I understand the limitations of driving on a spare tire, but what I do not see in any discussion is a requirement ore recommendation that the donut spare be replaced after use. Is this just implied if you drive on it to the 50-70 mile limit (vs. short trip(s) to the service station)? So, if my trip to/from work after the flat was about 50 miles, then I need to get the flat tire replaced AND buy a spare tire?
Ideally you should replace the donut spare with a full size spare tire and rim–much safer and it avoids this problem next time.
Does your Odyssey even have a spare? Some of them have “run flat” tires. If yours is that way, there is NO PLACE to put a spare other than flat on the floor in back of the rear seats, or on the roof rack. I don’t know where that leaves you if you completely blow one out…
As to your original question, a spare is just that, a spare to be used for short distances. If you have used yours for 50 miles, it’s probably not worn out. I’m sure you’ve met folks on the road who have been on spares for hundreds of miles because they can’t afford a new tire. THOSE are dangerous. If your spare has a couple hundred miles on it, and your Odyssey has a place for one, look for an unused one at a salvage yard. If it has enough space for a full sized tire and wheel, I’d go that route.
The 50 to 70 mile limit is per trip. They will go much further than that (in total) if you let them cool down before driving on it again. As long as it has good thread and is less than ten years old, there is no reason to replace the spare.
The recommended mileage limits are not based on the life of the tiny spare tire but on the damage that the smaller diameter tire causes to the drive train and the poor performance of the tire.
The mileage limit needs to be there to keep some unthinking people from driving continuously on a compact spare. Handling, traction and treadwear are all compromised with a compact spare so the warning is there for your safety and to keep the trial lawyers at a distance. As long as a compact spare has tread left, it is reasonable to assume that it can be used within the limits prescribed. On the drive wheels, a compact spare, having a smaller diameter than a regular tire causes the vehicle’s differential to work continuously. This is tolerable but not without a limit.
I wouldn’t buy a new spare. Inspect the old one, it’s probably fine. Make sure it’s full of air, 60 PSI?
I have an Odyssey with the same small spare tire, I would only use the spare in back, never on the front drive wheels. Probably not room for a full size wheel/tire in the spare compartment.
If your old tires were worn down, you may need more than one new tire though.
I didn’t replace my doughnut spare the one time I used it. It appears to have plenty of tread left. I think you should measure the tread left on the tire and make a decision based on that.
Your doughnut does not need to be replaced as long as it has sufficient tread and is used only as an emergency device and only until you get to a place where you can have the flat fixed.
IF you can…Many cars a full size spare WON’T fit where the donate spare fits.