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I’ve got a set of Fox Vanilla R forks on my Orange Patriot from 2006ish.
I’m 100kgs and the forks bottom out far too easily. Any drop off more than about 18 inches high and they bottom out, which is a shame as it’s otherwise an enjoyable and capable bike (by my standards). Not a surprise as I note that these forks originally came with 4 alternative spring ratings, and I bet I have the green or blue (lightweight rider) spring on mine.
Any advice on how I can up the rating (preload obviously already set at max).
I don’t think I’ll be sourcing the uprated (black) spring for a fork of this age! Unless someone’s got one still hanging on the garage wall from 2006??
https://www.ridefox.com/fox_tech_center/owners_manuals/08/eng/2008_om_eng.htm
Are there any workarounds?
If I can’t actually uprate the weight rating somehow, I was thinking of sticking a couple of inch long bits of thick rubber tubing at the top of the stanchions, just to take the sting out of the end of the travel. The sort of tubing that’s about 5mm wall thickness that car radiator hoses are made out of.
Looking for any cheap bodge solution that’s any improvement over what I’ve got. Spent £200 on the bike and don’t want to spend half that again playing forks.
Would volume reducers get me the result I want? Or are they not a coil fork thing? What about different oil. Not very experienced with suspension I’m afraid! I only just worked out there’s a spring in there. And only down one of the legs, which strikes me as extremely weird.
If I had springs on my legs, I'd want one on each!
I won’t be casing any 40ft gap jumps on it, just like to be able to do a 3 ft drop-off to flat without bottoming out the forks!
find a heavier spring of the right approx dimensions and slot that in? otherwhise whack a spacer in the bottom which will also add preload.
You could try increasing the oil volume in the spring leg. That would then cause the air spring to ramp up at the end of the travel. The downside might be increased pressure behind the fork seals. Worth a go though.
So, 5lab, does that mean slide the spring out and cut a disc of thick plastic the same OD as the spring and just stick it in underneath the spring?
Does my disc of plastic need a hole in the middle to let oil through (ie., washer)
Stick a wanted ad up on Retrobike, some there is bound to have a spare.
Depending on the travel, I *might* have a heavy spring lurking in my spares box.
Would a short hard plastic or aluminium tube, with the same ID and OD as the spring be what I need? In which case, I'll get the lathe going.
They are 32mm forks x 140mm travel
You could try increasing the oil volume in the spring leg.
This would be the first thing I'd try if I couldn't find a heavier spring. What this does is causes the spring rate to ramp up towards the end of the travel. You'll start off with a soft, supple spring at the beginning, but it'll become increasingly stiffer as it moves through the travel.
It's exactly the same effect as adding tokens in newer forks. Normally you can measure the oil level using a tape measure. Raise it by 10 mm or so at a time. If you overdo it, you'll just end up reducing the travel.
Putting spacers under the spring won't actually change the spring rate, it'll just increase the preload. It will help, but if the spring is too soft, you'll still bottom the spring out, you'll just have less travel.
A combination of adjusting preload and oil volume will give quite a bit of tuneability, as long as you avoid bottoming out the spring. Adjusting preload will help with sag, adjusting oil volume will let you tune how the spring rate ramps up towards the end of travel.
These will have been from a max 125mm fork, so no dice. Sorry.
Measure the free length of your spring, i've got a few springs in various lengths and weights, and pretty sure they're all Fox from around that era. You'll be welcome to it if i've got anything suitable.
preload won't affect bottoming out. You need a stiffer spring.
These will have been from a max 125mm fork, so no dice. Sorry.
That's does not necessarily matter. You can use a short one with either a spacer or second spring to make the correct length. Could even use a short elastomer.
nixie
These will have been from a max 125mm fork, so no dice. Sorry.
That’s does not necessarily matter. You can use a short one with either a spacer or second spring to make the correct length. Could even use a short elastomer.
A solid spacer will be no good, a 125 spring will most likely bind soon after that 125mm of travel and bottom out sooner.
Depends how much difference in length there is but yes a second spring or elastomer would be better.
Many thanks everyone,
Free spring length is 263 mm
Wire diameter is 3.2 mm
Outside diameter of uncompressed spring is 25.4 mm
Inside 18.8
Between the preload adjuster and the spring is a double conical shaped plastic spacer 30mm long.
I have temporarily added a 20mm spacer too, which makes the forks feel a lot harder compressing them in the workshop, but I now have no sag and suspect I may have shortened the travel.
My spring is blue coded by dabs of paint down one side. This makes it a lightweight spring as suspected.
The spring I need, if Fox 🦊 of that era will be black paint marked.
Adding an additional spacer will only affect initial sag. In fact you may blow through that travel more quickly now
preload won’t affect bottoming out. You need a stiffer spring.
This from poah is absolutely correct. The two key variables are spring weight and outside diameter - you can trim to the appropriate length.
As above, you really just need the stiffer spring.
Ask on the forums and scour eBay until one shows up.
Or sell the fork and replace with an air fork instead.
according to this, black is softest
page 10
Afraid none of mine are anywhere near the length you need, sorry.
preload won’t affect bottoming out. You need a stiffer spring.
I'm not sure this is true. If a spring is, say, 500lbs/inch and you have 4" of travel it takes 2000lbs of force to compress it to bottom out. If you precompress it by an inch you need 2500lbs of force, the first 500lbs of which won't move the forks at all.
It doesn't increase the force needed per inch of travel, but it does increase the force needed to bottom out
I'd agree with your statement 5lab.
I've massively increased preload, and now it's not bottoming out. It's just as nasty though as it now has no sag and tops out.
I definitely need to try to get the right spring.