Tyre size 225 50 17 to 215 55 17 ?

[nick heppinstall]

Bit of a panic here so starting a new thread. Local tyre place can fit me some Nokian WR's for £100+VAT.

They are 215 55 17 though. Current tyre size is 225 50 17.

Would this be OK ?

Would I have problems with the insurance because of the rolling radius ?

Edited by nick heppinstall on Wednesday 22 December 15:12

[nick heppinstall]

Any Tyre gurus out their help me out. Need to call them tonight to say yay or nay really.

[redtwin]

http://www.miata.net/garage/tirecalc.html

Dab the sizes into the calculator and you will see how much of a difference (if any) there is in rolling radius.

According to the calc your speedo will read 1.8% lower than actual ie: it will show 60MPH when you are actually doing 61.1MPH. Diffs won't care as long as you are changing out all 4.

Edited by redtwin on Wednesday 22 December 15:31

[eybic]

google "rolling radius calculator" I can't see your insurers having an issue with it but if the rolling radius is too far out it could cause issues form the car (diffs and speedo)

[hornetrider]

It's only a 1.5% difference so no real harm done from a driving point of view - I suspect only your insurers will be able to answer your question though.

Edited by hornetrider on Wednesday 22 December 15:29

[weezb]

Can't say yay or nay; you may have problems rubbing in the arches and your speedo will be out, try this for yourself:

http://www.alloywheels.com/tyrecalc.asp

[nick heppinstall]

Mmm. Thanks all for that. I think i'll just make do and get the proper size sorted for next winter. Too many iff's for my liking....

[rb5230]

nick heppinstall said:

Mmm. Thanks all for that. I think i'll just make do and get the proper size sorted for next winter. Too many iff's for my liking....

probably the bestidea!

Its fine reducing the profile of the tyre slightly as you know it is not going to cause issues with the rubber contacting the body or suspension but to increase it could be a bit risky, which could be possible safety issues and the knackering of a new set of tyres.

Also it would put your speedo out the wrong way i.e you will be travelling faster than the indicated speedometer speed which makes it a risk whereby you could accidentally be speeding, again if you were reducing the profile the opposite would be true so you would have a margin of safety.

http://www.carbibles.com/tyre_size_calculators.htm...

[hornetrider]

rb5230 said:

nick heppinstall said:

Mmm. Thanks all for that. I think i'll just make do and get the proper size sorted for next winter. Too many iff's for my liking....

probably the bestidea!

Its fine reducing the profile of the tyre slightly as you know it is not going to cause issues with the rubber contacting the body or suspension but to increase it could be a bit risky, which could be possible safety issues and the knackering of a new set of tyres.

Also it would put your speedo out the wrong way i.e you will be travelling faster than the indicated speedometer speed which makes it a risk whereby you could accidentally be speeding, again if you were reducing the profile the opposite would be true so you would have a margin of safety.

http://www.carbibles.com/tyre_size_calculators.htm...

Given the difference is so small I can't see there being any rubbing issues. Also, seeing as it's a 1.5% difference and speedos overread by a few mph I'dsay in this case the speedo would actually be more accurate.

OP - I would advise a quick call to your insurer.

[rb5230]

hornetrider said:

Given the difference is so small I can't see there being any rubbing issues. Also, seeing as it's a 1.5% difference and speedos overread by a few mph I'dsay in this case the speedo would actually be more accurate.

OP - I would advise a quick call to your insurer.

it depends what car it is on, some cars standard kit run very close to the cup of the shock absorber especially when heavily loaded. Your 2nd point yes it would more than likely give you a more accurate speedo as long as the driver remember this when going through a speed trap, as i know a lot of drivers do a bit more as there is a 10% tolerance.