We just purchased a 2015 Sierra Denali HD 2500 truck with Duramax/Allison. Love the truck! It is our daily driver AND we will be towing a 2016 Airstream 30' Flying Cloud. Airstream in this photo is, I believe, about a 27':We have been thinking of upsizing the 18" wheels and tires to 20" wheels and slightly beefier All Terrain tires (Nitto Terra Grapplers). This upsizing would also involve a "leveling kit" which raises the front of the truck 1 1/2". The stock truck sits at a bit of a rake.Is the rake of the truck intended to counter the tongue weight in the rear when towing?Are the stock wheels and tires much better for towing with than the upsized wheel/tire combination that we're considering?Would going with the upsized wheels and tires be a bad idea, with regard to towing?Moderator edit to re-size picture to forum recommended limit of 640px maximum width.

I don't know why you would want to make that change? Other than looks, I see no advantage. The 20s would likely ride rougher, and cost more. Those 18s are nice looking.To each his own, but would be a waste of money IMO.Jerry

By going with a larger wheel/tire you will be effectively raising your gear ratio. 3.73 may become more like 3.42 or 4.10 may become more like 3.73. Trucks computer may need reprogramming as well. Why change? Looks awesome as it is. Unless it's a macho thing....

If you just want to I think it wouldn't make that much difference. I really don't see any benefit in terms of towing. You have more than enough truck for that trailer. On a 2500 it should have E rated tires to begin with. The only beefing up you would gain would be a more aggressive tread design. Going for mud grips? My trailer is longer and heavier than yours and I only air my tires to 70lbs and it keeps the same footprint as when it has no load on it. I see nothing to gain but negatives unless you just prefer the look.

I would talk with your truck manufacturer/dealer first. I've seen other new truck owners say their trucks frame warranty was voided because a lift was added. You are modifying your truck chassis.... so be aware. Now having said that I see in GM online ordering guide the 2500 does have 20" wheels and tires with certain options. Again see your dealer.

As far as towing, you would not gain any benefits. In the long run it's your vehicle, have fun with it.

New Sierra Denali HD 2500 - upsizing stock tires/wheels?

DHart
Explorer
Apr 19, 2015
qchunter... thank you. We absolutely LOVE the truck.

We won't get the Airstream for about 8 weeks, so no idea on the truck squat that it will create... I don't think it will squat very much.

The dealer told me that they could adjust the speedo for larger tires, but that it would still be off by about 6 mph at 60 mph. I'm not liking that.

The factory stock tires are Goodyear Wrangler SR-A LT265-70-18. E-rated. I'm thinking we'll just run these tires until they're done and then, perhaps, go with a fatter set of 18"ers.
qchunter
Explorer
Apr 19, 2015
Nice truck! That is going to be my next truck.

My truck has the GM rake but with the tt hooked up it sits level and tows great. If I leveled it I would likely need air bags since my tt will squat the rear almost 2-3". I would say go for the level truck if you don't squat much with the trailer hooked.

I would also run the stock tires for a little bit then see how things go. I would definitely get the different tires but see how things ride first with the stock size rims. You might want the 18" rims with a little larger tires for more sidewall?

As for the speedo, the dealer might be able to do that?

Enjoy.
DHart
Explorer
Apr 19, 2015
Thanks for the comments.

We liked the looks of the larger wheels and tires and occasionally go off road into the desert and the Nitto Terra Grapplers are superior tires for that, with much thicker/stronger side walls - less likely to get punctured in the sidewall.

But the cost is pretty steep, the speedo would need to be adjusted, but still would not be accurate, and the tires would be slightly noisier.

Now we're thinking we will just leave it stock, for now anyway.
TexBohunk
Explorer
Apr 19, 2015
As far as towing, you would not gain any benefits. In the long run it's your vehicle, have fun with it.
JIMNLIN
Explorer III
Apr 19, 2015
I would talk with your truck manufacturer/dealer first.
I've seen other new truck owners say their trucks frame warranty was voided because a lift was added. You are modifying your truck chassis.... so be aware.

Now having said that I see in GM online ordering guide the 2500 does have 20" wheels and tires with certain options. Again see your dealer.
campigloo
Explorer
Apr 19, 2015
If you just want to I think it wouldn't make that much difference. I really don't see any benefit in terms of towing. You have more than enough truck for that trailer. On a 2500 it should have E rated tires to begin with. The only beefing up you would gain would be a more aggressive tread design. Going for mud grips? My trailer is longer and heavier than yours and I only air my tires to 70lbs and it keeps the same footprint as when it has no load on it. I see nothing to gain but negatives unless you just prefer the look.
ata3001
Explorer
Apr 19, 2015
By going with a larger wheel/tire you will be effectively raising your gear ratio. 3.73 may become more like 3.42 or 4.10 may become more like 3.73. Trucks computer may need reprogramming as well. Why change? Looks awesome as it is. Unless it's a macho thing....
MFL
Nomad II
Apr 19, 2015
I don't know why you would want to make that change? Other than looks, I see no advantage. The 20s would likely ride rougher, and cost more. Those 18s are nice looking.

To each his own, but would be a waste of money IMO.

Jerry

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New Sierra Denali HD 2500 - upsizing stock tires/wheels?

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