Need help on a spare tire question

I own a 1980 928 5 speed. When I bought the car it had custom brembo brakes and custom rims, and no spare. Driving around with no spare makes feel uncomfortable, of course that doesn’t stop me from driving the car. I know that some late model Porsches don’t have a spare, they come with a can of stop leak (goop) and an air compressor. I’ve been trying to figure what I should do about this. I could probably find a used original spare but I’m not sure it would fit my car any more. The brakes are large and my wheels have an unusual air valve, it is a 90 degree valve so it stays close to the rim and out of the way of the brake calipers as they rotate. I don’t know if the valve on the original spare would interfere with the brake rotors and I would hate to buy an original spare only to find that it doesn’t fit my car, which is the reason for this post.

As for using the inflatable goop and an air compressor, I’ve read that once you use these to inflate your tire most shops won’t want to fix the tire because of all the goop inside of the tire which would mean tossing two otherwise good tires and buying new ones. If you buy good quality tires as most of us do then that’s one heck of a cost for resolving a flat tire. Is the air valve on the original spare on the outside of the rim so that it doesn’t matter what size your brake calipers are? Does any one have a good suggestion for me?

I own a 1980 928 5 speed. When I bought the car it had custom brembo brakes and custom rims, and no spare. Driving around with no spare makes feel uncomfortable, of course that doesn’t stop me from driving the car. I know that some late model Porsches don’t have a spare, they come with a can of stop leak (goop) and an air compressor. I’ve been trying to figure what I should do about this. I could probably find a used original spare but I’m not sure it would fit my car any more. The brakes are large and my wheels have an unusual air valve, it is a 90 degree valve so it stays close to the rim and out of the way of the brake calipers as they rotate. I don’t know if the valve on the original spare would interfere with the brake rotors and I would hate to buy an original spare only to find that it doesn’t fit my car, which is the reason for this post.

As for using the inflatable goop and an air compressor, I’ve read that once you use these to inflate your tire most shops won’t want to fix the tire because of all the goop inside of the tire which would mean tossing two otherwise good tires and buying new ones. If you buy good quality tires as most of us do then that’s one heck of a cost for resolving a flat tire. Is the air valve on the original spare on the outside of the rim so that it doesn’t matter what size your brake calipers are? Does any one have a good suggestion for me?

Your air valve should be on the outside of the wheel, so never in danger of contacting the brake caliper...

Possibly you have S4/GT calipers on the car, and in that case an S4 spare tire would fit. I don't think you would have problems with an S4/GT spare tire fitting anyways unless they are truly custom brake calipers.

A photo might help one of us better understand, and perhaps some measurements of wheel back spacing.

Stan,

Thanks. I'm attaching a couple of photos with the tire on the car. If it will help I'll take the tire off to get a better view of the brakes. The fourth shinny picture shows the tip of the valve stem, it is nearly flush with the wheel.

Attached files [img]media/attachments/928=88-brake.jpg[/img] [img]media/attachments/928=89-caliper.jpg[/img] [img]media/attachments/928=90-caliper2.jpg[/img] [img]media/attachments/928=91-valve.jpg[/img] [img]media/attachments/928=92-wheel.jpg[/img]

Looks like a standard S4 caliper, so an S4 spare should fit. Where are you, maybe we can find someone close to you to do a trial fit. Would that help?

Ironically I have a set of those wheels, but only 3 good ones, and 1 bad one. Do you have an extra, or want 3 extras?

Attached files [img]media/attachments/930=93-bent_wheel.jpg[/img]