z ya Posted December 2, 2001 Share Posted December 2, 2001 Do you guys think that a 275/40/17 is a better fit on a 9" wheel or a 255. I know the 275 will have a slight buldge and the 255 will most likely have straight sidewalls. In the rear what would look and perform better all around? Quote Link to comment Share on other sites More sharing options...
CruxGNZ Posted December 3, 2001 Share Posted December 3, 2001 Do you have coilovers? Fender flares? I think 255's are a straight sidewall too with a 9" wheel. I'm guessing you have coilovers unless you are using a different backspacing with flares if you are going over 255's. I don't have my 17's yet so I couldn't help you with the looks part for the tires, but the way I see it, is if you can fit more meat under there, go for it. You will just be loosing a little performance with the side wall flexing during cornering. Am I right? Can someone else chime in and give their 2 cents too? !M! Quote Link to comment Share on other sites More sharing options...
johnc Posted December 3, 2001 Share Posted December 3, 2001 From a tire performance standpoint, you want the wheel width equal to or wider (up to 1") than tread width. Both Rudy from Kumho and Jeff from Hoosier have told me that repeadedly over the years. Your 255 tires should probably be on 10" wide rims and the 275s need at least 12". I suggest you install a set of 245s on the 9" wide rims. Quote Link to comment Share on other sites More sharing options...
fl327 Posted December 3, 2001 Share Posted December 3, 2001 So , I guess what I am after is max performance in a staight line with road race looks.[/QB] i think that setup will exaggerate the wheelhop associated with drag racing with an irs, when i was running low profiles205/55/15, it would hop a whole lot more than the 235/60/15's i run now, now it will shoot out with very little hop, but i dont launch it that hard anymore, there is a reason drag racers run the big sidewalls, and there are reasons that autoxers like small sidewall, the small is good for cornering, and the big is good for making me the king of import street racing. Quote Link to comment Share on other sites More sharing options...
fl327 Posted December 3, 2001 Share Posted December 3, 2001 ps. youve got the flares, run a 295/40/17 player. Quote Link to comment Share on other sites More sharing options...
johnc Posted December 3, 2001 Share Posted December 3, 2001 Well... the road race look IS wheels wider than the tires. Check out the repeats of the ALMS Petite Le Mans on Speedvision. But for drag racing, you want the wheels narrower than the tread so you can get more sidewall flex. So, maybe the straight sidewall is where you want to be. Also, be aware that tire tread widths vary even though the same tires might be listed as 255s. Quote Link to comment Share on other sites More sharing options...
fl327 Posted December 4, 2001 Share Posted December 4, 2001 thats what i was hollering right? tires wider than the rim for drag big sidewalls, way way way wider, fatman. and then for autocross skinnier than the rim so that you get that tight sidewall, good for cornering, great for cornering. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 4, 2001 Share Posted December 4, 2001 While we're on the subject (hope you don't mind me "borrowing" this thread z ya) what's the widest I can go on a 15x6.5 rim? I was planning on running 225/50/15 tires. Can I go wider or would the sidewalls bulge too much? Also wouldn't tread life be adversely affected by all the resultant flexing? Quote Link to comment Share on other sites More sharing options...
Owen Posted December 4, 2001 Share Posted December 4, 2001 I have 245/55-16 on my 16x9 wheels. Car isn't running so can't say much except for the sidewalls are pretty straight. Have 225 on the front and the tires are stretching, makes them look like donuts. Owen Quote Link to comment Share on other sites More sharing options...
z ya Posted December 4, 2001 Author Share Posted December 4, 2001 Who makes the 295/40/17's??? Quote Link to comment Share on other sites More sharing options...
johnc Posted December 4, 2001 Share Posted December 4, 2001 I've seen 225/50s on 6" wide rims but that was for an autocross application. 225/50s need an 8" wide rim although lots of Z ITS racers run 225/50s on 7" rims. So, my guess would be that the 225/50s are a little too wide for the 6.5" rims. I would run 215 or 205s on 6.5" wide rims. BTW... the different in performance between 225 and 205s is not that great (and probably not noticeable) on a street car. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 4, 2001 Share Posted December 4, 2001 Thanks for the tip John. I suppose its because the 225s curve out so much, ir reduces the lateral contact patch to where it isn't much bigger than 205s? This wouldn't affect the longitudinal contact patch much though would it? I am looking to run ~400bhp and I'm pretty much limited to these 15x6.5 rims, so what would you suggest to get the most power down to the ground? Quote Link to comment Share on other sites More sharing options...
Modern Motorsports Ltd Posted December 4, 2001 Share Posted December 4, 2001 "I was planning on running 225/50/15 tires. Can I go wider or would the sidewalls bulge too much? Also wouldn't tread life be adversely affected by all the resultant flexing?(15x6.5 rims)" Omar, I ran 215/60/14's on 14x6's and they rolled a LOT, tons of body roll such that it unnerved me in my otherwise 'tight' car. Shortly after mounting them on my 14x6's I had my 14x7 slotted mags ready......they felt really good on 14x7's, nic'n'tight by my old definition (which might be soft by my now hard as nails preferences . Hard to say how they'd feel on a 6.5" rim. What's the intended use? It's not the tread life that you'd lose most on if your tread is too wide, it's more that your tire will flex/roll and car body will follow and thus you won't have an optimal/flat contact patch of which to make best use of your rubber (ie. less than optimal traction). I'd pick a 205 which would be nice'n'tight, you might get away with a 215 but it's like cams.....more is sometimes less overall. Quote Link to comment Share on other sites More sharing options...
z ya Posted December 4, 2001 Author Share Posted December 4, 2001 I have coilovers and I just orders flairs. I dont want the wheel sticking out more than the tire look. I want the road race look but and going to be doing alot more drag racing than anything else. My wifes 01 stang has 245's on 17x8's and the sidewalls are staight up and down. So , I guess what I am after is max performance in a staight line with road race looks. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted December 4, 2001 Share Posted December 4, 2001 Zya, I run 275-40-17 on the rear and Use a 9.5 inch wheel. I know that Bridgestone makes 285-40s in a 17 on the RE70 model. Be carefull when selecting a tire and double check to see what both the tread width AND the overall "TIRE" width are...they will be different. You should also check and see what the manufacturer will recommend as far as wheel width for their specific tire models. I also strongly recommend contacting the manufacturer for this...Most guys at tire shops aren't as knowledgable about the science of tires as they should be. Anyway, John C. is right, for the most part, but again, the variations in sizing between makes and models is stagering, so Check the manufacturers website or call them. My 275s fit my 9.5s PERFECT and my 255s (Up Front) almost look stetched to fit...defenitely the "Road Race" look. Mike Quote Link to comment Share on other sites More sharing options...
Andrew Bayley Posted December 4, 2001 Share Posted December 4, 2001 Before I discovered the wonderful realm of Drag radials, I slapped on a set of (ready for this?) 245/60/R14's on stock Datsun 6 inch rims!!! The front tires are only 225/60/R14's. I'm not sure what I was thinking when I did this. I wanted the most possible traction on the street without going to a drag slick. Of course, the winter after I did this, BFG announced the release of it's drag radial. Doh! Straight line traction with these tires is OK, cornering absolutely blows. Sidewall flex is worse than my Econoline E-150 conversion Van. I do not recommend this combination. I wanted to keep the tire tall enough so I wouldn't loose a bunch of ground clearance, like I did with the old 215/6014's. I really needed to just buck up for a nice set of 15 or 16 inch wheels at the time. Of course, I was fresh out of school and broke as a GM Electrical Body Controller. On the other side of the coin, I also run a set of 275/40/R17 on 8.5 inch rims. I personally think the 8.5 rim holds the 275’s almost perfectly. The sidewall is almost perfectly perpendicular with the rim face. However, this is a set of Michelins. My older BFG ZR1’s had an ever so slight bulge on them, but one would have to get real close to even notice it. Like everyone has said before in this discussion, tire size will vary dramatically per manufacturer. Bottom line, measure everything for your self. I had a certain Z owner, who was avid that an 8.5 could never hold anything wider than a 255, look in disbelief at my 275’s on the same sized rim. Sure enough, tread width measured out to right around 8.5 inches… even though it was advertised as a 275. Get out there and tinker around a bit. After all, that’s what we are all about! -Andy Quote Link to comment Share on other sites More sharing options...
johnc Posted December 5, 2001 Share Posted December 5, 2001 > I am looking to run ~400bhp and I'm pretty much > limited to these 15x6.5 rims, so what would you > suggest to get the most power down to the > ground? Power to the ground is more a function of tread compund than tread width. A narrower, stickier tire will give you more traction than a wider, harder tire. A good example is my Contour SVT. On the street I run 215/50-16 BFG gForce KDWs on a 7" wide rim and for the occaisional autocross I run 205/50-16 BFG gForce TA R1s on a 6.5" wide rim. The R1s are significantly faster but their tread width is 1" narrower (I measured them). Ideally you should shop around for two more used rims to run on the back of your car for drag events. Mount up a set of BFG Drag Radials and put them on the car when you're at the strip. For the street I would stick with 215/50-15. I did a quick search on Tire Rack and you can get Dunlop SP Sport 9000, SP Sport 5000, SP Sport D87M, Pirelli P7000, and Goodyear Eagle GA tires in that size. The SP Sport 9000 would be the best tire but the Pirellis are a deal at $114 each. Quote Link to comment Share on other sites More sharing options...
Guest tom sixbey Posted December 25, 2001 Share Posted December 25, 2001 - about cornering - a small profile is helpful with radial tires, but sometimes a small profile wont necessarily help you. look at formula cars... they dont have tiny profiles now do they? - the sidewall flex created by a higher profile will actually help you attain traction during cornering because of the heat created by sidewall flex in bias ply tires. i dont think you want this on the street though... Quote Link to comment Share on other sites More sharing options...
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