Tyre size help

Hi I know a basic question, however my RR needs some new tyres it currently has 255/55/18 on the car, however I have been given two new tyres which are 235/60/18 can I fit these two on same axle ? And have the others still on the 255's ? Or do I need to get two more 235's and have same on all 4 corners ? And can the p38 run on 235/60/18 ok ? Or am I going to screw the car up ?

Thanks for your help everyone

Markcb73 said:

Hi I know a basic question, however my RR needs some new tyres it currently has 255/55/18 on the car, however I have been given two new tyres which are 235/60/18 can I fit these two on same axle ? And have the others still on the 255's ? Or do I need to get two more 235's and have same on all 4 corners ? And can the p38 run on 235/60/18 ok ? Or am I going to screw the car up ?

Thanks for your help everyone

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The 60 profile will affect speedo and also create a phenomenon where one pair of wheels will travel slightly further in each rotation. This isn't good for tyre wear, axles or transmission as that extra distance has to be absorbed somewhere! (I imagine it would be somewhat twitchy to drive )

The 235 will also most likely be too narrow to fit the rims correctly and thus I suspect would be dangerous. Wider tyres (within reason) are usually more common but you can't beat the right tyres for the rims IMO.

I'd stick them on eBay and put the proceeds to the correct sized tyre!

Your 235's will be running at 30.06mph when the 255's are doing 30.

This is sufficient to cause damage over a period of time.

Put them on front and pull the prop shaft, make it 2 wheel drive

Quick answer is no, you cannot fit different sized tyres on the same axle. Even if the have the same rolling radius, unless they are emergency spare space savers.