a few mk3 gti 8v questions about wheels and window

[Wayne]

Nope, to keep the speedo correct you would need 205/35/17

205/40/17 is close enough plus a lot cheaper and easier to find.

[gasketface]

worth a read http://www.golfgtiforum.co.uk/index.php?topic=216424.0

if your original tyre size is 205/50/15 and you put 205/40/17's on then the total diameter will increase by 10mm which will in effect put your speedo out

You can use this tool to see what i mean :- http://www.etyres.co.uk/tyre-size-calculator

If you put bigger wheels on without lowering the car will be higher,handling will therefore be worse and it will of course look like an off roader 

[andy_k]

Nope, to keep the speedo correct you would need 205/35/17

205/40/17 is close enough plus a lot cheaper and easier to find.

3% out by my reckoning - that's no close enough, that's the difference between not getting nicked for speeding and 3 points on your licence

Why mess around cutting corners and saving a couple of quid just for cosmetics?

[Wayne]

205/50-15         4.0in  11.5in    23.1in         72.5in        874        0.0%
205/40-17         3.2in  11.7in    23.5in         73.7in        860        1.7%

I had them on my mk3 and against GPS it was not far out.

[andy_k]

215/40/16 gives approx 886 revs per mile

205/40/17 gives approx 860 revs per mile

Your speedo will read just over 3% slow.

[Wayne]

215/40/16 gives approx 886 revs per mile

205/40/17 gives approx 860 revs per mile

Your speedo will read just over 3% slow.

So @ 70mph by my maths is + or - 2.1 mph so if you were caught @ 73mph I doubt they are going to throw the book at you, I believe guidelines are a 10% margin of error depending on the limit.

[andy_k]

Of course, that depends on your speedo being accurate

You may or may not have a 10% margin for error (depending on which force stops you) but why take the chance?

Your gearing would also be 3% out but hey, what do VW know about stuff like this?

[boneybradley]

2.5% is about maximum you can go to and according to etyres the diff is about 1.7%.

I don't see the issue with running 205/40x17

[Foreveryoungaus16v]

No issue, just won't perform and handle as good as 16

[CraigBest]

My car is on 17s tho not thru choice and the rides not that bad although it is lowered slightly. The speedo seems fine but that's going by those digital speed readers on the roads and what the car says matches it.