Tires

HockeyJoe · December 6, 2006

Hey all,

I don't know much about tires but I know I don't like the empty space in my wheel wells. I have an 05 silverado and currently have 245/70R17 on there now. I was wondering what size tire would fill up that empty space with out having to alter my brakes or anything else?

Thanks!

Joe

cerbomark · December 14, 2006

If you change the overall height (from ground to top of tire) 31 inches, you will have to reprogram the PCM for differnt size. You can go with a larger rim (18 or20) but then put a lower profile tire with no overall change. They will all fit over the brakes unless you go with a strange aftermarket wheel. I have a set of 18 s off a 07 Z71 , Take a look under the Marketplace section. They would fit on with no changes. If you want a differtn look, I guess you d look at a 32-35 inch combo. I m sure the offroaders can help with those questions. They will impact your fuel economy.

HockeyJoe · December 15, 2006

Thanks Mark,

I am looking to fill up the wheel well more. In your pic I like how your wheels and tires fill that up. So I might look into some wheels. It doesn't sound like I want to go too big because I don't want to have to reprogram anything. Too much of a hassle. Thanks again for the comment!

Joe

lowrider · December 15, 2006

You're comments are contradictory. If you want to fill up the wheel well more, than you want a tire with a bigger outer diameter. If you don't want to change any programing then you want to stay with the same OD. Also you have this to think about, If you do change the OD, you will also effectively change your axle ratio.

I was in the same situation as you. I have a set of '06 polished OE alloys that I bough from eBay, that I like a lot. I have a 3.23 axle ratio, that I didn't want to lengthen. I wanted to keep the same OD, and I wanted a wider tire. I also needed to get rid of the OEM General Americrap Tires. Anyway, I came up with 265/65/17s. They have the same OD as the 245/70s, are wider, and fit the wheel quite nicely. I put on Goodyear Wrangler SR/As which actually handle quite nicely.

Lou

HockeyJoe · December 17, 2006

Lou,

Well, I don't mean to sound contradictory, I want to fill up my wheel well more. I know that means I need a bigger OD. Also, I did some research and it seems that as long as I don't go bigger than a 285 then I don't have to reprogram my computer. Its my understanding that if I go from a 245/70 to a 265/70 then my tire will have a bigger OD because the 70% is coming from the 265 instead of a 245. That is just the way I understood what I was reading. If I am completely off then please let me know and bare with me because like I said I knew nothing about tires before this week. So thanks for you comments and please keep them coming!

Joe

lowrider · December 17, 2006

Lou,

Well, I don't mean to sound contradictory, I want to fill up my wheel well more. I know that means I need a bigger OD. Also, I did some research and it seems that as long as I don't go bigger than a 285 then I don't have to reprogram my computer. Its my understanding that if I go from a 245/70 to a 265/70 then my tire will have a bigger OD because the 70% is coming from the 265 instead of a 245. That is just the way I understood what I was reading. If I am completely off then please let me know and bare with me because like I said I knew nothing about tires before this week. So thanks for you comments and please keep them coming!

Joe

<{POST_SNAPBACK}>

Nope you're exactly right. You will have a bigger OD, and that number just happens to be 1". You'll got from an OD of 30.6" to 31.7". A difference of 3.6%. I don't know what you axel ratio is, but if it's 3:23 like mine, you will effectively change it to a 3.11. Your ECU will also be off a like amount. Don't know if that matters to you. But, it would to me.

Lou

HockeyJoe · December 26, 2006

Hey Lou,

I am not that familiar with what the ECU is? Emissions control unit? What does it effect on my truck? Thanks for the help!

Joe

superbee · December 26, 2006

Simply put, if your OD is bigger, the axle rotates less revolutions for any given distance, thereby indicating slower on the speedometer. You don't have to reprogram anything if you can live with a speedo that is a little off. The bigger change in OD the greater the error. Make sense?

lowrider · December 26, 2006

Hey Lou,

I am not that familiar with what the ECU is? Emissions control unit? What does it effect on my truck? Thanks for the help!

Joe

<{POST_SNAPBACK}>

No, It's Electronic Control Unit. The engine's and electronic's brain. It keeps track of the OD of the wheel the truck was originally shipped with. The above post is saying what I was trying to say, but neglects to say that with the lower engine revolutions will also be lower performance. With a 3:23 ratio, it's noticeable.

Lou

kdog55 · December 27, 2006

With a 1500 series truck you would be able to fit 265's in there. I had a 2000 that I put 285's on, but I needed a 3' body lift and some very subtle valance cutting. It looked awesome. Not too big, but totally different than stock. For a while I never did anything to my computer and the only difference it made was the speedo was off a slight bit. Maybe like 4 mph at 65 mph. Obviously this will throw off your gas mileage calculations, if that is a big deal. You will definetely feel a difference when it comes to the "quickness" of your engine. The taller tires will make it feel like you have less gearing in there. There is NO answer for this unless you actually change out your gears. A PCM upgrade or computer reprogram (Hypertech,Diablosport, etc.) will not make a difference in how the truck is geared. In other words, with the taller tires on there it will feel like it has less power when pulling out from a dead stop. Not a big deal, really, but it WILL be a noticeable difference. I eventually bought the Hypertech programmer and that fixed my speedo being off and the extra horsepower helped "mask" the fact that the taller tires were slowing me down on takeoff, but the problem was always there. But it never really got to me. I just knew it was there.

Now I have a 2500 HD that clears the same tires without a lift. Not that it helps you, but it was nice to just put on my tires and not worry about a lift kit and all the warranty problems and such!

I would without hesitation go with the 265's and maybe a slight torsion bar crank to level out the front end a bit (if your is a 4x4). That only takes a few moments to do and it is free.