Hi Richard

It is a "short term" solution to get you on the road... so the 10 year rule isn't as critical.  With that said, the tire is not exposed to sunlight, but I still recommend treating the rubber with a tire dressing. 

I use this... as it doesn't attract dust. https://tinyurl.com/n47k845c

My "spare" is close to 20 years old, and I wouldn't take it to highway speeds either (probably not recommended regardless, due to different tire size).

If you are planning on longer distances, always a good idea to put the spare in the rear.  If your front tire goes flat, put the spare on the rear, and move the rear tire to the front.  You will have better handling and control, should the spare be a different tire size or if it was to fail.

My 2 cents! FWIW

Jack R.

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Richard Koerner
Sent: Tuesday, March 9, 2021 1:50 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Life of spare tire in clamshell

I run 16" GoWesty alloys and correct tires.  But I keep a 14" Vanagon steel wheel (with 5 original nuts and 5 original bolts) with correct rated tire in the clamshell.  Brand new....well...it was 9 years ago.  And all that blowby heat from radiator; no rubber wear, but many cycles of hot and cold, expanding and then shrinking back, a tough environment.  No sunshine of course; ozone exposure same as other tires I guess.  I always keep it properly inflated.

So the question:  time to replace this unused tire?  For me, the spare is only to get to tire store to replace the 16" tire after failure.

Rich
San Diego