Forum Discussion

Nunyadamn's avatar
Nunyadamn
Explorer
Mar 07, 2018

Tires - Do I need to worry? Going bigger...

I just ordered some new wheels and tires. I have a stock 2015 F250 4x4 with a shell and tow my 2014 32BHDS. I have the stock Michelin Defender LTX M/S 275/60R20 with 3750@80psi weight capacity.

I am going to be putting on a 3" Rough Country Stage 2 lift kit, dual steering stabilizer, 20x10 Fuel Contra D615 wheels and Pro Comp 35x12.50R20 A/T Sport tires. The tires have a weight rating at 3195@60psi.

My weights with my stock setup is -

Truck and trailer with WDH connected
Steer Axle - 4580
Drive Axle - 4800
Trailer Axle - 7420
Gross Weight - 16800

Truck and trailer NO WDH connected
Steer Axle - 4300
Drive Axle - 5200
Trailer Axle - 7280
Gross Weight - 16780

Truck only
Steer Axle - 4800
Drive Axle - 3480
Gross Weight - 8280

So do I have to worry? Its such a big difference in weight ratings. The Pro Comps have 60k warranty so I thought they would be a good choice over the current stock tires. Now I'm a little nervous.

29 Replies

  • My only concern would be going from basically a 33" tire to a 35" you are losing your effective gear ratio. I would also look for an 80psi tire. As for the lift, I wouldn't be concerned, you are not going radical. I've been towing heavy toy-hauler style trailers with leveling kits, and aggressive mud tires on all my Super Duties, and have never encountered issues because of the the lift,or tires.
  • I would not do this. The lift and the tires will negatively affect handling and loading.
    Also, I hate to disagree with my forum brethren but if you do proceed, avoid BFG tires at all cost. They are just too soft for hauling duty.
  • Okay I'll go against the grain a little bit. The lift...meh. It's only 3". My truck more than a 3" lift taller than an equivalent truck from a few years ago. Granted that's stock versus aftermarket. I don't know the specifics of the lift you're doing, but if it's a quality manufacturer and setup I don't see much of a problem.

    The tires I'd be a little more hesitant about just because you're losing capacity and PSI which will likely add some squirm. I would think you could find a similar size tire to the one you're going to with a closer to stock weight rating at 80 psi so you might look into that some. But that said based on the weights you're posting you don't appear to be overloading the lower rated tires. I've never had any experience with pro comp tires so I don't have an opinion there.

    I'm not in the camp that says you can't tow safely with a reasonable lift and reasonably larger than stock tires...you just need to do your homework.
  • To each their own, but I would not lift my TV or go to a lesser rated tire.
  • rhagfo's avatar
    rhagfo
    Explorer III
    Lift, big soft tires, what could go wrong towing a 35' TT weighing 8,500#.

    Just not a good plan in my book.
  • Artum Snowbird wrote:
    OK, lets look at this honestly. You have a trailer with dual bunks at the back, so there must be some little ones involved. You will likely be filling the back of the truck with bikes and other things. You can usually plan on being half full of water, either from gray and black or fresh.

    So, the trailer is going to be carrying a lot of weight for all those people, the truck is too. The last thing you should do with a heavily loaded rig is raise it, and put on less weight carrying capacity tires.

    Yes, you need to worry a lot. Get stronger with add on stuff, not weaker and taller.
    Have to agree with this, the last thing I would want is less stability while towing.
  • With 20" wheels, I would not go down in the tire load rating to a 3195@60. As stated the 127/124S E @ 80psi is what I would recommend.
  • OK, lets look at this honestly. You have a trailer with dual bunks at the back, so there must be some little ones involved. You will likely be filling the back of the truck with bikes and other things. You can usually plan on being half full of water, either from gray and black or fresh.

    So, the trailer is going to be carrying a lot of weight for all those people, the truck is too. The last thing you should do with a heavily loaded rig is raise it, and put on less weight carrying capacity tires.

    Yes, you need to worry a lot. Get stronger with add on stuff, not weaker and taller.
  • Straight up: ProComp tires are generally regarded as bottom of the barrel.

    They are made by Cooper (which is not a bad brand) but 4Wheel Parts has a pretty low spec for their rubber.

    If you must have that size, check of these BFG A/T's

    LT 285/65R20 127/124S E BSW 34.5" 11.5" 8-10" 8.5" 15/32" E 3860/3525 lbs 80 psi 60.3 lbs 60

    From BFG's spec chart. I know it didn't come over well, but you get the idea. Rated higher than your current rubber.

    Sure it will cost you more, but there is definitely a reason.