Even though I said I'd take Friday off,
I had an errand so I stopped by the shop
and got some wheel building done.
So today it's wheels again (and so on).
I replaced the front wheel rim on the Zonda.
Just like the rear wheel, I changed from a C15 rim to a C17 rim.
Not just Zonda, but also Eurus and Shamal Ultra,
and Fulcrum's Racing 3 and Racing Zero as well—
all have different rim heights between front and rear wheels.
I've written about this many times before,
but the early tubeless valves that came with 2WAY-FIT rims
had relatively short lengths, so the rear wheel valve had minimal protrusion.
Depending on the pump head, it was sometimes hard to inflate—or impossible at all.
There were even people saying back then "the rear wheel valve is shorter!"
This is also related to the fact that the sticker lettering on the rim
is sized differently between front and rear wheels,
creating a design that makes the rim height difference less noticeable.
With these C15 Zonda rims, measured at the low-height section
of the rim away from the spoke hole rather than directly below it,
the front rim measured 23mm and the rear rim 27.5mm.
Since the rim heights differ front to rear, the rim weights differ
at a level that goes beyond individual variation. Naturally, the rear rim is heavier.
Whether you interpret this front-to-rear weight difference as
"making the rear heavier" or "making the front lighter"—
I think it's fair to say they lightened the front.
Speaking of other manufacturers,
Mavic's first-generation Aksium had 24 holes on both front and rear,
with the same rim part number, so the rims were shared front and rear.
This rim's measured weight was around 590g.
The original Aksium was built with bladed spokes, but
the second generation switched to straight spokes
with the front wheel becoming 20 holes only.
I've actually weighed the spare rims for both front and rear of this model too.
Just to be clear, the sample size isn't like one of each.
The 24-hole rear rim was around 590g like the original,
but the 20-hole front rim was around 540g.
It seems that manufacturers follow a process where they first decide
on the rear rim weight based on their considered weight limit,
then if sharing front and rear, keep it the same,
but if setting the front rim separately, make it lighter.
The Ksyrium also has different rim weights front and rear,
but this difference exceeds what would be expected just from
the rear rim being offset.
Making the rear rim heavier is probably to increase buckling strength.
When I write this, you might think it contradicts my recent idea
of putting the lighter rim on the rear when building both wheels with the same rim,
but that article was a response to the obvious mistake that
"lightening the rim has the same effect on both front and rear wheels,"
and was also a rebuttal to some vague notion of "the nomu Lab style."
Complete wheels are built without manufacturers knowing exactly
how and by whom they'll be used, so they have to accommodate users
near the upper end of their stated weight limit.
Campagnolo, depending on documentation, era, and model, might set
the rider's weight limit at 109kg, or 115kg total (rider and bike)
for the Hyperon Ultra DB, or 120kg for the Levante.
With my hand-built wheels—like nomu Lab Wheel No. 5—
I don't build the same wheel for a 60kg person and a 90kg person.
So if I ever had the chance to replace both front and rear rims
on an original Aksium simultaneously, I would still measure the weight
and put the lighter one on the rear.
Suppose there were two supposedly identical rims
where the lighter one was 20g lighter than the heavier,
and faced with rim buckling like what happened with this Zonda,
the 20g heavier rim on the rear wouldn't keep it alive—
that kind of difference wouldn't materialize anyway.
If anything, rather than trying to protect against the rare case
of rim buckling, benefiting constantly from a 20g lighter rear rim
seems like the better deal to me.
A 20g rim difference is something you might actually feel.
The second-generation Aksium front rim was
around 540g as I mentioned, but
for most people not right at the edge of a 100kg weight limit,
even if the rear rim were also 540g,
it's likely the rim won't buckle before the wheel's lifespan ends.
Yet despite saying all this,
manufacturers must resort to least-common-denominator design
tailored to people at the weight limit ceiling,
which—put negatively—is imposing the manufacturer's constraints.
The fact that this front-to-rear rim weight difference
shows up so plainly and visibly in the rim height difference
of Zonda and Shamal Ultra rims is precisely that.
If Zonda had the same rim height front and rear
but set different rim weights internally,
almost nobody would notice the weight difference.
By the way, this time I had the rare opportunity
of having both C15 and C17 Zonda rims (the C15 is used)
all in one place, and I measured all the rims' actual weights,
but I have no intention of telling you about them.
↑man, this guy's got a bad attitude
Thanks for waiting! Please take a look at these photos!
C15 front rim!
C17 front rim!
C15 rear rim!
C17 rear rim!
↑stop it already!
I had an errand so I stopped by the shop
and got some wheel building done.
So today it's wheels again (and so on).
I replaced the front wheel rim on the Zonda.
Just like the rear wheel, I changed from a C15 rim to a C17 rim.
Not just Zonda, but also Eurus and Shamal Ultra,
and Fulcrum's Racing 3 and Racing Zero as well—
all have different rim heights between front and rear wheels.
I've written about this many times before,
but the early tubeless valves that came with 2WAY-FIT rims
had relatively short lengths, so the rear wheel valve had minimal protrusion.
Depending on the pump head, it was sometimes hard to inflate—or impossible at all.
There were even people saying back then "the rear wheel valve is shorter!"
This is also related to the fact that the sticker lettering on the rim
is sized differently between front and rear wheels,
creating a design that makes the rim height difference less noticeable.
With these C15 Zonda rims, measured at the low-height section
of the rim away from the spoke hole rather than directly below it,
the front rim measured 23mm and the rear rim 27.5mm.
Since the rim heights differ front to rear, the rim weights differ
at a level that goes beyond individual variation. Naturally, the rear rim is heavier.
Whether you interpret this front-to-rear weight difference as
"making the rear heavier" or "making the front lighter"—
I think it's fair to say they lightened the front.
Speaking of other manufacturers,
Mavic's first-generation Aksium had 24 holes on both front and rear,
with the same rim part number, so the rims were shared front and rear.
This rim's measured weight was around 590g.
The original Aksium was built with bladed spokes, but
the second generation switched to straight spokes
with the front wheel becoming 20 holes only.
I've actually weighed the spare rims for both front and rear of this model too.
Just to be clear, the sample size isn't like one of each.
The 24-hole rear rim was around 590g like the original,
but the 20-hole front rim was around 540g.
It seems that manufacturers follow a process where they first decide
on the rear rim weight based on their considered weight limit,
then if sharing front and rear, keep it the same,
but if setting the front rim separately, make it lighter.
The Ksyrium also has different rim weights front and rear,
but this difference exceeds what would be expected just from
the rear rim being offset.
Making the rear rim heavier is probably to increase buckling strength.
When I write this, you might think it contradicts my recent idea
of putting the lighter rim on the rear when building both wheels with the same rim,
but that article was a response to the obvious mistake that
"lightening the rim has the same effect on both front and rear wheels,"
and was also a rebuttal to some vague notion of "the nomu Lab style."
Complete wheels are built without manufacturers knowing exactly
how and by whom they'll be used, so they have to accommodate users
near the upper end of their stated weight limit.
Campagnolo, depending on documentation, era, and model, might set
the rider's weight limit at 109kg, or 115kg total (rider and bike)
for the Hyperon Ultra DB, or 120kg for the Levante.
With my hand-built wheels—like nomu Lab Wheel No. 5—
I don't build the same wheel for a 60kg person and a 90kg person.
So if I ever had the chance to replace both front and rear rims
on an original Aksium simultaneously, I would still measure the weight
and put the lighter one on the rear.
Suppose there were two supposedly identical rims
where the lighter one was 20g lighter than the heavier,
and faced with rim buckling like what happened with this Zonda,
the 20g heavier rim on the rear wouldn't keep it alive—
that kind of difference wouldn't materialize anyway.
If anything, rather than trying to protect against the rare case
of rim buckling, benefiting constantly from a 20g lighter rear rim
seems like the better deal to me.
A 20g rim difference is something you might actually feel.
The second-generation Aksium front rim was
around 540g as I mentioned, but
for most people not right at the edge of a 100kg weight limit,
even if the rear rim were also 540g,
it's likely the rim won't buckle before the wheel's lifespan ends.
Yet despite saying all this,
manufacturers must resort to least-common-denominator design
tailored to people at the weight limit ceiling,
which—put negatively—is imposing the manufacturer's constraints.
The fact that this front-to-rear rim weight difference
shows up so plainly and visibly in the rim height difference
of Zonda and Shamal Ultra rims is precisely that.
If Zonda had the same rim height front and rear
but set different rim weights internally,
almost nobody would notice the weight difference.
By the way, this time I had the rare opportunity
of having both C15 and C17 Zonda rims (the C15 is used)
all in one place, and I measured all the rims' actual weights,
but I have no intention of telling you about them.
↑man, this guy's got a bad attitude
Thanks for waiting! Please take a look at these photos!
C15 front rim!
C17 front rim!
C15 rear rim!
C17 rear rim!
↑stop it already!