Today I succeeded in setting up a Surly Larry tire on a Large Marge rim to run tubeless. This is a notable achievement because the conventional wisdom on the ‘net is that fat bike tires are notoriously difficult to get a good bead seat on.
Well, I’d been planning to try this for about a week already. I had my bottle of Stan’s sealant in hand, and my presta-shraeder adapter (to allow me to use my air compressor). But luckily, before I got to try it I ran into a guy at a bike shop yesterday who rides a motorcycle, and he told me a trick that motocycle mechanics use to get reluctant beads to seat.
What you gotta do, see, is wrap a load compression strap around the circumference of the tire and cinch it down. This forces the center of the tire down and the sides outward.
This is the key trick, but i’m getting ahead of myself. Here are all the steps I took, in order.
- First of all, put a tube in that tire, pump it up, and ride it around for a few days. You don’t expect some brand new, curled and twisted tire to seat properly, do you? This point was driven home to me when I replaced my Larry with a new Black Floyd — I couldn’t believe how round the Larry was and how nicely poofed out the sidewalls were compared to the Floyd.
- Okay, get yourself a honkin’ big air compressor. You will never get that thing to seat using a hand pump. I used a Thomas Renegade that puts out 4.6cfm @ 100psi.
- Put a genuine Surly “Rolling Daryl” rim strip in the wheel. You won’t believe how tight these things fit. And on a Large Marge rim, they extend from sidewall to sidewall.
- Next, put a tube in that tire and pump it up.Get the bead to seat all the way around. (If you already had a Surly rim strip in the wheel and haven’t removed the tire yet, you can obviously skip this step.)
- After deflating the tire, carefully break the bead on only one side of the tire. This reduces the work you have to do later and doubles your chances of success. The rim strip will actually hold the other bead against the sidewall if you’ve installed it properly.
- Take a valve that you cut out of an old tube, put it through the hole, thread on the retaining nut, tape it down with several layers of duct tape (I used Gorilla brand), and punch a hole through the tape. Although Gorilla tape doesn’t seem to me to be any stickier than regular duct tape, it does appear to be much less porous. My advice: if you’ve got regular duct tape around, give that a try first.
- Apply “the strap” as shown in the picture above. Note that I had to cinch it down quite a bit tighter than shown in the picture before I was able to get a seal. Also, you’ll notice that the tire tends to bunch up in certain areas — there’s simply too much friction for the strap to slide around the tire as you tighten it. I had to redistribute the tension of the strap around the tire a few times before I got it to be even.
- Put a presta-shrader adapter on your valve. Apply the compressor. Note where air is escaping, and dick around with the bead and/or strap near that spot to try to get it closer to the hook on the sidewall. I found that I had to hold the sidewall in place in a problem spot with one hand while I applied the compressor to the valve with the other. An extra pair of hands might help, but I managed to do it alone.
- Eventually, I hope, you will get the tire to start inflating. When the strap gets so tight that the tire is starting to bulge on one side, STOP! If the tire is not obviously deflating then loosen the strap and resume inflation. If you’ve got a fast enough compressor, you should hear the bead pop into position.
- Now that you’ve proven to yourself that it can be done, deflate, fill with Stan’s (I used 4 scoops), and do it all over again. 🙂 Follow the recommended procedure for getting Stan’s to seal the tire, using soapy water to find the leaks, etc.