Location: Northern Florida, USA
(05-13-2024, 05:46 PM)enkei Wrote: Check out the work that went into "Jeanne (Robinson) Omelenchuk’s custom 1960 road racing bike" here:
http://classiccycleus.com/home/repair/museum-bikes-1945-to-1979/
To whit: "George cast the aluminum hub shells himself, producing hubs that were extremely wide by the standards of the day (heck, they’re wide by today’s standards, and we pack 11 cogs onto modern rear hubs). The rims were drawn or rolled or whatever the term is by George himself, and were lightened up for Jeanne with 32 half-inch holes machined out of the rim walls between each spoke eyelet."
What an incredible piece of work!
(The track bike George made for Jeanne is a few bikes further down the list)
I took a look since I figured the bike/components might be similar to the "lightening" done for Merckx' '72 hour record bike. No doubt that those are great quality built bikes. I still cannot understand the wider front hub which certainly added weight and I cannot see how it would improve performance. Regarding the drillium rims, I would be curious to have them tested for aerodynamics over weight since that can be a factor also considering you are adding air turbulence by doing that otherwise you would think companies would be doing that work today if it was an advantage. I can see more as a track thing than a road feature due potential loss of strength and rigidity of the rim. I am not going to grab my old rims and start to put more holes in them even if I knew they were designed well enough. I have never been very trusting of aluminium brake calipers that were drilled through; "dimpling" is okay, but I will not use those I have drilled sets I have that previous riders have already modified. One must assume that although designers of top racing equipment are trying to make components lightweight while avoiding catastrophic failure (Universal had made a dual cable cailper that would crush rims). Even then, that racing bike could have had its weight reduced by many means if you are already willing to go that route in its original design.
I have seen enough damaged parts that were not modified, but warping of chainrings, broken cranks, seats posts, and stems are much more prevalent in components wbich were initially designed with very little material, as well as those drilled and milled after for weight reduction.
Take care,
Jesper
"I am become Death, the destroyer of bicycles." NJS
Location: Northern Florida, USA
(05-15-2024, 01:05 PM)enkei Wrote: I suspect that the aero implications of drilling the rims wouldn't even have been in mind back then. Still, it's a good question. I'm sure it could be modelled to find out.
I'll start building my wind tunnel.
You are right about aerodynamics back then; just concerned about body position which even today is the main factor regarding aerodynamic advantages.
Take care,
Jesper
"I am become Death, the destroyer of bicycles." NJS