Tire Size and Speed???

Silvercreek Farmer · #21 01/03/08, 01:26 PM

I checked my mine with my GPS, 3 mph off at any speed. I just account for it. I have also noticed that different brand tires of the same size do indeed vary, not to mention treadwear...

**Cabin Fever** · #22 01/03/08, 01:47 PM

....or inflation pressure.

Phantomfyre · #23 01/03/08, 02:09 PM

Quote:

Originally Posted by Cabin Fever

My 1999 K1500 4x4 came from the factory with 265/75-16 tires. This is the tire size for pickup with the Z-71 option package. The K1500's without the Z-71 package came with 245/75-16 tires.

CF, my '97 is a 4X4 ext. cab with the Z-71 package, and the sticker inside the door says 245/75-16, and that's what's on the truck. Possibly the model year difference explains that? It's also possible that the previous owner bought a Z-71 sticker and slapped it on, but I'm pretty sure this came from the factory with the Z-71 pkg.

Silentcrow and everybody, I seem to have confused the thread by posting the data on my truck. Sorry 'bout that - I didn't mean to 'jack the thread, but I hoped since it was the same make and same issue, I could get an answer too.

My truck is the '97 K-1500 Z-71 with the 3" body lift and the speedo reading 10% faster than I'm really going. Also, my truck is black and named Jack.

I don't have another driver here right now to check the gear ratio, but the guy I bought it from said that only the body height changed when the lift kit when on. No suspension or gearing changes. He *planned* to do some other things, but didn't get to it and then decided he wanted a 3/4 ton instead and sold this one. I made sure to ask him because I wanted to use the truck to tow with, and didn't want a raised suspension and wanted the 3.73 rear end. I never second-guessed what the guy told me.

I thought about the radar "Your Speed" dealies being wrong, but the readings are consistent in different towns and even different states. I also tend to make people mad if I run with the speedo at 65 on the freeway. If I set the cruise at 72, they calm down.

CF, I don't worry about it much, but I never thought about the mileage being off, too. THAT worries me. I'll have to double-check next time I'm on the freeway and have mile markers... I hope the ODO is right - 10% could add a bunch of miles to poor Jack... like finding out there's a typo on your birth certificate and you're really 10% older than you thought.

Phantomfyre · #24 01/03/08, 02:14 PM

Anyone have any idea what the dealership's going to charge me to recalibrate the speedo? That may well play into how much I decide to worry about this issue... LOL.

**Cabin Fever** · #25 01/03/08, 02:32 PM

Quote:

Originally Posted by Phantomfyre

CF, my '97 is a 4X4 ext. cab with the Z-71 package, and the sticker inside the door says 245/75-16, and that's what's on the truck....

You got my curiousity up, so I went outside and checked my door sticker. It says 265/75-16. My pickup is a '99 K1500 extended cab, Z-71 and I'm the original owner.

Phantomfyre · #26 01/03/08, 03:20 PM

Quote:

Originally Posted by Cabin Fever

You got my curiousity up, so I went outside and checked my door sticker. It says 265/75-16. My pickup is a '99 K1500 extended cab, Z-71 and I'm the original owner.

Interesting... I guess they did change more than the grille between those two years.

In any case, the good news is:
1. We both got a little extra exercise today walking out to look at our trucks.
2. We have good taste in trucks.

silentcrow · #27 01/03/08, 09:31 PM

My mom mentioned things to my cousin tonight. It would NOT be worth the price to have everything corrected. I'll just keep setting my cruise where I think it's safe (interstates only). Not too worried about incorrect mileage readings since it's getting near the 150,000 mark. As long as nothing major goes wrong, I'll keep it going as long as I can.

Phantomfyre, my truck is black, too

But doesn't have a name.