M
Mikael Seierup
Guest
Made in Denmark. Unfortunately in danish. However its a good chance to see some danish homebuilts if
you squint at the small pictures. ;-) Torben Scheel might have the originals in a larger size.
http://www.hpv-klub.dk/Arrangementer/03-05-10_rulletest/default.asp
I will translate the comments for each of the bikes:
Odense Special:
1: loosefitting clothes.
Comments: Samme airresistance as the other highracer of the test, the Lolita. This rider is more
heavily built which indicates that the bike is a bit more aerodynamic. This is probably due to the
higher bottom bracket on the Odense Special.
Kildemoes damecykel:
2: Loosefitting clothes, box on rack, hands at the middle of the handlebars, upper body crouched
over handlebars to minimize airresistance.
Comments: The only upright was tested with the rider crouched over the handlebars which more or less
resembles the position on a roadbike. The airresistance was equal to the highracers despite the
rider being much smaller.
Leitra:
3: With full fairing and wheelfairings.
4: Without faring but with wheelfairings.
5: Without fairing and wheelfairings.
Comments: The Leitra is the bike with the worst aerodynamics when riding sans fairing. Probably due
to the very upright seatposition. The two frontwheels adds a fair bit of drag that is markedly
reduced when the wheelfairings are utilized. With its fairing on its fairly aerodynamic but is not
significantly faster on the road due to its weight.
Hjemmelavet forhjulstrukket lowracer (homemade FWD yada, yada)
6: Tailfairing, T-shirt.
7: Tailfairing with 6 kg of luggage, loosefitting clothes
8: Tailfairing, loosefitting clothes, rainjacket.
9: No fairing, loose clothes.
10: No fairing, loose clothes, rainjacket.
Comments: Attempt 2 should have yielded more airresistance than 1. That this is not the case is
probably a measurement error. On the other hand its obvious that the rainjacket add a significant
amount of drag. The tailfairing reduces the airresistance by ~25% whichs nets you 2-3 kph.
Optima Baron:
11: tightfitting clothes, wheeldisc on front wheel, aerohelmet
12: Tight clothes, 18 spoke front wheel, aerohelmet.
13: Tight clothes, wheeldisc on front, ordinary helmet
14: Tight clothes, wheeldisc on front, ordinary helmet, backpack dangling on arm
Comments: The most aerodynamic bike of this test. The first three tries have been repeated many
times to reduce statistical error, so the results are very reliable. The wheeldisc and the
aerohelmet seems to reduce drag by 5 and 6 percent respectively, which nets you 0.5-1 kph. In
attempt 4 the backpack is dangling on one arm and totally ruins the aerodynamics and dramatically
doubles the airresistance.
Homemade Zox-clone:
15: Tightfitting clothes, small seatbags.
Comments: This lowracer has lower drag than most of the other bikes. But the tires Schwalbe City
Marathon has a rather high rolling resistance, which slows it down.
Homemade FWD with tailfairing:
16: Tight clothes.
Comments:
Despite its low seatheight and a tailfairing this bike displays relatively high airresistance. Most
likely due to the upright seatingposition. The tailfairing probably doesn't help much either apart
from being handy to store stuff in as its too short for the upright seat. However the bike is still
relatively fast due to its Schwalbe Stelvio tires.
Homemade "Lolita" highracer.
17: loosefitting jacket.
18: loosefitting jacket, topbag behind seat.
19: loose jacket, topbag, arms in superman position
Comments: The Vittoria Corsa EVO CX tires makes the bike relatively fast in relation to the other
highracer of the test that has the same airresistance. The topbag does not affect anything
significantly but the position of the arms does. When the handlebars are tilted forward so the arms
are extended (superman) the airresistance is reduced by 18% which nets you 2 kph.
Evita-2:
20: Tightfitting clothes
21: Loose clothing
22: Dressed for touring with bags
Comments: This quasilow bike has relatively low airresistance. This is probably due to the narrow
handlebars that keeps the arms close to the body and partly because the seat covers the top part of
the rear wheel. Loose clothing means 6% more drag. Flapping clothes for touring and bags increases
drag significantly. In this case nearly 50 %.
Evita-1:
23: No helmet or jacket.
24: No helmet, loosefitting jacket.
25: helmet, jacket, bag, waterbottle
Comments: The old model of the Evita is a bit slower than the new. This is partly due to the larger
rider but probably also that the rearwheel is not out of the airflow behind the seat. The jacket
increases drag by 4% and all the kit increases it yet another 4%.
Regards Mikael
Note: I just translated it so I cannot argue the pros and cons of the conclusions and
assumptions. All errors and typos are mine unless I can come up with a plausible excuse or
blame someone else. ;-)
you squint at the small pictures. ;-) Torben Scheel might have the originals in a larger size.
http://www.hpv-klub.dk/Arrangementer/03-05-10_rulletest/default.asp
I will translate the comments for each of the bikes:
Odense Special:
1: loosefitting clothes.
Comments: Samme airresistance as the other highracer of the test, the Lolita. This rider is more
heavily built which indicates that the bike is a bit more aerodynamic. This is probably due to the
higher bottom bracket on the Odense Special.
Kildemoes damecykel:
2: Loosefitting clothes, box on rack, hands at the middle of the handlebars, upper body crouched
over handlebars to minimize airresistance.
Comments: The only upright was tested with the rider crouched over the handlebars which more or less
resembles the position on a roadbike. The airresistance was equal to the highracers despite the
rider being much smaller.
Leitra:
3: With full fairing and wheelfairings.
4: Without faring but with wheelfairings.
5: Without fairing and wheelfairings.
Comments: The Leitra is the bike with the worst aerodynamics when riding sans fairing. Probably due
to the very upright seatposition. The two frontwheels adds a fair bit of drag that is markedly
reduced when the wheelfairings are utilized. With its fairing on its fairly aerodynamic but is not
significantly faster on the road due to its weight.
Hjemmelavet forhjulstrukket lowracer (homemade FWD yada, yada)
6: Tailfairing, T-shirt.
7: Tailfairing with 6 kg of luggage, loosefitting clothes
8: Tailfairing, loosefitting clothes, rainjacket.
9: No fairing, loose clothes.
10: No fairing, loose clothes, rainjacket.
Comments: Attempt 2 should have yielded more airresistance than 1. That this is not the case is
probably a measurement error. On the other hand its obvious that the rainjacket add a significant
amount of drag. The tailfairing reduces the airresistance by ~25% whichs nets you 2-3 kph.
Optima Baron:
11: tightfitting clothes, wheeldisc on front wheel, aerohelmet
12: Tight clothes, 18 spoke front wheel, aerohelmet.
13: Tight clothes, wheeldisc on front, ordinary helmet
14: Tight clothes, wheeldisc on front, ordinary helmet, backpack dangling on arm
Comments: The most aerodynamic bike of this test. The first three tries have been repeated many
times to reduce statistical error, so the results are very reliable. The wheeldisc and the
aerohelmet seems to reduce drag by 5 and 6 percent respectively, which nets you 0.5-1 kph. In
attempt 4 the backpack is dangling on one arm and totally ruins the aerodynamics and dramatically
doubles the airresistance.
Homemade Zox-clone:
15: Tightfitting clothes, small seatbags.
Comments: This lowracer has lower drag than most of the other bikes. But the tires Schwalbe City
Marathon has a rather high rolling resistance, which slows it down.
Homemade FWD with tailfairing:
16: Tight clothes.
Comments:
Despite its low seatheight and a tailfairing this bike displays relatively high airresistance. Most
likely due to the upright seatingposition. The tailfairing probably doesn't help much either apart
from being handy to store stuff in as its too short for the upright seat. However the bike is still
relatively fast due to its Schwalbe Stelvio tires.
Homemade "Lolita" highracer.
17: loosefitting jacket.
18: loosefitting jacket, topbag behind seat.
19: loose jacket, topbag, arms in superman position
Comments: The Vittoria Corsa EVO CX tires makes the bike relatively fast in relation to the other
highracer of the test that has the same airresistance. The topbag does not affect anything
significantly but the position of the arms does. When the handlebars are tilted forward so the arms
are extended (superman) the airresistance is reduced by 18% which nets you 2 kph.
Evita-2:
20: Tightfitting clothes
21: Loose clothing
22: Dressed for touring with bags
Comments: This quasilow bike has relatively low airresistance. This is probably due to the narrow
handlebars that keeps the arms close to the body and partly because the seat covers the top part of
the rear wheel. Loose clothing means 6% more drag. Flapping clothes for touring and bags increases
drag significantly. In this case nearly 50 %.
Evita-1:
23: No helmet or jacket.
24: No helmet, loosefitting jacket.
25: helmet, jacket, bag, waterbottle
Comments: The old model of the Evita is a bit slower than the new. This is partly due to the larger
rider but probably also that the rearwheel is not out of the airflow behind the seat. The jacket
increases drag by 4% and all the kit increases it yet another 4%.
Regards Mikael
Note: I just translated it so I cannot argue the pros and cons of the conclusions and
assumptions. All errors and typos are mine unless I can come up with a plausible excuse or
blame someone else. ;-)
