Tubeless part two

The tubeless experiment continues and so far it seems worth it. On Sunday in Hamilton I raced on the Dura-Ace wheels. About 40 psi in the back, 35-38 in the front. After 3 laps warming up, the 9 lap race and a short cool-down there was no air-loss evident. If the tires burped I did not notice it during the race and could not tell based on the air pressure at the end. During the race the tires / wheels were never an issue. I had traction when I needed it, did not feel like the tires were “slow” on the short paved sections, and so on. Compared to Mud2’s - which is what I have raced for years- this was an improvement. So I will definitely race on this combination again. But how low the pressure can go without burping is still to be resolved.

I rode the converted Mavics once last week and then again on Tuesday (last) night at Centennial park.   This is still the wildcard set-up. I have been running 35PSI in these no problem. And based on a few quick experiments in the local park they can go much lower (25 PSI). I have bottomed out on the rim a few times without burping. My guess is that bottoming out the Dura-Ace wheels would cause a burp. But I am loathe to put that to a test given how pretty those wheels are.

And the traction seems really good with the converted Mavic set-up. So if there was a race on a rough course with lots of mud tomorrow (say Durham after a downpour) and I had to bring only one wheel-set this would be my choice. But this comes with two caveats.

One: Last night I set a personal record for crashing.  I don’t think it was the tires because I was having all sorts of brake problems. The front was either not working or grabbing and locking up – generally in downhill turns. So I was wiping out because the front wheel locked and slid – not because the back end came un-hooked. On the slick uphill sections I was hooking up fine. But this needs to be tested. If the tires suck on wet grass that would be a deal killer, at least until other tubeless tires exist. If anyone else was riding Hutchinson Bulldogs last night I would like to hear how they worked. Empirical data is always preferred to a guess.

Two:  This one may be mainly aesthetics but the tires did not mount up perfectly strait on the converted rims (they did on the Dua-Ace rims).  They look like tubulars that were glued by a drunk. This is, I assume, a function of the rim strip and how tight the tires are on the wheel. I am guessing that a bit more time evening out the rim strip would fix this. But that requires taking the tires off. And given how much of a pain they were to mount (and how lazy I am about this sort of thing) I am going to ignore this for now. But I do wonder if this increased the odds of a blow-out. I guess there is only one way to find out.

So to conclude for now. Both set-ups work. The Dura-Ace set-up is much lighter than the converted Mavics. So for anything short of a mud, rock and root festival this will be my choice for racing. But it is still an open issue as to what is the lower limit on tire pressure. The converted Mavics seem to hold serious promise, especially for nasty conditions. But that is still mostly conjecture. And I think the tires are generally a nice improvement on something like a Mud2. But that needs to have a follow up test on wet grass when I can slow-down without locking up the front end.

So it is a little safer to pass me – but you are still forewarned that I am riding experimental tires and anything can happen.