2nd Gen Non-Engine/Transmission Spare tire ?

[jkalchik]

I'm just about ready to go get a new set of tires for my 99 QC SB 4x4. Currently, I'm on stock LT245/75R16 tires. I'm thinking about moving up in tire size for a bit of fuel economy during my daily commute. I'm cranking 2150-2200 RPM, and it'd be nice to drop that down to 1900-2000 RPM.



Here's the question: What's the tallest tire people have been able to store in the stock location under the bed? Just by eyeballing it, it doesn't look like there's much extra room. I'm not averse to storing a spare elsewhere, but if I'm close in size, I'll put on a size that can be stored under the bed.



Oh, and before anybody asks, I do have a limited slip rear end, and I always buy sets of 5, with the spare in rotation.



Thanks in advance.

 

[BSMcCauley]

I've been running LT235/85R16 E on my '96 (about 1/2 narrower and 1" taller dia than stock on average) and there appears to be room for something a bit bigger in the spare rack as long as it wasn't too wide. I have to work this size around the rear sway bar when cranking the tire up. 2000 rpm runs me down the road a hair over 70 mph and if memory says my axle ratio is something close to 3. 54.

 

[jkalchik]

After I posted that this morning, I got smart (or a reasonable facsimile thereof. ) I pulled down a copy of BFG's AT K/O data sheet and stuffed it into a spreadsheet. I used the revs/mile to figure out what RPM I'd be running during my commute, as well as filtering out sizes that would fit on stock rims.

Looks like I'd be well advised to try those LT235/85R16 tires. I'd only be dropping around 90 RPMs, less than I was hoping for, but I also won't have to buy new rims, and won't have to finagle new storage for a spare. If my math is right, these are around 1. 4" taller than the stock size.

 

[Joe Mc]

I've been running 305/70/16s since late 01 and the spare actually fits between the rails - it takes a bit of finesse (couple of big screw drivers and such) once the cable lift gets it close, but it fits right in there. It's about 1/2" from my 4" tail pipe other than that it's fine.

 

[jkalchik]

Hmmm..... 2 problems from from my point of view with that size.

I really don't want to have to beat a tire back up into that space along side the highway.

It'd also force me to buy new rims, that size won't go on a stock rim. If I'm buying new rims, I think I'm going to 17" to reduce the sidewall height.

 

[analog]

just so you know your options, the 3rd gen rims are 17", and fit fine on our 2nd gens. I did the swap on my truck, and they look and drive as if they came on the truck from the factory. I picked my set up on craigslist. Guys will get rid of them cheap when they upgrade to fancy wheels.

 

[jkalchik]

That's a good thought.

I came to my senses and realized that my old tires were really beating me (and my truck) up. New set of LT285/85R16E tires got installed at lunch today, and boy, do they make a difference.

I'll be quite interested to see what kind of fuel economy I get this weekend. A 600 mile run across Wisconsin and da Yooper Peninsula, all right around 60mph.