Desflurane's Romaniacs Blog

Chronicle of My Participation in the World's Toughest Enduro Rally – Again…

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  • Husqvarna

TUbliss can be a TUbitch!!

Posted by desflurane on March 5, 2013

I can’t remember if I mentioned installing a TUbliss tubeless system in my rear wheel about a year ago.

Well, I did…

And it has been fantastic! I am completely sold on the product. The system (available for both front and rear wheels) essentially consists of a modified bicycle tire that sits in the rim’s center groove, replacing the inner tube or mousse. This “inner tire” is inflated to 110psi (7.6 bar or 760kPa) and acts as a bead lock, creating an airtight seal between the tire and rim. The hollow tire can be filled with much lower pressure than a tubed tire because the circumferential bead lock holds the tire’s sidewall in a vertical position forcing it to flex rather than simply flop over as it would do otherwise. Effectively, the TUbliss makes the tire’s sidewall much stiffer. As a further bonus, the inflated “inner tire” is a protective bumper for your rim, shielding it from rocks or other hard, unfriendly objects on the trail.

Take a look at the Nuetech website for more detail, especially this installation instruction sheet.

The end result is a tubeless wheel that is significantly lighter than a tube or mousse (pounds lighter, in fact) and if you throw in some sealant it is virtually flat-proof! As mentioned before you get to run much lower inflation pressures which translates into much greater tire flex and traction. I have been running 5.5psi in my Bridgestone M404 with excellent results – really good traction on the rocks and no worries about pinch flats or tube punctures.

Ok, so that is all well and good. I love the TUbliss system!

Along came the current issue of Dirt Bike magazine which contains an article describing running the TUbliss with ZERO pressure and obtaining near trials-tire traction while retaining the benefits of a knobby tire for sand and mud situations where a trials tire’s mini-knobbies don’t deliver.

The key to this clever trick is the Dunlop D739 Desert AT tire. It has a remarkably stiff carcass, but with no air in it, it is pliant enough to flow out over the ground and make the knobbies grab for traction. And flats are a non-issue if your tire isn’t inflated anyway.

My trusty 404 was nearing its demise anyway, so I put a 110/100-18 D739 on order!

The tire arrived and on a lovely sunny day (after a good ride) I decided to install!

Removing the much softer M404 was pretty easy. Here is what it looks like after I washed off all the sealant:

20130305-144504.jpg

Bear in mind that the red “inner tire” is completely deflated in the picture. Imagine it topped off with 110 pounds of pressure! Should provide decent rim protection!

Here is a closer look at the business parts of the system:

20130305-144517.jpg

At the 12:00 position you can see the schraeder valve that allows the red “inner tire” to be inflated to tremendous pressure. At about the 2:00 position you see the gold bead lock that prevents the tire from spinning on the rim as well as the thicker threaded stem that goes through its center. It is through this stem that the actual tire is inflated – or in this case – not inflated. When installed, the tire’s bead sits between the “inner tire” and the rim. You get the idea…

I began attempting to install the new Dunlop, seen here:

20130305-144531.jpg

The stiffness of this tire’s carcass became immediately apparent. Where other tires are fairly easy to deal with, just prying the carcass open far enough to admit the rim was a significant obstacle.

Mounting tires to a TUbliss-equipped rim is different than the standard operating procedure. The entire rim must first be inserted into the center of the tire, then each bead is levered into place from the outside (see Nuetech info if that doesn’t make sense). After an hour or so of wrestling with the Dunlop, I gave up and went inside to eat some lunch, planning to retreat to the motorcycle shop for assistance afterward.

As I chewed and muttered obscenities to myself I had a flash of inspiration. I recalled how a ratchet strap can be used to squeeze a car or ATV tire tightly enough to the rim to allow the bead to be popped into place with even the feeblest source of compressed air. The strap is placed circumferentially around the tire and is cranked down as tight as possible. This forces the carcass to open up, pressing the beads simultaneously against the rim just enough to create an airtight seal. Why wouldn’t the same technique allow this Dunlop-abomination’s ultra-stiff carcass to open up, permitting the rim to be levered into place?

Back to the garage!

Ignore the yellow zip-ties they were part of an ill-fated attempt to create a 'third hand' to hold a tire iron with - the emotions are still so fresh... I don't want to talk about it...

Ignore the yellow zip-ties they were part of an ill-fated attempt to create a ‘third hand’ to hold a tire iron with – the emotions are still so fresh… I don’t want to talk about it…


This was taken immediately after the moment of success! As expected, the carcass splayed open just enough to allow me to start tucking the rim inside (with the aid of tire irons and lots of soapy water). I nearly wept with joy at this point!

But my tears would only have been joined by tears of sadness when I discovered minutes later that armed with my tinker-toy, short, straight tire irons there was NO WAY I could pry the beads over the rim. The tire is just too stinking stiff! I admitted defeat after only twenty minutes of suffering, and found myself motoring toward the dirt bike store after all.

My good friend Paul – proprietor of said establishment – who knows the formidable D739 well, seemed thoroughly impressed that I had gotten the rim into the tire at all. We went back into the shop and with the aid of some proper, long, dog-legged irons had the beads seated in a matter of minutes.

20130305-144550.jpg

Here she sits, uninflated Dunlop snugly in place, bearing a light dusting of dirt from the vacant lot next door. I took a thirty second rip across the lot just to see if it worked before sunlight disappeared completely.

It did!

With zero psi, I didn’t appreciate any “squishiness” when I cornered hard and hammered the throttle!

I’ll report back regarding this setup’s performance after a real ride.

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3 Responses to “TUbliss can be a TUbitch!!”

  1. kitt stringer said

    Hey bud, I got some Goldentyres and Mousse in to test them out before the race- they worked quite well and I’ll be using them for the race for sure. I drilled out the mousse to soften it up- i think the mousse will last 2-3 days, while the rear tire only one day, and the front 2 days.
    also, here is a link to a video I made about my own preparations- http://www.youtube.com/watch?v=K3jc3bVlz_s&list=UUTqP6-mOb_0WPoCBT5-Eu6A&index=1
    see ya soon-
    kitt

    • desflurane said

      Hey! Love the video! Very cool stuff!

      It’ll definitely be Goldentyre tires and mousses for me in Romania. Dougie is pretty well sold on them, and since it’s his bike…

  2. Bahboo said

    Thank you!!!!!!!!!

    Ratchet strap worked a treat. Same deal – 739AT with Tubliss. No strap – no workie – no way.

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