Black Sunshine 07

i've decided to either go with 18x9's or 18x10's. my question for all you guys who have already done this is: i know you get more traction with a wider tire, but if i go with a wider tire/wheel will this speed me up or slow me down any? thanks guys

[sm=thanx.gif]

howarmat

added weight slows you down.......

GRABBER GT

Qutie a difference between the way the car rides from 17s to just 18s. The car steered lighter and felt more powerful with the 17s.

Argonaut

My experience is the change is negligible. My 'winter' tires are 235/55/17 on stock rims (not the bullits, not sure what the style is called). My 'summer' tires are 255/45/18 on 18x9 DD Bullits all around.

I have switched back and forth twice (had each set on twice)and can't say the car felt very different. I definitely would not say the car is less powerful with the bigger tires or they in anyway slow me down. Also Iam quite happy with the handlingboth ways, although the bigger tires have more of a tendancy to be tailhappy (but thats more a result of the tire, not the size). But this VERY much depends on the tire/rim combo you switch to. In my case, the bigger tires and rims only weigh about 2lbs more per corner. You can get 18" rims that are far lighter, so you could actually drop a few pounds by moving to a bigger tire/rim combo depending on what you buy.

Nuke

My takeoffs are faster nor have I noticed any difference at speed. You'd think rolling resistance would increase but I haven't seen it in my fuel mileage.

acascianelli

Wider tires = more weight + more rolling resistance = slow you down.

But, if you're getting wider tires because of traction issues, I think that having better traction will be more beneficial.

Norm Peterson

If the new wheel/tire package is heavier than the existing one, you'll slow down ever so slightly. Enough to be measured with timing equipment that's good to 0.001 second such as you might find at the dragstrip or at most autocrosses, sure (if you're that consistent anyway). But not enough to tell using just your butt-o-meter.

Some numbers to chew on using Argonaut's 2 lb/corner difference taken half as added wheel weight and half as added tire weight. These are the amounts of time quicker and shorter distance required for a 25 - 45 mph sprint in each gear (MT, no shifting). The distance numbers also represent the difference in a side-by-side race where the wheels/tires are different in weight but not diameter and everything else about the two cars and the driver capabilities/reaction timesis absolutely identical. I doubt that anybody is good enough to notice accelerations that differ by 1/5 of 1%. The differences in the distances, you'd notice, but only by comparison. You'd never see them if you first drove one car and then the other.

2nd gear 0.004 seconds 2.5"
3rd gear 0.008 seconds 5"
4th gear 0.012 seconds 7.5"
5th gear 0.020 seconds 12.5"


Norm

GidyupGo

.................more rotating mass too. Takes more energy to turn that big sucka.

SuperSonic05

I would agree that wider tires = more rotating mass, but the traction different between the two should make up for that. When I put on my Shelby rims, I didn’t notice a difference in weight. I sure there is but it can be more then a few pounds. The car grips much better now and I can’t wait to get it to the track.

Norm Peterson

Got the rotating mass effects part of it entered right, but I didn't also add the 8 lbs to the total weight. The spreadsheet works well enough, but isn't 100% user-friendly quite yet (even for its developer. [sm=sigh.gif] )

Trying again,

2nd gear 0.008 seconds 5"
3rd gear 0.016 seconds 10"
4th gear 0.024 seconds 15"
5th gear 0.045 seconds 28"


Norm