ls3powerz51

Sorry guys but i would like clarification before i spend $600-$700 on new tires.. So I am having ABS issues since i put MT ET Street 2 Drag radials on and was wondering if I go to a different size on the fronts, if they will work like stock. With my current size, the ABS goes into ICE mode a lot quicker and activates easier than usual and causes me to slow down a lot less. TC/AH works fine on current setup. I cant find anyone running front size 265/40-18 so i am just curious if the new setup below will work and not look too bad.... I like the ET Street 2 and dont want to go back to NT05r. The 305/35-19 diameters are way different in the MT Et street2 then the NT05R.


Stock Tires Diameter
245/40-18 25.7
285/35-19 26.9
Difference 1.2 1.046


Current (ABS Issues)
265/35-18 MPSS 25.3
305-35-19 MT ET Street 2 27.9
Difference 2.6 1.102


Before (Worked fine)
265/35-18 MPSS 25.3
305/35-19 NT05R 27.44
Difference 2.14 1.084

New Setup (Hoping this works)
265/40-18 MPSS 26.3
305-35-19 MT ET Street 2 27.9
Difference 1.6 1.06

Thanks and i'm sorry this has been beaten down but I cant return tires if I get them and have more issues.

RicK T

I can't provide a definitive answer but I'll say what's on my mind, maybe it will help others think about your question.

I guess you know the target stagger ratio front to rear is front diameter x 1.04, but I don't know how much wiggle room is built in before the computer has a problem.

So -

I'm surprised that you didn't have problems with this setup;

Before (Worked fine)
265/35-18 MPSS 25.3
305/35-19 NT05R 27.44
Difference 2.14 1.084

I would have said that a 1.08 difference would not work but apparently it does, at least it did for you.

So I have to believe that your proposed new setup, with a 1.06 ratio, would also work fine as it is closer to the target 1.04. FWIW, if you had asked the question about this ratio without the other info, I would have "guessed" that it would work, but nothing more than 1.06. I will count your experience as a learning experience for me.

Let us know what happens. TIA

z06scentair

Dealing with the same issues, only in 17/18 sizes

245/40/17
24.6"

345/35/18 mt et ss
27.8

Thinking of purchasing a 255/45/17
26.1

irok

what type of ABS issues are you having?I run 305/35 19 MT street ll and 295/45 17 MT street ll with stock size fronts with no issues.because of different tire compounds between front and rear the car I believe will stop quicker with the stock rubber on it.

TKOGTO

Read https://www.corvetteforum.com/forums...m-solo-dl.html
Post #9 reiterates your issue albeit without providing the ratio delta at which the problem begins. My guess is your experience gives a pretty good indication: 1.05 good, 1.08 good, 1.10 not good. Also, I recall reading somewhere else that a ratio change of 5% or more would create issues. This is in line with your results.

ls3powerz51

Soooo..... To help anyone in the future. I changed my front tires to the 265/40-18, which was closer to the 1.04' ratio, and its now working perfectly.

I'v had tires that wouldn't let me go over 100mph. I could then deactivate the AH and be okay. However, you can't deactivate/defect ABS. I wasn't having any AH issues so I figures that there was something wrong with ABS/Brakes. I changed all my calipers, rotors, brake pads, and added SS brake lines and still had issues.

When i was breaking hard, my car would just go into "ice mode" or pulsate the brake so bad it wouldn't stop effectivly. I ended up in the middle of an intersection at a stop light when it turned to red and i actually braked suddenly instead of flooring through the light. lol My brakes were very scary at highway speeds too. I came off an exit one day while braking and added a little more pressure to slow down quicker, and the front brakes flipped out and pulsed back and forth very hard. I could feel my wheels on the exit at 60mph goes left and right so hard while braking.

So lesson learned. I can now brake and stop on a dime before ABS kicks in. On wet roads, the ABS acts normal and works like new. So i hope someone can learn from this if they are having similar issues.

cclive

I just wanted to clarify that there are three systems here that you are dealing with and not just the two that you mentioned. Active handling, Traction Control and ABS. All three use the ABS system to activate brakes on individual wheels. If the front and rear tires are not close to the stock ratio, the Traction Control system can think that the rear wheels have lost traction and are skidding on the pavement from either too much power or too much engine braking. Also, the ABS system can kick in simply because of a substantial difference in braking traction from front tires to rear...independent of any size difference between them...so in this case the tire sizes wouldn't be involved. Remember that the ABS computer is expecting the front and rear tires to be the same model with the same friction characteristics...any change from this and the system may act strange under heavy braking.