2.9i S2 tyre choice on OZ rims. advice and recommendations p

[drak ula]

my S is off the road while i figure out how best to repair the top door hinges and i've been driving my bmw e30 320i cabrio for nearly a year now and love it, but had driven my neighbours 325i cabrio and lusted after that extra power, the difference hald a litre (and bigger valves, ports, throttle body etc.) makes is incredible! i have found the 320i to be brilliant handling and with plenty of grip, it has the bmw bbs 14 x 6.5j wheels with 195/65 marshall tyres which seem to work really well with that much (little) power.

but i recently bought a 325i coupe, it has currently has the same 14 x 6.5j wheels and same size tyres but with odd mismatched brands and the car has almost no grip at all!!!
even pulling away a bit briskly from a junction the tryes just spin in first and when i grab 2nd gear they keep spinning as i fishtail up the road trying to keep the car roughly in a straight line! yesterday i tried to beat the oncoming traffic onto a roundabout that other cars were waiting to join in front of me, i was impatient and overtook the cars in front of me at the give way line and sped into the gap between the road i was entering from and the cars coming around already on the roundabout, if i'd been in the cabrio 320i there would have been no drame, but in the 325i i got seriously dramatic sideways action all the way round the roundabout AND THIS WAS IN THE DRY ON A SUNNY DAY!!!

obviously the 325i needs more grip (i see why some had came with lsd but i can't afford one at the moment) so i intend to sell my 14s and buy a set of 15 inch bmw bbs wheels off ebay (i'm not keen on the look of huge bling wheels and love the look of the bbs cross spoke wheels and guess the extra inch diameter and half inch width should mean a slightly bigger but still worthwhile increase in 'footprint'.

the S has the same size rims (15 x 7" OZ) and is wearing 205 tyres that are in a horrible crumbly state, i believe the S also has roughly the same power as the 325i (170-180hp) and even less weight, so the question is what is the best tyre choice for everyday fast driving on the road, i've seen 205/55 and 205/50 on those rims, would 205/45 or even 205/40 be better still? and what brand and model of tyre is best in terms of grip per £? all advice and recommendations greatly appreciated. and if you all think i'm better off giving up on the old school 15s and getting some 17s then i'd like to know that too though i'm still hopefull that there's got to be some decent 15" grip out there. thanks

[Wiz]

Rolling circumference is the term I'm thinking of. You can't just stick lower profile tyres on the same size rim. The S runs 205/60 normally 215/55 is an other option which gives you more choice on tyre makes and models Toyo T1R's come to mind. If you want 45 profile your probably going to want 17" rims.
Personally i think the S suspension set up especially with the weight of the car works well on taller profiles.

The handling on the bmw will be bad if its on cheap mismatched tyres. Allways run the same make /model and condition tyres on the same axel IMHO.

Edited by Wiz on Saturday 24th October 10:10

[Gerald-TVR]

Hi Drak

This might help.

Norman

Edited by Gerald-TVR on Sunday 25th October 18:05

[Barkychoc]

I have always had good experiences with Continentals - but funds were tight so I went for Toyo's on the S - a full set of 4 was £249 fitted at my house by this outfit http://www.event-tyres.co.uk and I'd recommend them.

I also had a couple of toyo's at the same time on my daily drive and they are fine - I'm particularly pleased with the lack of road noise from them, thought I don't really do any performance driving in my car.

If you start going wider with the tread you need to go lower with the profile to retain the same overall diameter - the profile is the percentage of the width so a 205/60 is the same profile in terms of height of the sidewall as 225/50 or something like that, it may not be exactly right but I'm sure someone will come along, shoot me down and give you the right info shortly.

If you don't decrease the profile accordingly with width it upsets the gearing which also affects speedo readings.

[mannik]

I know this has been discussed before but going down to 55 profile on the 205's makes the ride height very low on an S and there will be trouble getting over speed bumps, sleeping policeman etc.
I had 205/55 on my S3C and changed to 60's which made life a lot easier.

Going to 60's limits tyre choice more but I have previously seen comments on Bridgestone Turanza's ER300, Dunlop SP Sport, Continental Premium Contact, as well as Toyo Proxy's as choices..(speed rating V or ZR,etc), all of which are good tyres

[Barkychoc]

If you go to 55 profile but increase the tread width to 215 (if this size is available) then you retain the same overall diameter and therefore ground clearance. 225/50 would also be the same - but you need to make sure you can accomodate the extra width (ie the tyres don't rub on anything) and don't forgt wider tyres won't make the steering any lighter
You'll probably also have to declare it to the insurance as a mod.

[clarenceboddiger]

[quote=Barkychoc] but you need to make sure you can accomodate the extra width (ie the tyres don't rub on anything) and don't forgt wider tyres won't make the steering any lighter quote]
And dont forget if they are a similar compound the wider tyre has a bigger contact area so may have less grip , it all depends on the co-efficient of friction for the compound.