Eight point V bar. From the moment I bought my first set of high quality road clinchers, I’ve ridden at that pressure. I started with that number because that’s the pressure the sidewall told me to pump them up to; I didn’t yet understand much about balancing the benefits of high and low pressures to optimize comfort and friction; I just pumped them up as instructed and off I went merrily down the road.
I’m not as thin as I’d like to be, which is the same thing as saying I’m fatter than I should be, though I certainly hope I climb well for my weight, especially as my third (and hopefully charmed) ascent up Haleakala is looming large in Vajanuary. The point is, I’m not a whippet and even if I starved myself for the next five months and subsist exclusively on IPAs (I draw the line at cutting beer out of my theoretical diet; I might get desperate, but I’m no savage) I’d still be an Eros Poli at best. Being a big guy, the only factor that mattered to me when it came to tire pressure was avoiding the pinch flats that plagued me during my time riding cheaper tires and that meant maximum pressure, no questions asked.
We always dialed our pressure in for Mountain biking and would pull a few pounds out of our road tires when riding in the rain, but by and large, tire pressure was tire pressure, and as far as I was concerned, more was better. I even had a set of 20mm tires on a makeshift TT bike I had that I blew up to a whopping 10 bar. In the last few years, however, the Cycling world has become obsessed with doing the limbo and seeing how low they can go on tire pressure. It all began with an article in Bicycle Quarterly which conducted an extensive and flawed study on the effects of tire pressure and tire width, and concluded that lower pressure and wider tires are faster and more comfortable than high pressure, narrow tires; the idea is that lower pressure allows small bumps to be absorbed by the tire rather than bouncing the bicycle (and rider) in the air, and that wide tires flex more efficiently than narrow tires resulting in lower rolling resistance. Its important to remember that this gain in comfort and efficiency also comes with an increased risk of pinch flats.
This is all well and good, of course, though we always have to be careful to remember the basic principles of such a compromise; lower pressure and wider tires also mean an enlarged surface area which necessarily means more friction; a perfectly hard, narrow tire on a perfectly smooth surface would have almost zero friction, to the point that you’d be unable to gain enough traction to actually move the bicycle at all. What we’re after, in a practical sense, is a balance between the two extremes which optimizes comfort and tire efficiency against reduced surface area and the risk of pinch flats.
I became infected with Tire Pressure Fever myself as the Cycling world became increasingly obsessed with tire pressure. Down went the pressure in my tires and immediately I felt sluggish and lethargic on the bike. Climbing out of the saddle, I could feel the tires flex as I unleashed the Awesome Devastation of the Toothpicks of Navarone. Cornering was like steering in molasses; turn the bars, weight the pedals and then wait a few moments while the bike got round to responding.
These observations first had me reaching for the pump and then got me theorizing about what is really going on with tire pressure and what pressure is right for a given rider. I say “theorizing”, but most other people would use something closer to “guessing assertively”. But that doesn’t mean I’m wrong.
Basically, it comes down to finding the highest pressure and narrowest tire you can that gives a rider of your weight the right amount of tire flex such that your bike isn’t bouncing as it rolls over the tarmac and allows it to roll efficiently, all while minimizing surface area, risk of punctures, and sidewall deformation when accelerating (cornering and climbing are basically the same as accelerating; the acceleration vector is just in some other direction than forward.) This means that each rider at each weight with different preferences on the sliding scale between the above compromises will find a different optimal pressure. Impressed by Tom Boonen’s tire pressure at Roubaix? Tread carefully; that pressure was dialed in based on very specific criteria and unless you’re eating the same cobbles and weigh the same as he does, you’ll need a different pressure to find the same balance. Bicycle Quarterly has a chart that shows what they believe to be the ideal pressure by rider weight, though I don’t believe a word of it; I do however entertain the possibility that I could be missing something based on the fact that I didn’t actually read the article.
Me? I’m still happily riding at 8 point V. I’m comfortable, I’m not flatting, and I’ve got good control. Besides, it just has a nice ring to it.
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@frank
I have absolutely no desire to ride with, or meet this guy. Can you imagine the stable he could have if that money was spent on carbon?
@frank
WOW !! A good example of over thinking or maybe not enough? I mean where does he keep the beer?
@Russ M
I bet he has the chicks bring the beer.
@frank
This is why we should be thankful that America poured billions into the space race. If NASA hadn't have needed miniaturise circuit boards to fit a house sized computer into the lunar lander, this is what your Garmin 500 would have looked like.
Either his guns deliver power on a Saturn V scale or his gearing is tiny.
@Chris
I suspect that's not all that's tiny.
However on another tack - what about a Lexicon entry for Saturn V's for guns like Forstermann's or Hoy's? Yeah I know, the Saturn V is a rocket but there is a V in there and its nearly Christmas.
@Chris
Oh (and I shit you not) Scotland is launching its first satellite next year - http://www.bbc.co.uk/news/uk-scotland-glasgow-west-17439236
@frank
I've made several attempts but have not, as yet, been able to come up with an imaginary crazed and ludicrous technological development for a bike that hasn't actually already been designed, patented, sold and (presumably) purchased by someone.
App to show you're going uphill - check
App to control gear changes - check
A bike that'll fly - check
Anti-skid - check
Rearview TV - check
I mean what's a cynic to to do if all his material is stolen before he even writes it?
@the Engine I read the artilce and he's got 105 fucking gears. Yes 105! 7.9 gear inches up to a much bigger number.
Don't read it. It'll make you feel odd.
@frank
You said it. Talking that guy down a few euros is like talking down a French tubular tyre artisan. Either that or my Québécois is getting in the way of the translation, hosti
@the Engine
All that is in Merckx's grace! MY EYES. THE GOGGLES DO NOTHING!