Another wheel day (and so on)... but before that.
This is from a little while back, but a customer brought in
an ultra-lightweight carbon rigid MTB frame from a certain brand
(or what used to be one).
Looking at it, only the rear triangle remained.
Sticking out from the rear triangle were the exploded cross-sections
of the top tube and down tube,
and touching the cross-section, I could've gotten injured from carbon splinters.
It didn't happen while riding—
the frame was on a car roof carrier, and they unexpectedly pulled into a drive-through
where it went "crunch" against the low ceiling.
The job for "just" that frame was
to recover the press-fit bottom bracket hardware from the rear triangle,
but as a related matter, they also mentioned:
"Lately, even XC frames are dominated by the BOOST standard,
and this broken frame was the last
non-BOOST frame they owned.
So I'd like you to rebuild the front and rear wheels that were on this—
converting them to BOOST hubs."
So they asked me to do a wheel build.
Another wheel day (and so on).
This is the front wheel of that pair.
HB-M8010 32H all CX-RAY
64-cross reverse Italian lacing with tied spokes—
I built this one a while back.
The BOOST standard widened the overlock nut dimension
by 10mm on the front and 6mm on the rear compared to the previous thru-axle standard,
but with push-fit style hubs that just swap out the end pieces,
the flange width of the hub body doesn't change at all,
so I think to myself,
"That's probably not going to make much performance difference as a wheel structure."
With Shimano hubs, by contrast, BOOST hubs are purpose-designed—
they're a completely different hub body with wider flanges
than non-BOOST hubs.
On front hubs, this reflects the full 10mm difference
directly in the flange width.
By the spec sheets, both current XTRM and XT go 60.2mm → 70.2mm.
On rear hubs, the 6mm difference is reflected... or rather,
XTRM comes in at +7.17mm and XT at +6.99mm (→here)
and they've somehow managed to widen the flange width by about 7mm.
It might be related to the freebody being Microspline.
On the other hand, as I've written in the linked article,
you can't convert a non-BOOST Shimano hub to BOOST
by swapping parts—
there's no flexibility there.
So for this front wheel too, we had to swap the hub,
meaning a complete wheel rebuild.
Oh nooooo
Something scattered all over the rim
and it's all whitened up!!!
Ah, it was just sealant that had leaked out and hardened
when the tire bead came up,
so it came right off with a little finger rubbing.
I'll use a Tni REVO MTB hub.
Confusingly, this is a different product from the Evo disc hub.
The Evo disc hub ships in 100mm and 135mm quick-release versions,
and can be converted via parts swap to 100×12mm or 100×15mm on the front
or 142×12mm thru-axle on the rear.
The current model is technically Evo Disc Hub II,
so watch out—the shape of the front hub thru-axle conversion adapter is different.
And the Evo disc hub cannot be converted to BOOST.
By contrast, the REVO MTB hub is BOOST standard only on both front and rear
(just to note: 110×15mm front, 148×12mm rear),
and comes in 32H spoke count only.
Recent lightweight XC rims (especially carbon rims)
tend to be 28H,
but for this job, since the wheels being rebuilt are 32H,
it worked out perfectly.
I disassembled the wheel.
I released tension on the tied 6-cross side, cut it, and discarded it,
but the 4-cross untied side could be reused
if I shortened the spoke length a bit, so I took it apart carefully.
As for the hub flange width,
when I align this side,
the REVO MTB is clearly wider,
so it definitely is BOOST-specific design.
I extracted just the spokes from the old hub,
cut them to length, and threaded them through the new hub.
The XT hub turned out lighter than I expected.
It's tough to make cup-and-cone hubs light,
but I guess it's because they've thinned the hub shell
and the rotor mount is centerlock.
Built.
REVO MTB 32H (only available in that count)
64-cross reverse Italian lacing.
I'll do the tie-spokes later.
This is from a little while back, but a customer brought in
an ultra-lightweight carbon rigid MTB frame from a certain brand
(or what used to be one).
Looking at it, only the rear triangle remained.
Sticking out from the rear triangle were the exploded cross-sections
of the top tube and down tube,
and touching the cross-section, I could've gotten injured from carbon splinters.
It didn't happen while riding—
the frame was on a car roof carrier, and they unexpectedly pulled into a drive-through
where it went "crunch" against the low ceiling.
The job for "just" that frame was
to recover the press-fit bottom bracket hardware from the rear triangle,
but as a related matter, they also mentioned:
"Lately, even XC frames are dominated by the BOOST standard,
and this broken frame was the last
non-BOOST frame they owned.
So I'd like you to rebuild the front and rear wheels that were on this—
converting them to BOOST hubs."
So they asked me to do a wheel build.
Another wheel day (and so on).
This is the front wheel of that pair.
HB-M8010 32H all CX-RAY
64-cross reverse Italian lacing with tied spokes—
I built this one a while back.
The BOOST standard widened the overlock nut dimension
by 10mm on the front and 6mm on the rear compared to the previous thru-axle standard,
but with push-fit style hubs that just swap out the end pieces,
the flange width of the hub body doesn't change at all,
so I think to myself,
"That's probably not going to make much performance difference as a wheel structure."
With Shimano hubs, by contrast, BOOST hubs are purpose-designed—
they're a completely different hub body with wider flanges
than non-BOOST hubs.
On front hubs, this reflects the full 10mm difference
directly in the flange width.
By the spec sheets, both current XTRM and XT go 60.2mm → 70.2mm.
On rear hubs, the 6mm difference is reflected... or rather,
XTRM comes in at +7.17mm and XT at +6.99mm (→here)
and they've somehow managed to widen the flange width by about 7mm.
It might be related to the freebody being Microspline.
On the other hand, as I've written in the linked article,
you can't convert a non-BOOST Shimano hub to BOOST
by swapping parts—
there's no flexibility there.
So for this front wheel too, we had to swap the hub,
meaning a complete wheel rebuild.
Oh nooooo
Something scattered all over the rim
and it's all whitened up!!!
Ah, it was just sealant that had leaked out and hardened
when the tire bead came up,
so it came right off with a little finger rubbing.
I'll use a Tni REVO MTB hub.
Confusingly, this is a different product from the Evo disc hub.
The Evo disc hub ships in 100mm and 135mm quick-release versions,
and can be converted via parts swap to 100×12mm or 100×15mm on the front
or 142×12mm thru-axle on the rear.
The current model is technically Evo Disc Hub II,
so watch out—the shape of the front hub thru-axle conversion adapter is different.
And the Evo disc hub cannot be converted to BOOST.
By contrast, the REVO MTB hub is BOOST standard only on both front and rear
(just to note: 110×15mm front, 148×12mm rear),
and comes in 32H spoke count only.
Recent lightweight XC rims (especially carbon rims)
tend to be 28H,
but for this job, since the wheels being rebuilt are 32H,
it worked out perfectly.
I disassembled the wheel.
I released tension on the tied 6-cross side, cut it, and discarded it,
but the 4-cross untied side could be reused
if I shortened the spoke length a bit, so I took it apart carefully.
As for the hub flange width,
when I align this side,
the REVO MTB is clearly wider,
so it definitely is BOOST-specific design.
I extracted just the spokes from the old hub,
cut them to length, and threaded them through the new hub.
The XT hub turned out lighter than I expected.
It's tough to make cup-and-cone hubs light,
but I guess it's because they've thinned the hub shell
and the rotor mount is centerlock.
Built.
REVO MTB 32H (only available in that count)
64-cross reverse Italian lacing.
I'll do the tie-spokes later.