Tyre size - is this right?

[EdmundIJones]

Hi,

My new 206cc 2.0 (2001 Y reg) has different size tyres on the front and back.

The fronts are: 205x50 R16
The backs are: 205x45 R16

Is this right or should they all be the same size and some previous owner has messed it up? If it is wrong, what size should I be going for, ideally I'd like to keep the fronts or the backs and not change all as they have plenty of wear left.

Thanks
Ed

[shadow]

205x45x16 all round is the correct size, have you had any problems/ warnings. sounds like they were put on to sell the car.

[EdmundIJones]

Thanks,

No warnings or problems with the car, it's been very good, the clutch is getting old I can tell but appart from that a fine/cheap car I have to say.

Out of interest, if you mix different size sidewall tires between front and back, that would it lead too, i.e. the x50's are on the front and x45 on the rear. Would you get incorect distance/speedo values as the rolling radius is too big?

[GrandadMonkey]

With the 50's on the front the speedometer reading will be 3.5% too slow so, if your speedo was totally accurate in the first place, when your speedo reads 60mph you will actually be travelling at 62.1mph. However as most speedometers read a little fast yours will probably read about right on the non-standard tyres.

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

If the car drives ok I'd be tempted to leave them as they are and only change them when they've worn out. It might get picked up at MOT time though, or if you have to make an insurance claim, when it might invalidate your insurance. You could check with your insurers to be on the safe side.

[EdmundIJones]

I've come to the same conclusion but I'm thinking of putting the 44's on the front to be accurate and the 50s on the back until they need replacing.

[shadow]

if you are leaving them on leave them as they are 50's on the front, that way they will wear out before the rears so when you come to replace them you will end up with 45's all round.

[GrandadMonkey]

I understand what you say Edmund but I have to agree with shadow. You can easily check the accuracy of the speedo by using your SatNav if you have one (or can borrow one).

[tenpole]

My 2002 1.6 currently has 195 55 r15 all around. I don't know if this is the correct size but that is what are fitted.

[gazza82]

Check the handbook or one of the internet tyre suppliers like BlackCircles

[tenpole]

Nothing in the handbook. Have come across a 195 55 15 entry on the Michelin site for 206cc.

[GrandadMonkey]

My 2002 1.6 currently has 195 55 r15 all around. I don't know if this is the correct size but that is what are fitted.

Our 1.6 Allure has the same size as yours (fitted from new) 195/55R15. Continental Premium Contact. We replaced one tyre after a puncture with a Continental Premium Contact 2 with a slightly higher speed rating 85V. Otherwise it is still on the originals after 31,000 miles.

[tenpole]

Our 1.6 Allure has the same size as yours (fitted from new) 195/55R15. Continental Premium Contact. We replaced one tyre after a puncture with a Continental Premium Contact 2 with a slightly higher speed rating 85V. Otherwise it is still on the originals after 31,000 miles.

That is the information I wanted. I did wonder if the rims were supposed to have 185 55 r15 but had someone put oversized tyres on the wheels, not that they looked it.
I did have some significant wear on both front insides and wondered if this was due to an oversize tyre. I guess both camber angles are out.

[gazza82]

Tracking is probably out ... people change the suspension arms and don't get them reset

[GrandadMonkey]

We have traffic calming humps (speed cushions) in our and other Leicestershire villages that "chamfer" the inside of front tyres.

See

http://www.leics.gov.uk/index/highways/ ... part_4.htm

and find the speed cushions.

[tenpole]

I do have speed cushions along my road. I never wanted them but there is never enough information on the negative effects of speed humps on the consultation.