I can only find 18 inch collapsible spares on ebay which will not work on the front because of my giant calipers. Don't want to spend big bucks for a new one if I help it. I would really appreciate your input on the following items:

1. Will an 18 inch spare clear my rear calipers and fit OK?

2. If I had a flat on the front could I mount the spare on the back then put the good rear wheel on the front?

3. Will the 10 inch wide rear wheel cause any clearance problems mounted up front considering the front wheels are 9 inch?

4. Will it be OK to tow a travel trailer a short distance with a collapsible spare on back if I keep it nice and slow?

5. Should I just get a full size spare and either mount the damn thing on the roof or stick it in the trailer somewhere?

 

Well thought out process and questions there. I don't have answers to your specific questions, but they are the right questions.

Another factor to consider is the rolling diameter of the collapsible spare vs. the other tires. I've tried to narrow down what the tolerance is on that before getting transfer case warnings, and I think it is somewhere between 1 and 3% (i.e., 1% is OK, 3% gets you warnings). I did not find any reliable definitive answers, so those numbers are based on my own experience (the OK one) and reports on here of problems.

If I were on a road trip, towing, in your situation (and other less extreme ones), the first thing I'd attempt is a plug repair of the punctured tire. Maybe I'd do a quick install of the collapsible spare to drive slowly to a place to do the repair. And of course not all tire failures can be plugged. And you might not want to do your first ever tire plugging like that - easier to do in your driveway.

The other thing that plug repair capability does is let you handle more than one flat tire. Not that you'd be running from the cops and hit the spike strips, but ...

 

The front to rear swap idea is a good one. That is standard protocol on 911's. If the rear gets a flat, move the normal front wheel to the rear. And put the spare on the front.

 

I may have an extra 19inch one in my garage that I'd probably be wiling to part with for a reasonable price. I'll take a look in the AM.

Cheers,
TomF

 

Would the spare clear the calipers on a Turbo Cayenne?

 

How about a spacer and a set of longer lug bolts?

 

Given the weight of these vehicles and the speed restrictions already suggested by the blow-up spare... I'd want to avoid adding more unstable variables to a problem. The tire swap scenario is probably 'less worse'.

While the cost of a proper spare might be a bit much, it'd no doubt seem cheap compared to the potential costs of a screw up from trying to half-*** it.

 

Thank you everyone for your helpful replies. I decided to buy a salvaged wheel that matches my set and make a full sized spare to carry while towing. Hopefully I will never need it but now I'm prepared if I have a flat that is beyond the help of tire sealant and plugs.

 

Glad you got it sorted out and it sounds like the best solution overall. As it turns out, I have an 18 inch on in my garage and not a 19. I still need to go and look at what size the spare is in my 2009 CTTS. It should be the same as required for your 2006 CTTS.

Cheers,
Tom