After much fine advice from you guys, I have now found a set of wheels with the correct offsets and sizes and put a deposit down too.

Please can I have advice on tyres now based on the following:

8 x 17 Front
9.5 x 17 Rear.

I have a C4, so appreciate that the rolling radius from front to back needs to be the same for the diff. I would rather avoid the tyres looking like balloons, would rather have a little stretch without compromising the handling if the tyres are over-stretched. What's the best solution??

Thank you in advance

Matt

 

I would stay with the factory sizes: Front - 205-50, Rear - 255-40.

Though your widths are not the C4 factory spec, which is 7Jx17 w/ 55 offset and 8Jx17 w/ 52 offset. BTW the 3.3 Turbo is 7Jx17 w/ 55 offset and 9Jx17 w/ 55 offset and the Carrera RS is 7.5Jx17 w/55 offset and 9Jx17 w/55 offset; all with the same tire sizes.

 

You don't mention what the offsets are, but Your 17" tires should have a lower profile, than the stock 16" tires, so you shouldn't exceed the 6% radius difference. You can easily fit 225's in the front, and 245's in the rear with an offset of 55. I did this, and added 5mm spacers to the front (to prevent tire rub at turn in) and to the rear, to give a little more space to the oil line.

 

Thanks for the replies guys.

Fronts are ET49 and rear are ET52 if this helps.

So on an 8" front - 215/45/17
9.5" rear - 245/40/17

In principle, how does this sound?

I'll make sure that I post some photos once they're safely on

 

I would go 225/40/17 front and 255/40/17 rear - but you need to look at the specific tire specs are for each tire. You need to know what the tire max width is and the tread width plus diameter - so you can figure out if you can run the tire. Some wider tires may require an additional spacer or steering stop washer. I run 225 frt ( 7.5 inch) and 275 rears (9 inch) with 15mm and steering stop on front and 18 mm spacer rear.

 

225/45/front will run no proble as will 255/40/17 rear with that offset. Factory is 52 front so your fronts will actually sit out 3mm further so suspension clearance should not be an issue.
I run 235 or 225 front on same size rim and 235 or 265 rears with no problems.

I'd go at least 225 front to help with the understeer.
ie a 205 will give sweet steering feel but with the much wider rear rubber you will have heaps of understeer.
FWIW, I highly recommend Dunlop Z1 Direzza tyres if you don't do heaps of kms. Awesome grip.,

 

I'll take the advice and go 225/45/17 and 255/40/17 then.

The rolling radius is virtually the same (a 0.24% diameter difference) and the 225s are suitable for a 7-8.5" wheel, the 255s are suitable for 8.5-10" wheel, should be perfect.

Thanks for your help.