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URGENT! tire size question- wife stranded

3K views 23 replies 6 participants last post by  Strongjeff 
#1 ·
Wife has my jeep. Hit pothole- blew out right rear tire. Rodian HP 20" on srt8 rims. Can I run the factory spare even though it's 1/4" shorter in overall diameter?

Rodian is 29.75" dia

Factory Fortera is 29.5" dia

I don't want to ruin the rear diff but seems this is small difference in tire size might be OK?
 
#3 ·
Scott, thank you so much for getting back quickly. So you feel even that small size difference could damage the diff? She's 1 1/2hrs away right now. So you wouldn't recommend driving that long. We have AAA and can have it towed if need be.
 
#4 ·
How many miles? I would just have it towed if your worried or can't get a tore local. I think it would be ok....but can't say 100%
 
#5 ·
Jeep is on a roll-back heading home now. It's 95 miles away and I didn't want to risk damaging the rear diff with two different sized tires.

Now I have to find a new tire and have the rim checked to make sure it's OK. Wife told me it has some 'scratches' around the lip because she couldn't get off the road right away and had to slowly roll with it for about a mile. Won't know how bad it is till I see it later tonight.
 
#6 ·
Wife has my jeep. Hit pothole- blew out right rear tire. Rodian HP 20" on srt8 rims. Can I run the factory spare even though it's 1/4" shorter in overall diameter?

Rodian is 29.75" dia

Factory Fortera is 29.5" dia

I don't want to ruin the rear diff but seems this is small difference in tire size might be OK?
you should be fine for temporary use, I don't think it will hurt any thing :thumbsup:
 
#7 ·
UPDATE: The roll-back flatbed arrived at my house around 9pm last night. Thank you AAA! This one tow paid for the membership- glad I got it now.

The tire was completely destroyed. Both side walls disintegrated and separated from the tread, but it stayed on the wheel. Looking at the tire damage I was expecting the wheel to be toast but it's not. There is one small 1/2" scrape on the outside lip and that's it. You can't even notice it when you step back a couple of feet. No wheel-well damage either.
I ordered another tire locally. It should be in tomorrow, then I can get it mounted & balance and get my Jeep back on the road.
 
#8 ·
I would have agreed with Scott on this one, 1/4 inch isn't a lot but a 1600 dollar transfercase is ;) especially in your case when you have AAA and a free ride home.
 
#10 ·
When you reduce the size of A wheel then you effectively change the output ratio for that axle. So now your rear axle is spinning faster than your front axle... burning up the transfercase.

Yes, your diff clutches wont appreciate a long trip slipping against each other either.
 
#11 ·
When you reduce the size of A wheel then you effectively change the output ratio for that axle. So now your rear axle is spinning faster than your front axle... burning up the transfercase.

Yes, your diff clutches wont appreciate a long trip slipping against each other either.
Well if thats the case then whats the point behind a donut spare on a 4x4. I have seen them on 4x4's...
 
#12 ·
My Jeep is back on the road! Purchased a new tire yesterday. The wheel checked out OK, not bent or cracked. Put new tire/wheel on last night and drove it to work today.

I did find some additional minor damage from the tire tread rubbing inside the wheel well. It caught the plastic rivit that holds the lower rocker panel inside the wheel well and ripped it off. I replaced that easily. Also, the separated tread rubbed through the rear sway bar end link rubber boot, exposing the grease pocket. I'll replace that this weekend.

Re- donut spares: I would think that the overall diameter of any donut spare should match the other tires on any vehicle. Otherwise different sized tires could interfere with TC, ABS or other stability systems.
 
#16 ·
Glad to hear everything's worked out and that almost no damage was found. Its fine as long as you stay within 3% of oem spec size. 1/4th inch will not hurt anything for temporary use. Id still advise against long term use but it wouldn't affect the transfer. If anything the jeep would wear that tire out faster and maybe pull to that side.
 
#13 ·
#23 ·
1, oddly enough Tire rack sell tires, what exactly do you expect them to say?

2, your donut diameter comment does not hold water, as what happens if its used when the other 3 are nearly worm out........................or are you going to say you rotate the donut through with your other tires??
 
#17 ·
An open differential/open transfercase it doesn't matter, with NV245 transfercase there are clutches in the transfercase and the diffs (dependent on options). Also, you're talking about another vehicle, is it one you know personally or one you just saw? It is not uncommon for people to up size tires even slightly and only up size the 4 mounted on the car leaving the spare untouched.
 
#18 ·
Then I guess you dont know that I am a mechanic. I can promise you a 1/4th inch will not hurt it. And yes its a vehicle I have personally seen. An 03 durango with the nv245 tcase. That truck belongs to my mother. Its got 265/70/16's on it and factory sized spare on it (yes is a full size) 245/60/16. Drove around for a month on it cuz it broke the belts in one of the wrangler silent armors. No harm came to it. Oh it also has lsd In the rear. It has full time AWD with a selector switch for 4hi and 4lo. Its a fully loaded slt
 
#21 ·
Yeah, I have no idea and aren't suggesting you are incorrect. I haven't seen the truck so have no clue!

I thought the '03 durangos came with either the 242, which would have 2WD, Full-time 4Wd, Part-time 4Hi and 4Low (like the Jeeps with the 242), or the 231 which would have 2WD, 4Hi and 4Low.

Didn't think there was anything else available.

Either way, I think now we are officially way off topic! The OP has already changed out the tire, and obviously the TC held up, so we can certainly all agree that the small difference in diameter was fine for the small distance driven. In any other circumstance, who knows (insert dramatic music).
 
#22 ·
Yeah, I have no idea and aren't suggesting you are incorrect. I haven't seen the truck so have no clue!

I thought the '03 durangos came with either the 242, which would have 2WD, Full-time 4Wd, Part-time 4Hi and 4Low (like the Jeeps with the 242), or the 231 which would have 2WD, 4Hi and 4Low.

Didn't think there was anything else available.

Either way, I think now we are officially way off topic! The OP has already changed out the tire, and obviously the TC held up, so we can certainly all agree that the small difference in diameter was fine for the small distance driven. In any other circumstance, who knows (insert dramatic music).
Agreed so ill let it go lol
 
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