old bikes and old tires

I got more work done on the XS650 this week, and might have it ready to ride tomorrow.


Here are the wheels and Shinko SR712 tires all set to go. I bought a new front, but I'm using the rear tire that came on the bike. With all of the older bikes being put on the road I thought I'd go over a few tire basics, like determining if the tires are good or need replaced. This bike only has about 12,000 miles on it, and being 32 years old has obviously spent some time sitting, so typical of what you find with an old bike.

Here's the rear that came on the bike, which was obviously much newer than the front. No cracking, soft and flexible rubber, and no flat spotting in the center. Looks good.

Looking at the date code "5109" shows that it was manufactured in 51rst week of 2009. So, this tire was likely installed in early 2010, so nearly a new tire. All good here, with plenty of years and miles to go.

Below is the front which was in really bad shape. It has a 3 digit date code "458". Before 2000 3 digits were used, meaning the tire was made in the 45th week of a year ending in 8. Tires from the 90s will usually have a triangle at the end, so going by this, the tire was made in 1988, 23 years ago. Bad. I don't use a set expiration date, most tires are in their prime for 5 years or so, and deteriorate from there, but by now anything that has the older 3 digit code should be suspect.

This picture below reminds me of those you see on a Craigslist ad showing how good the tires are. I'd guess that when a previous owner got the bike back on the road and replaced the rear, they probably looked at the tread left in the front and thought it looked fine. It doesn't look too bad at first glance, but it feels like plastic, and you can't indent it with a finger nail.

And look at this spot. This is on the left side, so likely where the bike sat for years on the side stand, maybe a concrete garage floor drying the tire like a sponge.

Before dismounting from the rim, I let this tire sit in the sun to warm, but it was still so hard I choose to do the reciprocating saw removal method. Just cut through the tire, and use a tire iron to lift the bead up to cut.

The new front from the Motorcycle Superstore, with a "2811" code, so made in the 28th week of 2011. Less than $60 for a new tire and tube, money well spent.

Good rubber makes a bike so much more fun to ride, and safer also.