Switched stem now slight gap from top washer?

Switched stem now slight gap from top washer?

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Discussion

AmiableChimp

Original Poster:

3,674 posts

236 months

Wednesday 10th February 2016
quotequote all
I borrowed a 100mm stem from a mate at work as my Scott has a 110mm as standard - wanted to see if I liked the slightly shortened reach.

After fitting it, there is a slight gap at the top when I put the top fastener back on - i.e. the new stem doesn't sit flush with the silver part it clamps onto.

Do I need to add a shim of some description or do I need to go for a different stem type?

New stem fitted:




Old stem:



AndrewEH1

4,917 posts

152 months

Wednesday 10th February 2016
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You either need to buy another headset spacer or cut a few mm off the end of your forks.

The stem is fine, all stems just have different fork clamp heights.

Tiggsy

10,261 posts

251 months

Wednesday 10th February 2016
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spacer - cost pennies!

Just bough one for GF's bike as put a shorter stem on that was just like yours (too short!)

Got a pretty red one!

matt-ITR

892 posts

188 months

Thursday 11th February 2016
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You need to add a headset spacer, otherwise you won't be able to tighten the headset.
If it is just a temporary measure to see if you like it, then you could just pinch a spacer from another bike.

upsidedownmark

2,120 posts

134 months

Thursday 11th February 2016
quotequote all
Yup. You *should* normally run at least a thin spacer between the stem and the cap in any case; otherwise for the cap to tension the whole thing the steerer would be inside the stem, rather than right through it..

AmiableChimp

Original Poster:

3,674 posts

236 months

Thursday 11th February 2016
quotequote all
Thanks guys.

Bought a set of carbon spacers from Halfords on the way home and after fitting a 5mm one, everything is nice and tight again.

Cheers.

FD3Si

857 posts

143 months

Friday 12th February 2016
quotequote all
upsidedownmark said:
Yup. You *should* normally run at least a thin spacer between the stem and the cap in any case; otherwise for the cap to tension the whole thing the steerer would be inside the stem, rather than right through it..
Eh? No, you just cut the steerer tube a bit shorter than the total stack height. There's absolutely nothing wrong with having a few mm of gap at the top of the stem.
If you cut the steerer level with the top of the stem and then have a small spacer, there's nothing hold the spacer laterally.You end up having to leave a few mm protruding, running a larger spacer at the top of the stack, then having extra ugly sticky-uppyness on top of the stem.


It's fine to do if you want to, and if you want the flexibility of being able to adjust, but it's not necessary, and hasn't been since the early 90's when Tioga first introduced the AheadSet.

Edited by FD3Si on Friday 12th February 09:29

upsidedownmark

2,120 posts

134 months

Friday 12th February 2016
quotequote all
There's nothing 'wrong' with it in as much as it's highly unlikely to cause you a problem (hence the quoting of should), but a stem is designed to have a steerer going through it, not half way through it. 'proper' procedure is to have the steerer proud of the stem by a mm or two, and use a thin spacer. Of course if you're more bothered about the aesthetics thats your choice.

FD3Si

857 posts

143 months

Friday 12th February 2016
quotequote all
upsidedownmark said:
There's nothing 'wrong' with it in as much as it's highly unlikely to cause you a problem (hence the quoting of should), but a stem is designed to have a steerer going through it, not half way through it. 'proper' procedure is to have the steerer proud of the stem by a mm or two, and use a thin spacer. Of course if you're more bothered about the aesthetics thats your choice.
Proper procedure according to whom?
There are oodles of bikes out there that come from the factory with the exact setup I'm talking about, It's not just about aesthetics, the less sticky up bits in front of me to smash my skeleton on the better. I'm not talking halfway through it either. When I was working in a bike shop I seem to remember the manufacturers ran them about 5mm below the level of the top of the stemwhen we assembled them, which compressed to about 3 mil after you preloaded the headset bearings. 3mm of clamping force that lies above the pinch points is pretty much insignificant.
Like I say, it's entirely personal choice, but to say you "should" is misleading. Manufacturers sell them like this, bike shops assemble them like this, guides from tool/HS/stem/fork suppliers detail it.

John Laverick

1,992 posts

213 months

Friday 12th February 2016
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FD3Si said:
Proper procedure according to whom?
There are oodles of bikes out there that come from the factory with the exact setup I'm talking about, It's not just about aesthetics, the less sticky up bits in front of me to smash my skeleton on the better. I'm not talking halfway through it either. When I was working in a bike shop I seem to remember the manufacturers ran them about 5mm below the level of the top of the stemwhen we assembled them, which compressed to about 3 mil after you preloaded the headset bearings. 3mm of clamping force that lies above the pinch points is pretty much insignificant.
Like I say, it's entirely personal choice, but to say you "should" is misleading. Manufacturers sell them like this, bike shops assemble them like this, guides from tool/HS/stem/fork suppliers detail it.
Agreed.

FD3Si

857 posts

143 months

Friday 12th February 2016
quotequote all
At the risk of labouring a point, here we go, here's an example:

Hope Instruction manual said:
The stem should sit, once installed
on top of all headset and spacers, so that the steerer tube is
approximately 5mm below the top of the stem (this is to
allow sufficient adjustment of the headset to take place)
http://www.hopetech.com/wp-content/uploads/2014/04/New-Stem-Instructions.pdf

(I can't believe I just had to look for an instruction manual for a stem!)
EDIT: And at the risk of being an arse, here's the manual for a Syncros stem:
http://media.canyon.com/download/manuals/SYNCROS-B...

Edited by FD3Si on Friday 12th February 13:55