GM Truck Club Forum banner

New tires, would like to regear to compensate

4997 Views 18 Replies 6 Participants Last post by  Rockstarrchevy81
I have a 2010 silverado 1500 with the 5.3L and the 6 speed, and the 3.08 gear. I have recently added a lift and tires and obviously truck no longer has the grunt off the line like it did. I know I need to change gear to fix this small issue, I would like to know which gears would be ideal for the new tires and still keep my mileage from falling thru the floor. I had the 265/65/18 tires stock, and now I am running a 305/65R18 almost exactly 2 inches taller, I know I will not get it exactly like it was but I was considering a going to 3.73's. Will they fir with my current carrier in my front diff? The rear diff should be fine. Any info would be greatly appreciated.
1 - 2 of 19 Posts
4.10. 56's would be way too steep with the 6 spd. Most charts out there do not take into consideration the ratios of the newer 6 spd transmissions. You have an 8.5" 10 bolt.
I have the same transmission and with 8.5 / 10 be surprised how effecient the Od is! Everyone told me I would be pushing 3000 RPMs with the 4.11 @ 85 I am just hitting 2500 rpms....the truck isnt even working hard at that range.

Depending on how much freeway driving he does I think 4.56 would be fine.

I used this calculator when figuring my new gears and it was pretty much dead on. I use .70 for the OD ratio...

With 4.56 @ 80MPH it puts him at about 2500 RPM.......his engine can take that all day long.
Driving in 6th on the interstate he will be fine, but city is a different story. The final drive ratios in the 6 spd are a good bit higher numerically. 3.73's in a 6spd in 1st gear is like having 4.88's in a 4 spd. Rockstar, I certainly wouldn't attempt a gear install unless you/your friend are well versed. Gears are very tricky business and can easily fail and whine if not setup perfectly.
1 - 2 of 19 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.