? about 18's and new track times

[Zippeh]

My buddy in his 94 mustang GT just recently put on some 18'' bullit rims, and changed the rear end gearing from 2.73's to 3.55's. That's it. Now pre tires and gears he ran a 15.28 but now with the tires and gears he can't break 15.4

his question for stangnet is : Could larger tires really hurt his 1/4 times that much?

 

[ECU5.0]

hes not gettin as good of a launch because of the smaller sidewall. notice how big the sidewall is on funny cars...helps out a lot. and the wheels are heavier than hell too. he probably roasted his tires comin off the line also. more than likely thats what happened. what were his mph?

 

[cjman15]

Those smaller sidewalls do kill a launch pretty quickly

 

[Zippeh]

hes not gettin as good of a launch because of the smaller sidewall. notice how big the sidewall is on funny cars...helps out a lot. and the wheels are heavier than hell too. he probably roasted his tires comin off the line also. more than likely thats what happened. what were his mph?

some of his slips :
60' 2.328 2.320 2.341
1/8 10.014 10.023 10.013
1/4 15.449 15.507 15.535
MPH 87.93 88.33 86.57

 

[ECU5.0]

dont know man...probably the smaller sidewall combined with the heavier rim and loss of traction. if his mph were around the same when he ran the 15.2 than traction is his problem

 

[Michael Yount]

What's the overall diameter of the new tire? If it's taller than what he had on there before, it's reducing the effective gearing in the car - in other words, a taller tire can reduce the effectiveness of the gear swap. Others also mention weight - it's rarely considered, but has a big impact on performance. Heavier wheels and tires take more power to spin - and that's power that was previously available to move the car more quickly. And neither of those factors has anything to do with traction - if his traction is worse than before, well that's 3 strikes against quicker times.

 

[Mustang5L5]

86-88MPH is pretty poor. He should be up to 92-93MPH stock. Something is wrong with his car.

It's not an AODE convertible with 500 pounds of stereo equipment is it??