How Bad is it if Spares Not Exactly Same Size?
#21
Le Mans Master
I was 19 when I bought my first Corvette, a 1963 convertible. Over the next 9 months I went through at least three sets of rear tires. I changed a bunch of flat tires in that time. I finally realized that trying to count the layers of cords on a 4-ply tire before changing it was futile! Well that and rear tires didn't last nearly as long as front tires on these cars back then.
I also learned to carry an old blanket in the carrier as well, it came in handy when you had to stuff a dirty, flat tire in the passenger seat.
The 4th set of rear tires lasted 37 years, and still held air when pumped up. Of course 36 of those years were in storage...
Good luck... GUSTO
I also learned to carry an old blanket in the carrier as well, it came in handy when you had to stuff a dirty, flat tire in the passenger seat.
The 4th set of rear tires lasted 37 years, and still held air when pumped up. Of course 36 of those years were in storage...
Good luck... GUSTO
Last edited by GUSTO14; 11-10-2018 at 07:12 AM.
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Roger Walling (11-09-2018)
#22
Instructor
OP- I share the exact scenario, only reversed. My 64 has Kelly 205/70/15's which are 26.3" in diameter. I just ordered an S-10 T155/90 D16 spare, which I believe is 27" in diameter. So, my spare will be .7" larger than the opposing tire if used on the rear. Same problem though.
I could not find a T155/80 D16 on a rim, anywhere, looked for months. Finally decided to go with the S-10 rim/tire, and if I cannot get a definitive (like you so far!)....I would put the spare in the front, and move a tire to the rear.
Like many, I have never gotten a flat while out cruising. However, I like being prepared, and would rather get out and jack up the car than sit there and wait for a tow, (AAA is sloooooow in these parts) or pump my tire with fix-a-flat, and hope she holds air. I carry a pretty well thought-out kit (with suggestions from folks here accounted for) to deal with possible road-scenarios: (belts/hose/battery boost, etc).
I could not find a T155/80 D16 on a rim, anywhere, looked for months. Finally decided to go with the S-10 rim/tire, and if I cannot get a definitive (like you so far!)....I would put the spare in the front, and move a tire to the rear.
Like many, I have never gotten a flat while out cruising. However, I like being prepared, and would rather get out and jack up the car than sit there and wait for a tow, (AAA is sloooooow in these parts) or pump my tire with fix-a-flat, and hope she holds air. I carry a pretty well thought-out kit (with suggestions from folks here accounted for) to deal with possible road-scenarios: (belts/hose/battery boost, etc).
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Lotsacubes (11-09-2018)
#23
Team Owner
I don't think you're gonna burn up a posi limping to a service station in 10-15 miles; beyond that you might want to consider the "double tire change". The S-10 is a nice alternative if you can find one; especially if you can find one that was never used and stayed under a truck bed away from UV light... The tire tub will close completely and there is room for some extra stuff in there too...
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Lotsacubes (11-09-2018)
#24
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Just do the math. The tire with the 26.3" OD travels 766.8 revolutions per mile. The tire with the 25.7" OD travels 784.7 revolutions per mile. Or 21.9 more revolutions per mile. If you go 20 miles the shorter tire will have to turn 438 more times than the taller tire. This will create lots of heat in the posi unit.
Well, if that bothers anyone, they can always let some air out of the other tire and make the rolling diameter closer. to the spare. But I wouldn't worry about it if you're not driving far.
#25
Drifting
My spare tire is made by SAMSUNG....... Make a call, flat bed shows up, hand them the Mastercard. Having said that, carrying a spare tire would do me no good since I don't have a jack either. I was in the towing business a few years back and have changed my share of roadside (highwayside) tires so not doing it anymore. I'm old and have pain in my shoulder, arm, knee and a bunch of other body parts so I'm fine with waiting for a tow truck. Finally, to answer the OP's question......, it won't hurt your posi rear if you tow a few miles, but you can always whip one of the front tires on the rear (if the same size) to have peace of mind...... or call for a tow ! Good Luck with whatever you decide.
Last edited by Jims66; 11-09-2018 at 07:00 AM.
#26
Team Owner
I'd rather try to go with SLIME Fix-A-Flat or the like....
I've seen some of those Bubba tow-truck and rollback operators and to most a classic car another job and they're not careful....
Worst case I'll change a tire roadside but with the distracted drivers and 55+ year old scissor jacks in various states of repair I wouldn't do it for fun...
I've seen some of those Bubba tow-truck and rollback operators and to most a classic car another job and they're not careful....
Worst case I'll change a tire roadside but with the distracted drivers and 55+ year old scissor jacks in various states of repair I wouldn't do it for fun...
#27
Team Owner
I can't believe anyone would rather have their car dragged onto a flatbed and then dragged off than to change a tire. You'll be sitting just as long waiting for the flatbed and who knows what area or what time of day. Some of you will spend 50 to $100,000 getting the car the way you want it and then let whoever is on duty that day drag your car around because you don't want to change a spare.
To the OP, I answered it very early on but I'll tell you plainly again, drive it with the smaller tire to a place to get it fixed. As little as the chances are you'll get a flat they're even half as much that it will be on the rear.
To the OP, I answered it very early on but I'll tell you plainly again, drive it with the smaller tire to a place to get it fixed. As little as the chances are you'll get a flat they're even half as much that it will be on the rear.
#28
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I can't believe anyone would rather have their car dragged onto a flatbed and then dragged off than to change a tire. You'll be sitting just as long waiting for the flatbed and who knows what area or what time of day. Some of you will spend 50 to $100,000 getting the car the way you want it and then let whoever is on duty that day drag your car around because you don't want to change a spare.
To the OP, I answered it very early on but I'll tell you plainly again, drive it with the smaller tire to a place to get it fixed. As little as the chances are you'll get a flat they're even half as much that it will be on the rear.
To the OP, I answered it very early on but I'll tell you plainly again, drive it with the smaller tire to a place to get it fixed. As little as the chances are you'll get a flat they're even half as much that it will be on the rear.
Look like something to investigate.
More Flats on Rear Tires by Jobst Brandt. Many sharp objects, especially those that lie flat on the road like nails and pieces of metal, more often enter rear tires than thefront tires. That is because the front tire upends them just in time for the rear tire to be impaled on them.
#29
Race Director
Buy a reproduction bias ply tire of the approx. same diameter of your radials and use. Mixing radials and bias ply is not recommended for long term use but to drive 10 - 20 miles for a repair I'm pretty sure most of us could handle it. FWIW - I have 205/70-15 tires including the spare which is on a steel rim and it fit in the tub with the longer bolts for the KO wheels.
#31
Drifting
I can't believe anyone would rather have their car dragged onto a flatbed and then dragged off than to change a tire. You'll be sitting just as long waiting for the flatbed and who knows what area or what time of day. Some of you will spend 50 to $100,000 getting the car the way you want it and then let whoever is on duty that day drag your car around because you don't want to change a spare.
To the OP, I answered it very early on but I'll tell you plainly again, drive it with the smaller tire to a place to get it fixed. As little as the chances are you'll get a flat they're even half as much that it will be on the rear.
To the OP, I answered it very early on but I'll tell you plainly again, drive it with the smaller tire to a place to get it fixed. As little as the chances are you'll get a flat they're even half as much that it will be on the rear.
#32
Racer
If you place your spare in a large black plastic lawn bag, the slippery vinyl of the bag allows the normally grabby rubber tire to slip right in, with lots less effort. It also allows for a cover if you need to put the flat in the rear of the car.
This tire size conversion chart is handy to determine different sizes that all have the same overall height. Just click the wheel size tab at the top and the appropriate chart is displayed:
https://tiresize.com/conversion-chart/
This tire size conversion chart is handy to determine different sizes that all have the same overall height. Just click the wheel size tab at the top and the appropriate chart is displayed:
https://tiresize.com/conversion-chart/
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#33
Melting Slicks
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Lotsacubes (11-09-2018)
#34
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I carry a tire plug kit and small electric compressor. This takes care of most types of flats and I’ve used it three times in 25 years. If I can’t fix it, I call for a tow. Simple.
I would not drive on mismatched sizes on the rear with a clutch pack LSD for more than what it takes to get to a shop for repair. While none of us would do this, human nature often says out of sight, out of mind. Next thing you know, 200 miles have gone by and we wonder why the posi doesn’t work anymore. Most of us are too **** for this as the mismatch would keep up awake and drive us crazy until we had the correct tires back on our baby.
I would not drive on mismatched sizes on the rear with a clutch pack LSD for more than what it takes to get to a shop for repair. While none of us would do this, human nature often says out of sight, out of mind. Next thing you know, 200 miles have gone by and we wonder why the posi doesn’t work anymore. Most of us are too **** for this as the mismatch would keep up awake and drive us crazy until we had the correct tires back on our baby.
#35
Melting Slicks
[QUOTE=GUSTO14;
I also learned to carry an old blanket in the carrier as well, it came in handy when you had to stuff a dirty, flat tire in the passenger seat.
I tried that but my wife would not get into the trunk!
I also learned to carry an old blanket in the carrier as well, it came in handy when you had to stuff a dirty, flat tire in the passenger seat.
I tried that but my wife would not get into the trunk!
#36
Team Owner
My wife is from West Virginia - I constantly jibe her about one leg being shorter than the other....at 65 she had to get a left knee replacement.
Coincidence ? I don't think so!
Coincidence ? I don't think so!
#37
Burning Brakes
I've got two cars that I never carry a spare in. For awhile I carried some of that Slime stuff you use as a temp to get to the tire store. I always buy new tires well before I need them. Haven't had a flat in over 15 years and I live in a small town in Oregon with farm equipment on the roads all the time.
#38
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If you place your spare in a large black plastic lawn bag, the slippery vinyl of the bag allows the normally grabby rubber tire to slip right in, with lots less effort. It also allows for a cover if you need to put the flat in the rear of the car.
This tire size conversion chart is handy to determine different sizes that all have the same overall height. Just click the wheel size tab at the top and the appropriate chart is displayed:
https://tiresize.com/conversion-chart/
This tire size conversion chart is handy to determine different sizes that all have the same overall height. Just click the wheel size tab at the top and the appropriate chart is displayed:
https://tiresize.com/conversion-chart/
BTW, I have 205/70s on my 1965 and that same size fits in the tire carrier. It was in there when I bought the car. Possibly the previous owner put the longer carrier bolts in to do this (I never check) but the point is IT FITS.
#39
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My wife is from the other side of the mountain of West Virginia. You keep up the short leg stuff and you'll likely wind up seeing it. The short one that has about half of it up where the sun doesn't shine on you.
Last edited by MikeM; 11-09-2018 at 01:33 PM.
#40
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St. Jude Donor '07
good luck, and God bless...
Bill
Last edited by wmf62; 11-09-2018 at 04:34 PM.
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Lotsacubes (11-09-2018)