[Willy Mo]

Posting this hear as well to see if i can get soem feedback.

OK, heres the deal, I am in need of some new rear tires soon. Currently running 275/50 (26x10.50) ET Streets. Since I have 4.10's, I want to go to a 28" tire so I up my trap speed. I am planning on building my rear end as well before this season, with either a tru trac or cobra diff and 31 spline axels. So the wanted opinion is on whether or not to keep the 4.10's and go to a 28" tire, or down the gear (3.73) and stick with a 26" tire. Or?

p.s. Im building the rear end to be stronger but theres also a whine on deceleration at high speeds. I set the backlash a little tight for the track when i did the 4.10's 2 years ago.

[saxmanJJ]

It's easier to change tires/wheels than gears.

I'd say keep the 4.10s, get a separate set of rear wheels and tires for the track would be the best approach.

[Willy Mo]

I am almost positive I am just gona run a 28" tire, but wanted everyones thoughts.

[Scott2001GT]

Originally Posted by saxmanJJ It's easier to change tires/wheels than gears. I'd say keep the 4.10s, get a separate set of rear wheels and tires for the track would be the best approach.

[casper gt]

in your case, 4.10's & 28's are a good starting point.

you'll most likely need/want the bigger tire, but will most likely want a little less gear.

[saxmanJJ]

It all depends on what you think you're going to trap (speed).

4.10s and 28" tires and a higher rev-limit will get you to around 120 MPH (at least).

I'm happy so far with 4.10s and 28" tires, but I've only been to 117 MPH so far.

The 28" tires will grip the track better than 26" tires (of the same width), that I know for certain.

[Willy Mo]

This is my predicament, Im going to build the rear end anyway, so that would be a good time to swap gears. But I will probably need tires before i build the rear. So buy 28" tires and see how they work, or buy another set of 26's and swap the gears. I want to run 11's, and by inputting my info in a trap calulator it says i will trap 117 at 6200rpm with 26" tires. Not that its very accurate, but im sure its a good idea.

[blownstang]

You should be in the 11's easy with 400rwhp and the et streets with skinnies and the little weight reduction you have. Full weight GT's with nothing but a drag radial run high 11's with your power level. What did it run N/A?

[Willy Mo]

N/A with just a couple bolt ons and 4.10's I ran a best of 13.50 at 101 with a 1.91 60'. that was on my DD bullits and nitto 555's.

[casper gt]

Originally Posted by Willy Mo This is my predicament, Im going to build the rear end anyway, so that would be a good time to swap gears. But I will probably need tires before i build the rear. So buy 28" tires and see how they work, or buy another set of 26's and swap the gears. I want to run 11's, and by inputting my info in a trap calulator it says i will trap 117 at 6200rpm with 26" tires. Not that its very accurate, but im sure its a good idea.

I'd keep the 28's, a K/B car hits the tires hard & 26's might not be the best idea.

I'm thinking 3.73's & 28's

[Willy Mo]

28's will replace the current 26's and we will see how it does if its still not enough I may drop the gear down.

[saxmanJJ]

Originally Posted by Willy Mo 28's will replace the current 26's and we will see how it does if its still not enough I may drop the gear down.

Good thinking!

I think staying with the 26" tires, you would definitely lack traction with your KB. 28" tires will probably be sufficient, but if not, you can go to a taller gear. On the street the taller gear may help with traction though. Gears are always a compromise!

[Willy Mo]

thanks guys!

[BADASS03SVT]

In a heavy low power car you want as much gear as you can handle rpm wise. Ideally you want to cross the traps at or just over your peak hp.

a 28 is always a better choice bc it has a bigger footprint on the ground = more traction. Also has a lot more sidewall to help with that.

You also have to remember....you run 4.10s now on a 26" tire.

going to a 28" tire is basically the same as tossing in a 3.80 gear.

I run 4.10s and a 28" and trap 134-135 @ 6600-6700.

[Willy Mo]

I wouldnt really call my car a heavy/low power car. But lower power none the less. car weighs 3190 with 404rwhp. should be good for 11's. I will be throwing 28's on there and see how it goes. probably a wider tire as well. I blow my 275's off pretty easy.

[BADASS03SVT]

Originally Posted by Willy Mo I wouldnt really call my car a heavy/low power car. But lower power none the less. car weighs 3190 with 404rwhp. should be good for 11's. I will be throwing 28's on there and see how it goes. probably a wider tire as well. I blow my 275's off pretty easy.

by low power Im saying power to weight ratio. is that 3190 w/ driver?

honestly at that weight and 400rwhp i would want low low 11s

[Willy Mo]

3190 with no driver and a half tank of fuel. The blower added almost 100lbs. If i hit 11's i will be happy. Then i will work out the bugs from there.

[Katfish]

Originally Posted by Willy Mo This is my predicament, Im going to build the rear end anyway, so that would be a good time to swap gears. But I will probably need tires before i build the rear. So buy 28" tires and see how they work, or buy another set of 26's and swap the gears. I want to run 11's, and by inputting my info in a trap calulator it says i will trap 117 at 6200rpm with 26" tires. Not that its very accurate, but im sure its a good idea.

Got a link for the trap calculator?