Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/5/84; site reed.UUCP Path: utzoo!watmath!clyde!bonnie!akgua!whuxlm!harpo!decvax!tektronix!reed!kehoe From: kehoe@reed.UUCP (Dave Kehoe) Newsgroups: net.bicycle Subject: How To Make Your Bicycle Faster Message-ID: <1644@reed.UUCP> Date: Sun, 9-Jun-85 22:01:06 EDT Article-I.D.: reed.1644 Posted: Sun Jun 9 22:01:06 1985 Date-Received: Tue, 11-Jun-85 07:49:44 EDT Reply-To: kehoe@reed.UUCP (Dave Kehoe) Distribution: net Organization: Reed College, Portland, Oregon Lines: 125 OK, net.bicyclists, here's the sum of my ten years and 20,000 miles of cycling experience and five years of bicycle shop experience. These points are in order of relative importance. 1) Position, Clothing and Training. I recommend spending $50 on a Bell helmet before you even think of riding fast. Next, spend $25 on a "Fit Kit." This is the most effective way to get your position correct. You can't ride efficiently or even safely if your feet are in an incorrect position, your handlebars too close, etc. No saddle will be comfortable if it's too high or too low. I don't find clothing to be that necessary. Lycra shorts, wool jerseys, and cleats are nice for long-distance comfort, but I commute in my street clothes. A bright yellow Gore-Tex jacket is necessary (maybe those of you not in Oregon don't need the Gore-Tex part :-)). Training is important, but riding long distances seems to be less effective than a) riding every day and b) riding as hard and as fast as you can. 2) Tires. At speeds below 20mph most of your energy is spent in overcoming rolling resistance in your tires. You can reduce rolling resistance in 3 ways: a) increasing air pressure; b) using more flexible tires; c) using latex inner tubes. Latex inner tubes are ineffective for commuting because they need to be pumped up every day. Flexible tires, such as Specialized Turbos, are faster than stiff tires, such as the Kevlar-belted Specialized K4's. The lighter tires should get more flats, but I haven't noticed this. I rotate Specialized Touring tires at 1000 miles and replace them at between 1500 and 2000 miles. I replace my tires after I get 2 flats because 90% of your flats are in the last 10% of the tire's life. *Be careful* riding new tires in the rain -- new tires are very slippery for the first 100 miles or so. I've put 2000 miles on a pair of Specialized K4's without any flats yet. Increasing air pressure is the most effective way to increase speed. I run my Specialized tires at 130psi. I've heard stories of Turbos run at 150-170psi, and Specialized claims they've put 220psi in their tires, but I'm skeptical. I've never had a blowout, but one of our customers misread a gas station pump -- he thought it said 70psi when it said 170psi. His Rigida 13-20 rim blew apart, and he went to a hospital because of hearing damage. He couldn't hear anything for 3 days because of the ringing in his ears. I've heard blowouts at 95psi, and they're *loud*. *Do not* pressure Rigida 13-19 rims above 95psi -- the tires will blow off. I'm not familiar with using sew-ups at very high pressures: the Olympic team's funny bikes use 200psi tires, Continental claims 150psi for their road tires and 180psi on their track tires, but I blew apart a cheap Wolber at 95psi. 3) Wheels. Light wheels are important because they are revolving weight, i.e. 1 pound of tires feels like 3 pounds of frame, derailleurs, etc.; 1 pound of rim feels like 2.3 pounds; and 1 pound of spokes feels like >2 pounds. Light wheels (including hubs) also improve handling and comfort, because they are unsuspended mass (also known as unsprung weight). I've had good luck with Super Champion Gentleman and Ambrosio Elite rims, and bad luck with Rigida 13-19's and 13-20's. Matrix Titan's (made by Trek) are supposed to be the lightest. Spokes are a little thought-of but important component. 14-16-14 gauge spokes weigh 105 grams less than straight 14's (for 72 294mm spokes). That's the equivalent of nearly 1/2 pound off, for only a few dollars more. I've put over 12,000 miles on 15-16-15 gauge spokes and I find them equally strong as straight 14's. I've used only 36-spoke wheels, but I intend to build a pair of 28-spoke wheels. Lon Haldeman uses 14-spoke front, 24-spoke rear (2 cross, high flange, 15-16-15). But he told me that he puts on 36-spoke wheels at the tops of hills. All the European pros use 32-spoke wheels. Most hubs are about equal. I think high-flange hubs build stronger wheels, but I doubt it's much of a difference. I also prefer Hi-E or Phil Wood hubs to Campy, because Hi-E is lighter and stronger. 5) Gearing/Drive Train. Efficient gearing is necessary for efficient cycling. The only crankset that I like is the Stronglight (model 93, I think). It's one of the few cranksets that allows you to experiment with different chainring sizes, and the only one that allows you to do this without spending a fortune. The crankset costs $60 (with 3 chainrings), and spare chainrings cost $12, and you can interchange inner and outer rings. I also like SunTour Ultra-6 freewheels because it's easy to get spare sprockets for (though I see the advantage of a cassette freewheel whenever I try to remove my Ultra-6 with a crescent wrench). The gearing that I found best (by experimentation) is 28-36 front, 13-21 rear. I spin 100-120rpm. The 36-inch low is necessary in Portland, and the 74-inch high spins out at 33mph, above which I rarely ride (going down hills you'll go faster if you stop pedaling and get into a tuck. Plus my drivetrain is 3/4 pound lighter than a 42-52 14-28, and the chain moves 1/3 slower. This seems to make spinning easier. 6) When riding at night I use a Soubitez halogen bottom bracket generator light, reflectors, Belt Beacon, and a yellow Gore-Tex jacket. -------------------------------- You'll note that none of the above mentioned frames, derailleurs, etc., which is where most people spend their bucks. In fact, most of the above costs very little money. A stiff frame is great for climbing hills, but is unpleasant, and even unsafe, anywhere else. With my tires at 130psi the frame needs a fair amount of give to keep the tires on the road at all times (such as hitting a pebble while cornering at a high speed). Also spokes break *solely* because rear triangles are too stiff (why haven't my motorcycle's spokes ever broken in +35,000 miles? They're not much heavier than bicycle spokes. Because my motorcycle has shock absorbers). Also, I need a 72-degree seat angle to get my seat into the most efficient position. I don't like long rakes or high bottom brackets because these make the steering to squirrelly. To make brakes more effective, use Scott/Mathauser brake shoes and Campagnolo cables. Don't use Elephant housings. With equal pads and cables, I find very little difference between my $10 Dia Compe sidepulls and my $100 Campies. This should keep net.bicycle interesting for at least two weeks. -- Dave Kehoe tektronix!reed!kehoe (503) 230-9454 "Why my thoughts are my own, when they are in, but when they are out they are another's." -- Susanna Martin, executed for witchcraft.