chrisc751

so im currently thinking of running 315/35/17s in the rears and got 18x8 for my fronts..thinking of running a 245/35/18...

anyone happen to know if that will trip my active handeling and traction control? the rears would be 25.7 and the front would be a 24.8 or even running maybe a 245/40/18?

Boostaholic

TRSCobra

I've been running a 315/35r17 rear and a 225/40r18 front on 18x7 wheels for several years now and never had any issues with TC/AH. Trick is to keep the front diameter a hair smaller than the fronts similar to how it came from the factory.

blaSSt

Height ratio of the tires is what matters. Factory R/F ratio is 1.04 and the computer is normally happy as long as you stay between 1.01 and 1.08, higher or lower ratios are where you can get into computer issues. The setup you are considering, 315/35/17 rear 245/35/18 front would be 1.04 and should be no problem. The 245/40/18 would have a 1.00 ratio (front and rear same size) which is more likely to be a problem.

chrisc751

Now how are u getting the 1.04? i assume im doing it wrong im getting the .9 by doing 25.7-24.8 = .9 im assuming im doing something wrong with my calculations. reason im asking is i just saw hooser makes a 335/35/17 which would be a 26.2 and i feel like the extra width would help me on the street but dont want abs problems or have to buy new front tires if i switch setups

Apocolipse

Ratio...not differential

chrisc751

care to explain some more?

Apocolipse

Ratio is division not subtraction. 25.4 ÷ 24.8 = 1.024

chrisc751

thank you. that makes alot more sense. so being the 335s would put me at 1.06 i should be fine since im between the limits

Apocolipse

That is correct

HOXXOH

If your street driving consists of fast corners, wide tires work best on both front and rear. If you are wanting straight line acceleration traction, then extra width tires are not an advantage, unless you have 550-600 whp or more and are willing to run very low tire pressure to create a longer footprint. The footprint length, not the width, is the key to forward acceleration.

chrisc751

reason i wanna go with the 335s are its a little taller tire sitting right at 26.2 over the 315s that are 25.7.
ive been running a 335/25/20 on mickeys and was able to get a 1.6 60ft. manual heads/cam car. that messured out to be a 26.6 tire
Setup i just picked up already has 315s on there but are in need of replacement. i dont wanna go to a 28in tire with the stock gearing i have and feel the 335s are my best option to bump up in size
car also will be on a 175 shot shortly. think the hooiser 335s would be my best option

HOXXOH

Things to consider:
Tire/wheel weight -- Your old MT 335/25/20 were 35# plus whatever ~12" wheel -- a Hoosier 335/35/17 is 27# plus the 12" wheel -- a Hoosier 315/35/17 is 26# plus a 9.5 or 10" wheel.

I've seen stock Z's with only a CAI on 275/40/17 (21#) with a C5Z front 9.5" wheel (19#) cut low 1.5 60ft times. My LS3 bolton with the same tire/wheel does high 1.4 times. Are you seeing the difference the weight makes?

Tread width vs height -- MT was 11.2 vs 26.6 -- Hoosier 335 is 12 vs 25.9 -- Hoosier 315 is 11.5 vs 25.6 -- and for ref a Hoosier 275 is 9.8 vs 25.7.
Did you notice the heavy MT has the shortest sidewall, while the Hoosiers have more sidewall and nearly identical height? How about the narrowest tread getting the quickest 60' times?
Of course if you use a 150 shot from the line, you'll need the 315's at a lower pressure to get the best footprint. A slight delay on the 150 shot can avoid instant wheelspin.