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Axle ratio and tire/wheel size on a 2500

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jm888

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I know there is a thread here about the 3.73 vs 4.10 but I am still a little confused because some people say you will not regret a 4.10 and some say the RPMs are too high with it. Some of the threads I have read are a little older and it is my understanding these used to have a 6 speed. But then I have also read posts where the 8 speed helped the 3.73 and that might be a better option so I am totally confused now! The other thing I am a little confused about is tire and wheel size. From what I gather, a smaller wheel size will have a better ride because the tires will have higher sidewalls. Is that correct? So first let me say that I am probably not going to do a lot of customization by getting new wheels or tires or anything so I would stick with the stock. I don't plan to off roading or anything with this and most of the driving will be on the highway making road trips and eventually pulling a travel trailer. This won't be a daily driver so my guess is I probably won't put more than 5k miles on it per year. I do think the anti-spin is worth it though. So from this information, what do you recommend for the axle ratio and stock wheels/tires available? And if there is even that much difference.
 
You don't lose anything going from the 3.73 to the 4.10. I never lost any fuel economy going from 3.73 to 4.44 gears. Gas engines love to rev and you can never have too much gear.
 
While I won't be towing everyday, I also won't be driving it every day. If it is good for the engine to rev a little higher, then it should be good. I probably won't drive this truck more than 5k miles per year or so. What about tire size?
 
For two tires with the same diameter, the smaller wheel will give you a smoother ride all other things equal.
 
jm888 said:
Is tire size going to affect things like MPG at all?
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Depends on how much bigger your going. It absolutely can. A larger or heavier tire will make it worse by a little bit. Your pushing more weight and depending on tread have greater rolling resistance. From what I've seen. Bumping up to 35 is negligible. From 37 on up you see a noticable drop

Wheel size shouldn't unless your going to some monster wheels that are really heavy.
 
I chose 3.73s after much debate. you really can’t go wrong with either and there is less than 10% difference between the two.

Ultimately I decided that because the 8 speed had such a wide range of ratios and a 5:1 first gear that 3.73s would work fine. I have been happy with mine on 285/75-18 (35”) I have a nice low cruising rpm and plenty of grunt for towing what I need
 
Ok, I guess the overall size of the stock 285/60/20" and 275/70/18" are about the same so mileage shouldn't make a difference between the two, but the 18" should have a slightly better ride? That makes sense if there is more sidewall, but I think I do like the black wheels so maybe I will go that route. I can't imagine it being that much difference. I don't understand the how the different gear ratios relate to the axle ratio but that sounds like something to research. If there is less than 10% difference between the two, then I guess it doesn't really matter much. I just figured higher RPMs would not be good constantly but maybe they are, or it sounds like it is not much difference. I am not going to be towing all the time, but since I probably won't be driving around much at all, then any of this is probably not worth worrying about too much.
 
jm888 said:
Ok, I guess the overall size of the stock 285/60/20" and 275/70/18" are about the same so mileage shouldn't make a difference between the two, but the 18" should have a slightly better ride? That makes sense if there is more sidewall, but I think I do like the black wheels so maybe I will go that route. I can't imagine it being that much difference. I don't understand the how the different gear ratios relate to the axle ratio but that sounds like something to research. If there is less than 10% difference between the two, then I guess it doesn't really matter much. I just figured higher RPMs would not be good constantly but maybe they are, or it sounds like it is not much difference. I am not going to be towing all the time, but since I probably won't be driving around much at all, then any of this is probably not worth worrying about too much.
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Yeah this is a little more in depth. From I've noticed the difference between 4.10 and 3.73 is really small mpg wise. I tow all the time and knew I was going to a 35 or 37 tire. My father in law doesn't tow much and keeps stock size tires. So he went 3.73. He gets better mileage on freeway. I actually do better in town. I do feel it makes a difference in towing. I seem to have better towing performance.
 
Rockcrawlerdude said:
I chose 3.73s after much debate. you really can’t go wrong with either and there is less than 10% difference between the two.

Ultimately I decided that because the 8 speed had such a wide range of ratios and a 5:1 first gear that 3.73s would work fine. I have been happy with mine on 285/75-18 (35”) I have a nice low cruising rpm and plenty of grunt for towing what I need
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I guess that is what I meant about the 8 speed making the 3.73 better, or what I have read, even though I don't really know what that means :) What kind of mileage do you get with yours?
 
jm888 said:
I guess that is what I meant about the 8 speed making the 3.73 better, or what I have read, even though I don't really know what that means :) What kind of mileage do you get with yours?
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The 8sp made everything better. I don't really hear anyone complain about 4.10 though.

I have a tall set of 35's. I see 12-13 on highway. 10-12 in town 8-10 towing. I live in the mountains. And the speed limit is 80.
 
jm888 said:
I guess that is what I meant about the 8 speed making the 3.73 better, or what I have read, even though I don't really know what that means :) What kind of mileage do you get with yours?
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~12-13 around town. 10 towing. Don’t do much highway unless I have a trailer hooked
 
Hello everyone - I do less than 8k a year daily driving. BUT - when I haul - which can be a couple times a month - I haul a 3 horse gooseneck with 2-3 horses. Sometimes haul on highways - sometimes up and down mountains on those highways.
I want to buy/order a 2021 2500 with Cummins engine - to replace my 2003 2500 Cummins. Would I be correct to get the 4.10? Sorry if this is a newbie question - but want to ensure I get or build what I need. I appreciate your help in advance! - Sarah
 
SAJ said:
Hello everyone - I do less than 8k a year daily driving. BUT - when I haul - which can be a couple times a month - I haul a 3 horse gooseneck with 2-3 horses. Sometimes haul on highways - sometimes up and down mountains on those highways.
I want to buy/order a 2021 2500 with Cummins engine - to replace my 2003 2500 Cummins. Would I be correct to get the 4.10? Sorry if this is a newbie question - but want to ensure I get or build what I need. I appreciate your help in advance! - Sarah
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You won't need 4.10 with the cummins and that light of load. Payload might be issue though. You may need 3500 depending on pin weight. It's real low in diesel 2500
 
SAJ said:
Hello everyone - I do less than 8k a year daily driving. BUT - when I haul - which can be a couple times a month - I haul a 3 horse gooseneck with 2-3 horses. Sometimes haul on highways - sometimes up and down mountains on those highways.
I want to buy/order a 2021 2500 with Cummins engine - to replace my 2003 2500 Cummins. Would I be correct to get the 4.10? Sorry if this is a newbie question - but want to ensure I get or build what I need. I appreciate your help in advance! - Sarah
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If you get the Cummins, the 3.73 will work well pulling a 3 horse trailer. With the diesel, you wouldn't benefit from the 4.10 until you starting pulling trailers that weighed over 12,000 lbs. I put 462,000 miles on my last truck pulling trailers from 5000 lbs to 16,000 lbs and never felt I needed the 4.10 rear. I have no experience towing heavy with a gas motor.
 
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