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Just got a Fox DHX2 secondhand (ridden a couple of times before bike changed) which has a 400lb 2.25% cane creek vault spring on it.
Sat on it I’ve got 36% sag so I think I need to go up to a 450lb spring.
The question is what makes of spring will fit - I can see Rockshox have red springs (red would be ideal to go with the red fork and a few red anodised bits on a raw frame)?
Rockshox have red springs for £35 which I like the price of but do they have different diameters of spring between makes?
There are different diameters yes. TF tuned site has some info on it. You may not care but the vault spring will be lighter than the cheap RS one. Have you tried sticking some preload on the spring?
Not yet - literally fitted it and sat on it to see what the sag was like. Can wind on some preload tomorrow - also need to check where the damping settings are. Fox have a chart for bass settings so going to start with that and see how that is.
Rockshox springs are a no go for Fox, they're too far apart (Fox 35mm internal, RS 38mm), but you can fit almost all the others, although usually require a spacer to stop any chance of movement of the spring as almost all other springs are 36mm inside diameter.
The 400lb x 2.25 means it's for a 2.25" stroke length, or 57.15mm, be wary of this incase you have a shock with a longer stroke length, and that is the issue.
I had a fox or a vault on my DHX2, but could fit almost all the others with the appropriate spacer ( https://j-techsuspension.co.uk/products/j-tech-shock-spring-adaptors).
Also remember you can do a turn or so of preload to get it dialled in a little more.
Be careful with winding on preload.
It doesn't make a huge difference to sag and can cause the spring to bind on its self if you try winding it more than a couple of turns.
I’ll ring j tech or tf tuned and see what’s in stock then. Ideally I’d like a red coloured spring but black would also be fine.
The vault seems like a good option as it’s not wildly expensive and it should just fit like the current one does / is quite light.
Thanks for the comments 👍
Looks like j-tech do a 35/38mm adapter - sounds like that means you could fit a Rockshox spring on a Fox shock....could be tempted to pick up a pair of those plus a 450lb red Rockshox spring. Will ring j tech Monday to check if I’m reading it right.
singlespeedstu
Full Member
Be careful with winding on preload.
It doesn’t make a huge difference to sag and can cause the spring to bind on its self if you try winding it more than a couple of turns.
I have never understood this issue the way Fox state it, they say if you wind it more than 2 turns, then coil binding when the shock is bottomed out, but bottoming out will cause coil binding in almost all instances, as you will have compressed the springs all the way, causing the coils to touch anyway?!
The way I understand it if you wind to much preload on the spring will bind up before the shock reaches full travel.
So it's basically limiting the travel.
bottoming out will cause coil binding in almost all instances
I’d hope I’d hit a bottom out bumper rather than have the spring coil bound at maximum travel for the shock.
I’ve always though calling it preload was a misnomer anyway, more a ride height adjustment. If you weigh x your weight will compress the spring y amount regardless of whether it was already compressed a little before you got on the bike. Never had a coil on a MTB though only motorcycles
Yeah, you're right, i should have said bottoming out with the force to get coil binding, so compressing the bumper enough, i've rarely seen this happen, especially on a mountain bike, so not sure how big an issue it is, Fox always state this issue, but others like DVO use this method for preloading to get the appropriate sag (as long as it's in the range for that spring).
It depends on the spring. Listen to the manufacturers of the spring, they know its attributes better than you. In general, do not run a shock with too soft a spring and try and mitigate that with preload and damper set up. You don’t just risk losing out on travel, you risk damaging the shock and/or frame. Especially if you’re a big rider and getting air.
the shock’s travel isn’t controlled by the amount that the spring compresses.
the amount the shock compresses is less than all the spaces between the coils. if the spring fully compresses the force will be put through the threads on the shock body and preload collar.
TFT used to do a spring swap on springs that you’d bought through them. it is an invaluable service when trying to find the spring that you want. i’d buy through a store that offered this service.
Just to add it’s a 210x55 shock so 2.25” is the right length spring for the shock as I understand it. It’s a 130mm travel trail bike but with a sufficiently progressive leverage curve that it can run a coil shock.
As above, TFT have excellent info on their site against all springs, even including the ranges included for the springs against stroke and so on.
Have to say i do think about getting one of those Fast Ichu springs on TFT, weight wise they're better than the Fox SLS i believe, but less than half the price.
they will also be available in metric sizes, but that one will fit.
get one of these
https://www.chainreactioncycles.com/nukeproof-superlight-enduro-spring-2-25-2-5-/rp-prod175497
TF tuned did have a table which showed how accurate each manufacturers springs were, can't find it right now but it's definitely been on their site. Also Birds spring rate graphs were spot on for me to get the correct spring weight, I ended up with an 434lbs spring (for 30% sag).
Providing the correct stroke coil is used it will not go coilbound when the shock is bottomed out, as mentioned above this would cause big issues.
Preload is used widely throughout the engineering world in this context and it's best thought of as the force that you need to overcome before the coil starts compressing. Once this force has been overcome the coil will compress at its usual 'x' Newtons per mm spring rate. I.E. (plucking convenient numbers out of the air here):
0 turns of preload shock will move as soon as force is applied. If rate = 10N/mm, 1kg would compress roughly 1mm.
1 turn of preload, say 1mm compression, the first kilogram would not move the shock, 2 kg would move the shock 1mm.
Often people say that adding preload makes your shock less effective, which is sort of true if you add too much. If you only add a little bit then you should (almost) always be past the point where the spring is not moving.
Sprindex looks interesting for a bit more adjustment, I'd love to have a play.
Sprindex does look interesting but cost is quite high.
With the 35-38mm adapter presumably the 38mm RS spring also has a larger outside diameter than the 35mm spring. If that is the case and the shock has a piggyback there is the chance the coil and piggyback could clash. Just a thought.
I’m thinking maybe I’ll just get the next weight up on the Valt and ig ore my desire for red goodness. Plus the Rockshox spring will be heavier than the Valt.
That Nukeproof spring also looks a good option.
Cane Creek Valt springs are very good and pretty accurate to the indicated weight. RS despite been very cheap the ones we have tested have been some of the most accurate springs. Needless to say the very worst ones were Ti-Springs.
Take a look at Pinkbike buy and sell, they have category for springs. I got a 2nd hand Valt from there for a reasonable price when I swapped my shock to a different bike and had to go up in spring weight. You may get lucky and find what you need.
I'd probably go for a 500lb spring. Look on ebay and find a cheap steel one to try. then buy a light weight one.
bottoming out will cause coil binding in almost all instances
No it won't - if it does you have the wrong length of spring.
Ideally you want no preload on the spring. Preload only affects the initial part of the stroke. It does not affect the spring rate further into the travel so you'll bottom out under the same force.
I think the 500lb one might be a bit too stiff - I went for a ride today and it felt pretty good. Still popped off jumps and lips but felt more glued down trying to bunny hop and lovely over roots.
Hard to tell if I bottomed it / how much travel I was using vs an air shock. It’s a 2021 DHX2 with the firm / open lever on it. Massive rubber bottom out bumper thing.
Going to order the Valt in 450 tomorrow and try to get it next day delivery so I can get it on the bike and a quick run out Wednesday night. Off to Llandegla Friday / Antur Stiniog Saturday / Machynlleth Sunday so would like it on and sort of setup before then.
Found the standard Fox settings had the lsr a bit slow for my liking so I sped that up a bit but left all the others the same. Didn’t seem to bob too much or wallow into compressions etc.
get the nukeproof from CRC and you'll get it tomorrow. used both valt and nukeproof springs. Got a 450 valt sitting in garage.
Before:
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Shocks:
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After:
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Looks great!