New Ram owner, Towing questions

[Squiggs]

Hello all,
I have a new to me 2013 ram 2500 limited with the 5.7 Hemi and 3.73 gears. It currently has 35x12.5 r17s toyo AT tires (that measure out to 33.5 at 60 psi) and a 2in leveling kit.
going off the spec sheet the truck is rated for 11,290 max towing. but that's with the stock tires of course.
I would like to tow a TT up to 7-8k up 6% grades and be able to hold at least 50mph with some throttle to spare if needed. Do you think that the truck is capable of doing that as the truck sits now? If not would moving down to something like 285/70/17 help? stock was 265/70/17. I would prefer not to re-gear or tune the truck, but if I do, it is what it is I suppose
Me and the wife will be looking at trailers and would like a idea of what size trailer to get. been reading mix experiences of how this truck tows with larger tires. I already know that it has trouble holding 65 with cruise control going up some mild grades.
Any advise would be appreciated.

 

[kurek]

I can't directly answer your question, here's the best I got:

I have a 2015 Ram 1500 with the 5.7, 6 speed transmission, 3.55 gears. Rated 9050 lbs towing. 285/70R17 tires. I have pulled two axle car haulers from California to Arizona with vehicles, heaviest one was ~7300 lbs including the trailer and the car.

That's less wind resistance than a travel trailer obviously it's just a vehicle on a flatbed not a big flat box but the weight is in the ballpark.

Legally I never exceeded 55mph while towing in California but I feel confident that if I did, I would have had no difficulty pulling that weight and even accelerating from 70+ to pass big rigs while traveling up the 7-8% grade from Indio to Chiriaco Summit. On similar grades in Arizona where the speed limit is 75 I similarly have had no difficulty with that. It does ask the engine to spin 4500+ RPM, but it really doesn't seem to mind doing that and temperatures never went too high, I think oil might have gone into the 230's range a few times. Transmission didn't give a dang one bit.

I don't tend to use cruise on grades or mountains, it's always playing catch up so I use that on the flats and drive the old fashioned way including manual downshifts to engine brake on descent grades.

If yours is struggling to sustain 65... well the first question did you recalibrate the truck for the larger tire size? If it doesn't know the tires are bigger your throttle and transmission aren't working at their best. It's cheap and easy to fix that and it's going to save you fuel whether loaded or not.

 

[Squiggs]

I can't directly answer your question, here's the best I got:

I have a 2015 Ram 1500 with the 5.7, 6 speed transmission, 3.55 gears. Rated 9050 lbs towing. 285/70R17 tires. I have pulled two axle car haulers from California to Arizona with vehicles, heaviest one was ~7300 lbs including the trailer and the car.

That's less wind resistance than a travel trailer obviously it's just a vehicle on a flatbed not a big flat box but the weight is in the ballpark.

Legally I never exceeded 55mph while towing in California but I feel confident that if I did, I would have had no difficulty pulling that weight and even accelerating from 70+ to pass big rigs while traveling up the 7-8% grade from Indio to Chiriaco Summit. On similar grades in Arizona where the speed limit is 75 I similarly have had no difficulty with that. It does ask the engine to spin 4500+ RPM, but it really doesn't seem to mind doing that and temperatures never went too high, I think oil might have gone into the 230's range a few times. Transmission didn't give a dang one bit.

I don't tend to use cruise on grades or mountains, it's always playing catch up so I use that on the flats and drive the old fashioned way including manual downshifts to engine brake on descent grades.

If yours is struggling to sustain 65... well the first question did you recalibrate the truck for the larger tire size? If it doesn't know the tires are bigger your throttle and transmission aren't working at their best. It's cheap and easy to fix that and it's going to save you fuel whether loaded or not.

Thank you so much for the info! That makes me feel a little better.
I pulled up my my speed on a GPS and compared it to the trucks speedo. It was reading about 2-3 mph faster than what my truck said I was doing. So I guess the previous owner may have tried to recalibrate it, but put the generic 35in tire size instead of measuring the actual height. I had to do that for my jeeps but always measured the actual height not what was stamped on the side wall.

 

[kurek]

I've always just gone by the manufacturer stated specifications, for example 35x12.5R17 Toyo AT's are apparently 34.5" according to the manufacturer. https://www.toyotires.com/tire-finder/size/35-12.5-r17/#

Obviously a tire with close to a half inch of tread depth is going to be a different diameter new than half worn but it doesn't need to be that precise you just don't want the engine computer thinking "dang I'm having a really hard time turning these little stock tires... " because modern vehicles take load into account when performing shift and throttle strategies.