121–130 of 152 posts
Two things jumped out at me: the simple/non-adjustable saddle support, and the absolutely slammed bars affixed just above the fork. Was that normal for track bars at the time?
Check out the Soviet Takhion [1] track bike for a similar handlebar setup. Cinelli also had a version of their legendary Laser [2] bike with that setup. 1: https://bikecult.com/works/archive/03bicycles/takhionVVVV.ht... 2: https://www.pedalroom.com/bike/cinelli-laser-aero-pursuit-34...
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I thought stiff was a problem with aluminum - stronger is better but is stiffer better? That said, I wonder if there is a way to make frames more comfortable without having the flex absorb pedaling energy.
I don't believe that the frame material makes much difference to comfort. The part that can deflect/absorb bumps and vibration the best is the tyre. So the answer to your question is bigger tyres at lower pressures.
A typical bike frame follows a truss structure: stiff and unyielding by design. Vertical compliance is going to be found elsewhere: tires, exposed seatpost, chamois/saddle, fork, handlebar, tape.
Yet, how many roadies do you find talking about suspension seatposts? It's all because in that subculture emulating present and past pro racers is seen as cool, and anything else isn't.
If you are curious, a few people like CYCLINGABOUT [0] and Overbiked Randonneuring [1] have done some measurements and the data suggests that suspension seatposts provide even more reduction in vibrations than wide tires.
It's interesting that trackies in the 70s were trying to reduce weight that much. I don't think it's perceived as especially advantageous these days. The high-ish end track bike I'm assembling now will be a little over 8 kg (almost 18 lb). We also race much bigger gears (typically 95-110 gear inches in mass start racing, bigger for sprinting) than mentioned in the article (72 gear inches). The position that is consid…
Maybe that's just mostly due to the UCI regulations? No point to develop a fully fitted 5kg bike if it has to be 7kg anyways I suppose
The discipline of cycling that's the most weight-motivated is hill climbing. Track cycling really doesn't have that as an issue, and definitely does have a materials strength issue, so I'm not shocked they're not building to a weight limit.
> He ruled out magnesium, which is best per unit weight in compressive buckling but is brittle and difficult to extrude. There's a fascinating, and very new, class of nano-laminate magnesium alloys called Long Period Stacking-Ordered (LPSO) alloys. These are very lean -- the standard version is 97% Mg + 1% Zn + 2% Y -- and they have outstanding mechanical properties. At an equal weight, they're much stronger and stif…
How’s it compare to carbon which is the most common high end, lightweight bike material these days?
That said, we can extrapolate from mechanical properties. If we assume that both materials are tubes with the same wall thickness, and that we're looking at T300 carbon fiber (by far the most common type) in epoxy resin vs a standard research grade of LPSO, then:
- The CF will be stiffer
- The CF composite will be slightly less dense (1.6 gm/cc vs. ~1.8 gm/cc)
- The CF composite will have a slightly higher tensile strength, but the difference is very small and could be nonexistent in practice.
- LPSO-Mg will be more damage tolerant -- with better resistance to abrasion and better capacity to flex in a recoverable way in response to extreme mechanical stress. (Cast Mg alloys are undoubtedly worse than CF, but LPSO-Mg is a lot more like an aluminum alloy in this respect. It's a pretty ductile material.)
- LPSO-Mg should in principle be cheaper, though this is likely not going to be the case for a long time.
- LPSO-Mg will have better mechanical damping properties, so might transmit fewer vibrations to the rider.
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Maybe that's just mostly due to the UCI regulations? No point to develop a fully fitted 5kg bike if it has to be 7kg anyways I suppose
Most competition bikes weigh significantly more than the 6.8kg limit, because weight just doesn't matter very much. A lot of state-of-the-art road and track bikes weigh around 8kg. On the flat, weight only affects you during accelerations - at a steady speed, it has no significant impact on performance. Aerodynamic drag and rolling resistance are constantly sapping away power, so features that reduce these losses are…
Earlier quoted context omitted.
Most competition bikes weigh significantly more than the 6.8kg limit, because weight just doesn't matter very much. A lot of state-of-the-art road and track bikes weigh around 8kg. On the flat, weight only affects you during accelerations - at a steady speed, it has no significant impact on performance. Aerodynamic drag and rolling resistance are constantly sapping away power, so features that reduce these losses are…
So it only matters on basically every classic non time trial race?
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You're not going up and down the track during an hour record. Just doing laps at the bottom (zero elevation change). Track surfaces aim to be very smooth in general.
> You're not going up and down the track during an hour record. Here the English language obscures the physics. Sure, the black line on the track is at a constant elevation. But the tire's point of contact is different from the system's center of mass (CoM). CoM is key here. When a rider tilts in the turns, the CoM lowers. In the straights, it raises. So, you _are_ going up and down during the hour record. The questi…
Earlier quoted context omitted.
Most competition bikes weigh significantly more than the 6.8kg limit, because weight just doesn't matter very much. A lot of state-of-the-art road and track bikes weigh around 8kg. On the flat, weight only affects you during accelerations - at a steady speed, it has no significant impact on performance. Aerodynamic drag and rolling resistance are constantly sapping away power, so features that reduce these losses are…
So it only matters on basically every classic non time trial race?
It's about optimizing the whole system, not just one part of it.
I find the obsession minimizing bicycle weight funny. It's not the bicycle weight that matters, it's the combined weight of bicycle and rider that counts. Rider weight massively outweighs the relevance of bike frame material, especially in the West where obesity epidemic has biased BMI upwards over the last half century.