Stem lengths - claimed vs. measured (Italian measurements?!!).

[Oms]

Hiya,

So - having decided to go for a longer stem... I measured my Deda Zero100 80mm stem, which was true to the claimed length.

I've received a new iteration of the same stem - Deda Zero100 90mm, which at first appearance appeared longer than that. Measurments indicate it's a 95mm stem.

Why on earth do they do that? What are your experiences with other brands?

Regards.

[MarshMellow]

Rotate the handlebar a smidge. 5mm is nothing to torch teh interent over.

[ghostinthemachine]

Sometimes they measure along the top face of the stem, sometimes the centre line, there is some variation from the forging process.

And really. That sort of tolerance variation, when combined with the variation in bar reach/rotation, brake lever reach/rotation and getting out of bed the wrong side, is all but irrelevant.

[GS100]

And really. That sort of tolerance variation, when combined with the variation in bar reach/rotation, brake lever reach/rotation and getting out of bed the wrong side, is all but irrelevant.

When stems are sold in 10mm increments, a 5mm 'tolerance variation', is pretty bad lol!

One assumes the other size variables you mention are accounted for when choosing a stem?!

[hannawald]

This is quite common and doesn´t only affect italian products.

[MarshMellow]

And really. That sort of tolerance variation, when combined with the variation in bar reach/rotation, brake lever reach/rotation and getting out of bed the wrong side, is all but irrelevant.

When stems are sold in 10mm increments, a 5mm 'tolerance variation', is pretty bad lol!

One assumes the other size variables you mention are accounted for when choosing a stem?!

Gloves.
No Gloves.
Thick Socks.
Medium Socks.
Thin Socks.
New Shorts.
Old Shorts.
No Shorts (nude bike ride)

Other size variables to account for. Really is not an issue and, I'm sure for a while it went unnoticed.

[neeb]

How are you measuring it?

A stem *should* be measured from the side, from the point half way down the steerer clamp and half way across, to the point in the centre of the handlebar clamp, i.e. intersecting a hypothetical line drawn in the exact centre of the handlebar tube. No other method is geometrically consistent. If you measure from the top or bottom you will get different values on each side to extent proportional to the stem angle.

To calculate reach and drop of a stem, you need this figure combined with the stem angle.

Unlike others I think it's important. While there are plenty of other things that will affect reach and drop, they are all quantifiable and cumulative. Sometimes you've already got the other variables maxed out (bars rotated and hoods positioned as far up (or down) as sensible/comfortable, etc), in which case it's really annoying if your new stem that's supposed to be 110mm is actually 115mm.

[synchronicity]

Why on earth do they do that?

Because they are Italian.

The same as how they weigh handlebars and saddles and such.
I once had a 3T handlebar with a claimed weight of... 215 grams.

[GS100]

And really. That sort of tolerance variation, when combined with the variation in bar reach/rotation, brake lever reach/rotation and getting out of bed the wrong side, is all but irrelevant.

When stems are sold in 10mm increments, a 5mm 'tolerance variation', is pretty bad lol!

One assumes the other size variables you mention are accounted for when choosing a stem?!

Gloves.
No Gloves.
Thick Socks.
Medium Socks.
Thin Socks.
New Shorts.
Old Shorts.
No Shorts (nude bike ride)

Other size variables to account for. Really is not an issue and, I'm sure for a while it went unnoticed.

Well yeah there's lots of variables aren't there, but that's besides the point. When all other geometries are given to the mm it's unhelpful to say the least.

I mean why even label it a "110mm stem" ? might as well just drop the nominal sizes and have 'S/M/L' or 'Short/ Long' labels. As much use.

[ehlpitel]

I've 100% noticed this- Zipp stems just seem longer than other brands.

[MarshMellow]

And really. That sort of tolerance variation, when combined with the variation in bar reach/rotation, brake lever reach/rotation and getting out of bed the wrong side, is all but irrelevant.

When stems are sold in 10mm increments, a 5mm 'tolerance variation', is pretty bad lol!

One assumes the other size variables you mention are accounted for when choosing a stem?!

Gloves.
No Gloves.
Thick Socks.
Medium Socks.
Thin Socks.
New Shorts.
Old Shorts.
No Shorts (nude bike ride)

Other size variables to account for. Really is not an issue and, I'm sure for a while it went unnoticed.

Well yeah there's lots of variables aren't there, but that's besides the point. When all other geometries are given to the mm it's unhelpful to say the least.

I mean why even label it a "110mm stem" ? might as well just drop the nominal sizes and have 'S/M/L' or 'Short/ Long' labels. As much use.

FWIW - OP is not even talking about 5mm; this is actually 4mm of stem length, decreasing in effective-reach as rotation of the stem in steering is increased.

I'm sure the enire cycling industry is on the edge of their deskchair because some stems are a skosh longer than what's being indicated.
In fact, my Deda 140mm stem measured 145 yesterday. Don't know what it is today... but the thing is this: Talk about pissed. Now I have zero idea what I'd be doing as thighs slap handlebar tops inside sprint zones.
Yeah - s/m/l large stems are going to be a thing.

[Oms]

How are you measuring it?

A stem *should* be measured from the side, from the point half way down the steerer clamp and half way across, to the point in the centre of the handlebar clamp, i.e. intersecting a hypothetical line drawn in the exact centre of the handlebar tube. No other method is geometrically consistent. If you measure from the top or bottom you will get different values on each side to extent proportional to the stem angle.

To calculate reach and drop of a stem, you need this figure combined with the stem angle.

Unlike others I think it's important. While there are plenty of other things that will affect reach and drop, they are all quantifiable and cumulative. Sometimes you've already got the other variables maxed out (bars rotated and hoods positioned as far up (or down) as sensible/comfortable, etc), in which case it's really annoying if your new stem that's supposed to be 110mm is actually 115mm.

Well I think that's it. I've taken the time to get a bike fit... select new bars (with the right reach)... only to find the new stem is a tad longer than I wanted.

I could have stuck with my last setup, rotating this and that as a workaround.

At least now I have some gorgeous new bar tape to touch and feel (even if I still have to work around the new setup slightly).

Still, my issue is getting the right reach/drop: From cold, it feels a bit of a stretch.... once warmed up it feels a bit small. Seems as I warm up I get more flexible and the bike feels smaller. Weird.