Tires size changing tow capacity

[NB Canada]

It will absolutely affect tow capacity. Every trucks rating is based upon it's weakest part. Just what that part is, and how much it affects it is a secret. The manufacturers
engineers do not share this info. sometimes it is pretty obvious. Other times not...and it sometimes gets hotly debated on some forums.

Capacity??? Can’t see it. As I stated “how well it tows” is different
As long as the tire rating is the same his payload won’t change from a taller tire

[Indy Tim]

I'm thinking of putting larger tires on my truck and heard it will affect tow capacity. Now first off, I'm no where near capacity or load limit of the truck but thinking ahead if we end up with a lager RV. I found a calculator to shows a decrease of 15 revs/mile. Anyone have an idea how this will affect towing?Attachment 45789

It will affect your towing capacity. The 2024 Duramax has 470HP and 975 lb-ft of torque and a 22,500lb max 5th wheel towing capability. My calculations based on the link shown below would be a loss of tow capacity of 2.6% or reduction down to 21908 ft-lbs. I believe you would exceed the payload capacity of 4178lbs before the affect of the tow weight reduction would come into play. Drivability would be affected but not sure if it would be noticeable.
https://fourwheeltrends.com/do-bigge...ng-capacity-2/

[Scott'n'Wendy]

If will affect it..but it won't change it. As suggested before it will be like a small change in gear ratio. The taller the tire, the bigger the change in the wrong direction. You will have a less acceleration from a stop, a little less grunt going up hill and a less ooompha when passing someone.

You should also be concerned about truck height affecting how level your trailer will be afterwards. Depending how high you go...you may have to modify your hitch or trailer.

[huntindog]

Capacity??? Can’t see it. As I stated “how well it tows” is different
As long as the tire rating is the same his payload won’t change from a taller tire

i did not use the payload word. though larger tires will put more stress on the wheel bearings, and if that is a weak link, it could be a payload factor.
larger tires make the motor work harder and more importantly the brakes. engine braking will not be as effective as well.i have known people that jacked up their trucks to put 44s on,then needed brakes every 3000 miles. those trucks may look tuff, but they cannot tow much of anything witout putting serious money into driveline upgrades.
an extreme example to be sure, but illustrates what upsizing does

[huntindog]

I have a 2024 GMC Sierra 2500HD AT4 arriving in the next week so don't have door jam info. I have the duramax 6.6 and GMC states the gear is 3.42. As for tires I'm considering, they have a load rating E. Hope this helps a bit but assume without door jam info it's limited. The 2024s are redesign and just being released so limited info so far.

the new trucks sit pretty high. Quite a few posts on them being too high for a 5th wheel. bigger tires may not work if a 5ver is in your plans

[Merk44]

It will affect your towing capacity. The 2024 Duramax has 470HP and 975 lb-ft of torque and a 22,500lb max 5th wheel towing capability. My calculations based on the link shown below would be a loss of tow capacity of 2.6% or reduction down to 21908 ft-lbs. I believe you would exceed the payload capacity of 4178lbs before the affect of the tow weight reduction would come into play. Drivability would be affected but not sure if it would be noticeable.
https://fourwheeltrends.com/do-bigge...ng-capacity-2/

Now we're getting somewhere. Great find. Thank you

[Indy Tim]

Now we're getting somewhere. Great find. Thank you

Ops, I meant 21908 lbs. If it were ft-lbs you could pull anything!

[Merk44]

Ops, I meant 21908 lbs. If it were ft-lbs you could pull anything!

lmao, wouldn't that be nice

[traveldawg]

thought I'd jump in here..... I don't think changing tires necessarily affects tow capacity in that the capacity is determined by the sticker on your truck. Not much way to change that.

However, putting on a tire that doesn't support the rear axel rating (REAR GAWR as posted on the manufacturer's sticker) will reduce the rated capacity.

So I guess having said that outlaid - it can reduce the capacity. But it won't increase it.

How it tows with different size tires is a whole different thing.....

[Stealth13777]

It will affect your towing capacity. The 2024 Duramax has 470HP and 975 lb-ft of torque and a 22,500lb max 5th wheel towing capability. My calculations based on the link shown below would be a loss of tow capacity of 2.6% or reduction down to 21908 ft-lbs. I believe you would exceed the payload capacity of 4178lbs before the affect of the tow weight reduction would come into play. Drivability would be affected but not sure if it would be noticeable.
https://fourwheeltrends.com/do-bigge...ng-capacity-2/

Great resource! Since we all hit payload before towing capacity, I agree no real factor there. I did the calc and it basically reduces rear gearing to an effective ~3.33 ratio. A 3.51 rear gear would fix it, but that’s such a small jump it isn’t worth doing (nor is it likely available).

It looks like it’s a swap for like spec tires, so my only concern is the additional 2in width being ok on factory rims. Or if not factory rims, making sure the aftermarket are rated appropriately (many aren’t). FWIW I think your factory tires are rated at 3750lbs each.