What effect Would a donut spare have on a differential?

[mrpj]

Originally Posted by Bluevitz-rs

With a regular open diff it will no effect. You should not if you have a limited slip diff.

However as others have said, you really shouldn't ever use a space saver on the front as 75%ish of your stopping power comes from the two front wheel. As well as steering.

I agree -
But if you are some distance from the nearest place where the flat tyre can be repaired or replaced, or home for access to another jack (if owned)or some means of supporting the car and only have the vehicle jack, there really is no other option. How many of us carry around a trolley jack, axle stands etc.?
Hence, I would suspect the 50mph limit to allow for the smaller width tyre.
I have been in that situation and, if driven sensibly, it does not pose a problem.
e.g. take corners much slower, think ahead, remain a longer distance from vehicles in front etc.

[Bluevitz-rs]

Originally Posted by mrpj

I agree -
But if you are some distance from the nearest place where the flat tyre can be repaired or replaced, or home for access to another jack (if owned)or some means of supporting the car and only have the vehicle jack, there really is no other option. How many of us carry around a trolley jack, axle stands etc.?
Hence, I would suspect the 50mph limit to allow for the smaller width tyre.
I have been in that situation and, if driven sensibly, it does not pose a problem.
e.g. take corners much slower, think ahead, remain a longer distance from vehicles in front etc.

You need to think outside the box a bit.

Jack up the rear and replace the rear tire with the spare. Then jack up the front and put that good tire on the front. Not too difficult

[SirDigby]

Originally Posted by Bluevitz-rs

You need to think outside the box a bit.

Jack up the rear and replace the rear tire with the spare. Then jack up the front and put that good tire on the front. Not too difficult

that's not really outside the box.

you should have learned this in driving class...

[mrpj]

Originally Posted by Bluevitz-rs

You need to think outside the box a bit.

Jack up the rear and replace the rear tire with the spare. Then jack up the front and put that good tire on the front. Not too difficult

You are, of course correct. I obviously forgot to put on my thinking cap.
I still don't think there is a more substantial risk by fitting it to the front IF care is taken when driving. Toyota don't offer any preferences or warnings in the manual either. If it was that impotant, they would surely advise rear fitting only?
In the U.K. it is usually avised, when replacing tyres, to fit the new ones on the rear i.e. if changing front tyres, swap the wheels, front to back. So fitting the spacesaver to the rear sort of negates that.
We don't rotate tyres/wheels which seems to be common in the U.S. nor is it part of the sevicing schedule.
I have an old classic car and all the tyres are no wider than the Yaris's "doughnut" with no limit on speed - however the max speed of the car is not much more than 60mph!

[Bluevitz-rs]

Originally Posted by mrpj

You are, of course correct. I obviously forgot to put on my thinking cap.
I still don't think there is a more substantial risk by fitting it to the front IF care is taken when driving. Toyota don't offer any preferences or warnings in the manual either. If it was that impotant, they would surely advise rear fitting only?
In the U.K. it is usually avised, when replacing tyres, to fit the new ones on the rear i.e. if changing front tyres, swap the wheels, front to back. So fitting the spacesaver to the rear sort of negates that.
We don't rotate tyres/wheels which seems to be common in the U.S. nor is it part of the sevicing schedule.
I have an old classic car and all the tyres are no wider than the Yaris's "doughnut" with no limit on speed - however the max speed of the car is not much more than 60mph!

It's more about the fact that the space saver is has the same section width as a front tire on a motorcycle. You can't predict an emergency braking or steering situation, so as to be proactive, you should simply always put the temporary spare tire on the rear.