Saturday, January 3, 2009

Tubeless Experiment

Thursday night I converted the front wheel of my 29er single speed to run tubeless. Not having any official supplies (Stans rimstrip, yellow tape, etc.) I decided to use what I had on hand.

Using an old, punctured road tube I cut out the threaded presta valve stem. I then removed the existing tube & tire from the rim, covered the existing rim tape with 3 layers of black electricians tape, inserted the presta stem, threaded on the bolt to hold it in place (I used pliers to get it good and tight) and remounted the tire (a 2.4 Continental Mountain King).

At this point I tried to inflate the tire using my floor pump and, when that failed, a C02 cartridge, with no luck. Luckily I have a neighbor who owns a nice air compressor. I drove over and we were able to easily inflate the tire. Unfortunately both the valve stem and tire sidewalls were leaking air so quickly that it was flat in a matter of minutes. However, I hadn't expected the tire to hold air at this point, but wanted to verify that the bead would seat and it would inflate without blowing off the rim.

With that test done I removed a section of bead, poured a bunch of Stans into the tire (I didn't measure as my bottle was almost empty so just dumped in what was left), reseated the bead and hit it again with the air compressor. As before I began losing air from around the valve stem and out the sidewalls but after shaking the wheel horizontally all the way around (rotating a few degrees each time) the hissing had stopped. I took it home and performed a few more sessions of shaking, laying the wheel on top of a bucket after I finished each, and it's held air ever since. The true test will come when I can get out for a ride (maybe next week I'll do a night ride on the neighborhood canal roads) but so far it's looking good.

17 comments:

KanyonKris said...

Look at you, McGyver! Props for doing some shop work and experimenting.

I'm not sure the electrical tape will hold over time. It might be OK, but the Stan's might dissolve the adhesive. Maybe put a strip of electrical tape stuck to itself in a bottle with some Stan's and see if the tape comes unstuck.

The yellow 3M polyester Stan's recommends is burly industrial stuff.

I've been somewhat disappointed that Stan's didn't last long in my tires. I had to refill them 3 times last year. It wouldn't be such a hassle if my rims held the bead when I deflate the tire, but since they don't I have to go through the bead sealing gyrations each time. I'll be trying the Bontrager juice next year to see if it lasts longer.

Bart G said...

Use wd40 on the bead and it seals right up, often times with a hand pump. With removable core and syringe you can add stans anytime without breaking the bead.

StupidBike said...

Next time if you use the tube trick, use a mtb or bmx tube, Conti's have removable cores.

KK, nothing lasts long, more than a few months, we live in a desert AND it shows that it is doing its job, sealing little leaks for ya, day in and out.

Watcher said...

Hey, so dopy question from a tubeless-newbie. I just had my wheels rebuilt with tubeless rims. Planning to try tubeless in the next little bit.... you guys use UST tires, or just non-UST tires with the sealant? Thanks-

pat t cakes said...

Watcher. you can use either standard or ust. standard will be much lighter, but ust will have a heavier and more durable bead and sidewall.
If your tough on tires make certain to avoid any specialized tires for running tubeless. I have split 8 of them on their first rides.

OilcanRacer said...

i been tubless for a long time now and really like the way tires feel at different air psi's without tubes. they just react better.

shwallabes and michelins have worked great for me tubeless for being non-ust tires.

rims with a inside vertical sidewall like stans make it way easier to inflate.

congrates on your experimental success.

Chris said...

I have been considering trying "getto tubeless" - I think your post will give me the push to do it. I have heard an alternative to electrical tape is to use a small filleted tube (24" for 26" wheel, 26" for 29" wheel). Blow it up, mount it, then use a razor to remove the outer half, leaving a tight rubber strip around the circumference of the rim. Did you consider this and if so, what made you decide to try electric tape instead?

UtRider said...

Watcher - I have ridden tubeless from day 1 of my short 3 years on a mountain bike. All of my tires have been UST until the Deer Valley ICUP when I started riding a pair of Continental Speedking Protection tires. I used them all summer with no problems and will go back to a non-UST tire for the summer again this year.

Chris - I used electrical tape because it seemed the closest thing to Stans yellow tape. Plus, I am somewhat of a weight weenie and thought the tape would be lighter than a trimmed tube.

KanyonKris said...

Bart - Soap & water has worked well for me to ease the bead sealing, but I'll remember the WD40 trick.

I have removable cores, but it doesn't do me any good because when I let the air out of the tires both beads break. The problem is the bead hook of my rims - they won't hold the bead without air pressure. I am planning to build a new front wheel and I will either use a Stan's or Mavic UST rim so the bead will hold even deflated.

I considered deflating the tire as low as I dared and using a syringe by poking the needle through the tire to add sealant. But even at lower tire pressure I would have to push hard on the syringe to overcome it and inject the sealant. I may try this method anyway just to see if it works or not.

StupidBike - I see your point, but I've been told other sealants last longer. Are you saying you've tried brands other than Stan's and they didn't last much longer?

KanyonKris said...

Watcher - Pat summed up the state of tubeless. I'll add that there are essentially 3 classes of tubeless: UST, Tubeless Ready, and any old tire converted to tubeless.

UST is a standard for a tubeless system that can take a beating and assures that any UST tire can go on any UST rim. The system is supposed to be leak-free so no sealant is needed, but some mountain bikers add sealant to prevent flats from punctures.

Tubeless Ready is harder to pin down, but basically manufacturers wanted to make tubeless tires that didn't meet all the requirements of UST yet still let consumers know the tires can be run tubeless. Usually the requirement they don't meet is sidewall thickness / porosity so Tubeless Ready tires almost always require sealant. For most mountain bikers, Tubeless Ready means a reliable tire system that weighs less than UST.

Most tires can be converted to tubeless even if they weren't designed for it. This is what Stan's promotes. The sealant seals the leaks so it hold air. This allows the widest choice of tires and rims / wheels.

I converted both wheels to tubeless with removable core valve stems and yellow tape to seal the rim. Some tires were fairly easy to get the bead to seat, but others were a real struggle. And I have to go through the struggle again each time I add sealant. While I like being able to choose any tire, the hassles of this method are annoying to me.

Going forward I will move to tubeless rims / wheels which usually allow the tire to be completely deflated and still hold the bead. This makes it much easier to maintain a tubeless system that uses sealant. I will also gravitate toward Tubeless Ready and UST tires since they just work better for running tubeless. I'm not a weight weenie, but the heft of UST tires turns me off and usually I can find a similar Tubeless Ready tire I like.

Is tubeless worth it? For me, yes. I like the feel of tubeless and the ability to take the air pressure way down without risking pinch flats. And trading sealant for a tube keeps the weight about the same and adds flat prevention. There is more maintenance with tubeless (sealant), but it is worth it when it avoids most trail-side flat repairs.

KanyonKris said...

I saw the ghetto tubeless first on AtomicMiles - http://www.atomicmiles.com/2008/10/ghetto-tubeless.html

You can buy that yellow polyester tape Stan's uses / recommends from McMaster-Carr (www.mcmaster.com), part #77075A23 for 3/4" wide (they have other widths).

Rick Sunderlage said...

The trick w/ the core remover, is to let the air out slowly and then remove the core. It works well for me.
I add Stans every 2 months.

KanyonKris said...

Rick - I tried slow, but the bead pops off every time. The problem is the rims. Below the bead hook is a sloped wall so when the air goes out the tire bead just slips down into the center of the rim. Other rims have a shelf under the bead hook so the bead stays seated. I'll be moving to rims (like Stan's) that work better for tubeless.

Anonymous said...

I converted some non tubeless wheels with a stans kit and they have held great, but I was not able to pump them up with a floor pump.

With Bontrager wheels they have plastic liners and seperate valves which makes it easier when getting a flat because you remove only the valve, and not the entire liner. Also I could pump up my tires with only a floor pump. Excellent seal!

KanyonKris- If you use a needle to inject Stan's into your tire, the "Micro sealing crystals" will clog up the needle and it will not work. Tried it for road tubes and had to slit them and then patch them up

-JM

KanyonKris said...

JM - thanks for the heads up on injecting Stan's wit ha syringe. What size syringe and needle did you use? If I used a really large gauge needle do you think it would work?

dug said...

kk, kenny uses a huge needle all the time, it works great. you need to let the syringe out to start, because the pressure will pop it out and hit you in the eye if you're not careful. not that it's ever happened to my eye.

KanyonKris said...

dug - that's good to know. I'll get a big syringe and try it.