Tyre Size Question

Post Tue May 16, 2006 7:16 am

I currently have 195/50 15s on my 318i, would putting 205/55 15s on the rear and leaving the 195/50s on the front make any performance/handling problems or issues?

Post Tue May 16, 2006 8:41 am

No problems, why not put them all round?

Post Tue May 16, 2006 8:55 am

it will screw up your speedo for starters.

Speedometer Difference: 5.302% too slow
Diameter Difference: 5.03%

www.1010tires.com
Warning any more than 3% and you run the risk of brake failure

Post Tue May 16, 2006 10:48 am

I have been thinking of putting them all round - they won't rub on any fenders? The suspension is all standard.

Post Tue May 16, 2006 10:50 am

205/55 is the proper sized tyre

Post Tue May 16, 2006 11:02 am

Sorry I mis-read your post, yes the profiles need to match else the wheels diameter will be incorrect and as Simon said cock up the speedo and effect the handling to a degree.

Post Tue May 16, 2006 11:23 am

you can run different sized tyres front to rear.. its the rear ones that dictate the speedo reading so putting them on the rear will make your speedo read correctly again and restore the original final drive ratio

Post Tue May 16, 2006 11:28 am

Jhonno wrote:you can run different sized tyres front to rear.. its the rear ones that dictate the speedo reading so putting them on the rear will make your speedo read correctly again and restore the original final drive ratio

good point

Post Tue May 16, 2006 3:41 pm

I think I might put them on the rear first, to sort out the speedo reading etc. Another quickie:
Should there be very little clearance between the front strut assembly and the tyre wall, as I had to move my front tyres to the rear as they were rubbing against the strut. I know that my front control arms are worn, could that attribute to the tyres touching the strut? How can I overcome that problem otherwise?

Post Tue May 16, 2006 4:00 pm

should be plenty of clearance.. what wheels are you running?!

the control arms wont wear.. the bush or the ball joints will tho btw

Post Tue May 16, 2006 4:55 pm

Sorry, my bad. I know the control arm bushes are worn, ball joints have all been replaced. Tyres are Conti Eco Contact 195/50 15. Any other suggestions?

Post Tue May 16, 2006 5:14 pm

Wookie wrote:Sorry, my bad. I know the control arm bushes are worn, ball joints have all been replaced. Tyres are Conti Eco Contact 195/50 15. Any other suggestions?

What about the size of the wheels the tyres are fitted too ?

Whats the offset ?

Post Tue May 16, 2006 10:13 pm

I must be honest and say I don't know what the offset is. I cannot even get a finger in between the tyre and the strut. Saying that, even with the spare wheel (original steel rim) the clearance is not very much more. Any ideas?

Post Tue May 16, 2006 10:57 pm

Sounds like the wrong offset

Post Tue May 16, 2006 10:57 pm

You need to know the offset of the wheel, it will be there somwhere. Probably on the back of 1 of the spokes, it will be an ET number

iirc they should be a ET25 on e30's

Post Wed May 17, 2006 7:10 am

I'll jack her up and take a look at the wheels...

Post Fri May 26, 2006 2:03 pm

I checked the offset on the rims - it is 40. Must I change the rims or is there an easier alternative?