Advice request - steerers and stems =]

[SquirrelStu]

I'm not sure if I should try and find some sort of shim (obviously not standards step down, or try another stem, if I can find another Marin lite one (I'd rather stay original).

 

[Gtpulse]

Scratching head.
A quick look on eBay and interweb confirms both stem and fork look correct for the bike.
In the first two photos the stem does look slightly oval but that could be the photo.
I’ve only encountered this issue once before and was on one of those quill adaptor type things, not on something that’s original to the bike.
Coke can shim could work but not ideal. The Marin Lite stems on eBay look the same so could be worth getting one to rule in/out.

 

[marc two tone]

Those diacompe headsets just had a plastic bung to finish it off, I believe that is why there is no star nut.
Everything else seems as it should be, as though it's a stem that's been somehow stretched or just some intolerance caused by....?....
Yes a nut and top cap will help and provided you use a shim/system with a low compressabilty, say steel, you should get away with it.
Nice bike.

 

[SquirrelStu]

Gtpulse - Yeah - glad it's not just me who's a bit confused - I could only guess, as marc two tone says, that the stem has widened over time - I guess that can happen, I mean it is like 25 years old.

Either way - yes I will get another stem to check, then failing that I'll find a shim. Top Cap ordered!

Thanks everyone! I really appreciate your help! =D

 

[SquirrelStu]

and... thanks marc two tone =D

 

[2manyoranges]

Hang on....pictures 3 and 4 shows gap in stem completely pinched down. No wonder it doesn’t grip. Out with the verniers to check the steerer tube (take stem off and check roundness and diameter of steerer tube) and then check inside diameter of stem with bolts cinched down and 1-4mm gap between gap faces. This looks very much like it could be an oversize stem or a damaged steerer - but most likely an oversized stem.

Remedy may just be new stem or a stem shim - they do exist. I’d go for a proper sized stem though.

 

[SquirrelStu]

Thanks 2manyoranges - haha ok I'll measure and give accurate measurements here:
(Bare in mind the cheapness of the callipers)

Steerer Diameter - "Front to Back": 28.5mm / 1.120"
Steerer Diameter - "Left to Right": 28.56mm / 1.125"
Stem (clamped) Diameter - "Front to Back": 29.37mm / 1.154"
Stem (clamped) Diameter - "Left to Right": 28.22mm / 1.112"

So it seems like the stem is barely gripping on at the sides.

 

[SquirrelStu]

aaaand that stem, when clamped, is ovalised - not sure if that's a normal expectation.

 

[raidan73]

The outer diameter of the steerer should be 28.6mm so your callipers may be very slightly out. It does appear to be a little oval, by your measurements. The stem also seems to have been a bit deformed too. I vote for a shim to sort it out.

 

[SquirrelStu]

The outer diameter of the steerer should be 28.6mm so your callipers may be very slightly out. It does appear to be a little oval, by your measurements. The stem also seems to have been a bit deformed too. I vote for a shim to sort it out.

Look who found the reply button - my power is growing!!

Thanks, yes - think you may be right - my callipers were very cheap, 10 years ago, so they are by no means accurate, but after several readings it seems like there is some ovalisation there and I guess the stem metal stretched a bit top to bottom.

Any suggestions on where to get a shim? I've had a look and can only find normal sizes - I guess I need one which is about 1.5 - 2mm thick. I may be way off on that math...