tire size and towing

mattfu · Post by **mattfu** » Mon Jul 16, 2007 6:16 am

im finally about ready to change tires, i have added PA 2" BL and 1.5" rear shackles and was planning to fit 31x10.5 tires, but recently bought a new travel trailer so now im often towing about 4000 lbs or so, now im thinking maybe i should plan to go down to a 30" tire, anyone see any problems or advice? or will i not notice much of a difference going with the larger diameter and trying to tow up mountain roads? i have the stock 235 75r 15 tires now and am worried bigger tires will rob alot of the power i now need for towing.

killian96ss · Post by **killian96ss** » Mon Jul 16, 2007 9:06 am

What is your gear ratio?

If you have 3.42's I would stay with the smaller tire, but if you have 3.73's then the 31's will work just fine.

The shackles you installed will probably increase rear end sway, so you might want to look into getting a rear sway bar, air shocks, helper springs, etc., to help with this problem if you plan on towing often.

You will know the first time out if you need these items.

Steve

mattfu · Post by **mattfu** » Mon Jul 16, 2007 9:17 am

i have the GT4 RPO code so i guess that means 3.73, i have towed over 1500 kms so far and sway is not a problem, rear end sinks alot though, looking at helper springs for the rear.

2kwik4u · Post by **2kwik4u** » Mon Jul 16, 2007 9:52 am

I have the 3.73's.....They are great for towing, but my mileage has suffered around town because of them I think.......In regards to the tires. If you are going from a 29" tall tire to a 31" tall tire, then thats only a ~7% increase. Not terribly huge jump, and you should be OK depending on how close you are to the limit of your tow ratings.

I know my boat is ~4k lbs, and I tow it at least twice a week to a local lake. I'm going to be SERIOUSLY looking at fullsize trucks in the springtime. While the crew does decent at towing the load, I just can't keep it cool while it's doing it. Granted I haven't spring for the high capacity radiator, or LS1 fans yet. I still think that looking forward, I can't go much larger with towable loads and this truck. Especially if I go up in tire size.