Tire Size Calculator

[Hardline]

I was playing around on this trying to determine the size tires I want to put on my truck.

https://tiresize.com/comparison/

 

[rags747]

You can definitely go up in size by reducing the profile of the tire. Obviously staying as close as possible to the original equipment overall diameter works best, there will usually be some discrepancy but the less the better. I think Tire Rack has a tire calculator as well.

 

[Tabascocat]

I have used something like this for my Ram but it didn’t work out. My truck has this automatic airlift/lift kit that adjusts to driving conditions. It lowers automatically when on the freeway and goes up on certain roads or offroad. I can’t really go up in size, just a better, tougher looking all-terrain tire.

 

[Oz-of-Cowboy-Country]

Wow I'm so out of it right now from lack of sleep. That when I saw the title I thought... who wants a calculator the size of a tire?

 

[RJ_MacReady]

What kind of truck and what do you do with it? I like to downsize the wheel diameter (18" to 17" or 17" to 16") and bump the tire size up to get more sidewall. Better ride and in the case of 18" vs 17", the tire selection/price is better on the 17".

You can plus size the overall diameter, but only to some degree without lifting. You have to watch the clearances, especially the front when turning the wheels. .8" increase is pretty decent. I went up about the same on one of my SUVs (went 18" to 17" and bigger tire for more 'meat') and had to break out a heatgun and pipe to reform the front splash guards in the wheel wells. Just looking from the side, the front tires look like they have plenty of clearance, but once you turn the wheel, you realize how close edges of the tires get to the splash guards.

One other thing, different brand/model tires can vary in actual width and diameter. Certain tires run large and others small. I have to deflate my spare tire half-way to get it under my SUV because the brand/model is about a .25" larger than the average, otherwise it can't clear the towing hitch bracket. Just for for thought.

What I learned the most, was going to an actual forum for the truck you're trying to upgrade. There will be a list of "Yeah, it works, no it doesn't work" on there. That's how I knew I could downsize my wheels and they'd still clear the calipers, and that I would need to used a heatgun on the splashguards, etc.

 

[John813]

It's a good start to figure out which way you want to go tire wise. @RJ_MacReady advice about checking out forums is good too as between offsets, tire companies with varying true tire sizes etc some setups can rub and others not even if they are close to the same spec.

A good example is the 19+ Silverado where some aftermarket wheels would hit the caliper as GM redesigned their brakes for the truck. While most companies re-designed their wheels to clear the caliper, some still run into that issue even if the offset they want to run works on 95% of other wheels.

 

[Vtwin]

Back when I used to upsize tires on my truck I used the calculator to get the max diameter that the forum experts had determined was the max you could go without a lift. It worked well and I never had to do any modifications. Before there were forum experts to consult you would measure, eyeball and the tire store guys usually could tell you from their experience.

Nowadays I stick to the stock size but go with a stiffer LT rated tire over the P rated that come from the factory.

Going to a bigger diameter definitely affects performance. Back when 4.10s and 3.73s were the standard rear end ratios it was still noticeable but not near as much as on the new standard 3.15s and 3.31s.

Some places around here won't put anything on other than what the sticker on the side pillar says the vehicle came with.

 

[triplets_93]

With the warmer weather today, I took my car to QuikTrip to air up the tires. They were all 8 pounds low. Then I had to remember where to reset the tire monitor...