[Closed] Air to Coil, should i make the change?

I'm about to, but then again I'm changing frames as well!

I've done it in the past. It is a teeny tiny bit smoother but for me, the advantages of air (adjustability and not needing to buy a new spring if you're not average weight) outweigh the benefits of coils. YMMV depending on what/how you ride.

Always thought coil on the rear was nicer. (for no other reason than it felt like it, so don't ask me)

Ditto what Clubber says about the front

Depends on what's important to you really and where you tend to ride. Fact is coil dampers still perform better than air shocks in their ability to keep the wheel on the ground and thus provide grip; the real question is whether that performance advantage is important enough to you to off set the weight penalty. Typically a coil shock will add upwards of 1.5lbs to your bike. You can off set some of that if you put a Ti spring on, but then we're talking £150 more on top.

I just don't see that an air damper being more easily adjusted than a coil is a even remotely an advantage. If you're buying a new damper, then whomever is selling it will give you the correct spring and even if not, price of a new spring is harldy high.

i ride whyte prestons ss and geared i have a differert times ran coil springs instead of the oe air shocks

air shocks have quiet high rising rate plus more stiction as there are more seals and a lot more seal friction
but the rising rate can help keeping large hits in control especialy if there is little rate change in the linkage
air springs will get stiffer as their tempreture rises

where as coil springs are normaly straight rate and a lot less friction so they tend to be good at small roots etc giving better traction especialy while climbing
but depending on the leverage ratio of the swinging arm system coil shocks can blow through their travel very quickly

you can get rising rate or multi rate springs but you have to pay and with a shock pump you have a whole range of springs in you bag

on the whole i have found my bike was better with coils but you have to get the spring rate right,, and unless you have a shop that can exchange springs or a box of springs,air shocks are easier to get right but dont give you the same level of traction

Went from dual air revelations to coil pikes. Honestly the performance is very very close if you take the time set the air forks up properly.

There really is a lot of guff that gets spouted about suspension isn't there. Yes springs are linear in their rate of compression, i.e. the force required to compress it 10mm is the same whether it's the first 10mm or the last.
BUT bike designers are bit more clever than that and do in fact design their suspension linkages to vary the leverage rate through the travel so that you can get a progressive rate from a coil. In fact you can get any kind of curve you want from a spring, falling, then rising then falling and so on and so on.
This nonsense that coils are better at small roots implying they aren't better at bigger stuff is also guff; coil dampers currently out perform air dampers on every surface - go ask the experts and they will back this up.
WHy would you want more than one spring; does your weight change that much over the course of time? You only need ONE spring weight, maybe with the chance to go up a notch if you're riding something like Fort William.
Coil shocks blow through their travel? I've read that this more likely to be true of air shocks actually; besides, once your spring rate is sorted, blowing through travel is a compression damping issue, not a spring rate issue.

compression damping does not and cannot hold the bike up unless you use it to lock out the damper ,, it's the springs job,,low compression controls the movement of the sprung weight of the bike ,, ( rider frame etc) and generaly high speed compression controls the sprung parts of the bike wheel swinging arm etc

if the spring rate is too soft you can get the sag right by putting in loads of pre load but the important thing to note is that more pre load does NOT increase the spring rate it only controls how much weight the spring takes before it moves it then moves at the spring rate

i havnt met an air shock that isnt rising rate,, as the volume of the airspring gets smaller the pressure rises expotentionaly ( sorry crap at spelling)
if you half the volume you double the pressure so you double the spring rate,

so normaly a quality bike would be designed with the rising rate of an airshock taken into account,,, if that was to be fitted as oe,

the other reason a coil shock could be better especialy ( but not exclusivly) on small stuff is as i said before is the lack of friction helps the suspension to react on small inputs as air shocks have about twice as many seals as a coil shock plus having 200 psi behind a seal makes for a lot of friction

i understand ade used to design bikes so i suspect he gets the benefit of the doubt geetee.

(apologies if i have got the wrong inference from your post)

Coil shocks and forks are simply better. There is no argument end of story, period!

Weight is the only advantage to air forks and shocks. If weight was no issue who would actually use air shocks?

geetee can you show me a frame with a rising rate that compares to an air shock?

Oh and si I look forward to "what tyres...mech...stem...ruscas for my chumba" threads :p

I run both, generally prefer coil - just seem smoother

Going to give it a go, starting with a DXH coil on the back

Just found this on MTBR so it has already been done, should be interesting!

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I run a coil shock on an older (2006) specialized enduro - swapped the air shock before building the bike and have never regretted it - it climbs ok (and i do like to ride up as well as down) and in the alps it performed really well, gripping the the trail really well at speed in a way that hair shocks dont seem to

did it look like this before?

[img] [/img]

run them all over time swapped between them frequently and both have advantages and both have disadvantages. A fox DHX5 has more adjustment and can be made to work better than a bottom end air and vice versa with some of the really flash airs.

The only real plus with coil over air I have found is when you bugger up the seals a bit of oil comes out but not all the air

I love the coil in my rear...

anyway, ancient (to those that buy on here) 03 Heckler and a TF tuned fifth has made the bike one fantastic all round bike. I'd never have air.

if the spring rate is too soft you can get the sag right by putting in loads of pre load but the important thing to note is that more pre load does NOT increase the spring rate it only controls how much weight the spring takes before it moves it then moves at the spring rate

Coil shocks and forks are simply better. There is no argument end of story, period!

blowing through travel is a compression damping issue, not a spring rate issue.

Not necessarily. It can also be due to the suspension design changing leverage ratios throughout the travel 🙂

i cant comment on a performance/feel point of view cos i dont notice small changes well but when i got my heckler I put a coil spring on. Im going to the alps in he middle of July and i got the coil from purely an alps point of view cos going dh all day I wont care about the weight. However, i've recently bought an air shock and intend to get it PUSHed for use on a lot of uk trails when going dh all day wont be an issue and I want the weight gaining to help cut down my bikes weight a bit. Its a five min job to swap them around so I can pick n choose depending on the trail as to which shock I think will be best.

Coils do get stiffer as they compress. You tend to design around a workable length change though.
I spec springs for valves in Nuclear power plants, although these are mostly disc springs (Bellville's) with very small deflections. The closest you'll get to true linear compression with a coil spring is a machined coil, but you'd need a bloody long one to get 4" of travel.
And they cost. Reckon on £2k - £3k each.
Beautifully machined components though.
[img] [/img]

cynic-al

did it look like this before?

I run air springs on one bike and coil on the other (and regularly swap the forks between bikes (terrible habit!!). I'm in broad agreement with what people have already said. Personally, I think quite a lot of rear shock performance depends on the design of the rear suspension & in the case of air, what pressure you're running - currently I'm riding a Pace FS, and the rear has quite a coil sprung feel to it. Advantage of air units is that you can fiddle around with pressures whilst out on a ride to fine tune for changes in terrain (er..unless you have a wife who moans about the amount of faffing about....ahem 😉

Having said the above though, IME, if you're weight is reasonably static and you can afford a decent coil unit with adjustable compression damping and get the right spring for your weight, I think coil units are the better option, particularly in the long term.

Small/fast bump sensitivity and traction in general always seems better with coil. I find that in general there seems to be much less stiction in coil forks - less internal seals(?). Tempting fate here - but I've never had any mechanical problems with coil units, but have had problems with two rear air shocks and two air forks in the last five years (one is currently undergoing warranty repair). One rear shock blew out half way round a ride in the Lakes. The only coil sprung fork that I didn't get on with was a Manitou Black(yuk!!), but this was mainly down to the non-existant compression damping. Never had any problems with Fox coil units - oh, and the latest Fox coil fork I bought came with 3 springs (soft/med/firm) in the box.

Good luck choosing 🙂

I just went t'other way and went from coil front and rear to air front and rear, mainly cos i got the shock and forks very cheap, Fox DHX air and Marzocchi 55 ata. I realise that both these items are designed for more aggressive riding and as such will have more reliability built in. I've found the rear shock to be a revelation compared to the manitou swinger unit i was previously using, simple matter of setting the sag, i set a third of stroke length if i'm just riding trails and i set it to a quarter sroke length for rougher trips, it has the advantage of a piggy back boost chamber whichhelps for big hit stuff, i lke the way air shocks ramp up toward the end of the stroke too.
The jury is still out on the forks tho, but i'm still getting my head round them, just setting the sag doesn't seem to work as well as the shock. And theres alot of bedding in stiction too. All in all i'm glad i did it. Weird thing is i did it cos i didnt think i was as aggressive a rider as i used to be but i've regressed into silliness since the changes!! Oh well!! Oh forgot to mention its all on an Orange patriot 66!!

air shocks have quiet high rising rate

Depends on the air shock. A high volume air shock will have less of a rising rate than a low volume shock.
Some high volume air shocks actually have a slight falling rate in the middle of their stroke, the DHX air is a good example.

depending on the leverage ratio of the swinging arm system coil shocks can blow through their travel very quickly

Not entirely true. Most bikes, if designed right will use a wheel rate that behaves well with various spring rates that the bike will be used with.

On the other hand, the 1st generation Nomad was designed with a slight falling rate in the middle of its wheel rate which was fine with a coil shock, but combine this with the above mentioned DHX air and you had a bike that wallowed and blew through its mid travel very easily...

rustler i dont understand how a spring of constant wire diameter and coil spacing can be non linear ?

belvilles we used to use them as bumpstops in another life,, they would be stacked large face to large face and shims placed inside each pair this way we could control the movement of each pair then pairs of different rates were stacked up to give springs of varing travle and rising rate curves depending on what circuit we were at,
the first problem was friction we eventualy found the the washers needed to be tumbled and molybenibum coated this improved things
the internal shim was very important also to stop the washers being flattened and being broken or distorted

opps a little side tracked there sorry

got a 04 5spot with a push dhx ti coil and a 09 rp23, coils better goiung down rp climbs better, coil seems to squat more climbing but flys downhill but the rp feels more propped up climbing while still feeling plush, both good 🙂

constant wire diameter and coil spacing can be non linear

Because as you compress it, the geometry changes (eg the amount the spring wire twist for a given linear compression of the spring) isn't constant so there is a [b]small[/b] exponential aspect to it (can't recall if it's rising or falling).

What about elastomers?

😉

Rising rate with hysterisis damping... 🙂