- On the inboard edges of the bead-seat ledges on this Shimano Dura-Ace Scandium road tubeless rim, you can see the little “humps” (I’d call them ridges, but the French UST inventors call them humps, pronounced “eoomp”). The humps seal against the rubber flap on a UST tire bead as well as lock the bead on in the event of a flat tire. Photo: Lennard Zinn | VeloNews.com
- Top view of the UST humps (or ridges). Photo: Lennard Zinn | VeloNews.com
- The little rubber flap extending inboard from the square carbon bead can be seen on the left in this photo. That flap seals on the rim hump. Photo: Lennard Zinn | VeloNews.com
- The bead flaps of the square road tubeless beads seal against the rim humps and, in the case of a puncture and sudden loss of air, the humps work to keep the carbon-fiber beads from dropping into the rim valley (which would allow the tire to come off of the rim). Photo: Lennard Zinn | VeloNews.com
We’ve had a number of questions recently over road tubeless wheelsets. We’ll address a few of those here today, and look at why wheel manufacturers aren’t using ceramic coating to solve the heat problem on carbon hoops.
Tubeless for touring
I have been riding road tubeless tires for a couple of years now and am completely sold on them. The ride is great and flats are practically nonexistent.
My question is, now that Hutchinson has introduced the Sector 28 tire, do you think they would be safe and reliable on a touring bike? I ride several self-contained tours a year and currently run 28mm tires mounted on Campy Record 8-speed, 36-spoke hubs laced to Mavic rims and have never had any problems with this setup. Secondly, would it be safe to convert these wheels to tubeless, using one of the conversion kits currently available, or would the Campy 2-Way Fit Eurus or Shamal rim be a better solution?
Yes, I think it would be a safe and reliable touring tire. It seems to be quite tough, and it of course eliminates most flats, which is certainly a safety issue, especially in loaded touring.
I am a believer in tubeless-specific rims for road tubeless tires, so my recommendation would be something like the Campagnolo 2-Way Fit wheels you mention. A tubeless-specific rim has the “hump” on the inboard edge of the bead ledge that Hutchinson designed the tires for. It is designed to seal against the extra rubber flap extending inboard from the bead as well as to lock the bead on. I’ve ridden a couple of kilometers of downhill switchbacks on a flat tubeless Hutchinson Fusion 2 in order to see if it held it on the rim (a Dura-Ace Scandium tubeless rim), which it did for almost two kilometers. That’s plenty of time to bring your bike to a standstill, in the case of a sidewall cut and sudden deflation, even if it’s loaded up with packs. And it is of course much safer than having the tire come off of the rim.
Tubeless conversions definitely work, and I’ve used Stan’s NoTubes a lot for cyclocross with no problems, but for the higher pressures and speeds on the road, I like that bead-lock hump.
High thread count in wide tubeless road tires
Watching Caley Fretz comment from the Giro about tire width choices the pro field has started to make in the last year, switching from 23mm to 25mm or wider tires for normal road stages, prompts me to ask these questions: does anyone at present make a high thread-count 25mm tubeless clincher tire? Does riding a lower thread count and heavier tire that is 25mm wide produce a better ride quality than a narrower higher thread count tire?
After riding Stan’s modified wheels and dedicated tubeless off-road wheels for 10 years, I decided to try tubeless for the road. Last year I built a set of Hed Bastogne-rimmed wheels primarily because of their wide rim bed (25mm I believe). Tire selection came down to Hutchinson 700×23 for the first set, and now I am riding Maxxis Padrone tires 700×23.
I am not a racer, but a commuter and a weekend Fred who is looking to match the kind of resiliency and feel of the Vittorias whose tubes he up until recently patched and whose casings he all too frequently would sew together.
I have been riding 25mm tubeless Hutchinson Intensives on my bike for some time now, and I’m quite happy with them. 127tpi is definitely not the 300tpi you’re used to in a handmade tubular, but that’s a fairly high tread count for a vulcanized tire in the first place, and, being tubeless, it is more supple than a tire and tube of similar thread count. I know of no tubeless tires in 25mm with higher thread counts than 127tpi.
New tubeless ready designation
Can you explain this new “new tubeless ready” mountain bike tire designation that’s popped up recently? My buddy Bob has a UST wheelset. In the interest of saving weight, he tried some standard tires, but they would not seat. However, he got the same Maxxis Ikon tire in their tubeless ready (TR) version and it seated just fine. I kind of thought tubeless ready was just a standard tire with a coating inside, but it seems it’s something more.
I’m curious because I’m finally thinking of converting my DT wheelset to tubeless. UST never interested me because of the weight, but another riding buddy has been running a Stan’s conversion on his DT wheelset, with standard tires, and it’s been working great. Would a TR tire work better for this, or does the latex make this unnecessary?
To get the UST designation, according to the licensing agreement, the tire must not leak — without sealant. I have been in tire factories in Asia in which workers tested 100 percent of the production of UST tires by inflating them on rims and submerging them in a huge water tank to check them for leaks. Consequently, UST tires have a thick layer of rubber coating the entire inside, as well as the rubber flap on the inboard edge of the tire bead to seal on the “hump” on the inboard edge of the bead shelf of a UST rim. This makes them heavier (generally as heavy as a standard tire and tube), and it also stiffens and toughens the sidewalls, which for many riders is an advantage over running a standard tire or a Tubeless Ready (TR) tire with sealant and no tube.
A TR tire is meant to be run tubeless, but it doesn’t have the no-leak requirement. Generally, it will leak without sealant. However, it does have extra rubber at the bead to seal along the rim shelf, as well as more rubber coating the inside than a standard tire, and, consequently, it will seal better than a standard tire set up tubeless with sealant. I believe that TR tires may also be held to a tighter tolerance on bead diameter than most tires, so the tire will tend to fit tighter as well.
Sealant obviously will not tend to seal the edges of the bead, since it is thrown to the outside of the tire as it spins, or to the bottom when it is standing still. There is no force during normal usage that would move sealant to the bead. And if there are too many leaks through the casing, it is hard for sealant on initial inflation to get everywhere. If you cannot get it to inflate, then you cannot slowly work the sealant around to wherever it is bleeding out of the tire.
The Stan’s system does allow you to build up the height of the rim bed with layers of tape, and even a rubber strip with integrated valve stem if the bead doesn’t fit tightly enough. So this makes it possible to seat a standard tire that otherwise might not seal on the rim due to a loose bead fit.
Ceramics for carbon wheels
I’m only curious because you’ve mentioned in a few articles that achieving good braking on carbon rims (especially clinchers) has been something of an engineering problem; whatever happened to ceramic-coated rims? I remember while racing cyclocross in the early 2000s in the Pacific Northwest, lots of riders rode Mavic CD rims, and at some point I built up a pair of Mavic T517 CD touring rims (quite burly), and they worked quite well in the rain.
So my question is: is it possible to coat carbon rims with ceramic (or similar) coatings? Would this help with both heat and braking?
Here’s your answer, from wheel designer Paul Lew of Reynolds:
Yes, I’ve tried this. There are two problems:
1. The adhesion between the carbon-epoxy and the ceramic is poor, and the ceramic tends to crack and “chunk out,” so this would be a warranty nightmare for the manufacturer.
2. The ceramic (an insulator) tends to make the heat problem worse. The concept that ceramic is an insulator is not lost on the solution. A thick coating of ceramic sufficient to insulate the carbon from the heat-effect of braking adds an unacceptable amount of mass, as the specific gravity of ceramic is high.
Director of Technology and Innovation Reynolds Cycling, LLC
Technology Founder Reynolds Cycling, LLC
Tubes with removable valve cores
Having just read your article dated 6th June 2013, I noticed you mention that QBP’s tubes have removable valve cores but not many others.
Both Continental and Schwalbe inner tubes have removable valve cores, two massive brands that are readily available at normal price.
Feedback on Zinn and the Art
I have your road bike book, and it’s my constant companion when I’m working on my bikes. This spring, I bought a ’cross bike with disc brakes. I don’t need your mountain bike book for but a few parts of it. Has it ever occurred to you and VeloPress to release a ’cross supplement to the road book with just bits of the mountain bike book to cover disc brakes, U brakes, and other things roadies only see for ’cross and gravel bikes? It’d be super helpful, and you’d sell a lot of copies.
We have not done a standalone supplement like that. However, I recently completed the 4th edition of Zinn and the Art of Road Bike Maintenance, and that has extensive cyclocross sections that include cantilevers and disc brakes, both hydraulic and cable-actuated. These of course would be applicable to gravel-road racing as well as cyclocross.