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coil shocks

49 posts & 19 voices | Started 11 months ago by trickydisco | Latest reply from amphibian

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trickydisco - Member

I'm seriously considering ditching my afr shock on my enduro (09) and getting a VanRC.

Will it really be like night and day? What spring would ppl recommend for a 70kg rider? (according to tftuned it's 424lb spring)

.. also does this video really demonstrate anything (seeing as it's static)?

www.youtube.com/watch?v=PQDCUa-KIyw

off to les arcs in 3 weeks and got told by some guy in the peaks that all the guys he rode with who had air shocks all 'cooked' and couldn't handle the amount of descending

Posted 11 months ago #
tracknicko - Member

what the **** is that video menat to show? which spooner made that?

Posted 11 months ago #
superted666 - Member

I'm no expert but allthough coil shocks are considered better performing due to the linear compression, testing a bike unloaded is useless as it doesn't replicate real world conditions.

Posted 11 months ago #
xiphon - Member

ha ha ha ha @ the youtube vid.

What a plonker.

Posted 11 months ago #
tracknicko - Member

i drop this bike and.... dunk

then i drop this completely different bike and... dunk.

now lets see it in slow mo. derduuunnnnkkk

wtf?

Posted 11 months ago #
LoCo - Member

eh!? the rebound is stupidally quick on the rear air shock or the piston bolt has broken off as happens with those shocks, shows very little

Posted 11 months ago #
MrCrushrider - Member

ha what a tit! great video!

Posted 11 months ago #
tracknicko - Member

id say it wasnt either of those two ideas loco...

Posted 11 months ago #
I_Ache - Member

Well for a start the Enduro SL and the Pitch might be very similar frames but they have different rockers so it isnt an exact and totally fair comparison. Also as pointed out in the video the Pitch is heavier and will fall to the ground faster and be less likely to bounce.

According to the video they are both set to the same sag and tyre pressure so what this video is showing us is that the back end of the Enduro bounces rather than sucking up the energy like the Pitch seems to. This (IMO) is more likely to be down to the damping rather than the spring. IIRC the AFR has some sort of platform damping and that will resist the compression of the drop in this test, we don't know how the shock on the Pitch is setup.

I would bet that if this test was repeated with identical damping systems the results wouldn't be so dramatic.

Posted 11 months ago #
LoCo - Member

or his compression it set on full, what you thinking nicko?

Posted 11 months ago #
tracknicko - Member

im thinking that its an air shock and the inherent slight stickness in tighter seals means that in a drop test of half the weight of a lightish AM bke, an air shock will do approximately **** all.

it isnt rebounding 'fast' it isnt actually rebounding. that bounce you are getting is all tyre. the shock hasn't even moved.

and as for that video showing anything to do with the original q of the OP?

hmmm.

Posted 11 months ago #
trickydisco - Member

so yes.. pointless video

So with regard to springs. I used the spring calculator

http://www.tftunedshox.com/info/spring_calculator.aspx

and it came out 424.. Should i go with 400 or 450 spring? (assuming i have wheel travel correct at 5.9)

@Loco have emailed ya

Posted 11 months ago #
tracknicko - Member

TD. i wouldnt swap my shock for the alps, unless you have a spare ready to go on that you can do for nowt.

i presume its just a holiday yes? couple of weeks max?

totally not worth it!

f all will happen to your air can.

IMO

Posted 11 months ago #
retro83 - Member

It says 'preload identical' then talks about sag...not the same thing. If he repeats the test with a softer coil (with more preload to get the same sag) I reckon he'd get a different result.

Plus as above, we don't know what settings those shocks have. Compression tunes, propedal, rebound etc. Not to mention the spring rate at the start of travel.

tl;dr that video means shit all

Posted 11 months ago #
trickydisco - Member

Na.. not just for the alps but all the time.. Not a big fan of my AFR shock if i'm honest and have heard many people say a coil shock totally transforms the enduro into the bike it should be

Posted 11 months ago #
tracknicko - Member

argh! the rebound/compression settings are irrelevant in that test.

LOOK AT THE SHOCK FFS. it never moves!!!

it isnt being restricted by oil flow through a compression circuit! there is no oil flow!!!

Posted 11 months ago #
tracknicko - Member

ah well fair enough then. coil will give you a much more 'active' ride

generally a touch more bobby unless you stick a fair amount of pro-pedal on, should have better small bump sensitivity, but obv be heavier.

Posted 11 months ago #
LoCo - Member

Hmmm, possibly just done a test on my Areil with an RP23 Boost valve, slight bounce with propedal set on hardest setting with rebound fully slow and about 10mm of shock movement.
With Propedal off and rebound same no bounce and about 15mm of shock movement.

and having looked at the video of him pushing them through the travel the Air shock is definatly quicker on the rebound so, would assume combination of seal stiction, rebound speed, compression setting and the extra weight on the back end of the Pitch.
It's a silly video anyway

Any how finished my coffee so back to work

Posted 11 months ago #
tracknicko - Member

sorry. not meaning to be too angry. just a really really **** test of shocks built for different purposes.

horses for courses. and IMO air shocks for xc bikes, coils for DH bikes.

all goes a bit wrong when you get into the grey area of 'AM' (whatever that is) but for me if im riding the damn thing up a hill AT ALL then i'd err on the lighter weight side of things and go air shock.

Posted 11 months ago #
LoCo - Member

Yes I'd agree with you if your more uphill orientated, not that Ihave the choice with the Ariel as it only takes an air shock and yes it is a crap video, still keeps the guy who did it amused and out of trouble

Posted 11 months ago #
xiphon - Member

A properly set up coil shock will pedal just as well as an air one.

I'm sure Loco would be happy to do it for you when it's due a service ...

Posted 11 months ago #
gravity-slave - Member

Bingo - stiction - no compression so no rebound, my money is on tyre bounce!

He states "Preload exactly the same - 25-30% sag". So that's exactly a 20% possible variation...

What about the compression tune in the shocks?

It's a pointless comparrison, but coil shocks do ride completely differently.

I was in a group that hammered the Alps, most on air shocks, only problem we had was punctures!

Posted 11 months ago #
molgrips - Member

LOOK AT THE SHOCK FFS. it never moves!!!

Still irrelevant, because it'll all change when he actually gets on it and rides it.

I've never noticed stiction as such on an air shock - perhaps due to the high forces involved when you sit on it. However what I have noticed is a non-linear spring rate - not so much rising at the end of travel, more falling at the beginning, which could be related to stiction - or could be not.

Posted 11 months ago #
tracknicko - Member

and being too damn awesome IIRC phil.

Posted 11 months ago #
tracknicko - Member

molgrips thats essentially what im getting at. it is ineed irrelevant as as soon as you weight the bike up all of that 'testing' changes.

interesting your falling rate shenanigans. hmmmm

Posted 11 months ago #
gravity-slave - Member

Oh yeah, that's what was blowing the tyres!

Posted 11 months ago #
amedias - Member

Also as pointed out in the video the Pitch is heavier and will fall to the ground faster

massive physics fail in that explanation....

Posted 11 months ago #
amphibian - Member

Tricky D - I've got an 08 Enduro and have also pondered the Van R coil shock idea. I decided not to in the end because I didn't want to lose any of the excellent uphill performance and I thought the bike is probably better balanced with air (or coil) front and back. I could see it leading to the purchase of some coil RS Sektors!

Have you tried doing the DIY air can service (dead easy and only takes about 10 mins) and trapping a bit of negative air when screwing the air sleeve back on? I found this made a fair bit of difference to plushness and small bump sensitivity and I'm now very content with the whole setup.

Posted 11 months ago #
molgrips - Member

interesting your falling rate shenanigans

Air is (often) stiff at first, then it goes slack for a while then ramps up again. So the sag means you sit at the slack bit, so the first bit of your travel is a bit sloppy. Not a huge issue for me at the rear since it can be designed out, but on the front it's what I really miss about coil forks.

What coil forks to replace my 66SLs? Must be beefy, 170-180mm, not stupidly heavy and must wind down. And preferably not cost £900.

Posted 11 months ago #
tracknicko - Member

yeh id assume thats you overcoming the static friction of the tight seals etc. to get the shock starting to move.

negative air spring is designed to sort this out for you and increase small bump sensitivity... can you up neg air spring pressure independently on your forks?

Posted 11 months ago #
molgrips - Member

No, actually, not on the 66s. But negative air also affects the spring rate throughout the stroke. The 66s have a crazy set up where there's a main chamber and a small cordoned off part of it that's meant to be to stop it bottoming out - separated by a floating piston that's limited with a piece of string. However depending on the relative pressure in each chamber you can make the chambers behave differently so the smaller one can become the main chamber.. couple that with being able to add air over the damper oil in the other leg - whose height you can also change - and you've got a lot of variables!

The best way of sorting it imo is a negative coil spring, because after a certain travel it has no effect at all. My Pace RC41s had the best spring curve and that's how they worked.

Posted 11 months ago #
tracknicko - Member

yeh i could see how that could work. heavier tho, and less adjustable.

it could still be done with air if there was an independent fixed length chamber, rather than the negative side activating on the opposite side of the primary air chamber.

potentially excessive though.

Posted 11 months ago #
trickydisco - Member

Have you tried doing the DIY air can service (dead easy and only takes about 10 mins) and trapping a bit of negative air when screwing the air sleeve back on?

Nope.. got any instructions? This is for the AFR right?

Posted 11 months ago #
amphibian - Member

It is for the AFR. It's simply a case of unbolting the shock, releasing the air via the shraeder valve, unscrewing the sleeve/can (anti-clockwise IIRC) and removing, cleaning up the insides if necessary (they're normally clean anyway) and the mail seal (not so spotless), smearing some suspension grease on the seal, slide the sleeve/can back onto the shock body, compress it and screw it on clockwise, bolt back onto frame, pump it up to pressure.

Negative air will be trapped by doing the above and should make the shock react better to small bumps and just feel a bit plusher.

Posted 11 months ago #
amphibian - Member

BTW, there are more comprehensive instructions with pics on mtbr if you search in the Spesh forum. For what it's worth I think the AFR shock is really nicely made (early productions glitches aside) and easy to maintain. It also works well when you do the above

Posted 11 months ago #