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  1. #1

    Default What are the best gears for 35's/37's?

    Currently I have 35in Toyo OC MT tires on my Silverado 1500, but after I install my body lift and these tires wear out, I may get 37in tires. My question is what gears will work best for both, or is that even possible? I have been told you can run 4.56 comfortably on both but can anyone confirm that?
    Attached Thumbnails Attached Thumbnails lift.jpg  

  2. #2
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    mfleetwood's Avatar
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    This gear ratio chart should provide you some guidance. You'll lose a little bit of power but will get better mileage.

    http://www.4x4offroads.com/gear-ratio-chart.html


    Mike (Denver, CO) - 2008 Sierra 1500 Z71 SLE 5.3L 4WD

    SUSPENSION: Rancho 4" Suspension Lift; Rancho RS9000XL Shocks; Rancho Skid Plates; Rancho MyRide Wireless Shock Controller;
    TIRES:
    BFG All Terrain KO 315/70/17
    DRIVE TRAIN: 4.56 Gears; Detroit TrueTrac Differential; True Cool 40k Transmission Cooler
    PERFORMANCE: DiableSport Predator Tuner; Custom Tuned by Diablew; Magnaflow Exhaust; AFE Cold Air Intake
    ELECTRONICS: Kenwood DNX6180 Touchscreen; Subthump box w/10" Kicker; Driver Information Center (DIC); Rear View Camera
    ACCESSORIES: Westin Brush/Grill Gaurd; Westin Nerf Bars; Truxedo Tonneau; 20% Tint; Tow Mirrors w/Heat & Signals

  3. #3

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    @mfleetwood is spot-on. Staying with 4.56's when you moved from 35's to 37's would result in better highway fuel economy on the 37's ... at the expense of power you had when on the 35's. Staying within the green band on the chart keeps you close to factory/OEM capabilities. You might consider 4.88's for your needs ... just realize that highway economy gets worse as you shorten the gears.

  4. #4

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    Thanks for the help, I forgot to mention that I will also be towing a small bass boat behind the truck.. will 4.56 still be good for both sizes or only 35's?

  5. #5
    Sr. Apprentice LURCH's Avatar
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    I would do 4:88's same money better performance, so what you have to drive a little slower until you get the 37's. No brainer, just my 2 cents!!!!!!

  6. #6
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    I'm not sure how heavy your boat/trailer are, if you have a lots of hills, or if you tow it often, but the 4:56s will be more sluggish.... but to what extent will depend on the variables. Or if your towing across flat land over a long distance, better mileage may be more appealing to you, so then the 4:56s will better suit those needs.

    I'd suggest once you get the tires on, try towing with your current gears and if you are okay or can live with the performance, then no need to re-gear. IMO, it's not that big of a jump between those sizes and am not sure you will notice a significant enough difference for it to be worth the cost.

    ---------- Post added at 07:35 AM ---------- Previous post was at 07:32 AM ----------

    Quote Originally Posted by LURCH View Post
    I would do 4:88's same money better performance, so what you have to drive a little slower until you get the 37's. No brainer, just my 2 cents!!!!!!
    Given his tires size I think has 4:56s already, thus re-gearing would be an additional expense.
    Last edited by mfleetwood; 03-15-2012 at 08:37 AM.


    Mike (Denver, CO) - 2008 Sierra 1500 Z71 SLE 5.3L 4WD

    SUSPENSION: Rancho 4" Suspension Lift; Rancho RS9000XL Shocks; Rancho Skid Plates; Rancho MyRide Wireless Shock Controller;
    TIRES:
    BFG All Terrain KO 315/70/17
    DRIVE TRAIN: 4.56 Gears; Detroit TrueTrac Differential; True Cool 40k Transmission Cooler
    PERFORMANCE: DiableSport Predator Tuner; Custom Tuned by Diablew; Magnaflow Exhaust; AFE Cold Air Intake
    ELECTRONICS: Kenwood DNX6180 Touchscreen; Subthump box w/10" Kicker; Driver Information Center (DIC); Rear View Camera
    ACCESSORIES: Westin Brush/Grill Gaurd; Westin Nerf Bars; Truxedo Tonneau; 20% Tint; Tow Mirrors w/Heat & Signals

  7. #7

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    Quote Originally Posted by mfleetwood View Post
    Given his tires size I think has 4:56s already, thus re-gearing would be an additional expense.
    If he's already got 4.56's I can't see going to 4.88's either; that's a lot of money for very little gain. However, I got the impression from the original post that he might be searching for a new ratio to which to move.

    @Buckhunter11b, can you clarify?

  8. #8
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    mfleetwood's Avatar
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    Quote Originally Posted by SurrealOne View Post
    If he's already got 4.56's I can't see going to 4.88's either; that's a lot of money for very little gain. However, I got the impression from the original post that he might be searching for a new ratio to which to move.

    @Buckhunter11b, can you clarify?
    Good call...yes, it is unclear as to what he currently has.


    Mike (Denver, CO) - 2008 Sierra 1500 Z71 SLE 5.3L 4WD

    SUSPENSION: Rancho 4" Suspension Lift; Rancho RS9000XL Shocks; Rancho Skid Plates; Rancho MyRide Wireless Shock Controller;
    TIRES:
    BFG All Terrain KO 315/70/17
    DRIVE TRAIN: 4.56 Gears; Detroit TrueTrac Differential; True Cool 40k Transmission Cooler
    PERFORMANCE: DiableSport Predator Tuner; Custom Tuned by Diablew; Magnaflow Exhaust; AFE Cold Air Intake
    ELECTRONICS: Kenwood DNX6180 Touchscreen; Subthump box w/10" Kicker; Driver Information Center (DIC); Rear View Camera
    ACCESSORIES: Westin Brush/Grill Gaurd; Westin Nerf Bars; Truxedo Tonneau; 20% Tint; Tow Mirrors w/Heat & Signals

  9. #9

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    Thanks for the replies. I currently have stock gears, I am planning on 4.56's . I would've installed then as soon as I got the tires but I was called up to deploy. I am getting gears when I return home, I just want to make the right decision. I don't have to go to 37's, my 35's are relatively new. Honestly, chances are I will stay with 35's add the body lift for additional clearance and get 4.56's. But I will be towing a boat over relatively flat terrain. Definitely no mountains in the Fort Benning, GA area. I really appreciate the help!

  10. #10

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    4.56's are probably the right answer for you, then. (Mine go in next Thursday!)

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