Dunlop SSR on a GT3 - size advice
Discussion
Can anyone tell me what tyres will fit here, I need a full set of Dunlop SSRs for my Mk1 GT3, but the correct sizes aren't available.
Normally the front tyres would be 225/40/18 on an 8" wide rim, but these aren't available, so have the choice of:
235/40/18
or
245/35/18
Funnily enough the 245 is actually a narrower tyre than the 235 at 251mm as opposed to the 258mm of the 235. What would the lower profile do to the handling/performance?
Would these tyres be too wide for a GT3 which normally takes 225 tyres - i.e. rubbing etc.
Normally the front tyres would be 225/40/18 on an 8" wide rim, but these aren't available, so have the choice of:
235/40/18
or
245/35/18
Funnily enough the 245 is actually a narrower tyre than the 235 at 251mm as opposed to the 258mm of the 235. What would the lower profile do to the handling/performance?
Would these tyres be too wide for a GT3 which normally takes 225 tyres - i.e. rubbing etc.
I don't knbow if this helps, but I had a similar problem with my 993 RS in that they only had 235s and not 225s in stock (of SSRs that is). I tried 235s and they have been fine. I get a bit of rubbing on full lock (eg parking) but this doesn't matter, also my car is very low compared to standard so this won't help.
I'm certainly no expert but have had some experience in changing tyre sizes recently and done a little research, so here goes...
Your current tyres, 225/40/18 have an overall diameter of 637mm
Changing to the sizes and profiles you've given will result in the following:
235/40/18 - 645mm +1.26%
245/35/18 - 629mm -1.26%
The general consensus seems to be that if you do change then you should stick to within 2% of the original diameter, which both of these do.
However, I've found that different makes of tyres can have very different overall widths - for example, I had 235/35/19 on my fronts which were Fulda's and they barely covered the rims, leaving them very succeptible to kerbing or also damage through potholes etc. However, changing to the "same" size in Michelin's has resolved the problem entirely. My point being that it may well be the case that the profile is subject to the same tolerances as the width, and so the above calculations possibly shouldn't be relied on.
I was about to say that this may not matter to you as you are looking (I think) to stay with the same brand, Dunlop, that should have the same standards through the range, but given what you've said about the 235s being wider than the 245s I don't know if that'll be the case either!
The other point to consider with widening the tyres at the front is this will probably affect the turn-in, but I would add that there are probably many more knowledgable people than myself to comment on this...
All my own humble opinion and I stand here ready to be corrected.
Hope that's of some help anyway.
Jem
Your current tyres, 225/40/18 have an overall diameter of 637mm
Changing to the sizes and profiles you've given will result in the following:
235/40/18 - 645mm +1.26%
245/35/18 - 629mm -1.26%
The general consensus seems to be that if you do change then you should stick to within 2% of the original diameter, which both of these do.
However, I've found that different makes of tyres can have very different overall widths - for example, I had 235/35/19 on my fronts which were Fulda's and they barely covered the rims, leaving them very succeptible to kerbing or also damage through potholes etc. However, changing to the "same" size in Michelin's has resolved the problem entirely. My point being that it may well be the case that the profile is subject to the same tolerances as the width, and so the above calculations possibly shouldn't be relied on.
I was about to say that this may not matter to you as you are looking (I think) to stay with the same brand, Dunlop, that should have the same standards through the range, but given what you've said about the 235s being wider than the 245s I don't know if that'll be the case either!
The other point to consider with widening the tyres at the front is this will probably affect the turn-in, but I would add that there are probably many more knowledgable people than myself to comment on this...
All my own humble opinion and I stand here ready to be corrected.
Hope that's of some help anyway.
Jem
ocho said:
By the way - I'm not particularly a fan of 996's, especially in red, but I'm loving yours!!!
Thanks ocho, there is something about the GT3 which makes it look that bit more aggressive, don't know if its the ride height or what, but I love it. The pic on my profile is a bit deceiving, the car is Zanzibar, which is a metallic red/orange, but seems to change colour depending on the lighting conditions...sometimes is can look this colour:
paulburrell said:
I've just ordered a set from Mr Tyre in Birmingham. They had both front sizes in stock but recommended going with the 245's. I'm no expert so took their advice and ordered them. Nice to see that they now have a limited number of the rear in stock. Total cost £535 delivered
what size rears did you get???
Paulburrell said:
Tiff
I got the 285 rears, if you need any get in quick as he only has a few left.
P.S. Are you the Tiff who works in the dental trade and knows Sean the builder with the back turbo?? If so Sean is just finishing putting a new roof on my house(at least part of it anyway)
Steve
yep thats me mate!
Tell sean Im going to a track day next friday (10th) at bedford. Its through Autocar.
Ill text him. You should try to come too.
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