First things first!

Only wheels for an MGF or TF will fit, because they have a pcd of 4x 95.25 Other MGs tend to have 4x100.pcd.

As to fitting 17s or even 18s, if you fit appropriate profile tyres so you don't increase the overall diameter of the wheel/tyre you can fit them. if you can find them with a pcd of 4x95.25mm that is.:lol;

David Aiketgate;16784 wrote: Only wheels for an MGF or TF will fit, because they have a pcd of 4x 95.25 Other MGs tend to have 4x100.pcd.

Um, MG maestros and montegos are MGs as well!

Also TR7s and hearlds amoungst others are 4x95.25 or should that be 3 1/2 inch?

CJJ;16778 wrote: A bargain. I might try 17s in the future, but more worried they will rub.

Rub as in rubbing the wheel arch?

Aha. I meant an MOT type inspection.

Anyway. A failed MOT doesn't over rule an existing MOT. This is why you are allowed to MOT before it is due. If it fails you still have time to fix it before the MOT is due.

But you can only test it 2 weeks (IIRC, might be 28 days) before the old MOT expires to take advantage of this rule, any earlier and it over rides the pre excisting MOT.

Just been comparing tyre/wheel combinations - a 205/40/17 has only 0.4 inch diameter increase from a 205/50/15.
The 16 inch variants 215/40/16 are actually slightly smaller (0.3 inch) diameter than the 205/50/15.

David Aiketgate;16794 wrote: Just been comparing tyre/wheel combinations - a 205/40/17 has only 0.4 inch diameter increase from a 205/50/15.
The 16 inch variants 215/40/16 are actually slightly smaller (0.3 inch) diameter than the 205/50/15.

Ok so I am an idiot...what does this mean exactly?

FreeKernow;16808 wrote: Ok so I am an idiot...what does this mean exactly?

In effect, any increase/decrease in diameter will increase the rolling circumference of a wheel. This will effect gearing, and crucially, will effect any error on your speedometer.

As an extreme example, if the rolling circumferance of your wheel were twice as big as normal, the wheel would cover twice the distance for every revolution. This means your odometer would read only half what it should, and your speedo will say you are doing 30 when you are doing 60.

Most normal packages are within the allowed error of the speedo. I believe speedos are allowed to over read by 10%, but not under read.

Oversized rolling circumferance will up your gearing too, which will kill your acceleration.

Here is the list of what wheels where on what MG's, as far as I am aware they are all interchangeable... As for what you need to do to upgrade to 17" I really dont know..

http://www.mgf.ultimatemg.com/group2/suspension/wheel_options_for_the_mgf.htm

To upgrade in size you need to lower the profile of the tyres you fit.

Some good info here http://www.tyres-online.co.uk/techinfo/alloy.asp about halfway down, although the rest of the info is good too.