increasing the tyre width .....

[Hurdy]

I've ordered R888's at 225/45/17's for my 17" TDPR1.2's (when they arrive)

Here's the link to their advised fittings on alloys...

http://www.toyo.co.uk/productdetail.php?identity=products&product_id=18

As you can see the 225 section on the 17" tyre already has a 231mm contact width, which is better than the 18" equivalent.

TC - with your camber adjustable top mounts you can get away with the 235 section rubber, but be aware that it is only just on the bottom end of the width fitting for the alloys at 7.5" wide.

I thought really long and hard whether or not to get the 235's with an 8" alloy, but without the adjustability of the top mounts (like TC) they would have rubbed and I wanted to be fairly low and clear under full suspension compression.

[Poverty]

IIRC VW racing fit 235's to their mk5's?

[Hurdy]

IIRC VW racing fit 235's to their mk5's?

Yes, but you can't just give an arbitary width like that without knowing everything else about the car...

Alloy diameter and width?
Suspension set up - VWR use a varied amount of set-ups including using top-mounts for extra camber adjustment
How low they go with the suspension.

These all contribute.

[Poverty]

IIRC VW racing fit 235's to their mk5's?

Yes, but you can't just give an arbitary width like that without knowing everything else about the car...

Alloy diameter and width?
Suspension set up - VWR use a varied amount of set-ups including using top-mounts for extra camber adjustment
How low they go with the suspension.

These all contribute.

19 inch 8.5 width for road and track use.

[Hurdy]

19 inch 8.5 width for road and track use.

Then they would NEED that width to get the tyre to fit, any narrower and it wouldn't be a race car it would be a stretched tyred show car

[RedRobin]

....

As Hurdy says, the suspension setup has to be taken into consideration as well when changing tyre widths.

[Teutonic_Tamer]

Guys i am ordering my R 888's on Monday for my new track wheels which are 17in by 7.5J.

Is it safe to put 235 R888's on a 7.5j wheel that is only for track days. TT is alluding above to them being put on a daily drive, my worry is the tyre wall when flying round a track.   

I can't comment specifically on the R888s, but even when using the same 40 profile, changing from a 225 to a 235 is only a 10mm overall increase - so that is just 5mm per 'sidewall'.  And on my PS2s, they fill the standard Monza II rims everso slightly better - and should help if you have a propensity to park near kerbs.  Doing some calculations proves that 235/40 18s makes the GTI speedo more accurate than the standard 225s

And on the track - well if you make the same preparations as you would with the standard width tyres - then you will, or will not cross the same pit falls.  It all depends on your driving style. 

[Teutonic_Tamer]

IIRC VW racing fit 235's to their mk5's?

Yes, but you can't just give an arbitary width like that without knowing everything else about the car...

Alloy diameter and width?
Suspension set up - VWR use a varied amount of set-ups including using top-mounts for extra camber adjustment
How low they go with the suspension.

These all contribute.

And don't forget the rim offset too. 

[xxx_mojo_xxx]

"And on the track - well if you make the same preparations as you would with the standard width tyres - then you will, or will not cross the same pit falls.  It all depends on your driving style.  "

Please elaborate...

[Teutonic_Tamer]

how much difference will 235 tyres make on a 7.5 inch width alloy over the standard 225 tyre

5mm wider for each sidewall!

[Teutonic_Tamer]

Has anyone got snaps of 235/40/18 tyres on a GTi.... like to see how they look before taking the plunge.

Also, are there any compromises that I need to be aware of?

Just do it.  You seriously wont notice a difference, appart from a marginal increase in the safety margin for kerbing your alloys.  The standard width is 225 - which is millimetres, and 235 is just an inrease of 10 mm.

[gazbutS3]

the sidewall will be slightly higher too, 40% of 235mm instead of 40%of 225mm, which makes it about 4mm taller which will make your speedo read slighty under which isn't a bad thing really

[xxx_mojo_xxx]

Only concerns are
1) it doesn't look odd with extra rubber bulging out from the sides;
2) degrade road handling;
3) increase the risk of scrubbing inside the wheel arches (esp. on my sportlines)

May be I should go for 230s instead?

Is anyone riding on 235s on stock Monza 2s - keen to hear from them... 

[Teutonic_Tamer]

Only concerns are
1) it doesn't look odd with extra rubber bulging out from the sides;
2) degrade road handling;
3) increase the risk of scrubbing inside the wheel arches (esp. on my sportlines)

May be I should go for 230s instead?

Is anyone riding on 235s on stock Monza 2s - keen to hear from them... 

Yes, ME!  I got one axle set of 225, and the other axle is 235.  They don't foul on anythhing, they certainly dont degrade the handling, and they dont look odd either!

[RedRobin]

Is anyone riding on 235s on stock Monza 2s - keen to hear from them... 

Yes, ME!  I got one axle set of 225, and the other axle is 235.  They don't foul on anythhing, they certainly dont degrade the handling, and they dont look odd either!

....235 on the front or rear?

Any particular reason you are riding this way?