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Author Topic: increasing the tyre width .....  (Read 21463 times)

Offline john_o

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increasing the tyre width .....
« on: June 16, 2009, 04:37:37 pm »
GTI Edition 30

standard is 225/40/18 XL

the easy option is to stick with this , but just for fun (I blame jonnyc for this...) I looked at 'options' using the tyre calculator at http://ejelta.com/



So I could run 255/35/18 or 265/35/18 quite easily, and I checked and at least Goodyear F1 Asymmetric are available in both these sizes...

Worth a punt ?
or just ruin the GTI setup/balance???
is there enough space on a std car to do this???
mmmmmmmm
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Offline mortygttdi

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Re: increasing the tyre width .....
« Reply #1 on: June 16, 2009, 05:26:37 pm »
Not quite sure you would be able to run any thing wider than a 245 with the risk of sidewall failure and also the risk of the tyre rubbing on the shock/spring I think a 265 would be very over the top any way and you wouldn't see the benifit to say a 235/40, Also if your running a set of pescara's are they not 7.5 wide cos that would limit your tyre choice down to a 235 at max? I might be just talking a load of BS but on my previous Focus ST225 I was running 235/40 on that and it stuck to the road like muck on a blanket.

Darren

Offline Hurdy

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Re: increasing the tyre width .....
« Reply #2 on: June 17, 2009, 01:01:11 am »
There are a couple of cars in the USA running 255 section rubber. It is possible, but you need to run a fair amount of camber to clear the arches, plus you'd need 8.5" wide alloys to fit safely. :smiley:

Jonnyc is running 235 section R888's which he measured at 240+mm for tread width.
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Offline john_o

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Re: increasing the tyre width .....
« Reply #3 on: June 17, 2009, 11:02:05 am »
cheers guys , so the rim width and clearance are an issue  :happy2:

Im wondering whether to go to 235/40/18 as every little helps BUT Im worried about the difference re triggering my ESP as Im only changing the fronts.
Be nice to try something different though.
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Offline tony_danza

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Re: increasing the tyre width .....
« Reply #4 on: June 17, 2009, 11:04:29 am »
Whilst a wider tyre on a small rim may improve traction, I'd be worried about how the sidewall performed on cornering - I could see it rolling a fair bit.
Sideways yo!

Offline john_o

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Re: increasing the tyre width .....
« Reply #5 on: June 17, 2009, 11:10:29 am »
indeed tony, with the 235/40 this concerns me (as the ratio hasnt changed).
however with the 255/35 if you can get it to fit its virtually identical to the original tyre for sidewall height.

what do you run on the track?
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Offline tony_danza

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Re: increasing the tyre width .....
« Reply #6 on: June 17, 2009, 11:27:29 am »
It's not the height so much, more the angle of the tyre wall. I think it would move around too much and be unpredictable, like a semi flat tyre??

I ran a 225/40/18 on a 7.5J - no probs.

Sideways yo!

Offline Teutonic_Tamer

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Re: increasing the tyre width .....
« Reply #7 on: June 29, 2009, 05:36:35 pm »
cheers guys , so the rim width and clearance are an issue  :happy2:

Im wondering whether to go to 235/40/18 as every little helps BUT Im worried about the difference re triggering my ESP as Im only changing the fronts.
Be nice to try something different though.

I have just put an axle set of 235/40 ZR18s on my standard GTI, with the standard Monza IIs.  When on the front, they actually make the speedo more accurate, on either axle, absolutely no issues with rubbing.  And you might find that 235s are easier to get hold of, as that is the most common size on virtually all modern Audis.  :happy2:

Don't forget to tweak your tyre pressures to cope with the different load indexes though.  :wink:
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Offline Teutonic_Tamer

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Re: increasing the tyre width .....
« Reply #8 on: June 29, 2009, 06:00:13 pm »
Whilst a wider tyre on a small rim may improve traction, I'd be worried about how the sidewall performed on cornering - I could see it rolling a fair bit.

The only time sidewall performance is questionable is when the sidewall is 'streched'.  Indeed, before this modern craze, the tread width was always wider than the wheel rim, rather than the other way round as is today.  Not the best of pics, but this shows that even OEMs are stretching!  All  :sick: IMVHO!
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Offline Msportman

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Re: increasing the tyre width .....
« Reply #9 on: June 29, 2009, 11:44:16 pm »
I'm running 235x 18 Dunlop D01J track tyres. Put them on this week on my Pescara's.
 They are ex VW Cup tyres and are superb for traction....they sit slightly fatter on rim being an 7.5j.
I used to run these on my BBS CH's on a 18x 8.5j rim and they were perfect....will review these later for these rims but initially they seem good....no clearance issues.

Ian
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Offline Janner_Sy

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Re: increasing the tyre width .....
« Reply #10 on: July 09, 2009, 07:48:15 pm »
how much difference will 235 tyres make on a 7.5 inch width alloy over the standard 225 tyre

Offline xxx_mojo_xxx

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Re: increasing the tyre width .....
« Reply #11 on: August 22, 2009, 12:14:38 pm »
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?

Offline bacillus

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Re: increasing the tyre width .....
« Reply #12 on: August 22, 2009, 12:51:20 pm »
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?

Why not just PM TT for some pics of his fitment?
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Offline Top Cat

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Re: increasing the tyre width .....
« Reply #13 on: August 22, 2009, 01:44:31 pm »
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.  :happy2:  :happy2:

Offline Janner_Sy

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Re: increasing the tyre width .....
« Reply #14 on: August 22, 2009, 01:52:29 pm »
225 R888s will give you a huge improvement, iirc i read somewhere on here, it might be one of jonnyc threads, but the 225R888 has a bigger contact patch than a 225 road tyre,