Last time I tried running latex inner tubes, I swore never to fit one again. But, like the urge to drink port, the desire to enjoy the feel of latex (inner tubes, that is) never quite goes away no matter how disagreeable the previous experience and is apt to return once it has been forgotten.
So, on opening a box containing tyres from Vittoria for test, I was not entirely displeased to find a box of the latest latex inner tubes from the Italian brand. By “the latest”, I mean the most recent type; until recently, Vittoria latex tubes were dark purple, very thin and perhaps ideally intended for use in tubular tyres. These are thicker and pink, the former attribute suggesting that they might be more durable.
Durability is something not readily associated with latex tubes. The material, obtained from the sap of the rubber tree, is more elastic than the black butyl synthetic rubber used for the vast majority of tubes, but it is also much more prone to bulging into an “aneurism”, as inflation of one outside a tyre will quickly show.
The third factor to consider with latex is its porosity, or reduced capacity to retain air compared to butyl. A good rule of thumb is that a latex tube in a 23c tyre will lose about 10psi overnight if inflated to 100psi. Since I inflate my tyres before every ride, this is not normally a problem.
Fragility, however, might be. I don’t like fragility where cycling is concerned, having always preferred to ride heavier but more robust components in the hope of minimising breakdowns. Do punctures count as breakdowns? They do if they aren’t the result of riding and there are plenty of stories around of latex tubes going bang during fitment.
I have never had this happen but the bulging tendency suggests how it might, since a thin latex tube will find its way through even the thinnest of gaps. I have removed latext tubes to find evidence of bulging into the space between the rim tape and valve hole, which is difficult to fill.
Get the tube even slightly trapped between the tyre and rim during fitment and it will bulge outwards from between them during inflation before exploding nicely. The interior of a tubular tyre, of course, offers no small orifices to explore and is a nice, secure environment for a latex tube.
The key to reliability, then, is to get the tube properly fitted inside the tyre and to ensure the rim tape is snug-fitting. Liberally dusting the tube in talc will help it seat equally all round, as will inflating it enough just to take shape prior to fitment.
Back, then, to the ride. When and where? Right now, I have latex tubes in two mudguarded road bikes. One, the Independent Fabrication Club Racer, wore latex tubes for the first day of my autumn tour, the rear being swapped for butyl when it flatted on day two while the front stayed put. The replacement butyl tube and another have since both punctured while the latex front tube is still fine.
Here was a perfect opportunity to sense any change in ride quality. Seemed to me that there was one, the latex rear providing a notably enhanced impression of the road surface. According to DA, it made a different sound. Perhaps it is easier to describe the effect of fitting the butyl tube, which in comparison felt slightly “dead” and heavily damped.
If anything, butyl provided more comfort on some surfaces because it was taking out high-frequency vibration, but then the latex tube could have been run at slightly lower pressure to much the same effect. Overall I’d choose latex for comfort and those I’m running right now impress every time they are ridden.
In terms of speed, fitting butyl seemed to slow the bike slightly but I’d want to carry out coast-down tests to be sure. In any case, latex is lighter which means a definite performance improvement in some circumstances. There is the possibility that, by shortening the time the tyre takes to return from compressed to proper shape, a latex tube can contribute to improved roadholding. Sounds reasonable.
I’ve had several latex tubes on the go now for a couple of weeks and only one has punctured, on tour when it was loaded and the tyre got a sidewall cut. Didn’t Dave Brailsford say something about the “aggregation of marginal gains”? This time round I still like them after a month and, even if the gains are marginal over butyl, gains they are.
Vittoria latex tubes price TBC.
