[CR]Technical trials - superlight bikes

(Example: Events:Cirque du Cyclisme:2002)

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Date: Tue, 7 Oct 2003 05:53:21 -0700
To: classicrendezvous@bikelist.org
From: "Jan Heine" <heine93@earthlink.net>
Subject: [CR]Technical trials - superlight bikes

Looking through the archives, I saw we discussed the French "Technical Trials" a while ago. Back then, there were doubts regarding the published weights of these machines, especially as it seemed hard to make bikes that light.

Having researched the trials for the latest issue of my magazine, Vintage Bicycle Quarterly, I now have better information:

- the lightest bike of all was a 1946 Alex Singer, at 6.875 kg (15.16 lbs.). Weights were established to the nearest 5 grams (0.005 kg). This weight is for a randonneur bike with fenders, lights (including a battery, so the light operates when the bike is stationary), 35 mm tires, at least 8 gears and a rack able to carry 4 kg (8.8 lbs). However, the weight is without tires and tubes. For a good set of hand-made Barreau 650B x 35 mm tires, add 500 grams (yes, they were light!), plus about 200 grams for lightweight tubes. So you get a 7.6 kg bike (16.7 lbs). Impressive!

- the weights were established by impartial "commissaires" - see the photo in the latest issue of VBQ, p. 24.

- The bikes weren't just show-bikes, but had to survive with no damage for 700 and more km (440 miles) on very rough roads in the mountains. To win the trials, you needed the most points. You gained points for light weight, high speed (so you wouldn't "save" your bike by going super-slow on the rough stuff), and special features (like a chain rest and anti-theft lock). You lost points for broken or damaged parts. The penalties for damages were so severe that only a bike arriving in perfect order stood a chance of winning. The Singer that was the lightest in 1946 only won because it didn't have any penalties, while an Herse (slightly heavier, but the faster average speed more than made up for it) was penalized for a broken rear light bulb and came second.

- How did they do it? It's too much to list here - you find the info in VBQ, with more than 90 Rebour drawings of "trials" bikes. Stuff like pedals with the center barrel cut away to expose the spindle, toe straps cut and riveted to the cages (so eliminate the "useless" part of the strap running under the foot), special seatposts incorporating the clamp and more. 3/10 and 4/10 mm tubing, of course. At http://www.mindspring.com/~heine/bikesite/bikesite/samples.html (scroll down a bit), you see a magnesium brake lever with its aluminum body welded to the handlebars (that eliminated that "heavy" clamp on the bars). Every gram counted - the coveted "record of lightness" was obtained by being 50 grams or so lighter than the others. In the next issue of VBQ (out in December 2003), Ernest Csuka shows a frame for one of the 1946 trials-winning Singer bikes and explains how they did it. He claims they could have made them a lot lighter, if the rules hadn't required huge lights and batteries among other things!

- Maybe even more impressive were the "series" bikes, which could not use modified components. With all standard components (and the fender/rack/lights/35 mm tires spec listed above), 8.4 kg (18.52 lbs) is very impressive (a Barra aluminum bike in 1946). Even when you add tires and tubes, 9.1 kg (20.0 lbs) is impressive for a "fat tire" bike!

- Were those superlight bikes for sale to the public? Of course not! They were neither durable nor beautiful. For events where weight did not count (meaning the fastest wins, rather than the classification being based on a formula that considered weight), like Paris-Brest-Paris or the Poly de Chanteloup hillclimb race, Herse and Singer equipped their riders with standard, lightweight bikes that weighed about 21-23 lbs. (again fully equipped randonneur bikes as the rules required, not stripped-down racers). Because they knew that weight does not really matter (within reason). Or almost - the 1948 Herse tandem we rode in PBP was equipped with more than a dozen aluminum nuts and bolts.

--
Jan Heine, Seattle
Editor/Publisher
Vintage Bicycle Quarterly
http://www.mindspring.com/~heine/bikesite/bikesite/