It's wheels again today (and so on).
Continuing from yesterday.
I built a rear wheel with an ultra-lightweight rim and carbon spokes.
Extra Light Cyber Rear SP Hub - 24H
Four-cross lacing.
For the front wheel with rim brakes, since it's neither the drive wheel nor subject to hub-side braking,
radial lacing is fine,
but for the rear wheel, even limited to hill climb applications,
it's undeniable that a wheel laced better is achieved by using lightweight steel spokes
with tangential lacing on the non-drive side with cross-connections,
and as an element that reflects in results,
I do wonder which is more significant—spoke stiffness or lightness.
But if you're going to excel at one specialty—the "held lightness" factor—
then I think that's fine too.
If your hill climb style doesn't involve much out-of-saddle climbing,
a rear wheel with equal-sided, non-drive-side radial lacing might not feel bothered
by low lateral or torsional stiffness.
In exchange for having light hub rotation, it's heavy in a way you wouldn't expect from racing parts
—though since it's concentrated in the hub body, that's alright—
and for certain manufacturers' hubs with unusually narrow flange widths,
I won't deny there's a place for them in triathlons or time trials
where you're clinging to aero bars and pedaling with virtually no out-of-saddle effort.
↑Non-drive side
↑Drive side
The spoke length on both sides is about flush with the rim edge.
I've taped the two final-crossing spokes on the drive side
so there's no slack,
and when you grip it, it looks like this.
I've tensioned it strongly enough that it won't deform any further
within the range of hand grip force.
On the non-drive side, it's like this:
It's hard to tell from the image,
but the deformation is definitely more pronounced.
I did tension it as much as the rim allows, though...
I wrote "as much as the rim allows" because
in this case, between the rim and spokes,
the rim has the lower limit.
The freebody has a warning that says "Do not use with gear ratios below 1:1."
With current 12-speed groupsets, except for SRAM's 46-33T crankset,
34×34T is normally the lowest gear ratio,
so you probably don't need to worry,
but when using a micro-compact inner ring like 32T or
setting up a single-ring front with a derailleur repositioning piece
(→here) to run a sprocket larger than the front inner ring,
sub-1:1 gear ratios are possible even on road bikes.
At exactly 1:1, one crank rotation equals one rear wheel rotation,
which is the same as a unicycle.
Compared to a 700C unicycle, the rear hub and BB aren't coaxial—
they're separated by a bit over 400mm and connected by chain, introducing
mechanical losses
(plus you're also fighting against the rear derailleur spring tension)
but the crank sits forward of directly below the saddle,
so two-wheelers are easier to pedal in that respect—that's the difference.
Shimano's 12-speed groupsets have only two sprocket options:
11-30T and 11-34T,
so complete bikes do come spec'd with 50-34T cranks and 11-34T sprockets,
and many people routinely select that gear ratio when building bikes,
but please don't make fun of bikes capable of 34×34T by saying "haha, basically a unicycle~"
By the way, Dura-Ace specifically is already confirmed to come with an 11-28T 12-speed sprocket
starting in 2023 onwards,
and the internal part number is "123456789148."
This represents the digits of each cog in sequence,
so the tooth count is 11-12-13-14-15-16-17-18-19-21-24-28T.
I wish they'd make it 11-12-13-14-15-16-17-19-21-23-25-28T instead, though.
Back to the subject—the rear wheel weight.
This is also the world's lightest rim, and with careful selection of the hub,
a rear wheel in the 300g range is possible,
which means a front-and-rear wheelset in the 600g range becomes achievable.
Continuing from yesterday.
I built a rear wheel with an ultra-lightweight rim and carbon spokes.
Extra Light Cyber Rear SP Hub - 24H
Four-cross lacing.
For the front wheel with rim brakes, since it's neither the drive wheel nor subject to hub-side braking,
radial lacing is fine,
but for the rear wheel, even limited to hill climb applications,
it's undeniable that a wheel laced better is achieved by using lightweight steel spokes
with tangential lacing on the non-drive side with cross-connections,
and as an element that reflects in results,
I do wonder which is more significant—spoke stiffness or lightness.
But if you're going to excel at one specialty—the "held lightness" factor—
then I think that's fine too.
If your hill climb style doesn't involve much out-of-saddle climbing,
a rear wheel with equal-sided, non-drive-side radial lacing might not feel bothered
by low lateral or torsional stiffness.
In exchange for having light hub rotation, it's heavy in a way you wouldn't expect from racing parts
—though since it's concentrated in the hub body, that's alright—
and for certain manufacturers' hubs with unusually narrow flange widths,
I won't deny there's a place for them in triathlons or time trials
where you're clinging to aero bars and pedaling with virtually no out-of-saddle effort.
↑Non-drive side
↑Drive side
The spoke length on both sides is about flush with the rim edge.
I've taped the two final-crossing spokes on the drive side
so there's no slack,
and when you grip it, it looks like this.
I've tensioned it strongly enough that it won't deform any further
within the range of hand grip force.
On the non-drive side, it's like this:
It's hard to tell from the image,
but the deformation is definitely more pronounced.
I did tension it as much as the rim allows, though...
I wrote "as much as the rim allows" because
in this case, between the rim and spokes,
the rim has the lower limit.
The freebody has a warning that says "Do not use with gear ratios below 1:1."
With current 12-speed groupsets, except for SRAM's 46-33T crankset,
34×34T is normally the lowest gear ratio,
so you probably don't need to worry,
but when using a micro-compact inner ring like 32T or
setting up a single-ring front with a derailleur repositioning piece
(→here) to run a sprocket larger than the front inner ring,
sub-1:1 gear ratios are possible even on road bikes.
At exactly 1:1, one crank rotation equals one rear wheel rotation,
which is the same as a unicycle.
Compared to a 700C unicycle, the rear hub and BB aren't coaxial—
they're separated by a bit over 400mm and connected by chain, introducing
mechanical losses
(plus you're also fighting against the rear derailleur spring tension)
but the crank sits forward of directly below the saddle,
so two-wheelers are easier to pedal in that respect—that's the difference.
Shimano's 12-speed groupsets have only two sprocket options:
11-30T and 11-34T,
so complete bikes do come spec'd with 50-34T cranks and 11-34T sprockets,
and many people routinely select that gear ratio when building bikes,
but please don't make fun of bikes capable of 34×34T by saying "haha, basically a unicycle~"
By the way, Dura-Ace specifically is already confirmed to come with an 11-28T 12-speed sprocket
starting in 2023 onwards,
and the internal part number is "123456789148."
This represents the digits of each cog in sequence,
so the tooth count is 11-12-13-14-15-16-17-18-19-21-24-28T.
I wish they'd make it 11-12-13-14-15-16-17-19-21-23-25-28T instead, though.
Back to the subject—the rear wheel weight.
This is also the world's lightest rim, and with careful selection of the hub,
a rear wheel in the 300g range is possible,
which means a front-and-rear wheelset in the 600g range becomes achievable.