Blog: May, 2013

26 May 2013

Road tubeless not so sure

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I’ve been riding my road tubeless wheels lately, playing with tire pressure. I started a little high but dropped down to 75psi on the front and 80psi on the rear. The comfort of the tubeless Ultremo ZX is beyond what I’m used to from clinchers but fast and sticky at the same time. Really nice.

Unfortunately the experiment came to a premature end today when I hit some unknown particle and sliced the rear tire. The cut was far too large to be managed with sealant and, adding insult to injury, sealant sprayed the face of the rider on my wheel. Without any loss of control I rolled to a stop and was pleased to find the tire well-seated in spite of total deflation.

The flat happened on Highway 8 east of Calgary at a spot covered with oil residue — yesterday that spot was host to a head on collision between an SUV and a semi-trailer truck. The SUV was launched 90 meters backwards; the truck caught fire and burned out. The SUV driver was killed and the truck driver was taken to hospital with injuries. There must have been some debris left behind.

It’s hard to say if another tire would have survived. The Ultremo ZX, at least in its clincher version, is known for performance but not for durability. I’ll get another and carry on.

Road tubeless has been around for a little while and it has gotten good reviews from the likes of Leonard Zinn. So far I’ve been reticent to try road tubeless but when Schwalbe released their excellent Ultremo ZX tire in a tubeless variant, I figured I’d give it a try.

To make this project work I dug up some NOS Shimano Dura-Ace 7900 hubs. For my first try I turned to my offroad rim vendor, Stan’s Notubes. I got their Alpha 400 rims in 24/28h to match my hubs and put them together with Sapim CX-Ray spokes. The Stan’s rims built up very smoothly and total weight came to 1500g on the nose — plenty respectable. On top of that I installed two layers of Stan’s 21mm yellow tape and 44mm road valves.

Mounting the tires was a little hairy. The Ultremo ZX tires needed levers and I drafted a pair of toe straps to hold the tires in place as I worked their final sections. There’s some skill involved and my speed was better on the second wheel. In the end I found compatibility between tire and rim was excellent. I had my air compressor ready to go but was able to seat the bead with a floor pump. Each tire got 2oz of Stan’s sealant and neither shows signs of leaking air.

Of course it’s all about the ride. My short test ride was very positive — I find the wheels extremely comfortable even with a skinny 23mm tire. Before blabbing too much I want to put more miles on these wheels and play with tire pressure. Details to follow.

08 May 2013

Nipple lubrication and locking

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Nipple lubrication and locking is a subject that arouses a little too much passion. Most methods have merit — after all wheels aren’t falling apart at every turn. In the past I’ve used linseed oil, different brands of anti-seize, grease, Wheelsmith SpokePrep, light oil, heavy oil and DT Spoke Freeze.

Products such as linseed oil and SpokePrep combine lubrication and thread locking in one. That’s convenient but I prefer to separate these functions. With an oil lubricant, I can add more during the build if I feel it’s needed. If you let the wheel tell you when it’s done, then some builds will take longer than others. And sometimes I have to leave a wheel and finish it later. With oil it’s no problem. My preference is for a heavy oil over a lighter one since heavy oil is more likely to stay where you put it. To ensure total lubrication I submerge my nipples oil, which is messy but effective.

In theory thread locking isn’t necessary but life is real and stuff happens. If you want low maintenance wheels that can handle a breadth of conditions, thread locking helps. I use DT Swiss Spoke Freeze, a product made in collaboration with Loctite. You might think Loctite acts like a permanent glue and without oil it does. But, combined with oil, Spoke Freeze locks nipples while leaving wheels serviceable. Soaking my nipples in oil ensures this outcome.

There are other thread locking strategies but I reject them for one reason or another. You can use a bit of glue on the nipple but at the risk of preventing future adjustments. You can buy self-locking nipples. In some cases these have thread lock compound pre-applied. In other cases, such as the Sapim product, nipples are manufactured with deformed threads that cause friction and prevent unwinding. A neat idea but increasing friction can induce windup during the build.

Nipple seat lubrication

It’s also important to prepare the nipple seat for building. On a rim with eyelets I use a drop of light oil. On a rim without eyelets, which I prefer, I first deburr the nipple seat with a light touch from a handheld drill bit. Then I lubricate the area with a small amount of grease. These steps help nipples turn freely and reduce the possibility of damage from friction during wheelbuilding.