Stem Nut/yoke Size

GhostlySM · Feb 12, 2014

Hi all,

First post, so go easy on me

Decided to grab one of these, along with an appropriate phone case to mount my mobile to the stem piece of my bike. Will be useful as a satnav when on long trips etc.

Anyway, can anyone do me a huge favour and measure the hole in the stem nut/yoke? I was planning on grabbing one of these to swap out with the original as the original has a cover across the top, IIRC.

The options given to me by the seller are:
- 13.3mm - 14.7mm (0.52" - 0.58")
- 15.0mm - 17.2mm (0.59" - 0.68")
- 17.5mm - 20.5mm (0.68" - 0.81")
- 20.5mm - 24.5mm

If you're unsure, please don't take a wild guess as I don't want to end up with a piece that doesn't fit

My bike is currently in storage as I can't ride it for another 3 weeks and don't have room for it at home until I get rid of my current bike, so I'm unable to measure it myself.

Apologies if I've used the wrong terms for the piece I need measured, really not sure!

Thanks for any replies

blackizzz · Feb 12, 2014

There's no hole in our stem nut... Sorry mate, you'll have to get a new nut if you want to fit that one!

GhostlySM · Feb 13, 2014

Thought that was the case. I assume the top cover part of it isn't removable?

Al B · Feb 13, 2014

The hole in the centre of the yoke measures 15.87mm (on my old one anyway). The thread for the top nut is 1mm pitch and by 19.89mm diameter so i assume it's a M20x1.
A ring type top nut as in the photo you linked should work fine. if you know a machine shop then sticking the nut in a lathe and getting the cap turned off would be easy enough.
Bear in mind there's no drain in the yoke so if you haven't got the mount in place water could collect inside, using the old top nut as a finger tight screw on cover would prevent that happening.

GhostlySM · Feb 13, 2014

Fantastic, thanks a lot Al, that's the exact info I was after!

If I did buy a replacement, is crap going to start falling apart when I swap them over? Also, does anyone know how tight it would need to be? I do have access to a torque wrench, if needed.

Al B · Feb 14, 2014

No and 110Nm respectively.

As long as you don't undo the bar clamps, top yoke and bottom yoke all at the same time it will stay in place, any 2 of the 3 you could probably get away with but not all of them together

GhostlySM · Feb 17, 2014

Cheers Al, will let you know how I get on

Chris Mason · Jun 11, 2014

Hi, what did you need in the end? Like, everything from start to finish, got same mount as you

Or better yet, does anyone know how to do this?

Stem Nut/yoke Size

Top Contributors this Month

Recommended Communities