Another day, another wheel (and so on).
I took in a Kolima Medium rear wheel from a customer.
It shares the same rim height as the company's "Aero,"
but initially the Medium came with a lighter rim than the Aero and spokes that were CX-RAY,
whereas the Aero used CX spokes,
so the Medium had lighter specs across both rim and spokes,
making it an extremely light model by comparison (past tense).
Kolima makes a low-profile rim called Winium,
and the first-gen Medium's front wheel is actually lighter than the Winium, though the rear is marginally heavier.
This reversal happens because of spoke count—
the complete Medium wheel comes in 18/24H front/rear,
while the Winium is 24/24H front and rear.
I pulled out the Kolima catalog to detail all this and shot a ton of photos for the article,
but I realized there was massive overlap with my old first-gen Medium post (→here),
so a ton of shots got binned.
So today I'm going to touch on some things that aren't in the old post.
The rear hub is a Kolima piercing hub.
Before this hub, there was a non-piercing version,
and that rear hub had weak sealing between the hub body and freewheel body,
so water would get inside,
which led to the absolutely bonkers idea of prioritizing drainage over waterproofing—
so they drilled holes in the hub shell to create this piercing hub.
As for rear hub dimensions, it's narrow flange, which isn't exactly praiseworthy.
There was an earlier hub with the same outpoke hooking radial pattern on the freewheel side,
but it was quite a bit wider flange, so I'm not sure why they went this direction.
The freewheel side is laced in 3-cross tangent with a hooking design,
judged by counting the number of crosses.
The flange shape is designed so the spoke head doesn't pop off easily even under low tension.
Shimano disc brakes—not the MTB XTRA... but XT was the first model,
and when XT came in the M750 series, the disc brake part number was M755,
so the brake became BR-M755, front hub HB-M755,
rear hub FH-M755 (→here).
Soon after came the M510 Deore disc hub, an ambitious design with
HB-M555 and FH-M555 (the number was oddly M555, not M515),
which featured the same hooking design as this Kolima hub,
and because there was something sketchy about it, it got discontinued in a heartbeat.
The successor HB-M525, FH-M525 went back to a normal rear hub.
↑M555 hub
↑M525 hub
The sketchy thing was that the spoke head hooking was weak,
so there were documented cases where, during a ride when a spoke head broke,
if the wheel was built loosely, the hooking would come undone and the wheel would start disassembling.
So Shimano hasn't made a hub with this kind of structure since.
The freewheel side has broken-neck spokes,
but the flattening direction relative to the neck bend is 90° different from standard spokes—
these are custom-order pieces.
Since it's Medium, the spokes are equivalent to CX-RAY.
This rim has a strong directional bias in how the valve hole is positioned,
and building it against this will cause problems,
and rims from Kolima in this era have a reverse relationship between valve hole and hole orientation
compared to most rims in the world—
what I call a reverse rim on this blog.
↑This is a Fulcrum Speed 55C,
but the newer Bora and Speed models from the wide-rim era are normal rims.
I only just noticed this recently.
Same content is in the linked article, but
for a normal rim with left-right equal Italian lacing, you'd use left-handed drop,
for normal rim with 46 Italian lacing you'd use right-handed drop,
but on a reverse rim, this inverts, so you use left-handed drop.
↑These are the old spokes from before the rebuild, which I'm not using anymore,
and the thread section is shorter than on standard spokes.
I mounted the original nipples both ways to get a close-up shot.
The short spoke thread is connected to the fact that the nipple starts with threading right away.
When it comes to figuring the spoke length correction for reverse-threaded nipples vs. just going with standard nipples,
the latter is easier,
so I'm not reusing this nipple.
Also, this nipple is brass,
but the nipples for the rebuild are aluminum.
It's built.
Leaf hub, 24H, half-comp 46 lacing.
I'll true it later.
It was originally a Campagnolo freewheel body,
but after rebuild it's fine to use a Shimano freewheel body.
Next up is something different—a customer brought in an Aero rear wheel.
The rear hub is a piercing hub, but the old type.
So is the Medium's piercing hub new?
Not exactly—it's the old-old type.
I'll explain that later.
Since it's Aero, not Medium,
the spokes are CX equivalent, not CX-RAY.
All else being equal, CX should be less prone to
Schuttel-touch, which is just a small difference.
This rim also has reverse hole orientation, so I set up the hub side for 46 Italian left-handed drop,
but I started the initial lacing treating it as a normal rim.I didn't get blurry for the article, but it worked out.
When you get the hole orientation or left/right drop wrong,
you end up with the valve hole sitting inside the final cross like in the image above—
not a good look.
It's built.
Black hub, 24H, black half-comp 46 lacing.
I'll true it later.
It's a Campagnolo freewheel body, same as before the rebuild,
but the spoke color is black per customer request.
As mentioned in the linked article,
the first-gen Medium's rim flexes quite a bit when you press the sides,
giving a sketchy feeling, so Kolima apparently got spooked.
The later-gen Medium switched to using the Aero rim,
with only the spoke choice (CX-RAY or CX) being different—a lazy update.
Some makers have ultra-light carbon frames that aren't flagship models and don't get supplied to pro teams—
basically "made for weight-obsessed amateurs"—
and the first-gen Medium was marketed in a similar vein.
Let me look at the nervous disclaimers in the catalog below.
Medium is the lightest wheel in our lineup (←not the Winium),
but it needs to be used on very smooth road surfaces.
Also not suitable for heavyset racers.
Medium is our lightest wheel,
designed for flat, clean roads.
Not suited for frequent racers or heavy riders.
Regarding our 2005 Medium,
the customer we had in mind doesn't race
and rides maybe a few thousand km per year.
So that's the first-gen Medium.
Now for the Medium with the Aero rim:
↑It's like the Rosetta Stone with French and English side-by-side.
Medium wheel
A lightweight wheel for people who aren't seriously racing road bikes,
or who ride maybe a few thousand km per year
Medium uses the same rim and hub as Aero.
By using super-light spokes (CX-RAY),
it's 120g lighter than Aero on both wheels,
but Medium has lower rigidity.
↑Different year, same text
The loose translation is mine. Sorry.
I suspect people used these without understanding this messaging and broke them,
leading to a flood of complaints and forced spec changes or discontinuation.
Exotic parts come with their own durability limits and risks—
you need to understand that to use them safely.
Now, about the freewheel body.
Both are piercing hubs, but different eras.
Between these two, Medium is older and Aero is newer,
Ah, this is the flange I mentioned earlier where the spoke head
seats pretty firmly.
The freewheel bodies are different.
The right side in this image is the Aero hub from today, the newer type.
These Kolima hub shafts have a 5mm hex socket on only one end,
but on these two hubs, the side with the hex socket is different.
With a 5mm Allen key in the hub shaft,
you tighten and loosen each end with a 15mm hub wrench,
but the shaft has no butting or blunt end—it's uniform throughout,
so aside from the hex socket, there's no left/right distinction.
So even though the Aero hub had a left hex socket,
you could also assemble it with the hex socket on the right.
Kolima freewheel bodies are broadly divided into two types: those for S-hubs
and those for other hubs (MCC, Aero, Medium, Winium non-S),
and this one is the old type for the non-S category.
It has a separate spring on each ratchet tooth—
the same style Campagnolo used during the 8-9S freewheel era.
It has no rubber seals,
but if you measure the outer diameter in this area outside the teeth—
it comes to 34.7mm.
The new type for non-S hubs has an outer diameter of 32.5mm here,
so the old (34.7mm) and new (32.5mm) types aren't compatible.
These freewheel bodies are both Campagnolo, so it doesn't matter,
but with Shimano freewheel bodies, the old type has no 11S option.
So if today's Aero were a Shimano 10S freewheel body,
you couldn't upgrade to 11S without rebuilding the hub.
I reassembled it with the hex socket on the right.
No deeper meaning.
Next, the freewheel body from today's Medium.
For convenience I'll call it the old-old type.
The ratchet teeth have a paw spring design—same style as on Evolite hubs.
We don't currently supply this same freewheel body.
It has a rubber seal, with a maximum outer diameter around 34.2mm in this area.
Since shaft and ratchet diameters are the same, waterproofing looks sketchy
(though it was sketchy to begin with),
but swapping to the old freewheel body should be possible.
However, for Shimano bodies, there's no 11S option.
Given all this, the Medium rebuild might have needed a hub swap after all.
For reference, non-S hub freewheel bodies are ¥14,000 both old and new,
while Evolite hubs are ¥13,000.
Rebuild labor and spoke cost are extra, though...
Finally, here's something: Medium, whether first-gen or later, has never been sold as a rim-only option. Aero and Winium have been.
So measuring a Medium rim is a rare opportunity.
The linked article has actual weight figures for the first-gen Medium,
and today's Medium turned out to be the same rim as Aero, as expected.
Also, today's Aero rim is from after the wide-rim update, and
it has a balance weight (around 10g?) sticker on it.
So comparing these rims' actual weights would reveal things like
"the first-gen Medium really is different from the later Medium" or
"Kolima barely changed rim weight in the wide-rim transition"—
but I don't really feel the need to lay all this out neatly for readers,
so I'm not posting the actual figures.
↑ugh this guy is being so full of himself and coy about it, totally annoying
Technical archive
I took in a Kolima Medium rear wheel from a customer.
It shares the same rim height as the company's "Aero,"
but initially the Medium came with a lighter rim than the Aero and spokes that were CX-RAY,
whereas the Aero used CX spokes,
so the Medium had lighter specs across both rim and spokes,
making it an extremely light model by comparison (past tense).
Kolima makes a low-profile rim called Winium,
and the first-gen Medium's front wheel is actually lighter than the Winium, though the rear is marginally heavier.
This reversal happens because of spoke count—
the complete Medium wheel comes in 18/24H front/rear,
while the Winium is 24/24H front and rear.
I pulled out the Kolima catalog to detail all this and shot a ton of photos for the article,
but I realized there was massive overlap with my old first-gen Medium post (→here),
so a ton of shots got binned.
So today I'm going to touch on some things that aren't in the old post.
The rear hub is a Kolima piercing hub.
Before this hub, there was a non-piercing version,
and that rear hub had weak sealing between the hub body and freewheel body,
so water would get inside,
which led to the absolutely bonkers idea of prioritizing drainage over waterproofing—
so they drilled holes in the hub shell to create this piercing hub.
As for rear hub dimensions, it's narrow flange, which isn't exactly praiseworthy.
There was an earlier hub with the same outpoke hooking radial pattern on the freewheel side,
but it was quite a bit wider flange, so I'm not sure why they went this direction.
The freewheel side is laced in 3-cross tangent with a hooking design,
judged by counting the number of crosses.
The flange shape is designed so the spoke head doesn't pop off easily even under low tension.
Shimano disc brakes—not the MTB XTRA... but XT was the first model,
and when XT came in the M750 series, the disc brake part number was M755,
so the brake became BR-M755, front hub HB-M755,
rear hub FH-M755 (→here).
Soon after came the M510 Deore disc hub, an ambitious design with
HB-M555 and FH-M555 (the number was oddly M555, not M515),
which featured the same hooking design as this Kolima hub,
and because there was something sketchy about it, it got discontinued in a heartbeat.
The successor HB-M525, FH-M525 went back to a normal rear hub.
↑M555 hub
↑M525 hub
The sketchy thing was that the spoke head hooking was weak,
so there were documented cases where, during a ride when a spoke head broke,
if the wheel was built loosely, the hooking would come undone and the wheel would start disassembling.
So Shimano hasn't made a hub with this kind of structure since.
The freewheel side has broken-neck spokes,
but the flattening direction relative to the neck bend is 90° different from standard spokes—
these are custom-order pieces.
Since it's Medium, the spokes are equivalent to CX-RAY.
This rim has a strong directional bias in how the valve hole is positioned,
and building it against this will cause problems,
and rims from Kolima in this era have a reverse relationship between valve hole and hole orientation
compared to most rims in the world—
what I call a reverse rim on this blog.
↑This is a Fulcrum Speed 55C,
but the newer Bora and Speed models from the wide-rim era are normal rims.
I only just noticed this recently.
Same content is in the linked article, but
for a normal rim with left-right equal Italian lacing, you'd use left-handed drop,
for normal rim with 46 Italian lacing you'd use right-handed drop,
but on a reverse rim, this inverts, so you use left-handed drop.
↑These are the old spokes from before the rebuild, which I'm not using anymore,
and the thread section is shorter than on standard spokes.
I mounted the original nipples both ways to get a close-up shot.
The short spoke thread is connected to the fact that the nipple starts with threading right away.
When it comes to figuring the spoke length correction for reverse-threaded nipples vs. just going with standard nipples,
the latter is easier,
so I'm not reusing this nipple.
Also, this nipple is brass,
but the nipples for the rebuild are aluminum.
It's built.
Leaf hub, 24H, half-comp 46 lacing.
I'll true it later.
It was originally a Campagnolo freewheel body,
but after rebuild it's fine to use a Shimano freewheel body.
Next up is something different—a customer brought in an Aero rear wheel.
The rear hub is a piercing hub, but the old type.
So is the Medium's piercing hub new?
Not exactly—it's the old-old type.
I'll explain that later.
Since it's Aero, not Medium,
the spokes are CX equivalent, not CX-RAY.
All else being equal, CX should be less prone to
Schuttel-touch, which is just a small difference.
This rim also has reverse hole orientation, so I set up the hub side for 46 Italian left-handed drop,
but I started the initial lacing treating it as a normal rim.
When you get the hole orientation or left/right drop wrong,
you end up with the valve hole sitting inside the final cross like in the image above—
not a good look.
It's built.
Black hub, 24H, black half-comp 46 lacing.
I'll true it later.
It's a Campagnolo freewheel body, same as before the rebuild,
but the spoke color is black per customer request.
As mentioned in the linked article,
the first-gen Medium's rim flexes quite a bit when you press the sides,
giving a sketchy feeling, so Kolima apparently got spooked.
The later-gen Medium switched to using the Aero rim,
with only the spoke choice (CX-RAY or CX) being different—a lazy update.
Some makers have ultra-light carbon frames that aren't flagship models and don't get supplied to pro teams—
basically "made for weight-obsessed amateurs"—
and the first-gen Medium was marketed in a similar vein.
Let me look at the nervous disclaimers in the catalog below.
Medium is the lightest wheel in our lineup (←not the Winium),
but it needs to be used on very smooth road surfaces.
Also not suitable for heavyset racers.
Medium is our lightest wheel,
designed for flat, clean roads.
Not suited for frequent racers or heavy riders.
Regarding our 2005 Medium,
the customer we had in mind doesn't race
and rides maybe a few thousand km per year.
So that's the first-gen Medium.
Now for the Medium with the Aero rim:
↑It's like the Rosetta Stone with French and English side-by-side.
Medium wheel
A lightweight wheel for people who aren't seriously racing road bikes,
or who ride maybe a few thousand km per year
Medium uses the same rim and hub as Aero.
By using super-light spokes (CX-RAY),
it's 120g lighter than Aero on both wheels,
but Medium has lower rigidity.
↑Different year, same text
The loose translation is mine. Sorry.
I suspect people used these without understanding this messaging and broke them,
leading to a flood of complaints and forced spec changes or discontinuation.
Exotic parts come with their own durability limits and risks—
you need to understand that to use them safely.
Now, about the freewheel body.
Both are piercing hubs, but different eras.
Between these two, Medium is older and Aero is newer,
Ah, this is the flange I mentioned earlier where the spoke head
seats pretty firmly.
The freewheel bodies are different.
The right side in this image is the Aero hub from today, the newer type.
These Kolima hub shafts have a 5mm hex socket on only one end,
but on these two hubs, the side with the hex socket is different.
With a 5mm Allen key in the hub shaft,
you tighten and loosen each end with a 15mm hub wrench,
but the shaft has no butting or blunt end—it's uniform throughout,
so aside from the hex socket, there's no left/right distinction.
So even though the Aero hub had a left hex socket,
you could also assemble it with the hex socket on the right.
Kolima freewheel bodies are broadly divided into two types: those for S-hubs
and those for other hubs (MCC, Aero, Medium, Winium non-S),
and this one is the old type for the non-S category.
It has a separate spring on each ratchet tooth—
the same style Campagnolo used during the 8-9S freewheel era.
It has no rubber seals,
but if you measure the outer diameter in this area outside the teeth—
it comes to 34.7mm.
The new type for non-S hubs has an outer diameter of 32.5mm here,
so the old (34.7mm) and new (32.5mm) types aren't compatible.
These freewheel bodies are both Campagnolo, so it doesn't matter,
but with Shimano freewheel bodies, the old type has no 11S option.
So if today's Aero were a Shimano 10S freewheel body,
you couldn't upgrade to 11S without rebuilding the hub.
I reassembled it with the hex socket on the right.
No deeper meaning.
Next, the freewheel body from today's Medium.
For convenience I'll call it the old-old type.
The ratchet teeth have a paw spring design—same style as on Evolite hubs.
We don't currently supply this same freewheel body.
It has a rubber seal, with a maximum outer diameter around 34.2mm in this area.
Since shaft and ratchet diameters are the same, waterproofing looks sketchy
(though it was sketchy to begin with),
but swapping to the old freewheel body should be possible.
However, for Shimano bodies, there's no 11S option.
Given all this, the Medium rebuild might have needed a hub swap after all.
For reference, non-S hub freewheel bodies are ¥14,000 both old and new,
while Evolite hubs are ¥13,000.
Rebuild labor and spoke cost are extra, though...
Finally, here's something: Medium, whether first-gen or later, has never been sold as a rim-only option. Aero and Winium have been.
So measuring a Medium rim is a rare opportunity.
The linked article has actual weight figures for the first-gen Medium,
and today's Medium turned out to be the same rim as Aero, as expected.
Also, today's Aero rim is from after the wide-rim update, and
it has a balance weight (around 10g?) sticker on it.
So comparing these rims' actual weights would reveal things like
"the first-gen Medium really is different from the later Medium" or
"Kolima barely changed rim weight in the wide-rim transition"—
but I don't really feel the need to lay all this out neatly for readers,
so I'm not posting the actual figures.
↑ugh this guy is being so full of himself and coy about it, totally annoying
Technical archive
Products Mentioned in This Article
- 🛒 Sapim CX-RAY spoke
- 🛒 Kolima Winium bicycle rim
- 🛒 Shimano XT disc brake M755
- 🛒 Campagnolo freewheel body
* Amazon affiliate links — prices may vary
Original Japanese post: のむラボ日記 #4213