New truck, needs tires..

[DustinB]

Hi guys, I recently traded my 72 c20 for an 85 gmc c3500. It needs new tires and I was wondering what the best size to run is? It has ultra Goliath wheels on the front and outer duals in the rear. Thanks guys!
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[79 silverado]

It partially comes down to what your goals are and what you will be using the truck for, also how much work you want to do.

As you switch the tire and rim sizes you can play with the sizes according to your needs, it goes up and down accordingly. Opening the door should show the original GM label and tell you what the factory size you were set up for was.

For example: a 235/75/15 is a basic popular 1/2 ton size. What this means is the width of the part of the tire that touches the road is represented by the 235. The 75 reflects the sidewall height as a percentage of the tire width. The last number is the rim size.

A 235/75/15 is almost the same exact height overall as a 255/70/15 or a 275/65/15... for each 20 increments wider you go you can step down 5 in the sidewall proportion and maintain basically the same height.

Why does this matter?

Different width tires have different performance characteristics, and also can only fit on rims of certain widths... This is why you see guys go from 15x7 to 15x10" rear wheels, to accommodate the wider tire size, it has to do with the edge of the tire seating well on the trim (the bead).


A wider tire is heavier and takes more power to turn. Bigger tires decrease fuel mileage. If you go with a size that doesnt maintain an equivalent overall height it will effect the accuracy of your speedometer, with a shorter tire making it read somewhat higher than it really is, and a bigger tire making it read lower than you really are driving.

If you are into off-roading you will pick a bigger tire. Towing you may choose a taller skinnier tire. Ride quality, the rest also make a difference. All of this is not to mention the appearance factor.

So all of that said, think of the look you want and your priorities - do you want to save some gas mileage and go smaller, or get a little more height and appearance at the expense of a little less fuel mileage? A fatter tire loses some of that mileage....

[Skunksmash]

Order em from onlinetires.co m cause you'll save $150-$200 over any retailer. Just ordered 4 new tires for my stang and it was $750 total. The cheapest retailer I could find near me was discount tire, and they wanted $950 for their least expensive tire. I got a set of michelins.

[oldmann1967]

Originally Posted by Skunksmash

Order em from onlinetires.co m cause you'll save $150-$200 over any retailer. Just ordered 4 new tires for my stang and it was $750 total. The cheapest retailer I could find near me was discount tire, and they wanted $950 for their least expensive tire. I got a set of michelins.

That is great as long as you can dispose of the old tires, mount and balance them yourself and still come out ahead. Discount tire is never the cheapest here. I always find the best deal at my GM stealership believe it or not.

[DustinB]

i ended up getting a good deal from a friend of mine, he had four brand new tires sitting in his garage that he didnt need, they ended up going with a different size for his dually so he sold me the four for 100 a piece, i only had to buy two at full price. thanks for the advice!

[Skunksmash]

Originally Posted by oldmann1967

That is great as long as you can dispose of the old tires, mount and balance them yourself and still come out ahead. Discount tire is never the cheapest here. I always find the best deal at my GM stealership believe it or not.

Any of your typical mom and pop shops will mount and balance all for tire for around $40. Had that done twice when ordering from online tires. Some places won't but they're just stupid I guess. After all what would you rather have 0 dollars or 40 dollars, and somebody somewhere is more than willing to mount and balance that set of tires. Did it twice already when ordering tires online. The disposal fee was $2.30 per tire so that's not really an issue. I figured it all out, and I still saved somewhere in the area of $200 over retail, ordering online. But that's typical, you can always get better deals online.