Larger tire hard on trans when towing?

[glennwest]

All i can help you is share my experience. I bought a 2005 Duramax dually. Was towing a DRV, it weighed 17k. Truck came with 205s and previous owner had put 235s on it. Looked normal with these tires. It pulled hard, fan was very active in summer, mpg was bad, Eventually I put orginal tires back on, Looked too small, Night and day difference, less fan, better mpg, run much better, pulled better in hills too, Made me a firm believer in stock tires if towing.

[charliez]

Over time could it cause a check engine light...who knows for sure but probably not.



It won't. About the only thing is the speedo will be off a little bit. A percentage, so the difference gets larger as the speed increases. Alot of after market programmers can adjust for it now.

[BigSkyCountr]

As mentioned earlier going up in tire size loses you your mechanical advantage in gearing. 30 In tall tires give you a circumference of 94.2 inches. 32 inch tall tires give you a circumference of 100.48 inches. The difference being a little over 6%. That means the 4:30 gears you looked so hard for just turned into 4:04's. You will take off slower, make towing harder on your vehicle, but you will lower rpm by 6% and on a flat road your gas mileage may improve slightly. Your speedometer will be off 6%, unless you reflash. Not to mention 32 inch tires are going to weigh more than 30's making it harder to stop them when you need to. Insignificant? Not really. On a 2003, 4.0 litre Jeep Wrangler going from stock 28's to 35's or even just 33's requires a lot more ground to stop. If fact going up to 35's really requires new front spindles, larger brakes and discs. Not to mention they are heavier to change on the side of the road and more expensive. But on the other hand, they do look cool!