Yet another tire size question please

[GMJimmy]

Yeah I know, do a search! I did but it's impossible to find what I'm looking for. I have a 68 C10 fleetside short box with a 72 C10 rear end. It's lowered 2-1/2 inches in the front with drop spindles and 3 inches in the back (I think). It's got disc brakes on the front and drums on the back. I'm presently using 15X8 Rally wheels 5X5 with a 4.25 inch back space with 245-60's on the front and 245-60's on the back. I would like to put Ridler 645 wheels on it but don't know what size to go with. This is a driver and I'm thinking of using equal size tires all the way around but I need some ideas and opinions on this. My theory is if I have a flat I can use a spare of the same size on any corner. With different sizes front and back and a posi rear end i'd need two spares? The truck would look a lot better with larger wheels on the back but I'm wondering what most people would do. I'm thinking of 17's or 18's X 8's.
Any suggestions would be appreciated.
Thanks.

[Warrens69GMC]

https://www.summitracing.com/parts/u...9850/overview/

[GMJimmy]

Originally Posted by Warrens69GMC

https://www.summitracing.com/parts/u...9850/overview/

Thanks but these are the same as what everybody is using and I need help with tire size. I have already picked my wheels. Ridler 645's.
Jim

[BILT4ME]

Carry a spare that matches the REAR axle. If you have a flat on the rear, you just change it. If you have a flat on the front, it just steers funny until you get the tire fixed.

So you can put on whatever size tires you want. Not the most convenient, but it works.

The new Challengers don't even have a spare in the car. It comes with a can of fix-a-flat and a small air pump mounted in the trunk. Seriously.

[GMJimmy]

Originally Posted by BILT4ME

Carry a spare that matches the REAR axle. If you have a flat on the rear, you just change it. If you have a flat on the front, it just steers funny until you get the tire fixed.

So you can put on whatever size tires you want. Not the most convenient, but it works.

The new Challengers don't even have a spare in the car. It comes with a can of fix-a-flat and a small air pump mounted in the trunk. Seriously.

Good advice but my concern is the spare won't fit the front properly. I have a 2011 Corvette that doesn't come with a spare either. It has run flat (extended mobility) tires. I'm going to put different size tires on my truck and get a spare to match the rear as you suggested and I have AAA anyway so I think I'm worried about a minor issue. I still need to know what size tires and wheels guys are putting on these trucks?
Jim

[Mike C]

'69 short step leaf spring truck. 2 1/2" spindle disc conversion and 2" springs in front. DJM flip in the rear netted 7". I'm not a fan of how 20" rims look on these trucks and went with 17's.

235 55 17 in the front on 17x8 zero offset (4.5" backspace) wheel and 275 55 17 on the rear on a zero offset 17x9 (5" backspace).

On a stepside truck this is about the biggest tire you could run with that much drop in the back. I like how the wheels tuck and the slight rake this netted.

[Overdriven]

I personally like how these trucks look with wider and taller tires out back for a bit of rubber rake. Up to you how you want to deal with issue of having a spare though. I've seen some trucks that look really good with square stance (same size all around) too though.

Biggest piece of advice I can give is to measure your truck. Every truck is going to be a little different as far as drop and how big of a gap between the tire and wheel opening looks good can be subjective. So, on flat, level ground measure from the axle centerline to the fender/bed. Determine how much gap you want between the tire and wheel well opening and you now have the radius of your tire. Figure out your wheel size and then you can decode the exact tire size.

I personally would go with 18" vs 17" wheels. 18" is just more common these days and the tire selection is better.

[Mike C]

You are correct with tire availability and the 18" rim. I would probably go that way if I was doing it again, but I'm not sure if I could have done it for as inexpensively as the 17's since they were just $140 per wheel.

I have not figured out my spare situation yet. I will probably do something if I ever get to do Power Tour, but I still have the 6 lug tire mount on my fender so I need to score a 5 lug. The 29" tire in the rear is pretty close to a 215 75 16 which is what I would try and find for the side where I could get the OEM hubcap but his is a fleet so less of a concern what the spare looks like.

[hdff]

Originally Posted by BILT4ME

The new Challengers don't even have a spare in the car. It comes with a can of fix-a-flat and a small air pump mounted in the trunk. Seriously.

I have a 2003 z06 corvette that came that way except it is a portable air pump, not run flats

[Overdriven]

Originally Posted by Mike C

You are correct with tire availability and the 18" rim. I would probably go that way if I was doing it again, but I'm not sure if I could have done it for as inexpensively as the 17's since they were just $140 per wheel.

I have not figured out my spare situation yet. I will probably do something if I ever get to do Power Tour, but I still have the 6 lug tire mount on my fender so I need to score a 5 lug. The 29" tire in the rear is pretty close to a 215 75 16 which is what I would try and find for the side where I could get the OEM hubcap but his is a fleet so less of a concern what the spare looks like.

Cost is always a factor for most of us and I don't doubt 17" is a bit less expensive for tires and wheels. Also 17" may be fine if the size you want/need is common for newer a production vehicle. I did a quick search not too long ago for tires and the selection was more limited for 17" in the size I wanted to go with. In 18" I could get everything from grocery getter all seasons to very racey Pirelli Corsa's in the same tire size. My generalization is based on this, but of course may vary depending on the exact size you want.

As for a spare, get some fix a flat, a small compressor and a good plug kit. The link below is for the best plug kit I've come across. Aluminum handles on the tools and super sticky plugs (you can buy refills of just the plugs) that seal the leaks very easily. I've been very happy with it and will never buy a cheap kit from the chain auto parts stores again. I just need to get another to keep in the truck when I get my new wheels and relocate the fuel tank to out back.
http://safetytireseal.com/safety-sea...pair-kits.html

[Mike C]

Since the side mount spare is a feature of my truck and I'm dragging it around anyhow I figured it should probably fit. LOL

And AAA is always available but I would rather solve my own problem first.

[GMJimmy]

Thanks everyone for your input! It's very helpful. I have 275-60-15's on the back and have roughly 1.75 to 2.00 inches of space from the bed to the inside edge of the tire and about .75 inch from the outside of the tire to the inside lip of the fender until the suspension is compressed completely where the outside edge then rubs slightly on the inner part of the fender. Looks like I could use 1 inch more back spacing. These rally rims are 15X8 with a 4.25 inch back space. I was worried about lower control arm clearance with more back spacing but not with 17 or 18 inch wheels.

So those of you that are running 18 inch wheels, what tires are you using and what is the back spacing of your rims?
Thanks.
Jim