I won't enter into the tire width debate. But I will offer the following data point. On a timed group ride a couple of years ago this guy came in 21st out of 107 on a Hilsen with 23 mm Continental tires:
http://tinyurl.com/yldr4yv I didn't get to talk to him about how the Hilsen handled with 23s, but when considering the race results, the skinny tires don't seem to have been a detriment. Whether fatter tires would have made him faster is impossible to know, I suppose, but I somehow doubt it, given that the route was essentially one long climb from beginning to end, with some sections with steep gradients. By the way, this guy's bike build was rather unconventional in Rivendell's scheme of things: he had a threadless fork/stem, Campagnolo wheels, and a Campagnolo Record gruppo, which included carbon cranks and levers. I would imagine that his Hilsen was considerably lighter than a more typical Riv build. All of which is a long-winded way of saying that at least one person out there has transformed an ostensibly "country bike" Hilsen into a "road" bike and is successfully using it in that guise. Aaron On Dec 3, 10:46 am, Tim McNamara <tim...@bitstream.net> wrote: > On Dec 3, 2009, at 9:09 AM, newenglandbike wrote: > > > Not to throw a wrench in your plans for the AHH, but Jan Heine et. al. > > recently published results of an extensive test involving various > > tires/widths and speed, and they found that rolling resistance is a > > *weak* function of tire width. In other words, tire width had > > little to do with rolling resistance. They found that wider tires at > > moderate pressures are actually faster than narrow tires at high > > pressures. I do not have the issue of BQ (I'm working on getting a > > copy) but is in Vol. 5, No. 1 (Autumn 2006). > > > Does anyone here have the article? > > Yeah I do as do several of us, and Jan reads this mailing list too. > I've always had some problem with that particular report which I've > discussed with Jan at great length (without convincing him nor he > convincing me). However, the results did match pretty well with what > one would expect (tries with thick rubber being slower, tires with > knobbier treads being slower, etc.). > > However in the last issue of BQ they published a *very* interesting > test using a Tune PowerTap to measure the power necessary to maintain > speed over smooth and rough pavement. In both cases they found the > fatter, softer tires (a Panaracer Pasela 700 x 37) to take less power > than a skinny hard tire (Bontrager 700 x 25) to maintain the same > speed. Over smooth pavement the differences were smaller but still > significant; over rough pavement the differences were startling. I > found this article fascinating and hope that Jan does more with it. > Directly measuring the watts it takes to roll a tire seems to me to > provide the most immediately useful data about tires. Exciting > stuff. (OK, I'm a geek). > > The short version is that skinner is not necessarily faster; higher > inflation is not necessarily faster. On the steel drum rolling > resistance machine, all other things being equal, wider is faster and > harder is faster. On the road, wider is faster and softer is > faster. There is no doubt a point of diminishing returns or we'd all > be riding Pugsleys with 4" wide tires. > > The main issue with rolling resistance is hysteresis, the loss of > energy in flexing the tire and tube. Thinner tread, supple casings, > etc. roll faster. This appears to be true on steel drum RR rigs and > on the road. > > In practical terms, I did many crits, road races and club rides on my > cyclo-cross bike with Avocet 700 x 32 slicks. I was just as fast on > that bike as on my "race" bike with 700 x 23s. -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to rbw-owners-bu...@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
