Gearing with a 28x10.5 tire

[nolanator]

Hey everyone,
I am moving up in tire size from a 25" tall tire that was on my 16x8 GTA wheels to a 28x10.5 MT slick. I haven't gone to the track with this car, but I was wondering if it may still be practical to use my 3.42 gears with this tire. On the street I was able to launch at 6psi off of the transbrake without too much spinning, so could I compensate by coming off the brake at higher boost, or should I just look into 3.73s?

turbo: Precision 6766CEA
converter: AC 9.5" 3500NLU
trans: EA Stage III

 

[turbobitt]

Don't mess with the gears. Will probably be better with what you have. Some even going to 3.23 or 3.00 at high power levels.
AG.

 

[GNBRETT]

turbo cars like gear

 

[Mr.Spool]

I am moving up in tire size from a 25" tall tire that was on my 16x8 GTA wheels to a 28x10.5 MT slick. I haven't gone to the track with this car, but I was wondering if it may still be practical to use my 3.42 gears with this tire. On the street I was able to launch at 6psi off of the transbrake without too much spinning,

the taller tire will allow you to hit it with more power, however you will notice right away you will need more boost to 60ft the car and the converter should feel a little looser.

 

[Mr.Spool]

so could I compensate by coming off the brake at higher boost, or should I just look into 3.73s?

leave at higher boost,i wouldn't swap out the gears to make that small of a change.

 

[chris kirk]

Don't mess with the gears. Will probably be better with what you have. Some even going to 3.23 or 3.00 at high power levels.
AG.

Totally true and great advice..... I had 3.73 in my old 8.5 and hated them. I now have a Ford 9" with 350. Hope I like it.

 

[T- Type Tim]

I have run
3.90s
3.42
And now 3.50s

No difference I can tell with 3.42 to 3.50

The 3.90s
We're a lot of fun on the street but never ran the track with them

 

[chris kirk]

I have run
3.90s
3.42
And now 3.50s

No difference I can tell with 3.42 to 3.50

The 3.90s
We're a lot of fun on the street but never ran the track with them

I hated my 3.73s. I put in new 3.42s that cost me $600 then decided to go with a 9". Stupid..... I didn't think there would be much of a difference between the 3.42s and the 3.50s and I'm also going to an 18" wheel, so that should offset any/most of the difference in the higher gear ratio. Thanks for the info.

 

[TT/Ameasap]

Mopar guys understood gearing and tire combos a long time ago. I followed what they do....Stick as tall as a tire you can under there and compensate for gear where you need it. I can hit the DR's hard on the street without spinning. This is with a good suspension setup tho. I launch at 8-10psi and you can see results in sig below.