Need help with tire sidewall aspect ratio

[stangGT97]

The stang is in need of some new shoes, and I was hoping to put a slightly wider tire on my stock 8" wheels. I'm looking at the BFG KDW tires, in a 255 width. I know the stock tire specs are 245/45r17, but what should it be with the 255s? I can get the 255/40r17s or 255/45r17s, which would you recommend? For some reason, the tread patterns on the two tires are different, and I really like that of the 255/40 tire. The 255/45s are going to be taller than stock, and the 255/40s will be shorter... I'm just having trouble deciding which way to go. Thanks for your help!

 

[Gearbanger 101]

Go with the 255/45/17's. The increase in height is minimal and won't throw things out of whack, or give your car that 4x4 look like running a set of 40-series tires would.

 

[Pennywise2]

I have the 255/45/17's on my stock wheels and they are perfect.They
are a tad taller and fatter than the stock 245/45/17 tires.I like them alot
better personaly.Also as far as tire selection go's get Goodyear Eagle F1
GS D3's they are the best tire I ever had they stick like glue you will love them.

 

[Red2000GT]

Since you're lowered 2" then the slightly lower aspect ratio of the 40 series won't look bad,I'd say go with the 255/40/17's.

 

[Stang|ess]

tread pattern is different because you're probably looking at 2 different tires. there's the KDW, then KDW2.

I say go with 255/45 .

 

[tomustang]

http://www.miata.net/garage/tirecalcold.html

 

[stangGT97]

tread pattern is different because you're probably looking at 2 different tires. there's the KDW, then KDW2.

I say go with 255/45 .

hah, yeah you're right, for whatever reason I never saw the KDW2 labels.

Pennywise, I'd get the GS-D3s but they're a little out of my range right now, so thats why I'm getting the KDWs. Thanks for the suggestion though, maybe next set

Tom thanks for that link, the sidewall height isnt too different between the two. I think I'll pick up a speedcal to correct just to be sure

 

[hognutz]

255's will fit on the 8's. I would just stay at 45 series. if you go down to 40's series you will be putting extra miles on your car if you don't reflash for the correct revs per mile.

 

[CdnNavybob]

hah, yeah you're right, for whatever reason I never saw the KDW2 labels.

Pennywise, I'd get the GS-D3s but they're a little out of my range right now, so thats why I'm getting the KDWs. Thanks for the suggestion though, maybe next set

Tom thanks for that link, the sidewall height isnt too different between the two. I think I'll pick up a speedcal to correct just to be sure

I've been running a set of KDWs for nearly 3 years now (six months out of each year, plus autocross). They are an awesome tire for the money. Yes, the GS-D3's are one of the best tires out there, but they also cost a hell of a lot more. My KDWs allowed me, a fairly inexperienced autocrosser, to beat a BMW M3 with a much more experienced driver around the track 4/4 laps in heavy rain. Considering how bad he kicks my butt in the dry, I think that says a lot about the tire.

 

[loosescrew79]

I would say go with the 40 series. With your car being lowered 2 inches I think it will look good.

As far as the speedo being off, you could adjust that with what ever you used to correct it from the gear change.

 

[stangGT97]

I would say go with the 40 series. With your car being lowered 2 inches I think it will look good.

As far as the speedo being off, you could adjust that with what ever you used to correct it from the gear change.

I don't think the speedo was ever corrected This car is a lemon and a half, you wouldn't want to know some of the things I found out about it after bringing it in for a clutch job. I'm just trying to do the best with what I have.

I will be raising the car back up a bit, but I still think the 45 series has a little too thick of a sidewall already, so adding to it probably won't look so good. I actually calculated out the sidewall height for stock, and the two 255 options I have
Stock - (245/45) = 110.25mm
255/40 = 102mm
255/45 = 114.75

So the 40 profile will shave a total of 1.65cm off the sidewall. The 45 series will add 0.9cm. And I can't decide which way I want to go I don't want truck tires, and I dont want elastic bands...