This is now week 3 I have been delaying the order of some tires. I dont see much consistency between the 17" and 18" stock rear tires so I will ask you all.

Im getting a 19" rim and must run a 255 or 265 (dont ask).

Which is more suited? 255 35 19 or 255 40 19? I cant find a 265 that fits so lets just stick with the first 2 choices.

I can run Potenzas with the 40s but only Proxies with the 35's.

My only question is WHICH size, not judged by tire TYPE but by tire SIZE. Please consider I have stock 17s. Keep in mind stock 18s are apparently DIFFERENT. (WTF!)

Thanks
Scott

 

hmm k.

 

40-Series. If only for ride quality. I think looks between 35-Series and 40-Series are negligible.

 

Ok i thought so too, then i looked at the options.

Since i started with a 17" setup the overall diamater is as follows

17's= 26.3in
19" 40s= 27.0in Thats bad if comparing to the 17s
19" 35s= 26.0in Thats good when compared to the 17s


When comparing to stock 18s the story changes

18's= 26.7 in
19" 40s= 27.0in Thats good when compared to 18s
19" 35's= 26.0in Thats bad if comparing to 18s

See it goes either way!? Depends on what Im comparing it to. So you still think the 40s?

THanks
Scott

 

ONE QUESTION..... Do you want your car to be slower off the line but rev lower when cruising OR do you want your car quicker off the line with lower top end. IF you go with the 35, you will have quicker acceleration...If you go with the 40 you will have slower acceleration....Also, do you plan on lowering your car? If you don't, you may want to go with 40's for looks... I am lowering my car before I change my wheels...Then I plan on going with a setup that is slightly lower(smaller) than stock for better acceleration....
Jason
NJ

 

Good thread!

My question is if it matters if I started with 17" (I did) or 18"? I do not know if the ECU is program different if you had stock 17" tires vs 18" thus accounting to ABS etc for different stock rolling diameter. If not, my bet is the stock track model was set up for more optimal performance and I should use that set up for trying to calibrate my new tires to stock rather than using my 17" stock set up as a referance point.

I am in the same situation, I want to either get 265/285 ft/rear tire combo or 275/295. The 275/295 calcs out to be better suited in a 35 series tire when calibrating it to stock diameters (hard to get a good selection of 265/285 tires in all brands). I wish it was 40 series for a better ride. I know the series is a percent of the tire width so being these are bigger tires, the width increases. I just think going 40 series looks great just like 35 series but when you go 35 series, it gets to the point that there is not much there to protect the wheels itself.

If I am not looking at it clearly, please comment.

Jeff

 

IMO, I would base it off what you have now.. I doubt that the ECU is programmed different, but your butt dyno is. The 18" setup is taller overall then the 17" setup, thus making it slower off the line. Also, if you are looking for a little more comfort or protection for your rim, then you may want to go a 40 series. But. just remember , bigger the tire(wider and taller), the HEAVIER it is. This all goes back to unsprung weight. Also going that wide, 275/295 is probably not that important unless you plan on giving your car another 100 HP or so...... All this from me and I am still undecided on my setup. If I go with 18's, then I'll probably run a 245/40 in the front and either 255/40 or a 275/35 in the back. If I go 19's, then a 245/35 in the front & a 255/35 or a 285/30 in the back. I would like a 265 in the back but not to many tire choices..

Jason
NJ

 

The guys at HRE told me the HRE's are not the lightest wheels but are stilll lighter than stock and that the bigger tire wt is mostly negated by lighter wheels and when they drove the car for a week, it did not seem slower. I hope they are correct in their accessment.

Jeff

 

I believe the analog speedo is calibrated for the 18's anyway. So, moving up in overall diameter will, if anything, make your analog speedo more accurate.

Whether or not you'll notice slower acceleration is purely a function of if you want to drag race people a lot. If you do, then maybe the 35's are better for you. I really think that the difference between 35's and 40's aren't enough of a factor to negate the effect of drivers in a drag race.

I would take ride quality over the small change in acceleration. The statement about lowering the car is also something to keep in mind.

Good luck.