Ridden & Reviewed: Road Tubeless

To road tubeless, or not to road tubeless? That is the question.

Ask any of the folks around the shop that ride mountain bikes and they’ll almost all universally tell you that yes, of course they ride tubeless. But ask any of the roadies and the number is bound to be much smaller. Why is that?

For years, since at least the introduction of Universal System for Tubeless (UST) standard in 1999, mountain bike riders have enjoyed the benefits of lower pressures, added traction, the elimination of pinch flats, and when ridden with sealant, the virtual elimination of smaller punctures thanks to tubeless. One reason that it caught on with trail riders is the fact that on a mountain bike where rims are wider, tire volumes are higher, and air pressure is lower it’s easier to set a dedicated UST system up and know that the tire will hold air and stay on the rim.

Of course, official “systems” invite tinkers and work-arounds, and things like Stan’s came to be along with a host of do-it-yourself techniques that looked to covert any wheel and any tire into a tubeless set-up. Some work and some don’t, but now tubeless in one form or another is the sure-fire leader in MTB tire technology.

For the road the fear is simple. At 90 to 100 psi or more, the tire blowing off the rim is that much more possible. And at typical road speeds, and on pavement, such an occurrence is likely to be catastrophic. Like rolling a tubular off a rim if the gluing isn’t done properly. For tubeless to work on the road, there has to be a way of ensuring as much as possible that there isn’t a chance the tire is going to let go of the rim. Enter the Road Tubeless standard, essentially UST for skinny rubber riders.

A tubeless set-up eliminates the need for an inner tube by utilizing 5 things: a rim constructed with a precisely shaped hook for the tire bead, a rim bed that has an un-drilled inner wall and/or rim strip that snaps into place covering spoke holes, valves that sit in the rim with a grommet to keep them from pulling through, a liquid sealant of some sort, and a tire that has a precisely shaped bead that snaps into place on the rim. The rim hook and tire bead essentially ensure tire security. The rim strip and sealant essentially ensure no flats.

I’ve been riding both Bontrager’s new Race Lite TLR wheels and Shimano’s Ultegra tubeless wheels since September and I’d say that for the recreational road rider I think road tubeless is the way to go.

Bontrager’s Race Lite TLR wheels are reliable everyday hoops.

Shimano’s Ultegra tubeless hoops are everyday wheels. There are certainly lighter, more aerodynamic options out there. Still, at right around 1500 grams (without skewers and cassette) and $700.00 they are reliable and cost effective making them a good choice for an everyday wheel, even when run with tubes. Full aluminum constriction with bladed spokes, the inner rim wall does not have spoke holes so no rim strip is needed. Shimano suggests not running sealant, and doing so will void the warranty if corrosion happens as a result of any sealant. But aluminum resists such corrosion pretty well, so I’ve been running sealant with no visible corrosion. The hubs are really quite smooth. Like all Shimano hubs, they run on loose bearings, which many folks swear are faster than cartridge bearings. Whatever it is, they feel like they spin forever.

Shimano’s Ultegra tubeless wheelset have a slightly more refined appearance.

Bontrager’s Race Lite TLR wheelset is a slightly lighter offering at roughly 1440 grams according to my scale (again, without skewers and cassette) and a similar retail price. Also full aluminum construction, the Bontrager wheels would also make a great training/everyday wheelset. Bontrager not only anticipates the use of sealant, but they in fact offer a tubeless conversion kit for their tubeless ready wheels that includes rim strips, valves, tires, and Bontrager’s own sealant. The hubs don’t feel quite as smooth in hand as the Shimanos, but that could be my perception more than anything else. While the Shimano wheels feel stiff with no real noticeable flex, the Bontragers feel like they spin up a bit faster. Perhaps the rim weight is lower, but without the ability to weigh just the rims, I’m not sure.

Shimano hubs are noted for their smoothness.

When I got the wheels I did stick them in the turing stand and check them out a bit. The problem with nearly any wheel with aero spokes is truing the wheel and keeping the spokes in proper allignment. When out of the box a new wheel can need a minor tweek and each of these were no different. The minor annoyance of the aero spokes aside, both pairs of wheels set up fairly easy. Install rim strips on the Bontragers, install valves, mount one side of tire, pour in sealant, finish mounting tire, and inflate with a compressor to make sure the tire bead snaps into rim hook. After doing it a couple of times it was quite easy. Still, the compresor was a must have in terms of initial set-up.

A close-up of the Bontrager Race Lite rear hub. The higher end Race X Lite features DT Swiss internals.

I rode the Bontrager wheels a bit with the their second tier R2 23 mm road tires mounted and the Ultegras with Hutchinson’s Intensive road tubeless offering in a very narrow looking 25 mm width. But soon I switched both wheelsets over to Vittoria’s XG Pro TNT cyclocross tire for ‘cross season. When ever I was mounting tires to either of the wheelsets, and regardless of what tire I was mounting to what wheel, I noticed that it was a bit harder to get tires on the Bontrager hoops. While frustrating, I was reminded by some of the shop mechanics that this is, in fact, a good thing since as mentioned above we surely don’t want the tire coming off at the wrong time. Also, regardless of wheelset or tire I was riding I ran sealant from Austin’s own Orange Seal.

A look at the rim hook and valve on Bontrager’s tubeless set-up.

I was quite impressed with durability of both wheelsets. I “burped” a tire only once when riding the Bontrager wheels. Through no fault of the wheel, on a slight off camber, bumpy turn the tire “let go” of the rim momentarily on one side and air escaped (hence burping). I say no fault of the wheel because I was trying to see how low I could run the air pressure with cyclocross tires. As it turns out 27 psi is far too low to reliably run the Vittoria cx rubber in tubeless configuration at race speeds at my weight (160 pounds). For the rest of my rides, through every crash, every race start, every loose turn, every dropping of the bike at the top of a run up or banging into the barriers, across every sand pit, and over every rock the wheels never showed any signs of abuse, despite getting plenty. Only after the one burping incident, which I caused, did I need to true the Bontrager rear wheel and I never needed to true the Shimano hoops after initial set up. The brake tracks stayed clear and free of heavy marking and showed limited wear across three months of use on both wheelsets.

The big advantages that I see to road tubeless are improved ride quality as a result of being able to run lower pressures and virtual  flat elimination. I’ve been running about 85 psi on the road with tubeless road tires and it feels good! The 25 mm Hutchinsons, as mentioned, seem pretty narrow. But at 85 psi I’m putting plenty of rubber on the road, improving traction and cornering in the process, and getting more comfort out of the ride. (For cyclocross I reliably ran 30 to 35 psi on the Vittorias without once burping a tire.) Not once during ‘cross season did I get a flat. Despite puling out thorns seemingly every week, the sealant always took care of such punctures. And despite hitting large unseen holes and dips at about 30 psi at race speeds, since there was no tube there was no possibility of pinch flatting. Moreover, I’ve had the same experience on the road. Small road debris and seams don’t result in flats the way they likely would if running tubes. And the best part is that if I were to get a flat, I could simply install a tube and ride home.

The Ultegra rims look machined from a distance, but instead featured reinforced spoke holes to keep the inner wall intact for tubeless application.

Still, there are limited options for high-end tubeless wheels, although more and more are coming to market, including carbon offerings from Bontrager and others from Shimano. Slightly more problematic is the small selection of tubeless road tires, particularly higher end, supple race tires. But I suspect that too will change, just as it did for mountain bikes.

Given the very, very similar weight of the complete wheelsets (the Bontrager and Shimano front wheels actually came in at the same weight on my scale) and their similar cost and ride quality I’d say it’s a toss up between these two offerings. As for road tubeless, I’d say it’s a must for anyone riding primarily for fun and fitness, especially folks that are riding longer miles and want to reduce the chance of a flat as much as possible. The ride quality improvement from lower pressure is a bonus, which will improve even more as more tire offerings come to market. If you’re wanting to try out road tubeless, talk with our rentals department as they have some of these great wheelsets to demo!