Tire size and rim size

Oct 29, 2005 9 Replies

I just purchased a 97 K2500 Ext cab LB. The truck is to be used for some towing (2 horse trailer) and a lot of hauling (wood, stone, hay, etc.)



The truck came with 285/75R16 tires on 6.5 rims. These tires do not need to be replaced immediately, but probably won't make it too far beyond this winter, so I've started the shopping for replacements.



Stock tires for this truck are 245/75R16. I wanted to go with



265/75R16, load range D. Everywhere that I look, tho, they suggest that this size tire should go on a 7.0 rim, which means that the 285s should probably be on at LEAST 7.0 rims.

So, my questions:


  1. What does it do to a tire if it is run on a rim that is too small?
  2. What tires will give me reasonably good traction in the fields/woods w/out singing (too loudly) to me when I go down the highway?

Your input will be sincerely appreciated.



Keith


Inline...

Wears out the center, causes wander, poor handling.

BFG A/T KO, Michelin LTX A/T, ProComp A/T...

Go with the stock size, load range E

I have a 1994 Silverado 4x4.It calls for 285/7516. Last year I bought rims from a neighbor who had a 2004 Tahoe.

My factory rims were pretty rusted.I had my tires which were new mounted on the Tahoe rims.

I had my tires rotated last week and noticed the center of the tires seemed worm more than treads near the sides.

I am wondering after reading this post that these rims are not wide enough?? I also noticed I would drift or wander a little on the highway.Looked at the front-end all seemed good.

This would explain why the wear in the middle and am wandering.

Does anyone know what size goes on the Tahoe 2004. 265 or 245???

When I buy new tires I should buy the size for the rims,than my speedometer would be off???

Not too bright on my part.

Thanks Doug

I went to a site to calculate difference in tire sizes.If I put the 265's on.Would I cause damage to trannie???

Stock Tire - 285/75R16 >Search Tires Tire 1 - 265/75R16 >Search Tires Section Width: 11.22 in 285 mm Section Width: 10.43 in 265 mm

Rim Diameter: 16 in 406.4 mm Rim Diameter: 16 in 406.4 mm

Rim Width Range: 7.5 - 9 in Rim Width Range: 7 - 8 in

Overall Diameter: 32.83 in 833.88 mm Overall Diameter: 31.64 in 803.65 mm

Sidewall Height: 8.41 in 213.61 mm Sidewall Height: 7.82 in 198.62 mm

Radius: 16.41 in 416.81 mm Radius: 15.82 in 401.82 mm

Circumference: 103.1 in 2618.7 mm Circumference: 99.39 in 2524.5 mm

Revs per Mile: 633.5 Revs per Mile: 657.3

Actual Speed: 60 mph 100 km/h Speedometer1: 62.2 mph 103. km/h

Speedometer Difference: - Speedometer Difference: 3.756% too fast Diameter Difference: - Diameter Difference: 3.63%

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Wear just in the middle means too much air pressure OR the rim is too narrow for the tire your running. Wear on the outer edges with little wear in the center and your running under inflated or the rim is too wide. However with a rim that is too wide tire wear will probably be the least of your worries, without the proper rim/tire fit the bead will come off VERY easily and usually when you really don't want it to.

Want an easy way to tell if the tires have the correct air pressure? Set the air pressure where you normally run it with the vehicle loaded as normal (full tank of gas and whatever else you normally carry in it) and using a large piece of chalk make a wide mark across the face of the tire in about three evenly spaced locations on each tire on the vehicle. Now drive it across a straight and level paved area like a parking lot. DO NOT TURN OR BRAKE while doing this. Now take a look at the chalk marks. If you see a nice even spot worn off across the entire tread width your on the money with tire pressure for the vehicle as it sits. If the middle is worn more then the rest your running too high and if the edges are worn more than the center your running too low. You can use the same trick to tell how bad the tires are rolling under in cornering as well by marking the edges of the tread up toward the sidewall of the tire. It also works as a quick check of alignment. If the chalk is worn away on the inside edges of the tires but is mostly there on the rest you have a problem with toe-out being too high, Worn on just the outside and you have too much toe-in. All little tricks you learn at the track that also work on the street.

Running a somewhat larger or smaller tire size will not damage the transmission. Tires need to be the same size all the way around.

Many people run 265 tires on these trucks with the stock wheels....( I have also ) on my 92K1500. I've never had anyone comment that the stock wheels were too narrow for a tire of this size.

A larger than stock tire can damage tranny best it puts more load on tranny and forces RPM lower at same speed and I question a 94 truck coming stock with 285 tires anyway. Smaller tires will not hurt anything except speedo calibration.

I agree. I don`t think that truck calls for 285's. I looked at putting them on my '97 1/2 ton and they would rub when you turn. That`s a big tire.

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