I'm due a new set of tyres on my Coupe and wondering if anyone knows which sizes are suitable? It's currently got the standard 155/80 x13 but it's woefully under geared (approx 15mph per 1000rpm). I'd like to fit something a little larger to reduce the revs, has anybody any experience of different sizes? Many thanks.

Membership Number: Lapsed

Tim is the one to speak to, as he'll know. His contact details are in Parliamo, as 850 registrar.

Membership Number: 5260

I've also got an 850 series 3 coupe and I have 175/70 R13 tyres on mine, but I checked the useful website below and it turns out the diameter is pretty much the same as yours:

http://www.mintylamb.co.uk/?page=tyre.htm

I haven't thought of my car as under-geared before but I don't tend to go on motorways so I find it fine for A roads.

Membership Number: 12358

Hi Kevin

175/70/13 is as big as i would go with a standard car

165/80/13 does fit on the rear but doesn't change things much that you would notice whilst driving and i would accompany these on the front with 165/70/13.

If you fit anything much bigger it starts to look funny on the rear.

the route to go down for the gearing would be either change the gearbox to one from a 850 saloon which will give you about 16.4mph per 1000 revs.

or even find a ring and pinion set that is 9/41 or something like it, this gives about 18mph/1000

coupe runs 8/37
saloon runs 8/39
van/camper runs 8/35 ish please check these to the hand books as they are from memory

in summary go for the 175/70/13 an consider the gearbox option for another day, but please choose a good quality tyre, economy brands loose you energy and dont take the sideways force that the 850's can create at the rear.

i hope that all makes sense

Tim

Membership Number: 5222

Many thanks Tim and Tony, 175/70's it is ...

Membership Number: Lapsed