Truck Tires

[teverheart2002 (Premo)]

Expensive way to go, but have you thought about 19 1/2 inch wheels with semi tires. We are thinking about doing this for my F-350, and interested if anyone has done this on here. A website that we were given is: www.ricksontruck.com

[gumbo]

Originally Posted by DoWhat

Right now I have;
P265/75R16

Do you think it would be stupid to go with;
P275/70R16

A little height and width.

On the new style Chevy and GMC Pick ups you have to watch out for tire to front bumper clearance when you turn the wheels.

[MMDad (Premo)]

Originally Posted by gumbo

On the new style Chevy and GMC Pick ups you have to watch out for tire to front bumper clearance when you turn the wheels.

Truck Tires

[gumbo]

Originally Posted by MMDad

Truck Tires

I seen that..The reason I made my post is because the Chevy and GMC truck only has about an inch of clearance to play with from the factory.
The clearance is only a small problem. It's a little more complicated than the redneck tire gage (turn the wheels see if they fit)
The front end geometry of the new Chevy and GMC trucks are very temperamental because of the long spindles used.
For every tire size you go up the more caster gain you get, unfortunately on the Chevy and GMC trucks they already have a ton of caster gain.
So by adding to it, it causes sever tire wear much like the I beam suspension of the older F-150 and 250.
You can adjust the initial caster but not the caster gain
The caster gain is built into the spindles geometry, so by increasing the tire size you are increasing the geometry angle of the spindle, also by do this you throw off the Ackerman steering and the bump steer geometry thats built into the suspension.
In layman terms. Caster gain is how much your tire leans in or out at the top for every degree the tire is turned.
By increasing the height the more the tire leans.
The more the lean the more the tire wants to ride on the inner or outer edge.
Clearance is the least of the problems..
If the truck is a daily driver do not go over one tire size up on the newer Chevy and GMC trucks and if you go up one size do not expect the same wear you got from the stock size.

[MMDad (Premo)]

You've gotten a lot of "expert" opinions, but what does your owner's manual say?

[gumbo]

Originally Posted by MMDad

You've gotten a lot of "expert" opinions, but what does your owner's manual say?

Not opinion... fact
I build and design race car suspension.
I also own a collision repair shop.

BTW..A owners manual will recommend the same size tire. Your front end geometry is designed for the size tire on your vehicle.
Some designs are just more temperamental than others.

[MMDad (Premo)]

Originally Posted by gumbo

Not opinion... fact
I build and design race car suspension.
I also own a collision repair shop.

BTW..A owners manual will recommend the same size tire. Your front end geometry is designed for the size tire on your vehicle.

Relax, Dumbo. I wasn't slamming you.

Without knowing year etc. you can only make an informed opinion. I was asking for what the owners manual says because it might recommend a different tire than either of those he mentioned. If you start with the manufacturers recommendation, you have a lot better reference to start with.

[bcp (Premo)]

I do heavy towing so on my I use the Wrangler All season 10ply.

they are rated 10 for snow, and when you only put 60lbs of air in them the ride is not too bad going down the highway. They are also quiet tires as they do not have the standard aggressive tread that causes the noise.

a little steep on price but I have had good luck with them.

I just replaced the two back ones and I think the out the door price was around 450 bucks.

[fddog]

Originally Posted by gumbo

I seen that..The reason I made my post is because the Chevy and GMC truck only has about an inch of clearance to play with from the factory.
The clearance is only a small problem. It's a little more complicated than the redneck tire gage (turn the wheels see if they fit)
The front end geometry of the new Chevy and GMC trucks are very temperamental because of the long spindles used.
For every tire size you go up the more caster gain you get, unfortunately on the Chevy and GMC trucks they already have a ton of caster gain.
So by adding to it, it causes sever tire wear much like the I beam suspension of the older F-150 and 250.
You can adjust the initial caster but not the caster gain
The caster gain is built into the spindles geometry, so by increasing the tire size you are increasing the geometry angle of the spindle, also by do this you throw off the Ackerman steering and the bump steer geometry thats built into the suspension.
In layman terms. Caster gain is how much your tire leans in or out at the top for every degree the tire is turned.
By increasing the height the more the tire leans.
The more the lean the more the tire wants to ride on the inner or outer edge.
Clearance is the least of the problems..
If the truck is a daily driver do not go over one tire size up on the newer Chevy and GMC trucks and if you go up one size do not expect the same wear you got from the stock size.

We install camber/caster bushings everyday, and do cut outs on trucks to fix caster

[Pete (Premo)]

Seems strange to me too. I have a GMC K1500 and I have 245/75/R16's. The same model truck also comes with 265/75/R16's like the one sitting next to mine in the parking lot.

I don't know why but it seems that GMC does a run with 245's and then some with 265's. I cannot imagine the front end geometry is different between the trucks off the same production line because of tires size. Seems like it would screw up the efficiency of the line having to match suspension part to tires.