MidnightRacer Posted January 2, 2012 Share Posted January 2, 2012 I've been hammering the search functions and really am none the wiser. I have some new 18 inch rims for my car which are wider than stock and the current tyres have a fair bit of stretch on them. I'm looking at replacing all 4 and have found a lot of references to using a 245/40/R18 and a 275/40/R18 combo but calculating the sizes seems to make the difference way out at that. (about 3.7% as a pose to 2.7 on stock) From what I can figure a 245/40 and 265/40 would be a much better combination. (although thats slightly under at 2.4%) is anyone here running wider tyres on 18's and if so what are you running? I know the rears will wear faster than the fronts so will having a larger difference to start with be a better bet? Thanks Kev Quote Link to comment Share on other sites More sharing options...
MidnightRacer Posted January 2, 2012 Author Share Posted January 2, 2012 I might have just found the answer to this. It seems that 265/40's are very limited and bloody expensive! best pairing I can find are probably Falcon 452's on a 245/40 and 275/40 without going into crazy money territory! anyone running this setup on here? Quote Link to comment Share on other sites More sharing options...
Stew Posted January 2, 2012 Share Posted January 2, 2012 I run 245 and 285 with 30 profile rubber on my 20s, the difference is the same even if the diameter isn't. Loads run 235/245 and 275 with 35 profile on the rear of 19s with no issues. I can't see their being an issue. Quote Link to comment Share on other sites More sharing options...
Beau Posted January 2, 2012 Share Posted January 2, 2012 I think once the rear wheels have a larger diameter than the front you will be fine. The ECU will re calibrate it self. So once the rears are bigger there should be no problem but I wouldnt go down a size on rubber, get something to fill the arches, plus your speedo will be inaccurate. I run 265 35 19 front and 285 35 19" rear. Quote Link to comment Share on other sites More sharing options...
4RE Leather Posted January 6, 2012 Share Posted January 6, 2012 I had serious problems when experimentin . I never got into 3rd gear or above 40 mph. I think I started a long thread on the subject. I ended up with bridgestone protenza 050A 96Y all round. Rear 275/40/18 front 245/40/18 For some reason my car hated the OEM rear 245/18/45 on the Front and me putting 275/18/45 on the rear. I don't know why but RS Tyres at coulsdon (bless em) scratched there heads with that one. I think you guys gave me the above comvo that I am using now. What I did wonder was what was the widest width I can get on the 18" Rear Ray's? My mate has Ferrari 355 and he is running 245/40/18 on the front and 295/40/18 on the rear and it just feels so planted. Admittedly I spaced all 4 corners with 20mm's but I would prefer more rubber on the rear if possible without changing the wheels. Thenoname Quote Link to comment Share on other sites More sharing options...
Ekona Posted January 6, 2012 Share Posted January 6, 2012 Toyo (for example, easy website to navigate hence my use of them here for an example!) don't recommend anything over 255 on an 8.5" rim. I can't find the wheel size for OEM F355 rears, but if they're 10" then they'd be more than happy with 295 on the back. Did you try running the wheels with those tyres without the spacers? How much power are you putting down now? If you really need more grip from your tyres, you'll either need to consider larger wheels or moving to a better tyre: What tyres are you using now? Quote Link to comment Share on other sites More sharing options...
Sam Mcgoo Posted January 6, 2012 Share Posted January 6, 2012 My mate has Ferrari 355 and he is running 245/40/18 on the front and 295/40/18 on the rear and it just feels so planted. Hmmm.... I think the fact it feels so planted might not just be the size of the tyres. Quote Link to comment Share on other sites More sharing options...
ChrisS Posted January 7, 2012 Share Posted January 7, 2012 My mate has Ferrari 355 and he is running 245/40/18 on the front and 295/40/18 on the rear and it just feels so planted. Hmmm.... I think the fact it feels so planted might not just be the size of the tyres. I know it's off topic and I now that I should now better,but, up for my fav post for a long while. Quote Link to comment Share on other sites More sharing options...
Sam Mcgoo Posted January 7, 2012 Share Posted January 7, 2012 My mate has Ferrari 355 and he is running 245/40/18 on the front and 295/40/18 on the rear and it just feels so planted. Hmmm.... I think the fact it feels so planted might not just be the size of the tyres. I know it's off topic and I now that I should now better,but, up for my fav post for a long while. Quote Link to comment Share on other sites More sharing options...
nzr350z Posted January 7, 2012 Share Posted January 7, 2012 +1 on the PLANTED Ferrari,wouldnt expect any other Quote Link to comment Share on other sites More sharing options...
Ekona Posted January 7, 2012 Share Posted January 7, 2012 You'd be surprised, a 355 is old now and I'd expect a 350 to have a substantially better chassis, it's more the mid-enginedness of the Fezza that will make it feel more planted. Quote Link to comment Share on other sites More sharing options...
Dblock Posted January 8, 2012 Share Posted January 8, 2012 Not even in the same league. You'd be surprised, a 355 is old now and I'd expect a 350 to have a substantially better chassis, it's more the mid-enginedness of the Fezza that will make it feel more planted. Quote Link to comment Share on other sites More sharing options...
Ekona Posted January 8, 2012 Share Posted January 8, 2012 I wouldn't say that, the 355 isn't that much worse in terms of chassis, but tech does move on and the 355 is starting to feel its age now sadly. Great looking cars, and even better sound, but ageing albeit gracefully. Quote Link to comment Share on other sites More sharing options...
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