Is there an advantage of having air over a coil other than weight and not fussing with springs?
Its to go on a 140mm Turbo Levo.
Im thinking of changing the front & rear travel to 160/160 or 160/150.
Current air shock is 197.6x47mm
Thinking of going 200 x 51 (ttx/cc) or 200 x 57 Fox

A lot depends on the progressiveness of the linkage. Some bikes are designed around the progressiveness of an air spring so you get naff all mid stroke support, or even worse a falling rate in the middle if you fit a coil.

*Stares angrily at turn of the century Marin frame in the corner of garage*

Progressivenes has little to do with midstroke support. Usually the bikes designed for aor shocks have midstroke support designed in to the leverage ratio – so moving to a coil wont give you less midstroke support – it will give you more and likely a harsh ride. What it would lack with a coil is bottom out support – if the bike is designed specifically for air.

Watch that you don’t end up running a shock with too long a stroke (the 200×57 in particular) as you might find the rear wheel/swingarm hits the frame. Can’t see the 200×51 bringing about any issues but the 200×57 may well do some damage.

Thats what i was going to check and if necessary get a different clevis/yoke if avaiable. If it doesn’t work with the 57mm I’d go with the 51mm. Trying to weigh the options.

Given graves and Keene both run coils on their bikes and specialized spec a coil on some models itsprobably safe to say the specialized linkage works with a coil.

Tempted to go to coil myself. Similar weight and always have problems with air shocks as I have to run them at max pressure to get the correct sag.

I’m 235lbs and run a ohlins coil on a bike with a very progressive linkage, designed around an air shock, and I would never go back to air, the difference is night and day, as well as how smooth it feels the rear wheel tracks perfectly and traction is massive. I’d recommend one with a pedal platform if you do a bit of climbing. In pedal / firm the ohlins moves very little on climbs, yes it is slightly less efficient but not much. They weigh about 500-600g more but then I weigh a shed load more again. If you are bothered about weight the save a few 100gs and go Ti spring.

My DHX2 with an SLS spring is 700g – so only 250g heavier than a 200×57 X2 float.

Sod all.

Because forks have a 1:1 leverage ratio coild have an even bigger difference on the front.

I’m running a Cc DB coil on my stumpy, love it.

I’m 200lb geared up too.