Spare tire donut speed limit

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Originally Posted By: ShamusEgg
I remember the donut had rating of 55MPH, no more than 50 miles ?

It is the most dangerous to exceed on the highway. It is simply not as much tire as what is supposed to be there.

Inflate to 60PSi.


That's more what the manufacturer says you can do rather than what the tire is capable. Some vehicles - off the top of my head, I can think of dodge Neon, pontiac Vibe/Toyota Matrix say up to 2400 miles or something.
 
Also, a donut spare should only be used on the rear for handling/braking reasons, provided the tire size is the same front/rear and can be rotated accordingly. Amazing how many times I've seen people on the highway going 70+ with a donut spare on the front.
 
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Originally Posted By: funflyer
Also, a donut spare should only be used on the rear for handling/braking reasons, provided the tire size is the same front/rear and can be rotated accordingly. Amazing how many times I've seen people on the highway going 70+ with a donut spare on the front.


I don't think that is correct. I think you want the best tires on the rear to prevent the vehicle from losing traction at the rear last - and this includes worn tires and donut spares.

Also, It should not be a surprise for the specs for a donut spare to be higher than the called for max. I had a professor in college who said engineers should over design and under utilize - that is if you are designing something, make it more capable than the minimum and if you are specifying a finished product, make the specs higher than the minimum. So a donut spare ought to have a higher speed rating that what is stamped on the sidewall as the maximum speed.
 
Or pulling a trailer 80 mph on 65 mph tires with 25 psi in them

On GM or other with G80 locker - not supposed to put small tire on that axle - do double swap.
I own full size spares for 3 vehicles ...
 
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Originally Posted By: CapriRacer
I don't think that is correct. I think you want the best tires on the rear to prevent the vehicle from losing traction at the rear last - and this includes worn tires and donut spares.

Also, It should not be a surprise for the specs for a donut spare to be higher than the called for max. I had a professor in college who said engineers should over design and under utilize - that is if you are designing something, make it more capable than the minimum and if you are specifying a finished product, make the specs higher than the minimum. So a donut spare ought to have a higher speed rating that what is stamped on the sidewall as the maximum speed.



So you want to lose traction on the front wheels first? Whether braking or in a turn? Sorry but the best always go on the front for the opposite reason you stated here.
 
Originally Posted By: funflyer
Originally Posted By: CapriRacer
I don't think that is correct. I think you want the best tires on the rear to prevent the vehicle from losing traction at the rear last - and this includes worn tires and donut spares.

Also, It should not be a surprise for the specs for a donut spare to be higher than the called for max. I had a professor in college who said engineers should over design and under utilize - that is if you are designing something, make it more capable than the minimum and if you are specifying a finished product, make the specs higher than the minimum. So a donut spare ought to have a higher speed rating that what is stamped on the sidewall as the maximum speed.



So you want to lose traction on the front wheels first? Whether braking or in a turn? Sorry but the best always go on the front for the opposite reason you stated here.

No. Rear spin out is harder to control for an average driver. That is why all tire manufacturers and most tire shops recommend you put better tires on the rear.
 
Ditto - and stability systems tend to make the "rescue" tagging one of the rear wheel brakes (been there) before the rear of the car/truck/SUV starts to swap ends ...
 
Originally Posted By: funflyer
Originally Posted By: CapriRacer
I don't think that is correct. I think you want the best tires on the rear to prevent the vehicle from losing traction at the rear last - and this includes worn tires and donut spares.

Also, It should not be a surprise for the specs for a donut spare to be higher than the called for max. I had a professor in college who said engineers should over design and under utilize - that is if you are designing something, make it more capable than the minimum and if you are specifying a finished product, make the specs higher than the minimum. So a donut spare ought to have a higher speed rating that what is stamped on the sidewall as the maximum speed.



So you want to lose traction on the front wheels first? Whether braking or in a turn? Sorry but the best always go on the front for the opposite reason you stated here.
Your probably don't know, but CapriRacer is a tire engineer. Higher tread tires go up front.

I personally put the "best" tires up front, not necessarily the deepest tread. Sometimes a pair of tires is getting old with deep tread, and a newer pair is lower in tread with 1/2 tread. I'd use those up front so it's less likely of a blowout losing control.
 
OP tread is about a donut spare - not buying tires in two's which I would never do ...

But if you buy only two - thought Michelin says on the rear ...

I think Allstate Insurance gives the same advice ...
 
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Originally Posted By: 4WD
OP tread is about a donut spare - not buying tires in two's which I would never do ...

But if you buy only two - thought Michelin says on the rear ...

I think Allstate Insurance gives the same advice ...
funflyer said "but the best always go on the front for the opposite reason you stated here."

And CapriRacer's "reason" was: "I think you want the best tires on the rear to prevent the vehicle from losing traction at the rear last"

funflyer meant deepest tread tires should go up front
 
Originally Posted By: 4WD
OP tread is about a donut spare - not buying tires in two's which I would never do ...

But if you buy only two - thought Michelin says on the rear ...

I think Allstate Insurance gives the same advice ...


Yep, that's the general advice.

On a FWD best-tyres-on-the-back happens naturally (without rotation), since the fronts usually wear faster.

Buying tyres in two's is thus the obvious response to the situation, rather than its cause.
 
Allstate writes it up about hydroplane issues in the rear being the concern ... That means tread depth ...
In any case - I bought 5 per set ...
 
Originally Posted By: Klutch9
Every spare tire donut I've seen (not full size) has in bold letters a warning not to exceed 50 or 55 mph on the sidewall. The other day while checking the pressure on the Fusion's spare, I noticed that the tire has an 'M' speed rating, which should be good up to 81 mph. What gives?! Maybe it's for the morons who drive on the donut for several months at a time.


the mismatch in size skews the balance of the car. It's not a tyre limit, as much as it's a car issue.
 
At least the balance is good.

Also don't forget that quite a few donut spares are diagonal tyres, rather than radial. We all know mixing diagonal and radial on a car isn't good.
 
You are are really screwing up balance of vehicle putting a donut with vastly different traction abilities. Keeping speed lower at least makes an emergency maneuver or slippery conditions possible.

Stability control can possibly compensate but would work overtime.
 
I think I remember an article in Car & Driver in the early 90"s when they drove a car with 4 temp spares for many miles (like around the outline of the US of A) at normal speeds with no problems. It seems like some cars have temp spares that are the some diameter as the regular tires and some temp spares are much smaller. My Audi Quatro has a full size spare (on a matching alloy wheel!) but the newer ones have a temp spare (battery in the trunk), but it is the same diameter as the other tires.
 
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Originally Posted By: John_K
My wife hit something and called AAA to put on the donut spare. The guy gave her the 55 mph maximum speech. Probably for liability purposes.

AAA told me "50." I checked my owner's manual, which says clearly up to 65 mph for up to 3000 miles. So 100 miles over several days until my new tires come in, at a top speed of 55-60, should be fine.

The spare is supposed to be at 60 psi, and it is.
 
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