All else kept the same, more sidewall makes the tire more tolerant of pavement roughness and small bumps. Meaning that the vertical load at the tire treads varies less from one instant to the next, and with less change in vertical load there is less variation in forward bite. You might say that the average amount of grip is higher even though static grip remains about the same.

Taller sidewalls also soften the hit - make it take just a little longer and consequently a little less likely to completely overwhelm the available grip and put you into a full-blown case of wheelspin.

Wheel width also gets involved, particularly when taller profile tires end up on narrower rims even though the tire section width was kept the same.


Norm

 

To a point, yes. Lateral distortion and rotational distortion (where the angle that the tire tread actually ends up being "steered" to is slightly less than the amount that its wheel is steered in) both detract from cornering/handling behavior. Vertical tire flex is a different matter, but is not something the end user can tune without affecting the first two distortions.

Suspension geometry and the car's roll stiffness ultimately put a limit on how short you can go with the sidewall and still obtain more benefit. A short sidewall tire is generally more sensitive to the camber that it is forced to run at than a tall sidewall tire, and I suspect that you can also run into the matter of "average grip" laterally. BTW, "operating camber" varies - sometimes considerably - from the camber that you set at alignment time.


Norm

 

One question, did you change anything with your suspension at the same time you swapped wheels/tires? If you lowered your car, you may have chosen springs that are much stiffer in the rear, and depending on how much you lowered, you will have affected the weight transfer of the cars suspension, and therefore less traction from the rear at lower speeds.

Secondly, a taller or larger diameter tire provides more traction by increasing the contact patch. Also, with such a wide wheel and wider tire, it is very important to ensure your inflation is not too high, as the tire center will become the primary contact area until it wears down to become even across the surface of the tread.

 

I had the rims and tires put on before i had the suspension done..


currently im thinking the lack of traction is almost 100% caused by lower temps and summer tires compared to my previous all seasons since i thought the traction was alot better with the new tires when i 1st got them on,, it was summer at the time. I just didnt expect 70* to be considered too low for summer tires to preform 100%.