tube eliminator

[Major Softie]

Duane, the main purpose of the device is for dirt bikes. Bikes running in sand and really soft dirt need to run very low tire pressures to "float" on the soft soil. These low pressures lead to rear tires spinning on the rim. This was then addressed with "rim locks," which hold the bead against the rim in one spot. However, this still leaves them vulnerable to "snake bite," which is when the low pressure tire hits a sharp bump, the bead moves away from the rim, and the tube gets pinched between the bead and the rim - causing an instant flat. Bicycle mountain bikes have similar issues.

Basically, this device is a rim lock that holds the entire bead pressed against the rim and also seals the air in the rim and the tire, so you can run very low pressures in the tires but not have the snake bite problems. It must have two schrader valves, as it has about 100 lbs in that skinny little tube that is pressing the bead against the rim, but you would also need a way to inflate the tubeless tire to a lower pressure. If I ran a dirt bike in the desert, the device would seem very attractive to me, regardless of whether it actually weighs any less than a standard tube.

[SteveD]

Yes, it does. It's the instant blowout that makes it catastrophic.

I guess what I'm asking is that if one experiences "side-force trauma" then that in itself might be catastrophic enough to cause a fall, even if the tyre isn't doesn't experience the instant blowout.

[Duane Ausherman]

Thanks Major, you explained what the website sort of alluded to, but just failed to actually say. I guess that it reads OK for the dirt bikers, but isn't as good for the street riders.

[vanzen]

Thanks Major, you explained what the website sort of alluded to, but just failed to actually say. I guess that it reads OK for the dirt bikers, but isn't as good for the street riders.

"Not as good for street riders" perhaps only by virtue of the fact
that the device has not been subjected to the DOT for approval,
nor has it been APPROVED by the DOT for street use.
Obviously a Tubliss is subject to the same laws of physics whether on dirt or pavement
and should keep a tire tight to the rim in either scenario -
although sustained high speed operation might be a differential to consider.
(but given the speeds of today's dirt bikes – maybe not ! )

Ultimately we have a similar dillema as that posed by tube-type cast wheels being used without tubes.
The Tubliss product was designed and is marketed for off-road use only.
The corporation isn't going to conduct thorough evaluation for a non-intended use
and the device does not conform to current DOT mandates regarding street use.
There will be (already are) those who will disregard this detail.

The Tubliss, and other devices like it, have become quite popular on street bikes having conventional spoked wheels.

resources:http://www.tubliss.com/
http://www.motorcyclecruiser.com/tech/t ... index.html
http://www.ultimatemotorcycling.com/alp ... s_a_system
http://www.motorcycledaily.com/2007/02/ ... _tubeless/

[Major Softie]

Yeah, I didn't mean to imply that it wasn't any/as good for street use (although, as many have noted, not strictly legal). My point was that the marketing of the device that Duane had trouble understanding was aimed at dirt riders, and contained some assumptions that dirt riders would understand without them being explained.

I don't know if the tubliss was designed intended only for dirt riders, but it's being marketed that way, and it's sized that way. They offer no sizes for Supermoto and, in fact, aren't even wide enough for later airheads, as they only go up to a 2.15 rim. Those other companies may offer other sizes. Someone must be covering the Supermoto bikes.

[vanzen]

Yes, these devices cannot be advertised for street use as they are not DOT approved for street use.
But given the fact that they are being used safely in racing in the dirt and on the track –
available in sizes to fit (for example) Ducati classic sport bikes with wire wheels –
it's a given that they WILL be used on the street by anyone with a wheel to fit and the inclination.

Ken's original question here was about using this device in a Lester – I would not.
I have countless miles on BMW flakes without tubes ... and would not install a Tubliss in a Flake or a Lester:
1) due to the extra unsprung weight, and
2) due to my positive experiences of running tubeless in a tube-type rim ...
I'd run either of these tube-type cast wheels without tubes or the Tubliss device.

On the other hand,
if I had an old airhead with conventional spoke wheels, and found a Tubliss (or the like) to fit –
I would see it as, perhaps, the best option available to do without tubes and I would buy me some !

... but that would be my decision, my ass at risk,
and a decision based upon my experience of the comparative difference in handling sans the weight of tubes,
my experience with tubes and blowouts, and my positive anecdotal evidence of running tube-type rims without tubes.