33x12,5 tires on Silverado 4x4 1995?

[Danish Farmer]

Hi gyes

Planning to put on 33x12,5 tires on the truck. She´s currently on standard 265x75.
Will I need to order the rims with a certain back spacing or will a standard 8 in wide, 15 in rim fit and leave clearence in the wheel well ?

Looking forward to your replies, and to get some decent rubber under her :hihi:

Thanks:hello:

 

[handcannon]

Is suspension stock height?

On my 94 K2500, stock suspension, I put 265/75/16 Toyo M55 tires on and had to do some trimming. The rims were not stock offset so that is where my problems stemmed from. Due to the increased offset (not sure how much, didn't measure) the tire did contact the lower inner edge of the bumper.

I'm assuming the pickup you are wanting to put these tires on is the one in your avatar. Here's some pics of my pickup. Look at the tire and bumper to see how far out the tire sets. I don't see any fender flares in your avatar and my first pic is with a fender flare. The second pic is without a fender flare. Third pic is farther back and showing both sides. Sorry for the crooked pics. I was on a slope when I took the pics.

I was going to start my pickup, turn the steering wheel a bit to show you how close the tire comes to the bumper. But I haven't started it in almost a week and I forgot and left the GPS plugged in. After the glowplugs cycled the batteries didn't quite have enough oompf to turn it over fast enough to fire. I put the charger on it for overnight so tomorrow I'll be able to get more pics.

Anyhow, If you have a wide rim with stock offset I'm thinking you'll have more clearance problems than I did. With my greater than stock offset, as the steering pivots the tire, the outer corner of the tire tread is actually put into closer contact with the rearmost edge of the bumper. It's kind of hard to explain, but it's like the farther the rim/tire combo sets out from the ball joints the greater the arc of the circle becomes as the tire pivots to turn the vehicle. As this arc becomes larger the tire comes closer to the bumper, or other body parts.

You may have to mount a tire, put it on the front and see just how bad the clearance problems will be.

Don

 

[SnowDrift]

Hi gyes

Planning to put on 33x12,5 tires on the truck. She´s currently on standard 265x75.
Will I need to order the rims with a certain back spacing or will a standard 8 in wide, 15 in rim fit and leave clearence in the wheel well ?

Looking forward to your replies, and to get some decent rubber under her :hihi:

Thanks:hello:

You can look at my photos to see what a set of 33x12.50-16.5 tires look like on a K2500HD, but keep in mind that my front axle is wider than yours - can't recall how much, though. I think it's 3" total width more on mine, versus your 1500. I ran the same tires on my previous K1500 and had much less rubbing than I have with this truck. I had the front raised about 1" or so with the torsion bars and had to cut the bottom corners of the front bumper for clearance.

My rims are 16.5x9.75 Eagle Alloy - you can look up the backspacing. I would stick with a 16" wheel, though, if I was you because the backspacing will be better for the application.

If you're running a 12.5" tire, you want more than an 8" rim, though. A 16x10 wheel will serve that tire well.

 

[handcannon]

Here's some more pics to show how close the tire is to the wheel well edge and the bumper. These are with the tire turned as if going into a corner.

Pic 1--- This is after trimming the bumper and air dam, left side wheel without the stock fender flare. In the top part of this pic you can see the upper edge of the bumper with the original factory edge. Where the radius starts is where I started the cut to provide clearance for the tire.

Pic 2--- This is the rear of the left wheel well showing clearance to the tire. I was able to get by without doing any cutting.

Pic 3--- Since I do have the stock fender flare on the right wheel well I did do a small amount of trimming just to make sure the tire wouldn't make contact with the rear edge of the flare.

By the way, my tires measure 30.5 inches in diameter from the corner of the tread to corner of the tread on the other side. With 33 inch tires your going to have some real problems with clearance.

Don

 

[Danish Farmer]

Handcannon, thanks that´s a very good describtion you give me here, and I thank you for illustrating with pictures too. Great.

I just want to be sure, you are talking about your 265/75/16 tires ? -and the clearance problems have been with them ?
Thats the standard size (At least for my truck) so how come all that rubbing ? Which tires did you run originally since the 265´s are causing problems?
---or is it just your greater back spacing that gives troubles up front ?

I am confused :hihi:

 

[handcannon]

Yes, they are 265/75/16 size, and on aftermarket alloy rims. I also have a second set of 265/75/16 tires on stock steel rims. This second set of tires have the tread worn down almost to the wear bars so they are smaller in diameter than the first set of tires. With the stock backspacing and stock width rim I have no clearance problems.

The problem was because of the greater backspacing of my alloy rims. Looking down from on top, think of the ball joints as the center of the circle as you turn the steering. The wheels and tires with the greater backspacing set out farther from the "center". Consequently, as the steering turns the tire like you are going into a corner in the road, the greater backspacing has moved the tire outwards, increasing the radius, and out closer to the fender.

This greater backspacing that I have would be just like a wider rim with standard backspacing. The outermost edge of the bigger tire would be setting in a similar location to my tire, and would have similar problems like mine did.

I hope my description helps you to visualize this.

Don

 

[Ed HD]

I ran 285/55R18 tires on my 98 Tahoe and had to do some minor trimming on the painted plastic that makes the wheel-well behind the bumper.

Crappy pics, but you get what I mean. You will need fender flares. I got an equipment warning from a State Trooper, since I had an inch and a half of tire sticking out up front. On my truck it was $400 for the flares, yours will be cheaper.

 

[THEFERMANATOR]

Also I wouldn't reccomend a 15" rim. Most 15" rims will not clear the brakes and such on the 88+ trucks. Go with at least a 16" rim. This is why most go with a 295/75/16 as it is pretty close to a 33 X 12.50.

 

[Yaz]

I ran 285-75-16's on my 94 Yukon with stock aluminum rims with no rubbing even when plowing. However my front air-dam was removed for the Plow hooks. The aftermarket wheels with any offset pushing the wheels out is going to give you your trouble.

 

[handcannon]

The aftermarket wheels with any offset pushing the wheels out is going to give you your trouble.

You said it better than I did. The point I was trying to make was that if the OP used wider than stock rims for bigger tires, even with stock offset, he'd have problems.

Don

 

[Danish Farmer]

OK gyes.
I ended up bying 285/75 16 tires for her, and I would say that you dont want to go bigger unless you want to lift the body.
The wind channel needed to be cut a bit, so like the lower corners of the fender.
On the rear of the wheel wells the mud flap needed to dissapear, and thats all. But if they were any bigger, modifications to the height of the body needed to be made.
The offset on the rims are 1 inch more than normal. Tires are General AT2 Grabber. The have a noce ride but steering becomes very hard
Will post picts later

Thanks for the help

 

[Danish Farmer]

I promised some pictures of her with the new rims. Here goes.

 

[NVW]

Nice looking truck, the rims look good on it.