, green on 2010
Class you race: Sport

 

[buckoW]

Rider weight (lbs or kg): 185lbs
Rider height (ft/in or m): 6'1"
Bike (brand/model/year): Scott Gambler
Rear travel (in): 215mm
Shock stroke (in): 3.5"
Shock model: 2010 RC4
Shock spring rate (lbs/in): 325
Fork model: 2009 Fox 40RC2 WC
Fork spring: Blue (compression fully closed)
Class you race: I don't

 

[frango]

Rider weight (lbs or kg): 68kg ~ 150lbs
Rider height (ft/in or m): 170cm ~ 7'7"
Bike (brand/model/year): 2010 Glory S
Rear travel (in): 8" - 200mm
Shock stroke (in): 2.75"
Shock model: 2010 RC4
Shock spring rate (lbs/in): 300lbs (DSP Ti)
Fork model: 2010 RS Totem SOlo Air
Fork spring: ~50PSI
Class you race: I don't

 

[Steve M]

Warning: excessive nerdery to follow...

Rider weight (lbs or kg): 185lbs
Rider height (ft/in or m): 6'1"
Bike (brand/model/year): Scott Gambler
Rear travel (in): 215mm
Shock stroke (in): 3.5"
Shock model: 2010 RC4
Shock spring rate (lbs/in): 325
Fork model: 2009 Fox 40RC2 WC
Fork spring: Blue (compression fully closed)
Class you race: I don't

Interesting, your setup in particular interests me since you seem to be pretty into the tuning stuff too. Is the Gambler a particularly progressive frame? Reason I ask is that my setup has a normalised (vertical) stiffness ratio of roughly 1.35 front to rear, whereas yours is more like 1.20 (or lower really because of the high air spring effect of the RC4), ie relative to static weight bias, my front end is ~35% stiffer than the rear... whereas yours is ~20% stiffer in the front than the back relative to the amount of weight on each wheel (unless the Gambler has a REALLY short chainstay or super slack head angle or something that I'm not accounting for). If the Gambler's leverage rate is particularly progressive then that may explain it, but I'm a bit surprised that given how much our tuning ideas seem to correspond that your setup is so different from mine. How heavy is your 40's compression tune, or is it stock?

To compare directly:
My values:
Normalised vertical front wheel rate: 188.9 N/(m.kg)
Normalised vertical rear wheel rate: 139.3 N/(m.kg)
Normalised stiffness ratio: 1.35

Your values:
Normalised vertical front wheel rate: 202.3 N/(m.kg)
Normalised vertical rear wheel rate: 168.4 N/(m.kg)
Normalised stiffness ratio: 1.20

Interestingly you also run overall stiffnesses about 7% higher in the front and about 20% higher in the rear.

Thanks to everyone who's replied. Anyone who wants some info on what their stiffness ratios are like (I realise hardly anybody is actually going to know what it means, let alone care haha), just ask and I'll chuck your numbers through the calculator. Ahh only people with coil springs front and rear though please, CBF working out effective spring rates for air forks since I don't have the chamber volumes on hand.

 

[sethimus]

i would be interested

 

[Viv92]

Is it something to do with a bike being balanced front and rear stiffness wise? I'd be interested to see how mine comes out.

 

[Steve M]

i would be interested

Not sure what actual rate the BOS spring is, google turns up nothing, but I'm going to guess at it being roughly 45lbs/in which is equivalent to a green spring in a 40. With that rate on the front:
Norm. FWR: 204.4 N/kgm
Norm. RWR: 171.9 N/kgm
Stiffness ratio: 1.19

If it's in fact 50lbs/in (possible though that's pretty freaking stiff):
Norm FWR: 227.0 N/kgm
Norm RWR: 171.9 N/kgm
Ratio: 1.32

Is it something to do with a bike being balanced front and rear stiffness wise? I'd be interested to see how mine comes out.

Pretty much, yeah.
With the 350:
Norm FWR: 184.9 N/kgm
Norm RWR: 148.3 N/kgm
Ratio: 1.25

With the 400:
Norm FWR: 184.9 N/kgm
Norm RWR: 169.44 N/kgm
Ratio: 1.09

Note that all these calcs are based on the manufacturers' claimed spring rates, if they're off then so will be the calcs. Near bottom out these would also become unreliable due to significantly varying fork progression, and if your frame is particularly progressive the calcs will be off too - your relative rear wheel stiffness around the sag area will typically be LOWER (ie softer) and thus the real stiffness ratio would be higher if your frame is quite progressive.

Also take note that these numbers ARE JUST NUMBERS that are relatively arbitrary and only good for side by side comparisons. They are NOT a comprehensive model or "absolute" information on bike setup, it's only the fact that all the bikes are being compared in exactly the same manner that makes this comparison any use at all (and even then, only if you're a massive bike nerd like myself haha).

 

[Viv92]

This is going a bit off topic, but anyway...

Going on what your magical calculation says my bike has a very stiff rear relative to the front. I can run a medium fork spring but it feels pretty firm, and the soft doesn't feel too soft either. With the 350 spring my bike feels kind of balanced, but the front feels firmer if anything, even with the BOS. I don't understand how anyone that weighs 90kg can run a 350 spring, even with a shock like an elka?

My BOS is OK but it's not great. It feels only slightly more damped on my frame than a DHX (which felt like it had pretty much nothing on my frame). I think it's because my frame is halfway between 2 BOS tunes, and I reckon I got the less damped of the two.

Also the fork springs piss me off. I reckon I'm kind of in a dead zone where there is no good spring. I have a 2010 Race which is turning into a team (minus the drop stop) as soon as the parts become available, do you think it would be worth going to a world cup for the extra spring rate adjustment?


DH bike setup is like this for me: XC hardtails are much better.

/hijak... I'm just frustrated I can never seem to get this right no matter how much effort and money I put into my damn bike

 

[William42]

If you're doing it on most bikes, I would also be interested to see what I'm at.

 

[SkullCrack]

Rider weight (lbs or kg): 170 lbs
Rider height (ft/in or cm):5'11"
Bike (brand/model/year): Intense M6, 2009
Rear travel (in): 9.3
Shock stroke (in): 3.5
Shock model: Vivid, Push-tuned
Shock spring rate (lbs/in): 300
Fork model and year: RS Boxxer Team 2010
Fork spring: Yellow
Class you race: Sport

 

[-C-]

I'd be interested to know what my 'stiffness ratio' is (ooh err) - because my bike feels like the rear is slightly softer than the front, which is how I prefer it I think.

Rider weight (lbs or kg): 175 lbs
Rider height (ft/in or cm):6' 2"
Bike (brand/model/year): Empire AP1/2009
Rear travel (in): 8.5
Shock stroke (in): 3.0
Shock model: BOS Stoy
Shock spring rate (lbs/in): 350
Fork model and year: RS Boxxer Team 2010
Fork spring: Medium
Class you race: Old gits.

 

[bullcrew]

I'd be interested to know what my 'stiffness ratio' is (ooh err) - because my bike feels like the rear is slightly softer than the front, which is how I prefer it I think.
.

I thought I like it that way as well till we rode the crack, (no pun ) theres a tiny drop into the Gout that has a 9' high wall on the other side and it goes almost straight up the last 2 feet. You drop in Gout (fork is BOTTOMED) feels like your riding no suspension rough and bottomed then you lean hard to make a right into rough switchback that 2-3' wide hauling and hitting doubles. Had the front end stiff and it was tracking weird got all but 3/4" of travel and my line was scattered at best.
Let some pressure out took the bxr to 33% sag and it was day and night difference. Blew through the canyon and jumps clean and where I wanted to be the whole time.
Cant say Id huck it this way, might turn up the Hi speed a smidge and play with the low a little for big stuff but for racing applications its getting close.

BTW it was Jerry (hippietech suspension) and I out there tuning so it was by good experience the adjustments were being made. Hed watch a line and bike then have me adjust a bit.

Not to mention he has tweaks for the new Boxxer that make it absolutely plush. I messed around with his 1 day then he custom tuned and tweaked internally a little bit and then I played with it again. WOW!!!! The guy has it dialed.......

As soon as this ones broke in its getting tuned by him!

 

[Steve M]

This is going a bit off topic, but anyway...

Going on what your magical calculation says my bike has a very stiff rear relative to the front. I can run a medium fork spring but it feels pretty firm, and the soft doesn't feel too soft either. With the 350 spring my bike feels kind of balanced, but the front feels firmer if anything, even with the BOS. I don't understand how anyone that weighs 90kg can run a 350 spring, even with a shock like an elka?

It's all about leverage ratio, though I do like a soft setup for the back. People on Foes 2:1s can run stuff like 175lbs/in springs. I actually ran a 300 on the RC4. Linear changes in leverage ratio result in quadratic changes in required spring rate, ie if you double the leverage ratio you'll need a spring that's four times the stiffness in order to get the same rate at the wheel.

As I also said, this is just a relatively arbitrary number, all it lets you do is compare one setup to another, it doesn't give you any absolute information on whether a bike is "balanced" or whatever. For starters, leverage rates mess with things a bit on most bikes, and there is no consideration of damping here whatsoever - only relative spring rates. However I personally find the information quite interesting. It is in a sense equivalent information to the undamped natural frequency of each end of the bike, however if I posted it as such, everyone would be going "So that means my front wheel moves at 2.4Hz?" which isn't actually the case at all. The frequency information gives a more linear means of comparison if you're looking at vibration transmissibility and response, but not in terms of sag.

If you're doing it on most bikes, I would also be interested to see what I'm at.

As I said, I don't have an air spring equivalent rate calculator, sorry. If you want to measure the volume of the Solo Air cartridge chambers for me I'm happy to calculate it, but otherwise no go unfortunately. The closest I could get would be to compare PSI recommendations from RS per rider weight and make the assumption that the air spring rate is similar or the same as the coil spring recommended for that weight.

I'd be interested to know what my 'stiffness ratio' is (ooh err) - because my bike feels like the rear is slightly softer than the front, which is how I prefer it I think.

Rider weight (lbs or kg): 175 lbs
Rider height (ft/in or cm):6' 2"
Bike (brand/model/year): Empire AP1/2009
Rear travel (in): 8.5
Shock stroke (in): 3.0
Shock model: BOS Stoy
Shock spring rate (lbs/in): 350
Fork model and year: RS Boxxer Team 2010
Fork spring: Medium
Class you race: Old gits.

What's the "medium" spring - yellow or silver? Assuming it's yellow (stock, which is pretty stiff for your weight):
Norm FWR: 212.3 N/kgm
Norm RWR: 138.7 N/kgm
Stiffness ratio: 1.53 (pretty high!)

If it's silver:
Norm FWR: 185.8 N/kgm
Norm RWR: 138.7 N/kgm
Ratio: 1.34

 

[-C-]

What's the "medium" spring - yellow or silver? Assuming it's yellow (stock, which is pretty stiff for your weight):
Norm FWR: 212.3 N/kgm
Norm RWR: 138.7 N/kgm
Stiffness ratio: 1.53 (pretty high!)

If it's silver:
Norm FWR: 185.8 N/kgm
Norm RWR: 138.7 N/kgm
Ratio: 1.34

It's the stock spring yes - i've read a lot about spring weights on the new Boxxer but everything I have read pretty much implies i'm in the range for the yellow, albeit they are a little 'out'.

Based on the info you have shown, I think i'll bung the soft spring in and see how I get on.

 

[jackalope]

Rider weight (lbs or kg): 190 lbs
Rider height (ft/in or cm):5'11"
Bike (brand/model/year): 2005'ish V-10
Rear travel (in): 10"
Shock stroke (in): 2.75"
Shock model: CCDB
Shock spring rate (lbs/in): 500 lb Ti
Fork model and year: RS Boxxer Team 2007
Fork spring: stock?
Class you race: Beginner Bearded Women

 

[W4S]

Rider weight (lbs or kg): 185lbs
Rider height (ft/in or m): 5'6"
Bike (brand/model/year): Turner DHR 2008
Rear travel (in): 8.5"
Shock stroke (in): 9x3.5
Shock model: CCDB
Shock spring rate (lbs/in): 400
Fork model:2010 RS Boxxer
Fork spring: Yellow

socket, how stiff are my ratios?

 

[Steve M]

Rider weight (lbs or kg): 185lbs
Rider height (ft/in or m): 5'6"
Bike (brand/model/year): Turner DHR 2008
Rear travel (in): 8.5"
Shock stroke (in): 9x3.5
Shock model: CCDB
Shock spring rate (lbs/in): 400
Fork model:2010 RS Boxxer
Fork spring: Yellow

socket, how stiff are my ratios?

Norm FWR: 202.3 N/kgm
Norm RWR: 151.0 N/kgm
Stiffness ratio: 1.34

 

[-C-]

Socket - I just checked the RS manual.

Yellow spring is aimed at 140-160lbs
Red (stock) is 160-180lbs

Bit confused now, as i'm running the red. Rear spring is fine, correct amount of sag, so maybe RS spring weights are way out on the forks?

Any suggestions?

 

[LOOnatic]

Rider weight (lbs or kg):195
Rider height (ft/in or m):6
Bike (brand/model/year):MoreWood Izimu
Rear travel (in):8.2
Shock stroke (in):3.5
Shock model: Avy DHS
Shock spring rate (lbs/in):350
Fork model:08 Boxxer Team
Fork spring:Stock(yellow)+2spacers
Class you race:HucKing