Are these tires too old?

I checked the manufacture dates on my tires today- the front tire was apparently made in 1998 and the rear tire was made in 2002.

Both tires look almost new... will I be ok to still run them?

One thing people don't know about is that if the bike or tires were stored close to an electric motor(wash machine,dryer,or freezer) the ozone generated by operation of the motor will attack the rubber and age it faster than normal.

I'd spend the money for new tires as it's better to have piece of mind than worry about what might have been.

OK I priced some new tires...not bad.

Now, I have a couple more questions...does this bike have tubes? (it has spoked wheels).

Also do the factory tire sizes or 3.25-H19 4PR and 4.00-H19 4PR translate into a "metric" size? Those don't seem to be the easiest sizes to find.

And what does the 4PR stand for? 4 ply radial?

Things that you should look for in a worn out/old tire.
-any bald spots?
-does it have some kind of wear pattern around the edge of the tire tread? This is called cupping.
-are there any chords showing?
-is there any cracks in the rubber, side wall or between the tread grooves?
If your answer is yes to any of the above I would scrap the tire. If it's cupping it may or may not cause a problem. Depending on how bad it is. In the past, I've had front tires with cupping that would make the front end wobble at certain speeds. Changing the tires always fixed the problem.
For what it's worth, that's my take on tires. Hope it helps.

Most tire makers have conversion tables for metric to american sizes. Just go to the various sites and list what ya got and they will recommend a size.

Yes your tires have tubes in them as nobody has made spoked wheels not leak air.

Dry rot on the sidewall rubber means it's time to dump them.

I would get rid of them. The front will be a 100/90/19. I just had a Dunlop put on last week. $125 for the tire tube and rim strip, mounted and balanced. Good piece of mind.

MFolks wrote:

Yes your tires have tubes in them as nobody has made spoked wheels not leak air.

Yes your tires almost with 99.9999% accuracy have tubes but....

www.motorcyclecruiser.com/tech/tubeless_tire_seal/index.html

Check the rear wheel size again. I would think the rear rim was 18" and not 19" but I could be wrong as I have never owned a 750 twin. The front is a 100/90-19H where the H is the speed rating. The rear will be a 120/90-19H and that is a strange size. In any case, buy some new rim strips which are big rubber bands that cover the ends of the spokes inside the rim to keep them from coming in contact with the inner tube. Buy new inner tubes and last use the correct tire sizes. I use Dunlop 404s on my KZ1000E1 as they last pretty good, have decent wet/dry traction and have plenty of load rating for a heavy bike. Your bike is lighter and you could use some less heavy duty tires... When you shop for tires, keep in mind that denniskirk.com will match and beat ANY legit quote you find elsewhere including shipping so get your best deal and then go to DK as they have the stuff in stock and ship quickly.

While you could chance riding on your current tires, I would look very carefully for cracks which are signs of dry rot. I personally would put fresh rubber on the bike.

4PR means 4 ply rating

And the rear is an 18" not 19"

Yes they are tube type wheels, my 750 twin has tubeless wheels and tires, but that's because it has the optional Morris Mag wheel kit installed.

There's nothing in the world wrong with running 10 yr old tires unless they show signs of dry rot.
This brings a question though. A few days ago I was sitting here in the shop and hear this explosion, run to the front door, as did everyone else in the area. We are all looking for the cause and there was a semi truck attempting to make a right turn, but having a hard time making the turn because of traffic. Finally he makes the turn and I could see rubber shreading off one of his trailer tires. So I'd assume this was the explosion, a semi sitting in traffic that had a tire blow. Now was this a 10 yr old tire that just decided to blow? which I would doubt or a case of tire heat from lack of air? Which I would think, but I've never heard a tire blow like that.
Back to motorcycle tires, there is no "metric equivalent" to a 3.25-19 or 4.00-18 tire. Yes there are sizes that work for sure, but not the same. A 100/90-19 is pretty close, but wider than the 3.25. A 110/90-18 is close in the rear for width, but to low profile. A 120/90-18 is too wide and still low profile, so it makes the circumference about right at least. You can get 3.25 or 4.00 tires all day, just few stock the size. Dennis Kirk has a lot of choices in these size.

I mistyped, meant to put 18 for the rear wheel size.

Anyway- Like I said, the tires look great. Good tread, no dry rot that I can see. It's my understanding the bike pretty much just sat in a garage. Feels like the tires might be a little low on air though.