The window sticker from my '09 1500 Quad Cab with the Big Horn Regional package 25G tells me i have a full size restricted use spare tire.
Does this mean the rim is 20 inches like the other 4 wheels?
Or is it 17 inches?
If it is 17 could I get a 20 inch rim and put a 275/60R20 tire on it and would it fit where the spare tire is kept?
Thanks,
Jack

 

Maybe this thread will answer your question.

https://dodgeforum.com/forum/4th-gen...nderneath.html

I recall from another thread that an owner with a flat on the rear performed a two tire/wheel change with the 17" spare. Put the spare on the front and put the good 20" front wheel/tire on the rear.

The 1/2" difference in diameter tween the 17" spare and stock 20's is reputed to be acceptable for short term use. Personally though, I would not use a shorter spare on the rear if I had a Limited Slip Differential (LSD). The expense of repairing a differential CORRECTLY and THOROUGHLY is about $1,300 and few rear end shops will take the time to do an accurate set-up on a Dodge 9.25" diff. I know this from experience as do others on this forum who have had diff. work, both at independent shops and Dodge dealers.

If I had a 4wd and LSD, I'd find an OEM 20" wheel and tire to match...do whatever it takes to fit it in the spare tire rack and be done with it. Having had tire issues far from a metro area when on a road trip, I can tell you that the expense of modifying in advance is far less than dealing with tire matching in remote areas.

 

My spare is a 235-85/17. The diameter measures 32 inches. The 275-60/20 measures 33 inches.
This would make the 20" tire only 1/2" closer to the tailpipe. The tailpipe has a heat-shield at the closest point.
I am beginning to think that the small difference between the two tires diameter would not cause any problems when used for a short distance. I don't have LSD.
Jack

 

why not just throw it in the back of the bed its gonna go get fixed anyway cant drive around with that lawnmower tire on for long.

 

The rear differential is part of the drive train isn't it?
My '09 has the lifetime drivetrain warranty.
I should be alright with the original spare tire.

 

Ok so I had s flat in my 09 ram 1500 20" wheels my spare is 17" had to drive 300 miles to get home. Now I have had nothing but trouble steering wheel shaking seats shaking. Been to two dealers several times tire shop and regular little shop nobody can figure out what's going on. Was told to buy 4 new tires. The Nitto terra grapplers that were on the truck were new. 295/60/20. So I just bought 4 275/60/20 going tomorrow to have them put on hoping it fixes problem. Wondering if I tore something up in rear end from driving 300 miles with a smaller tire on same axle?

 

The spare tire shouldn't be any smaller than the tires on the truck, unless they were replaced. From the factory they are the same size.

Beyond that, unless you have a locking rear diff, I don't think that even if the tire was smaller you'd have ruined anything; and you would have felt it driving hard, struggling to keep it straight on the road, and squealing tires going around corners. With standard open diff, absolutely no problem. With LSD, I suppose possibly, but I doubt it; I'm pretty sure they are just a standard clutch type and 300 miles is really not that far.

 

I can understand a manufacture using a limited use tire on a passenger car, but on a full size truck, many of which are 4 wheel drive is just plain stupid. I would be nervous to use that balloon looking thing if I was towing a trailer or using the 4 wheel drive. There should be a correct sized 20 inch wheel (steel) and a tire that exactly matches the rest of them on the truck. This is what the previous generation Rams had for spares when they were equipped with 20 inch aluminum wheels.

 

I would like to see a picture that shows the spare is NOT "full size" and same or greater capacity as the four regular tires. Just a wheel size of 17" versus 20" is a total non-issue.

If you care about what it LOOKS like, then go ahead and buy another aluminum wheel and matching tire. Most people never even need to use a spare tire, and charging everyone for a full match (and expecting them to rotate it AND replace the spare when buying 4 other new ones) is not very reasonable for the general populace.

 

Don't have my factory spare anymore. It was a 17" steel and a full size restricted use tire.
If I recall the size of the spare was very close in diameter to what was on the ground with the 20" rims.

When I replaced the stock tires, I purchased a cheap 20" rim along with 5 Michelin LTX MS2 tires. The 20" rim spare fits just fine in the spare tire rack under the truck.

Now all the tires are the same. I just didn't want to pay Dodge or the junk yards the price they wanted for a matching rim.
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