As some of you might know ive just put a fox coil shock on the back of my enduro to try and stop some of the pedal bob i was getting with the 5th element air shock.

a couple of people on mtbr have said that the coil shock will feel completely different to the air shock , but they havent said why??

so the question im asking is , will there be a huge difference and if a coil shock is so much better than an air shock why arent manufacturers fitting them on all their bikes?

cheers

steve

air shocks feel dead in comparision.
coil are more smooth/linear

Yes. Coils is much more consistent and controlled performance.

Weight. Adjustabilty for a wide rAnge of rider weights.

Thats odd, considering that 5th element shock were pretty much the first 'platform/anti-bob' shock to market for mtbs.

yes, they do feel different. more compliant, generally plusher. heavier and not as adjustable.

The rate a spring compresses remains the same through its design movement where as, as the piston of an air shock is pushed in the effective spring rate increases as the air pressure inside the can increases and so is non linear.

eg, the last mm of a coil movement will need the same force as the 1st mm took to move it but in an air shock it might need 10 times the force of the 1st mm of compression simply because the air pressure in the shock might be 10 times what it was before any compression.

as a result the compression of an air shock isn't linear.

I did make all that up though so could be wrong. 😀

Also, if a seal pops on your air shock and the back sags you can't ride. If the dampener on your coil shock pops, the spring will still operate still (but with no dampening) but it'll be a bit hairy at full on speeds but at least it won't spoil your day.

Coil shocks also have better small bump sensitivity and lack lockout/propedal levers so i dont know why the think the fox coil will stop your pedal bob?..its likely to get worse!
Generally coil shocks weigh more but give better performance/feel, hence they are specced on bikes with more emphasis on going down. Air vice versa.
You would have probably been better off with an rp2, rp23 or monach.

Also, if a seal pops on your air shock and the back sags you can't ride. If the dampener on your coil shock pops, the spring will still operate still (but with no dampening) but it'll be a bit hairy at full on speeds but at least it won't spoil your day.

True, but you're not comparing like for like…if the spring snaps on a coil shock you dont really want to ride it either.

this dhx has propedal , anti bottom out and rebound adjust so hopefully it willwork!!

Renton – the amount of air pressure in the piggy back chamber of the DHX will affect the degree to which the pro-pedal and bottom out work, i.e. the higher the pressure, the more pro-pedal and anti-bottom out effects will be felt.
I have to agree with Stuart though; if it was pedaling performance you wanted, you would have been better off with a Fox RP2/RP23. These dampers have much higher levels of pro-pedal damping than the DHX to the extent that you can virtually lock out the rear end. The DHX won't get anywhere near that level of pro-pedal damping although it should still improve on your Fith Element.
Having said that, the DHX coil on the Enduro works very well and you're likely to notice a whole heap of other significant improvements as a result.
In terms of what it will 'feel like', should should find yourself being able to carry more speed over rough section; the bike will feel smoother and more composed; you should find the bike has more grip while cornering and doesn't feel as harsh on heavy landings, unless you've cranked the bottom out all the way in and the piggy back pressure set to 200psi.
From memory I used to run something like 150psi in the piggy back and had the bottom out, set all the way out, i.e. the least amount of resistance when I ran one on my Enduro.

generaly ( note the last word)

coil springs are linear rate ( can be designed as rising rate by different gaps between coils or tapered wire)
air shocks are rising rate ( the degree of rising rate is determined by the starting and ending volume of air canister)

often the damping circuit of both air and coil are simular

air shocks seem to have more stiction due to extra seals also high pressure on seals ( air pressure) gives lots of stiction

coil shocks allow you to set the ride height(sag) indipently of spring rate by adjusting the preload

air shocks you adjust air pressure to adjust ride height( sag) but this changes spring rate,, unless you have adjustable canister volume

on the whole I have found my whyte preston works better on coil springs more supple better quality of ride, but on the front it needs the rising rate of the air spring to stop it diving through the travel but the extra stiction means the ride quality isnt as good,,

coil better ride linear rate more weight

air rising rate more stiction less weight

you pays yer money takes yer choice

i wish there was a thanks button on here!!

cheers geetee1972.

im not after better pedalling performance, if i wanted that i would have gone to a hardtail.

what im after is a shock that doesnt feel like a pogo stick, that spikes its way over big hits .

but i also want something that can be pedaled up a hill without to much bob.

the bike has an air talas on the front !!

More importantly, coils just look cooler. 8)

'what im after is a shock that doesnt feel like a pogo stick, that spikes its way over big hits .

but i also want something that can be pedaled up a hill without to much bob.'

Try a Cane Creek double barrel. Independently adjustable rebound and compression circuits. You can climb with virtually no pedal bob, hit 15 ft drops on the way down and never have the rear wheel leave the ground, just put one on my tracer, it is phenomenal. Outclasses any shock I have ever ridden.

Highly priced though, but well worth it, totally transforms a bike

Don't forget to pump up the piggy back whatsit before mounting it in the frame or you have to (1/2) take it out to pump it up on an enduro

here's mine, coil'd up.

OK its heavy and it bobs a bit but so what. I can still pedal it uphill.

No one to my knowledge (except marzocchi with their roco tst) make a coil version of an rp2/rp23…i would imagine there is a market for them on bikes like these. I would love a coil on my spicy, but use the propedal lever lots when climbing.

hit 15 ft drops on the way down and never have the rear wheel leave the ground,

how???

Your 5th element shock shouldn't have bobbed. Must've had something wrong iwth it, or been set up wrong. You do have enough pressure in the damping chamber don't you?

geetee1972

fuke me, impressive science fella, actually made sense to me too when i read it a few times, shows that some people actually know what they are talking about and offer sound advice, good thread!!

I agree with stuartanicholson there need to be more coil shocks with a proper pro pedal leaver. If you had the cash could Mojo put the damping circuit including the lockout leaver from a DHX air into a DHX coil?

Andy m.

the dhx coil does have propedal adjustment(15 clicks i think)but it doesnt have a lockout.

This got me thinking whether frame manufacturers design their suspension linkages for a particular shock type?

If air has non linear spring rate through it's travel then the linkage can be designed to vary the rate of shock compression through the travel to give a consistent apparent spring-rate of the wheel travel (eg the linkage compresses the shock more at the start and less at the end of the travel) – if you put a linear spring-rate coil onto this linkage the suspension would feel comparatively softer in the latter stages of travel. The inverse would apply if fitting an air-shock to a coil-designed linkage.

Perhaps that's why fitting a coil spring to an air-designed linkage feels so smooth, it's because the travel is a lot softer in the latter stages?

Oh, and the pedal-bob correction (pro-pedal etc) is all related to the damping rather than the spring so I can't see how fitting a coil instead of an air shock will change that.

If air has non linear spring rate through it's travel then the linkage can be designed to vary the rate of shock compression through the travel to give a consistent apparent spring-rate of the wheel travel (eg the linkage compresses the shock more at the start and less at the end of the travel) – if you put a linear spring-rate coil onto this linkage the suspension would feel comparatively softer in the latter stages of travel. The inverse would apply if fitting an air-shock to a coil-designed linkage.

Yes, like the Cannondale Prophet for instance

5th element air shocks were so bad they put 5th element out of the shock business. spesh offered a 50 quid upgrade to a dhx air to sort the problem.

pretty much any shock will be better.

What coogan said. Ti spring for the bling win.

Damping and spring response are two separate things.
Damping can change how the shock responds, the springing medium determines how the shock initially behaves.
The air shock usually has a high resistance to initial movement, as the bump force to overcome the air seal static friction (stiction) is quite high. Because coil shocks dont have the additional stiction of the air shock, their inital movement requires a loss less initial bump force, hence the small bump sensitivity.
Damping will control the shocks movement once its started moving.

I'm glad Padowan finaly pointed out that the better designed frames that are built to use air shocks from the concept have a changing compresion rate as the wheel travels through its arc to take into consideration the rising rate of the shock.

I'd have also thought that you need some element of this non linea compression to stop you blowing through the entire travel on big hits whilst giving you a plush ride over the smaller stuff?

Dude sell the coil and get an RP23
Coils are excellent for descending (i have one on me AM blood)
In my opinion (and just about every rider on this forum) the RP23 is a groundbreaking shock suitable for all other types of Mountain Biking.
ps the DHXAir is a horrible horrible shock

Anything is better than what you had. I changed from a 5th elemment to a fox float r, and the difference was incredible. The bike didnt neeed propedal anyway, so just in terms of performance, the shock was much plusher, and far more controlled.

Weird that apparently everybody thinks the dhx air is rubbish.
I've got one and love it.

How Jedi?

I just put a Fox Coil on my Heckler and TBH it just blows my 2009 HV RP23 out of the water – It's very plush, smooth and has a more linear feel to it! Ok I have no pro pedal, but I do spin very smoothy (albeit slower) up climbs, but the feel of the bike down more than makes up for it.

The problem with RP23 SC bikes is that they get valved LOW for compression & rebound, (they only have to order 1 type of tuned Shock from Fox – to keep the cost down) – these low valved shocks are absolutely useless on a single pivot bike like a Heckler!

Anybody who has a Heckler with a Low valved shock, i feel sorry for you – DON'T suffer, either send it to TFtuned to get re-valved/pushd or better still get a Van R Coil for £189 form MOJO!

the problem i have with regards to fitting a rp23 shock is that the shock fitted to an enduro normally is a specific length and im not sure if they do a rp23 to fit??

Renton's right – that model Enduro uses an 8.75" by 2.5" damper. The RP23 only comes in 8.5×2.5. The DHX Air can be had to fit, as can the cane creek!

Mojo can supply customer lengths of shock IIRC.

I'd have also thought that you need some element of this non linea compression to stop you blowing through the entire travel on big hits whilst giving you a plush ride over the smaller stuff?

Damping sorts that. My coil Mz 66 forks had an extra bit of high compression damping at the end of the stroke to stop you blowing through it. Worked nicely it did too. The air ones have an air chamber for that instead.

Interesting all this coil/air talk. Personally I notice the difference between the two much more on a rear shock than on forks.

In fact I prefer a coil rear end and air up front.. am I odd (or just inbetween spring weights!)??

It's easier to overcome the design issues of using an air spring in a fork versus a rear damper; you've got many more times the air volume to work with so there are less issues with the ramp up of pressure and less heat dissipation issues, plus they are easier to seal as the spring is contained inside the fork leg. The seals then present less stiction.
In terms of outright performance (basically front end grip) a coil will still out perform air (by all accounts from the guys at TF), the difference is much more marginal and like you say, if you're right between spring rates, maybe air makes more sense.