Not another day of wheel building (abbreviated). Well, actually yes.
The last Saturday of the month is normally closed, but
I've been coming into the shop for the past several months just to build wheels.
This month I was lucky enough to get a day off, so
I came in and built my personal wheels.
I sourced DT's XR331 rim. It's an MTB rim, but
DT follows a naming convention for their MTB rims by category:
XR Cross-Country
XM All-Mountain
EX Enduro
FR Freeride
BG Big Ride (Fat Bike)
—with a two-letter prefix on the model name.
The XR331 is particularly narrow among the XR series.
With inner width/outer width (mm):
XR331 is 20/23.5, XR361 is 22.5/26,
XR391 is 25/29.
A 29" XR331 can be used as a cyclocross rim.
The profile is triangular in cross-section, like Stans' Ironocross.
The Ironocross rim width is 20/23.2, so
the rim width and profile are virtually identical.
Now that Ironocross has been discontinued, it's become clear recently that
this rim is extremely useful as a post-Ironocross replacement.
The reason I hadn't noticed this before is
that DT's previous distributor didn't stock it.
Unlike the RR411db, this is not an offset rim.
In terms of the logic when assembling into a wheel, RR411db is superior—
I'd call it good enough that with a hub's degree of lateral runout
you don't need lacing thread when built semi-competitively—
but the first point for calling this rim "post-Ironocross" is
its light rim weight.
For a 29" version the spec is 380g, but
the four rims I got this time weighed 373, 373, 381, and 382g respectively.
The Ironocross specified maximum spoke tension is 930N, but
the XR331 is rated at 1200N, likely due to the use of the PHR washer.
The specified air pressure: Ironocross is 45psi ≒ 3.1 bar, but
DT rim pressure varies by inner rim width and tire width.
For the XR331, with an inner rim width of 20mm,
according to the manufacturer's chart the compatible tire widths are 28–62C,
with 7.8 bar for 28C and 2.9 bar for 62C.
For a 32C as would be used for cyclocross, it's 6.8 bar.
The ERD (Effective Rim Diameter) with washer is supposedly 606mm,
but this is a classic DT outright lie. I should measure it myself.
My understanding of ERD differs from the general understanding of ERD,
and there's a possibility that DT's given ERD is actually the general industry standard—
no, that's not the case.
The ENVE rim I built yesterday had an ERD spec-to-measurement difference of only 0.3mm, so
I went with the spec value when building the wheel.
Also, Mavic's published ERD figures match up with my measurements almost exactly.
Yep, DT is the odd one out.
What I use for spoke length calculations is the ERD radius,
and 303mm—that's right there with the numbers for
Ambrosio Nemesis tubulars and Mavic GEL280 etc.
—now-ancient, super-low-profile tubular rims.
And the second point for why this rim can serve as "post-Ironocross" is
that its rim diameter is about the same as the Ironocross, so
(unless the Ironocross wheel's spoke length is drastically wrong)
you can move spokes between rims. That's really helpful.
The XR331 comes in both 28H and 32H, and I stocked up on the 28H.
I always notice that whenever I write something like this here, distributors' inventory of that rim drops rapidly.
The distributor seems to have plenty of rim stock, so naturally a complete buyout was impossible anyway.
Speaking of which, those #14 12mm silver aluminum nipples I bought out before are still on backorder.
Yeah, that was a bad move on my part.
I built the rear wheel.
The reason I've got a screwdriver in the valve hole will be explained later.
DT 350 hub 28H, semi-competitive 4-cross lacing with lacing thread, gold aluminum nipples.
It's a disc-brake rim but not a disc-brake hub—
people ask how I'm supposed to brake with this—
but for my purposes it works fine.
I also built my partner's front wheel.
DT RR411 rim.
The RR411 for rim brakes, which has a braking zone,
comes in both offset and non-offset versions, and this is obviously the non-offset type.
With the RR411db for disc brakes,
offset rims are theoretically effective even for front wheels, so there's no non-offset version available.
Black hub 20H with
Sapim aero star bright type II spokes, radial lacing (drive side) and
nipples in purple, green, and red from the valve hole.
Since 20H can't divide evenly by three, I'm doing 7-6-7 nipples of each color.
When using two colors, the wheel looks like two colors as it spins,
and with three colors you can see there are three colors (obviously),
but with this particular three-color arrangement sometimes it looks like there are more than three colors.
If you're concerned about complementary color relationships, you might put light blue between the purple and green
and do five nipples of each color.
About why I've got a screwdriver in the valve hole.
As I've mentioned before, on DT rims
when one side's sticker phase is directly at the valve hole and diametrically opposite,
the other side's sticker is offset by 90°.
If this is an offset rim,
when viewed from the right side (freehub side) for rear wheel use,
the valve hole phase will have no sticker.
When building front and rear wheels with disc hubs and RR411db rims,
due to building the offset direction opposite front to rear,
the valve hole phase sticker presence/absence necessarily reverses between front and rear,
but when building with RR411 non-offset front and RR411 offset rear,
unless the front rim's valve hole is oriented with the no-sticker side on the right,
the position relationship between valve and sticker will differ between front and rear wheels.
So today's front and rear wheels are both non-offset rims, but
I've aligned them both with "sticker-free valve hole phase to the right side".
The washers that came with this rim were
the new type with front-back direction dots, so
I actively consumed the old type, and it's now nicely depleted.
I use Stans tubeless rim tape for the rim tape.
The rear wheel will run tube with a clincher for now.
The XR331's holes on the outer edge are oddly large,
while the RR411's are not (just slightly larger than the valve stem diameter),
but in either case I use the heat of a soldering iron to make the hole just large enough for the valve to pass through.
Stans rim tape comes in widths of 21, 25, 27, 30, 33, and 36mm,
but at our shop we use just the two narrower sizes: 21mm and 25mm (in the image above).
The jump from 21mm to 25mm seems oddly large,
and if 21mm was followed by 24mm
it would be a nice 3mm increment across the whole range, which I wish were the case.
Even Stans rims sometimes seem like they really ought to be 23mm, so
we also keep DT's 23mm in stock.
For adhesive creep performance along the rim shape under pressure,
Stans seems superior, and
since DT rim tape doesn't get holes from soldering iron heat,
we tend to use Stans tape more often at our shop.
The last Saturday of the month is normally closed, but
I've been coming into the shop for the past several months just to build wheels.
This month I was lucky enough to get a day off, so
I came in and built my personal wheels.
I sourced DT's XR331 rim. It's an MTB rim, but
DT follows a naming convention for their MTB rims by category:
XR Cross-Country
XM All-Mountain
EX Enduro
FR Freeride
BG Big Ride (Fat Bike)
—with a two-letter prefix on the model name.
The XR331 is particularly narrow among the XR series.
With inner width/outer width (mm):
XR331 is 20/23.5, XR361 is 22.5/26,
XR391 is 25/29.
A 29" XR331 can be used as a cyclocross rim.
The profile is triangular in cross-section, like Stans' Ironocross.
The Ironocross rim width is 20/23.2, so
the rim width and profile are virtually identical.
Now that Ironocross has been discontinued, it's become clear recently that
this rim is extremely useful as a post-Ironocross replacement.
The reason I hadn't noticed this before is
that DT's previous distributor didn't stock it.
Unlike the RR411db, this is not an offset rim.
In terms of the logic when assembling into a wheel, RR411db is superior—
I'd call it good enough that with a hub's degree of lateral runout
you don't need lacing thread when built semi-competitively—
but the first point for calling this rim "post-Ironocross" is
its light rim weight.
For a 29" version the spec is 380g, but
the four rims I got this time weighed 373, 373, 381, and 382g respectively.
The Ironocross specified maximum spoke tension is 930N, but
the XR331 is rated at 1200N, likely due to the use of the PHR washer.
The specified air pressure: Ironocross is 45psi ≒ 3.1 bar, but
DT rim pressure varies by inner rim width and tire width.
For the XR331, with an inner rim width of 20mm,
according to the manufacturer's chart the compatible tire widths are 28–62C,
with 7.8 bar for 28C and 2.9 bar for 62C.
For a 32C as would be used for cyclocross, it's 6.8 bar.
The ERD (Effective Rim Diameter) with washer is supposedly 606mm,
but this is a classic DT outright lie. I should measure it myself.
My understanding of ERD differs from the general understanding of ERD,
and there's a possibility that DT's given ERD is actually the general industry standard—
no, that's not the case.
The ENVE rim I built yesterday had an ERD spec-to-measurement difference of only 0.3mm, so
I went with the spec value when building the wheel.
Also, Mavic's published ERD figures match up with my measurements almost exactly.
Yep, DT is the odd one out.
What I use for spoke length calculations is the ERD radius,
and 303mm—that's right there with the numbers for
Ambrosio Nemesis tubulars and Mavic GEL280 etc.
—now-ancient, super-low-profile tubular rims.
And the second point for why this rim can serve as "post-Ironocross" is
that its rim diameter is about the same as the Ironocross, so
(unless the Ironocross wheel's spoke length is drastically wrong)
you can move spokes between rims. That's really helpful.
The XR331 comes in both 28H and 32H, and I stocked up on the 28H.
I always notice that whenever I write something like this here, distributors' inventory of that rim drops rapidly.
Speaking of which, those #14 12mm silver aluminum nipples I bought out before are still on backorder.
Yeah, that was a bad move on my part.
I built the rear wheel.
The reason I've got a screwdriver in the valve hole will be explained later.
DT 350 hub 28H, semi-competitive 4-cross lacing with lacing thread, gold aluminum nipples.
It's a disc-brake rim but not a disc-brake hub—
people ask how I'm supposed to brake with this—
but for my purposes it works fine.
I also built my partner's front wheel.
DT RR411 rim.
The RR411 for rim brakes, which has a braking zone,
comes in both offset and non-offset versions, and this is obviously the non-offset type.
With the RR411db for disc brakes,
offset rims are theoretically effective even for front wheels, so there's no non-offset version available.
Black hub 20H with
Sapim aero star bright type II spokes, radial lacing (drive side) and
nipples in purple, green, and red from the valve hole.
Since 20H can't divide evenly by three, I'm doing 7-6-7 nipples of each color.
When using two colors, the wheel looks like two colors as it spins,
and with three colors you can see there are three colors (obviously),
but with this particular three-color arrangement sometimes it looks like there are more than three colors.
If you're concerned about complementary color relationships, you might put light blue between the purple and green
and do five nipples of each color.
About why I've got a screwdriver in the valve hole.
As I've mentioned before, on DT rims
when one side's sticker phase is directly at the valve hole and diametrically opposite,
the other side's sticker is offset by 90°.
If this is an offset rim,
when viewed from the right side (freehub side) for rear wheel use,
the valve hole phase will have no sticker.
When building front and rear wheels with disc hubs and RR411db rims,
due to building the offset direction opposite front to rear,
the valve hole phase sticker presence/absence necessarily reverses between front and rear,
but when building with RR411 non-offset front and RR411 offset rear,
unless the front rim's valve hole is oriented with the no-sticker side on the right,
the position relationship between valve and sticker will differ between front and rear wheels.
So today's front and rear wheels are both non-offset rims, but
I've aligned them both with "sticker-free valve hole phase to the right side".
The washers that came with this rim were
the new type with front-back direction dots, so
I actively consumed the old type, and it's now nicely depleted.
I use Stans tubeless rim tape for the rim tape.
The rear wheel will run tube with a clincher for now.
The XR331's holes on the outer edge are oddly large,
while the RR411's are not (just slightly larger than the valve stem diameter),
but in either case I use the heat of a soldering iron to make the hole just large enough for the valve to pass through.
Stans rim tape comes in widths of 21, 25, 27, 30, 33, and 36mm,
but at our shop we use just the two narrower sizes: 21mm and 25mm (in the image above).
The jump from 21mm to 25mm seems oddly large,
and if 21mm was followed by 24mm
it would be a nice 3mm increment across the whole range, which I wish were the case.
Even Stans rims sometimes seem like they really ought to be 23mm, so
we also keep DT's 23mm in stock.
For adhesive creep performance along the rim shape under pressure,
Stans seems superior, and
since DT rim tape doesn't get holes from soldering iron heat,
we tend to use Stans tape more often at our shop.