Syncros stem issues

[NickD]

The bars worked as is on my Kona around 10 years ago, with a Uno stem, but that was a thinner, single bolt stem - no shim.

The only thing I can think of is that the bars narrow after a fairly slim clamping area, and as the bolts are a fair way apart thay possibly aren't actually clamping directly on the bar. Bar is made by 'Rito'.

That could well be it. If the bulge of the bar is much narrower than the stem clamp (and those early Syncros stems had a very broad clamp) the pinch bolts might be trying to clamp the sloping edges of the bulge. It should be fairly obvious if that's the case though.

Just a couple more points on the difference between the road and mtb stems. Because the road stem needs to be threaded around a curved bar, Syncros road stems either have a narrow one-bolt clamp with the underside cut away, or a broader, hinged two-bolt clamp. With a broad two-bolt clamp and no hinge, yours is certainly an mtb stem with a 1" clamp.

I'll try and get some pics later on. The battery has run out on my calipers so I can't do precise measurements at the moment.

Battery?

:roll:

I doubt my poundshop non digital calipers would be precise enough.

Thanks for the help - I may try a couple of shims under the bolts, otherwise try and find a bar with a larger clamping surface - the clamping surface on the bars is only an inch or so, and the stem does cover up some of the writing on the bars, so there may not be enough pressure on the clamping surface with the bolts being off to each side.

 

[one-eyed_jim]

I may try a couple of shims under the bolts, otherwise try and find a bar with a larger clamping surface - the clamping surface on the bars is only an inch or so, and the stem does cover up some of the writing on the bars, so there may not be enough pressure on the clamping surface with the bolts being off to each side.

I think I'd go straight for a new bar. It wouldn't be easy to shim your bar effectively, and bars are cheap. Just make sure you get one with a very wide central bulge. Those early Syncros stems had some of the widest bar clamps made.

 

[mikee]

my 1 1/4" question was in referance to the fact that a 1 1/4" quill stem
with a 26.8 bar clamp would be alpinestars specific

 

[one-eyed_jim]

my 1 1/4" question was in referance to the fact that a 1 1/4" quill stem
with a 26.8 bar clamp would be alpinestars specific

28.6mm (1 1/8") innit?

http://i453.photobucket.com/albums/qq25 ... 0005-3.jpg

I must admit, the possibility hadn't crossed my mind. Did Syncros ever make such a thing?

 

[mikee]

yeah but most bars are 25.5 1"
alpinestars from 91 (i think) had 26.8 center bars

think modern o/s bars are 28.6

syncros did make an astars stem , my lbs had some bitd £90 each

 

[MikeD]

Current "OS" bars are 31.8mm.

 

[one-eyed_jim]

yeah but most bars are 25.5 1"

25.4

alpinestars from 91 (i think) had 26.8 center bars

28.6!

think modern o/s bars are 28.6

31.8

syncros did make an astars stem

Now that, I didn't know.

 

[mikee]

yeah but most bars are 25.5 1"

25.4

alpinestars from 91 (i think) had 26.8 center bars

28.6!

think modern o/s bars are 28.6

31.8

syncros did make an astars stem

Now that, I didn't know.

christ heads up the arse today eh ?
bloody engineer too

 

[FluffyChicken]

That is a MTB stem and a 90/91 version.
apart from teh not a lot to clamp to,
It could be that the stem has been over tightened at some point and bent the nut hole sections in a bit as they are only welded on (this changed in later versions.

close up pics of the clamping section.

 

[jonboy]

That is a MTB stem and a 90/91 version.
apart from teh not a lot to clamp to,
It could be that the stem has been over tightened at some point and bent the nut hole sections in a bit as they are only welded on (this changed in later versions.

close up pics of the clamping section.

Yeah, that's my thoughts too. I reckon it's been over tightened on a bar with a think layer of paint and the clamp has been stretched. I have an old Syncross stem and although it does bite the bar the gap is almost completely closed. You could try filing theinner surfaces of both sides of the clamp where they meet? It would need re-painting though. I reckon a bar with a wider center section is definitley a change that's needed. That might fix it, if not shim it with coke can. Good luck.