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Discussion Starter · #1 ·
When I bought my 2007 ram it came with 20" tires and instead of the 3.55 gear they installed like a 3.7x or 3.92 gear to help with the taller tire. The standard gear for the trucks with 17" tires was a 3.55.

Does anyone know if they are still doing this on the 2009+ rams? or do they figure they have the extra HP and TQ now so they can still use the 3.55 gear with the 20" tires?

The 2009 Ram I had was equipped with 17" tires and would smoke them at will from a standing start. (QC 4x4) My new 2012 Ram 4x4 CC with 20" tires is a little heavier I'm sure but it doesnt even attempt to spin the tires from a dead stop.:4-dontknow:
 

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In past models and I'm pretty sure in present models you can order either 3.55(standard) or 3.21 or 3.92. I think there is an aftermarket option for 3.7X also. From the factory, you have to pay a few hundred bucks for either 3.21 or 3.92 I'm pretty sure.
 

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Discussion Starter · #3 ·
Hmm that would explain the doggy performance. I think they should have put a lower gear in the trucks that came equipped with 20" wheels. Hopefully when the 8-speed tranny comes out it will help the low end performance.
 

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you can only get, 3.21, 3.55, 3.92 and 4.1 on rt models. 3.73 is only available on the HD trucks. i have 3.55 in my sport and are fine with me. our trucks also have torque management, keeps from spinning tires, although some guys post they spin there tires whenever they want.
 

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Isn't the over height/diameter the same between the 17" and 20" in wheel combinations? More sidewall on the 17 inch tire/wheel combo, less on the 20's? I had them swap out the 17's in favour of a set of 20's off of a Laramie... I haven't noticed any difference in the speedo... I think! Height seems the same... The traction control on these trucks try and give you max traction which should equate to better acceleration. I have had a lot of cars with 3.23 & 3.55 gear sets and they would smoke the tires for miles with less HP. Just wouldn't go anywhere fast! Traction is good... Unless you like burnin'up your tires... Just replaced a set of 20" rubber on a rebuilder 09 Challenger... $$$ Yikes!
 

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^correct the diameter overall is roughly the same usually (with oem wheel/tire combo's). There is probably 1-2" max difference, if that. But 17" wheel/tire combinations are usually significantly lighter, which makes them easier to turn.
 

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1-2" seems like a pretty big deal to me in tire diameter. The 17"s do have the smaller dimensions though don't they...?
 

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Well I said "if that". Not sure, I know my tires are just about exactly 31.5" diameter on my 17" wheels(aftermarket tires and wheels, but IIRC it's oem size which is 265 70 17). What are ya'lls 20" wheel/tire sizes? IIRC my friend that has an RT with oem 22" wheels said his tires are 32" diameter. Basically the same.
 

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My 20's measure out at exactly 32"... can someone check there 17" tire diameter? I am curious what if any difference there is...
 
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