AWD and Factory Spare Tire Question

[WVKayaker]

it appears their might be room to mount a full size spare where the donut spare is. Anybody here consider this? Can a 29" donut tire be mounted to the factory spare rim? I really don't want to carry a full size wheel and tire in the van.
Thanks for all the replies. It is always appreciated!

You should be able to fit a full size 29" tire under there,my tire is roughly 28" and fits under no probs.

Whats the concern with the full size spare? bottoming out,weight? you know were going to bug you to get the right size tire,LOL.

I just don't want to carry a full size spare IN the van. If I can mount a full size underneath then I'm good to go...

[phr1$k37]

Yups! As stated mine is under there 24/7 no problems. I bought the older style *89 5 star Safari rim for $40 locally.

[DON]

I want to thank everyone for putting this on the forum. I also want to accuse everyone who posted here of jinxing my van!!

Story; I bought new tires at the end of summer for my 02 AWD,225/75's. Wed. I was in a construction site for a job and ran over a bloomin nail. I hate job sites . Luckily I hadn't driven on it and noticed it at lunch when I went to my car. Short work day that day. I put on the spare drove to Costco told them I'll be back tomorrow to have them install and rotate the rest. They called me later that day. They destroyed the tire and had to order a new one. 4 business days!

Now, I know the spare is taller than the tires I am running, and was really concerned about the transfer case. I have had to fix 3 in my AWD lifetime and was tired of the cost. Then I remembered the hint about the fuse. I called my service adviser and asked him and he said "Pull it!"
I sure can tell the difference. With the fuse in the back end makes a lot of noise with that spare on.
So either "Thank You" or
"Curse You"
Don

[WVKayaker]

Pulling the fuse was a great tip! Sorry if we jinxed ya

[dunedog]

If you had the flat in the rear you need to make sure you don't have a G80 set up (posi)

[phr1$k37]

If you had the flat in the rear you need to make sure you don't have a G80 set up (posi)

hah ha ... Carry the full-size spare.

[DON]

If you had the flat in the rear you need to make sure you don't have a G80 set up (posi)

Dang, I think I do

[dunedog]

Don, This is only a problem if you are running oversized tires.The donut works fine and is the same diameter as the stock 215's.

[DON]

I'm running 225/70's

[T.Low]

Great thread.

I was scouting the local tire stores for any Chevy truck "take-offs and the manager said the Astro AWD system is pretty darn finicky when it comes to different sized tires. He said he's seen it even when a fresh full sized spare is rotated in with some used tires. Is it really so sensitive that rotating a full sized spare into the 5 tire rotation is going to set off the awd system?

I want to carry a full spare on a spare tire carrier like 9dawgs has on the back door of his van. (was a pictire of it somewhere around here, but now I can't find it.) But if this guys info is true, how can I avoid that problem?

[Astrophysics]

My 2003 AWD Astro is running BFG TA KO 225/70-16 tires ( ie. one size bigger than stock) on the alloy oem rims.
These tires are stiff and strong and since they are load range C they have stiffer sidewalls.
Each tire weighs 3 or 4 pounds more the factory 215/70-16 street tires and it reduces my city mileage to about 14 or 15 mpg.
I have set up my Astro for camping and mountain bike trips so I thought the agressive strong TA KO tires would be a good thing for now.

for my "full" size space I bought a BFG Long trail 215/70- 16 and it fits fine in the donut under the car.
I put a piece of light weight chain inside an old bicycle inner tube and used the chain to lock the spare.

I like the AWD AStro but the turn circle is about 44 ft. I need to plan ahead for some of the tight turns in parking garages etc.

Astrophysics

[potskie]

For those who have or want to use a full size spare I would recommend getting it on a matching rim and including it in your regular tire rotation. As tires wear they get smaller and tossing a new shiney one on with older tires may still cause problems especially if you are on pavement. The rule of thumb when I was a tire jockey was 3/16 of inch of difference max between tires on a GM AWD or else you will see damage.

[phr1$k37]

3/16 ... man ... I am way too lazy to get the spare on every once in a while. How long can you go without damages? Not known?

[potskie]

3/16 ... man ... I am way too lazy to get the spare on every once in a while. How long can you go without damages? Not known?

Just include the spare in your regular rotation. You know that thing your supposed to or should do about every second oil change or so.

On pre 99 vans you can see damage pretty quick as the viscous coupling in the transfer case can overheat and get damaged with extended use. Not sure about after 99. See the problem especially when your on dry pavement is the fact that nothing is slipping. If the tires are slipping is the only time it should be on but with not matching tire sizes even more than 3/16 of an inch will cause the transfer case to thing it's slipping constantly which will over heat the transfer case pretty darn quick. Same as driving a 4X4 on pavement over 35KM/h will cause substantial damage or if all the tires bite at once while offroading.