Jon R
Senior Member
I am ordering a new truck (GMC 3500HD SLT CC LB SRW Gas) and would appreciate any experience or opinions you can offer on selection of tires/rims from the available options.
The base tire/rim is LT275/70-18. The optional tire/rim is LT275/65-20. (The spare is LT 275/70-18 no matter what.) I remember reading that the 20 inch wheel is 1/2 inch wider. I think it's 9 inches wide and the 18 inch wheel is 8.5 inches wide. The wheels are cosmetically similar, and the option is only $500 more. Using a tire comparison calculator on line, the base 18" wheel package has an overall diameter of 33.2" and the optional package overall diameter is 34.1". That gives an undeflected sidewall of about 7.5 inches on the base wheel and 7.0 inches on the optional 20 inch wheel.
The 20 package probably looks slightly better to many, but I don't care all that much about tire size cosmetics. I want to be able to air down the tires safely on washboard roads both unloaded and with a FWC Grandby (won't be doing extreme off-road stuff), but I want a smooth ride without excessive wandering and sway on the road. I will be doing a lot of highway miles, and will occasionally tow a boat trailer. I'll be using LT load range E tires. I don't think I care about losing 1/2 inch ground clearance with the base package, and in fact the lower truck height may help with getting the truck with Grandby in my 8 foot garage door.
I was only able to test drive trucks with the 20 inch wheel package. It was not a bad ride by any measure, but I did feel the road bumps more than I would like. Of course some of that may unavoidable in a one ton truck. I'm leaning toward the base wheel package thinking it will have a noticeably better ride due to more sidewall, and the additional sidewall is good when airing down. (A bonus would be the spare is the same size.) On the other hand, I don't want to later wish I had bought the 20s for some reason I haven't thought of. Do any of you have any experience comparing such a relatively small difference in tires/rims? Will the ride difference be noticeable on the road, and is the 1/2 inch sidewall difference between 7 and 7.5 inches enough to matter when airing down? Any other opinions to offer?
Thanks
The base tire/rim is LT275/70-18. The optional tire/rim is LT275/65-20. (The spare is LT 275/70-18 no matter what.) I remember reading that the 20 inch wheel is 1/2 inch wider. I think it's 9 inches wide and the 18 inch wheel is 8.5 inches wide. The wheels are cosmetically similar, and the option is only $500 more. Using a tire comparison calculator on line, the base 18" wheel package has an overall diameter of 33.2" and the optional package overall diameter is 34.1". That gives an undeflected sidewall of about 7.5 inches on the base wheel and 7.0 inches on the optional 20 inch wheel.
The 20 package probably looks slightly better to many, but I don't care all that much about tire size cosmetics. I want to be able to air down the tires safely on washboard roads both unloaded and with a FWC Grandby (won't be doing extreme off-road stuff), but I want a smooth ride without excessive wandering and sway on the road. I will be doing a lot of highway miles, and will occasionally tow a boat trailer. I'll be using LT load range E tires. I don't think I care about losing 1/2 inch ground clearance with the base package, and in fact the lower truck height may help with getting the truck with Grandby in my 8 foot garage door.
I was only able to test drive trucks with the 20 inch wheel package. It was not a bad ride by any measure, but I did feel the road bumps more than I would like. Of course some of that may unavoidable in a one ton truck. I'm leaning toward the base wheel package thinking it will have a noticeably better ride due to more sidewall, and the additional sidewall is good when airing down. (A bonus would be the spare is the same size.) On the other hand, I don't want to later wish I had bought the 20s for some reason I haven't thought of. Do any of you have any experience comparing such a relatively small difference in tires/rims? Will the ride difference be noticeable on the road, and is the 1/2 inch sidewall difference between 7 and 7.5 inches enough to matter when airing down? Any other opinions to offer?
Thanks
