Can I use a 30" spare tire with my set of 33"s? (1 Viewer)
- Thread starter JCruse
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gofast
SILVER Star
You want to swap a new ring gears in?
this is the kind of question that is impossible to answer quantitatively, of course.
you may find somebody who did something similar (distance, speed, sizes) and may comment on the outcome but then what would that mean for somebody else?
So, it's most likely all guesses and subjective opinions.
Mine is that I would probably choose driving back over walking or calling a tow truck. Fully unlocked of course. Going slow and stopping frequently to let the VC cool off, if that even makes a difference. If I'm feeling particularly anal or paranoid I might check the temp of the TC and diff housing from time to time with an IR thermometer.
you may find somebody who did something similar (distance, speed, sizes) and may comment on the outcome but then what would that mean for somebody else?
So, it's most likely all guesses and subjective opinions.
Mine is that I would probably choose driving back over walking or calling a tow truck. Fully unlocked of course. Going slow and stopping frequently to let the VC cool off, if that even makes a difference. If I'm feeling particularly anal or paranoid I might check the temp of the TC and diff housing from time to time with an IR thermometer.
- Thread starter
- #5
That sounds a lot better than $200, but wouldn't a worn down 33" tire be almost 30" already? I know the original 31's were 29 something with 4/32's tread left.
Oh, the farthest I'm 'most likely' to travel normally is about under 30 miles.
Not really, just pick up a spare from your tire store(s) in the same size. Last 315/75r16 spare I got was 40-50% tread they had out back. Close enough for me to get home. I would not put 30mi on a tire with that much difference.
Im no expert, just my thoughts.
id search for a decent used one. just for peace of mind. i found one with barely any use for 50 bucks. you may have to drive around to a few tire shops but 285 isnt that hard to find.
93yotasr5
Come and take it
i wouldnt try it.
- Thread starter
- #9
I have 315's and had trouble finding NEW ONES to buy. Tire rack for instance currently has NONE. Neither does the STS chain. Mavis said they had to order a set and three days later said they couldn't find four! Finally I HAD to go to Firestone to get the Destination A/T's in that size. WTF?
So I may have trouble finding a used one of these, so I guess I'll have to take any 33" tire.
Thanks everybody.
.
315 is closer to 35. i think its 34.6 if you have 305 thats a 33. and yes any 33 will work for a spare if you have a 33 it doesnt need to be the same width just height. same goes for 35s you just need the height width doesnt matter and for used tires the mom and pops shops are best. the big chains usually dont keep used tires around.
WHY 
The differentials job is to allow the tires to spin at different rates. If you've got a smaller tire then it will spin it up faster, just as if it was doing the same thing to an outside tire during a turn. To me I really doubt using a smaller tire would cause for concern...
Although I wouldn't be the first to try this notion...
Although I wouldn't be the first to try this notion...
The differentials job is to allow the tires to spin at different rates. If you've got a smaller tire then it will spin it up faster, just as if it was doing the same thing to an outside tire during a turn. To me I really doubt using a smaller tire would cause for concern...
Although I wouldn't be the first to try this notion...
The wheels arent spinning at THAT different rates for an extended period of time, and that rate will go up when you turn. The diff heats up more than its meant to, the oil looses its qualities and things start to go bad.
Also, you have the instability issues, specially when the smaller spare it installed on the front. A lot of people say they will remove a rear tire, install it on the front and then install the spare on the rear to avoid the instability, truth is when the time comes to change the tire they are too lazy and just install the spare on the front (from experience).
Get 33" spare, used in good condition or new, either way. but make sure its in the same size.
It's just not that expensive for a little piece of mind on top of the other reasons not to get a at least a size same spare regardless of it is the same brand/model. Like said I would just get a decent used condition spare in the same size if you want to save some $$.
I got flamed a couple years ago on here for letting it rip on someone who wanted to use a different spare, so I've learned that lesson.
I'm with retrofive that it makes the most sense to track down an inexpensive, worn tire that matches the size of your 4 driving tires for the spare. It's just the best way to prevent irreparable damage to your drive train due to axles turning at different rates. A worn 33 is way bigger than a 31.
I'm with retrofive that it makes the most sense to track down an inexpensive, worn tire that matches the size of your 4 driving tires for the spare. It's just the best way to prevent irreparable damage to your drive train due to axles turning at different rates. A worn 33 is way bigger than a 31.
Polar Bear
Is it supposed to sound like that?
I measured the outside circumference of my 33" tires and went to the junk yard and started measuring their used stock. A worn 315 turned out to be a perfect match, and I traded them straight across for the new condition factory spare. I just had to pay for the mount and balance. 15 bucks out the door.
^^^^ This is very close to what I was taught by an old LC mech: That a normal diff is not designed to spin at different axle rates for an extended period (as would occur with substantially different size tires), and that the diff bearings would overheat at normal road speeds.
