'06 coiler rear shock help

Koiler

hi,

not too sure uf this is the right section but...

i need some help with the rear shock on my 2006 coiler. its a fox vanilla R coil of the same year.

although its a 2006 model, i bought it new about 6 months ago. (so i dont think its worn out. yet.)

heres the problem, i ride up at chicksands quite a lot, and ive noticed when riding, on some of the steeper/ faster jumps on some of the trails, as i go 'up' the jump, i can feel the shock bottom out, now ive wound the preload adjuster almost to its recommended limit (the manual says no more than 2 full turns of pre load)

even with the spring wound right down, i can still feel it bottom out.

i weigh just under 11 stone. do you think i might need a 'bigger' ie heavier spring on there or do i need a new shock? something a bit burlier?

does anyone have any recommendations?

or is it just down to poor technique?

thanks in advance,

ben

delcol

what number is on your spring.. look on mojos website they have a spring rate guide on there and get the appropriate spring...

your spring is probably to soft.

Koiler

super fast!

that sounds like a plan, ill go and have a nosey in the bike cave.

thanks for your help

konadawg

Check the sag, that will be an indication of whether you need a heavier spring or not.

I needed one on my Reign X, went up from 500lbs to 600lbs feels OK now.

if so look up CRC and the "nukeproof" ones they sell, cheaper than fox.

delcol

check here

http://www.mojo.co.uk/Website2010/html/springcalc.html

Koiler

ok, thanks for the help so far,

so on the spring, it says 450 x 2.39

thats obviously 450lbs is the 2.39 the shock stroke? or is that the travel for that spring? (or is that the same thing?)

with a weight of 154lbs and looking at mojo's calculator, it says i need a 392lb spring, if ive got a 450lb spring, then surley im well within the limit?

or have i misunderstood?

konadawg

Koiler wrote:

ok, thanks for the help so far,

so on the spring, it says 450 x 2.39

thats obviously 450lbs is the 2.39 the shock stroke? or is that the travel for that spring? (or is that the same thing?)

with a weight of 154lbs and looking at mojo's calculator, it says i need a 392lb spring, if ive got a 450lb spring, then surley im well within the limit?

or have i misunderstood?

2.39 is the spring stroke i.e how much the spring can be compressed before it becomes coilbound. Often under-quoted though for safety. My NP spring is 2.25 (same as shock stroke) but measuring the gaps in the coils x the number of gaps shows that I have more stroke than the original Fox 2.35. Plus there is the shock "bumper" so in reality the shock's stroke is less than the quoted 2.25. Anyway any replacement should at least equal the shock stroke. It can be more, no problem, in such case check free lenght to ensure it physically fits.

Your calculations may or may not be accurate depending on whether you got the rear wheel travel right, plus the shock stroke, and hence the leverage ratio.

Koiler

konadawg wrote:

Your calculations may or may not be accurate depending on whether you got the rear wheel travel right, plus the shock stroke, and hence the leverage ratio.

i used the calculation of

rear wheel travel (inches) 6

shock stroke (inches) 2.39

rider weight (Lbs) 154

that gives the results

leverage ratio 2.510460251046025

spring rate 392.1499973739955

the only problem i can see with that might be the shock stroke may be incorrect?

so, to do it accurately, i need to measure the stroke of the shock?

or can i presume that its close enough to 2.39''?

nicklouse

how much sag are you getting?

20-25% that is fine.

it is not a jump bike.

Koiler

sag is about 25% ish

i know its not a jump bike.

im talking about jumps on trails. sculpted rollers and small gaps etc

its the steeper ones (ie 'steeper launch ramp') of these that are causing it to bottom out as the rear wheel ramps up into the jump if you know what i mean?

if i went up to say a 550lb spring, would it do any harm? provided i could still get 25/30% ish sag? or would it be to stiff :shock:

konadawg

Well.

The travel is 6 inches.

But the stroke of the shock (forget the spring) seems to be 2", at least on 2005 models. This, if correct, changes matters considerably.

With that info and your weight MOJO says 560 lbs.

For my bike and weight it says 596 and I have a 600 which feels right but I would not have any problems with a 650 I don't think so I would say that Mojo's calculations are pretty reasonable, you should not be oversprung with them.

nicklouse

ok we need to know what the stroke on the shock is as the 2006 info is corrupt on the Kona site. (you could ask there)

2005 has a 2" stroke. the 2007 has a 2 1/4" stroke.

yes a 1/4" can make quite a difference.

Koiler

nicklouse wrote:

a 1/4" can make quite a difference.

as my missus keeps telling me!

i cant seem to find out what the stroke is.

if i unwind the preload adjuster all the way, and measure the 'rod' poking out the end, is that an accurate way of measuring the stroke of the shock?

thanks again for all the help so far

Koiler

sorry for the double post.

but as i was typing the last one i was flicking through the manual for the coiler and it has the info in there :oops:

i did check the manual for the shock but didnt think to check the bike one :roll:

it says the stroke is 2.00 inches, which, as said above would indicate i should be riding a 560lb spring with my weight at 154lbs

it also says that the real wheel travel is 6.1'' not 6. so that takes me up to 570lbs

so i guess im after a new spring? 600lb? is it better to be slightly over than slightly under at say 550lbs?

thanks

konadawg

Koiler wrote:

sorry for the double post.

but as i was typing the last one i was flicking through the manual for the coiler and it has the info in there :oops:

i did check the manual for the shock but didnt think to check the bike one :roll:

it says the stroke is 2.00 inches, which, as said above would indicate i should be riding a 560lb spring with my weight at 154lbs

it also says that the real wheel travel is 6.1'' not 6. so that takes me up to 570lbs

so i guess im after a new spring? 600lb? is it better to be slightly over than slightly under at say 550lbs?

thanks

Cool! Some definite answers at last.

What spring you choose will depend on the style of riding.

Most DHers seem to prefer a softer spring with more sag.
If you are more into playing around at parks and the like, or would be riding the bike in xc/am mode, then I would think a stiffer spring is the way to go.

Then there is personal preference. Soft or stiff (don't ask the missus ;-))

Either way there is not too much in the difference.

Koiler

thanks for the help!!

i quite like the way it rides at the moment, (minus the bottoming out) so i reckon i might go for a 550. or should i get one thats a higher rate? ie 600lbs

how much difference does 50lb make on a spring? anyone know?

the coiler is my only steed (at the moment ) but its a bit of a pig to pedal around so im thinking about adding to my collection with a hardtail for general XC type fitness stuff and try to make the coiler a little more fun orientated for bombing around chicksands etc

so i reckon thats another tick in the 550lbs box?

i wish i knew about this stuff!

konadawg

End of the day it's suck it and see!!!

Koiler

ok, one last question on this...

i think im going to give a 550lbs spring a go. if i cant get the right sag, ill try a heavier one!

im looking at one of these http://www.chainreactioncycles.com/Mode ... elID=15607

i cant find one that matches the exact measurements of the one i already have but according to the description on crc it says its ok to use a spring that has a longer stroke than the stroke of the shock. is that right?

so if my shock has a stroke of 2'' can fit a 2.25'' spring? will it make any difference to the way it behaves?

thankyouplease

ben

konadawg

You already have a 2.39 spring so fitting a 2.25 spring will be OK. At least to just make sure (but confident of) check the free lengths but again since a 2.39 fits it is quite inconceivable that a 2.25 stroker would not.

So it's a "go" then!

konanige

I know its an expensive option but I just put an rp23 on my coiler and now I can make it ride any way I like plus it shaved a pound off the weight.

nick1962

The whole spring/shock/stroke length can be confusing.

) I changed the rear spring on my 2006 Colier to a Fox 650 x 2.35(from MOJO) as opposed to the 450 x 2.39 that was on it new. I weigh 12 stone and this sorted out the excessive bounciness. MOJO were very helpful and sorted it all out for me over the phone.

If you are buying from elsewhere or online make sure you get the right inner and outer diameter spring too as some springs are too wide and don't sit at the top and botttom of the shock correctly(Manitou). I think it needs to be 31mm inner 45mm outer.

konadawg

nick1962 wrote:

If you are buying from elsewhere or online make sure you get the right inner and outer diameter spring too as some springs are too wide and don't sit at the top and botttom of the shock correctly(Manitou). I think it needs to be 31mm inner 45mm outer.

It's best if you buy a spring that is specific for the shock type and not really mess with other brands etc unless you know the dimensions.

You can buy original (expensive) or aftermarket such as Nukeproof or Eibach, they will come in different sizes and it will be set out for which range of shocks they will fit, so no real need to "experiment".

The actual dimensions will vary a tad simply because to stiffen the spring, thicker wire will be used, so you may not often find these listed, except for the free length (which is not critical as long as it fits).

For Fox, Vanilla are considered "normal" sized, (if that counts for much) but the coil on the DHX is considered "oversized" so just because they are both Fox does not count for anything - so buy by the catalogued application not by assumption.

Replacing the spring on my Giant was interesting - the increased OD due to thicker wire meant that while it fit the shock no problem, getting the shock back into the frame's "cage" was something else!! All for just a mil or so.

I ended up slowly introducing the shock in the frame by "screwing in" the (un-tightened) spring!