TOPIC:

While refinishing my rear wheel, I started to wonder if I could run my new tire sans inner tube. It had the inner beads like a modern rim, but it does not have "Tubeless" cast into the spoke like newer KZ's. Only a "TL" at the end of the DOT code.







I know that Kawasaki used a tube back in the day, and no dealer would accept the liability of telling me I didn't need one, so I did some research.

I found little information by searching through forums (this one and others dedicated to older bikes). The general consensus was that tubeless rims needed an inner bead to retain the tire to the rim in the event of a loss of pressure. This did not apply to all, as some bikes had no inner ridges on front wheels marked "Tubeless".

A few said that "TL" stood for tubeless. Hmm. That's what I first thought when I examined my rims, but I wanted to find that in writing before trusting my life to it.

Some had the opinion that regardless of the rim's design, if it had used a tube from the factory it needed on now. Well I know that my KZ used ignition points, but seems to work just fine with newer electronic technology. Could it be the same for tires?

First stop, ask the manufacturer. They built it, so they should know what the casting "TL" means.

Enkei is a Japanese manufacturer, so the only contact I could get was there US distributors.


Not much help except telling me that TL was the profile the the wheels bead.

Next stop was to ask the DOT. It is printed in the DOT number right? Trying to find standards and regulations from '78 was futile, so I ended up emailing them. The didn't know what "TL" stood for either, but they did share their regulations from that year.


It does tell me that the "T" before the wheel size states that the wheel conforms to the standards of the Tire and Rim Association.

So here is the reply from the Tire and Rim Association.

Hi Josh,

Thank you for your message. The ‘TL’ designation is the Rim Contour code which coincidentally denotes ‘tubeless.’

I went ahead and attached the page from our 1978 Year Book (Standards Manual) that has the contour details.

It’s always good to hear from folks in the field. Don’t hesitate to ask if you have any questions in the future.

Kind regards,
Rudy Consolacion
The Tire and Rim Association
175 Montrose West Avenue, Suite 150
Copley, OH 44321
Voice: (330) 666-8121
Fax: (330) 666-8340





You'll also note that rims less that a certain size would not have the inner bead, hence why front wheels can be labeled "Tubeless" and lack the ridges.

Here's a 1980 KZ550 cast alloy wheel which has Tubeless cast into it (but it doesn't have TL anywhere).
The ridge on it is less prominent than yours.

I'm believe that "TL" preceded "tubeless" designation. This would probably only apply to '76 to '80ish.

Great info here! My 750E has "tubeless" cast into the front wheel but no extra rim "bumps" for the bead.

I know quite a few guys that take early tube type wheels and modify the valve stem hole to accept a tubeless valve stem. Never heard of any problems with such mods.

Hey nitrokeeb - thank you for the detailed info - with citations - and for all the legwork! I imagine a lot of people have the same question and it's good to have a definitive answer.

We had a similar thread about my 1980 KZ1000b Ltd,my rear has a tubeless with the TL designation and the front is a tubed tire.You can see a definate difference between the depth of the center "channel' on them.

I converted to cast wheels in 1978. They never did hold air with tubeless tires, so I run tubes. I had to fight with the dealer last time I had tires mounted.

Nitrokeeb,
Thank You! That's a lot of very good info in one place. It also answers a nagging question for us.

There are Lester mags on two of our Z-1's. One set was purchased very early after Lester's introduction to the market, 1975 or so. In their advertising propaganda, Lester was touting their wheels' ability to run the then newly-introduced tubeless tires. There were no indications on those early Lesters that they were indeed TL rated. Later production Lester wheels have TL rating cast into them. The documentation you posted solves the mystery as to the whys and wherefores of the presence (or lack thereove) of the inner bead retaining ridges on some Lester wheels and not others, when all were supposed to be TL rated.


Good Ridin'
slmjim & Z1BEBE

Mine are Lesters - they won't hold air.