Lose Your Tubes

I feel like I spend a lot of time talking about wheel and tire technology on Off the Rivet.  It’s alright though, because wheels and tires are very important.  They are your first line of defense against the road—affecting everything about the way your bike rides and feels under you.  So here we are yet again, about to embark on another wheel related post, but don’t let out that knowing groan—thinking you know what’s coming.  You don’t. 

Tubeless technology is something that has sat on the periphery of road cycling for quite some time now.  Mountain bikers embraced tubeless wheels and tires quite a while ago, though the technology was much easily applied to wheels where pressures from 15-30psi are desirable.  Road wheels and their sidewalls must support much higher pressures, and thusly the technology has been more difficult to adapt.  But I’m not here to give you a why and how road tubeless came about.  I’m here to tell you about whether this technology is worthwhile or not.  

For several weeks now, I have been road testing Fulcrum’s Racing 1 Two-way Fit Wheelset.  I tried to approach this testing period with no preconceived ideas about whether tubeless wheels were a good or bad idea, and simply judge them by their performance on the road.  

Fulcrum's UltraFit technology creates a bead where both tubeless and traditional tube systems can be used.

Before I get into the ride though, let me explain a bit of how the Fulcrum Two-way fit works.  Because the bead of a road tubeless wheel and tire have to support several times the pressure of their MTB bretheren, there has to be an incredibly tight fit between rim and tire. 

This tight fit, along with a cup of Stan’s NoTubes sealant, allows you to run the wheels with no tubes.  Not having tubes may seem daunting at first, but it actually works out to be a big advantage.  Less flats and less rotating weight.  Pinch flats are a non-issue on road tubeless wheels—there are no tubes to pinch, and most small punctures are filled quickly by the sealant.  This makes for the possibility of many flat free miles—although they are still susceptible, as all tires are, to large gashes or cuts in the tire. 

The performance and ride benefits of losing your tubes are also numerous.  The absence of tubes gives these wheels a ridiculously low rotating weight that makes the wheels feel light and snappy, despite them being a sturdily built aluminum wheelset.  Their acceleration and responsiveness are these wheels main selling points—no ordinary achievement for an aluminum wheel.  This is all due to the fact that you no longer have to spin up the weight of two inner tubes. 

Mavic's Ksyrium SLR wheels.  The Ksyrium line has long been the standard for lightweight aluminum wheels.

By the numbers, Fulcrum’s tubeless offerings stack up well against their non-tubeless counterparts.  The gold standard for lightweight aluminum wheels has been Mavic’s Ksyrium line for many years.  Here is how the Fulcrums compare:

Mavic’s tube filled Ksyrium SLR flagship aluminum wheelset comes in at 1,400 grams and 1,800 bucks.  Plenty competitive are the Fulcrum Racing Zeros (one step up from the set I tested) who weigh in at 1,460 grams and will set you back $1,650.  These weights are for the wheelsets alone, which means you still have to add tires and tubes in the case of the Mavic wheels, and tires, sealant, and valve stems in the case of the Fulcrum wheels.  I’ll save you the tedious math and cut to the chase:  tubeless set ups come out about 100-150 grams ahead of traditional clinchers when you figure in tire/tube weight vs. sealant, etc.  So the “virtual weight” of the Fulcrum wheels could be described more like 1,310-1,360 grams—depending on which tire you choose.  This pattern bares itself out across the extent of both the Mavic and Fulcrum wheel lines.  The other comparable wheelsets have prices within $50, and weights within 100 grams of each other. 

So the numbers add up, but what about the ride?  Well I have no complaints.  I rode these wheels in as many situations as I could.  Through gravel, rain, rough roads, and a couple local crit races, the wheels performed admirably in all conditions.  Considering the way my brain works, this is saying something.  I tend to be quite judgmental when it comes to bicycle components, especially ones that are on my personal bike, so when I came back with a verdict of “pretty good” and “no specific complaints” that is somewhat of a ringing endorsement. 

My tire of choice for my testing period.

Well, actually, let me back track a second.  I do have one specific complaint.  There are not enough tire choices.  Only two companies that are readily available make tubeless compatible tires: Hutchinson and Maxxis.  I chose the Hutchinson Fusion 3 23c tires.  I would normally opt for a larger diameter tire, but the only 25c tubeless tire available is a rather heavy long distance training tire.  If there was a high performance 25c tubeless compatible tire on the market, this review would literally complaint free. 

By far the most impressive part of these wheels is the way they accelerate, both uphill and on the flats.  I noticed a substantial difference between the Fulcrums and my everyday wheels.  Normally a wheelset with such twitchy response will mean making a sacrifice in the durability of the wheels, but I had no problem riding these in pretty rough conditions—rough gravel roads and a rainy crit race.  I’m not the biggest most powerful rider in town, but these wheels were plenty stiff.  All without a single flat.  

The ride quality is something unlike I have ever ridden.  It feels different on the road than both traditional clinchers and classic tubular tires.  The ride is smooth while still feeling wonderfully in touch with the road.  The absence of tubes means no internal friction between inner tube and tire, which leads to a smoother ride and lower rolling resistance.  This video from Fulcrum’s marketing department has some interesting illustrations as to how rolling resistance is reduced by losing your tubes. 

I experimented with a wide range of tire pressures, starting high and working my way down until I felt I was in danger of “burping” the tire.  Burping a tubeless tire happens when the bead or the tire momentarily separates from the rim, resulting in a sudden loss of pressure—though usually not enough to cause a completely flat tire.  Burping is a fairly common occurance on MTB tires because of the large diameter of the tires and the leverage that provides on the bead, but I never once burped the Fulcrum road system.  I felt rather nervous about burping when I was riding the tires as low as 65 psi (on a 23c tire!!), but I never actually burped the tire.  My sweetspot for the tire pressure came in around 80-85 psi.—far lower than I would normally run my 25c tube filled tires.  At this pressure the ride was wonderful and stable.  Cornering was sticky and predictable. 

Overall I was quite satisfied with my tubeless experience.  It is certainly a viable technology for both racing and training.  The market simply needs more options.  More tires to choose from, more techs who endorse and install them, and more riders who are willing to embrace new developing technology.  Soon enough we might see tubeless occupying a decent market share, but that takes commitment from manufacturers as well as consumers—something I think could be coming sooner rather than later.  For what it’s worth, you can count me in.