Howdy all,

I have a very tall, steel mountain bike stem that is missing the stem bolt. The bolt needed is of the allen-head recessed head type. The 10" measurement is from the bottom of the head recess in the stem cap to the bottom end of the wedge.

I believe that 5/16" is the usual diameter of stem bolts, with 22 or 24 TPI pitch. The OD of the stem I have is 21.1mm (correct for the fork it's going in). I do have a 21.1mm wedge, threaded 22TPI. I could obtain another 21.1mm wedge with a 24TPI thread if the bolt I end up finding is made so.

Yeah, I know it would be easier to just buy a new stem with a bolt, but I'm trying to keep this cheap. The stem is for my girlfriend's old three-speed. She's quite tall, and wants a more upright riding position. I've already checked the LBS, including the Reno Bike Project, which has bins of such things.

Since it's unlikely a hardware store would have a 10" long 5/16" fine thread allen screw, I've thought of just using a piece of all-thread, with a washer and nut sitting on top of the stem cap. The problem is that I think that 5/16" all-thread usually is NC (18TPI). I suppose I could use the next size up of all-thread, and drill and tap the wedge to that thread size.

Thanks,
Darron in Reno, NV

One option: https://www.mcmaster.com/#93250a064/=3emfv8
Note this is stainless. A few yrs ago I was looking for a metric
variant in 7mm and SHCS were available up to 7-8" long, but not
in English sizes apparently. McMaster has a warehouse in Nevada somewhere.

That's a good option, thanks.

I'm on short notice to get her playa bike ready to go to Black Rock City in a day or two, though, so I took another option. I bought a grade three 3/8" x 11" NC (16 TPI) bolt, which will fit the wedge and stem top cap with a little machine work. Couldn't get a grade 5 or 8 bolt in this size, nor a fine thread one long enough. I'm also using two grade 8 washers under the bolt head to keep it from digging into the original stem top cap recess that was meant for an allen-head bolt.

Darron

I'm willing to bet that the threading on your stem bolt is metric not SAE.

Scroll down to the stembolt. https://www.gaerlan.com/bikeparts/parts/stem/stems.html

I don't have the original bolt, so I can't tell if it was metric or SAE. The wedge I have is just a random one I grabbed from a bin at the Reno Bike Project. It is threaded 5/16" x 22TPI, which is British Fine thread.

Yes, that's EXACTLY what I need- thanks! I'll grab one of those to install later on. For now, my larger bolt retrofit will have to do, as my tall woman is hitting the road to Burning Man in a few hours. I'll be making no changes to the stem itself, so installing the correct bolt later on will present no difficulty.

Darron