New tires, would like to regear to compensate

Discussion in 'Wheels & Tires' started by bluavalancheZ71, Aug 29, 2011.

  1. bluavalancheZ71

    bluavalancheZ71 New Member

    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.
    Thanks
    Blu
  2. sstoner911

    sstoner911 New Member

    If this truck is 4 wheel drive you need to change both fron and rear to match. I wouldnt go any more than 3.23 with that size tire.
  3. mfleetwood

    mfleetwood Moderator

  4. bluavalancheZ71

    bluavalancheZ71 New Member

    SS, yes the truck is 4wd and since I was talking about concerns for the front diff should have been a give away ;). And you think a 3.23 gear is right? Or did you mean 3.73?
    Thank you fleetwood, the chart helps. But 1 concern, question I have is will I need to get a new carrier for the front diff will it all fit in the case?
    Since I have the 6 speed and reading the other posts about this I'm really considering going to the 4.11's and calling it a day
  5. sstoner911

    sstoner911 New Member


    ya I want sure if you had a 4x4 since you were talking about keeping the rear the same.....with a 18 inch tire 4.11 may bring your rpm to high at freeway speeds.

    ---------- Post added at 08:37 AM ---------- Previous post was at 08:08 AM ----------

    I have 4.11 with 32 inch tall tires..at 65mph my rpms at 65mph are 2200 , at 85 they run 2500rpm.
  6. I have 4.10's with 34.5" tire and at 60mph I'm turning 1,900 rpm's. My tach says 2,100 but may scanner says 1,900 rpm's . I go with the scanner because every factory tach is like a factory speedo, there off a little.

    ---------- Post added at 11:02 AM ---------- Previous post was at 11:01 AM ----------

    Also, welcome to the club.
  7. sstoner911

    sstoner911 New Member

    Wait..i mis read your post..how tall[HR][/HR] is the new tire?
  8. bluavalancheZ71

    bluavalancheZ71 New Member

    New tires are 33.6 tall stock were 31.6 so a 2 inch increase in height
  9. I would go with the 3.73 for MPG's or the 4.10's for a little more power off the line.
  10. sstoner911

    sstoner911 New Member

    Ok...4.11 or maybe even 4.56 would be ok..... 4.11 for sure.
  11. mfleetwood

    mfleetwood Moderator

    When I was shopping around for my 4:56 gears, I was told that I have the smallest housing; however, no one mentioned that there could be a problem with them fitting, but I did get a few recommendations to get rid of my G-80 since I do a ton of off-roading and the smaller rear-ends like I had tend to blow up pretty easy when 4 wheeling.

    With my 4:56 gears, my 4" lift, and my 34.5" tires, I am still getting about 14mgh city and 18mpg hwy....but I also have it custom tuned and some other mods that help with getting better mileage. I leaned toward the side with a little more power and less mileage, as this is not my everyday driver and I spend a lot of time climbing hills. I'd go with the 4:11s with your set up...I think you'll be happy with the extra power and won't really notice the mileage difference (too much!:glasses:) .
    Last edited: Aug 30, 2011
  12. bluavalancheZ71

    bluavalancheZ71 New Member

    I do have several other upgrades done to the truck, like a corsa cat back exhaust, banks ram air intake and an edge power programmer. I appreciate the help, but I have 1 more question what size axles are in these trucks now a days both the front and rear so I can start looking at prices. I was considering canning the G80 rear in favor of a detroit e locker
  13. Blackout07

    Blackout07 New Member

    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.
    Last edited: Aug 30, 2011
  14. sstoner911

    sstoner911 New Member

    I have the same transmission and with 8.5 / 10 bolt.....you be surprised how effecient the Od is! Everyone told me I would be pushing 3000 RPMs with the 4.11 @ 75MPH.....at 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...

    http://www.rearendparts.com/pages.php?pageid=16

    With 4.56 @ 80MPH it puts him at about 2500 RPM.......his engine can take that all day long.
  15. Rockstarrchevy81

    Rockstarrchevy81 New Member

    I thinking about regearing and i was looking at the Gear Ratio Chart. I see that with me upgrading to 35's soon next year a 4.56 would bring it back to factory ratio and 4.88 and 5.13 have more power gains. I do drive on interstate a bit and wonder if the rpm's would be up too high for running 35/12.50/R20 20x12 rims along with 4.88's or 5.13's? I assume the 5.13's are too much for highway purposes and think the 4.56's and 4.88's would be better..?
  16. As I've mentioned before on this site I don't like any gear more than a 4.56 in a 1/2ton axle. Because the axle housing is small the ring & pinion have to be small so the when you machine more teeth on the ring & pinion the teeth are thinner in order to get all the gear teeth so when you go over 4.56 the teeth are getting thin. Go with 4.56's.
  17. Rockstarrchevy81

    Rockstarrchevy81 New Member

    Oh okay thanks for letting me know had no clue. I found 4.56 gears for front/rear for around $440 which i guess isn't that bad. I would rather me and my buddy install them i want be paying labor for this! How hard is the install and how long will it take for both front/rear?

    I also will buy the Maghytec cover for my rear diff. when i buy the gear's. I plan on buying gears and cover first then buy new tires and rims along with my body lift!:happy:
    Last edited: Aug 31, 2011
  18. Blackout07

    Blackout07 New Member

    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.
  19. Rockstarrchevy81

    Rockstarrchevy81 New Member

    Yeah me and my buddy have it he works at the Gm dealership he's a mechanice he knows just about everything about the nnbs silverado ha!

Share This Page