The custom stem thread


I dug up a few custom stems this morning and I thought it would be interesting to share knowledge about them, pros and cons, material used, the fabrication process

Here are a couple I made over the years, mostly for fun/practice reasons

New one on the way

The mighty fancy high accuracy jig to make them

I make them with 25Crmo4 tubing (EU metric equivalent for 4130 ) so the ID always need to be reamed to size to fit 1" or 1 1/8" steerer and handlebars.
All tubes are at least 1.4mm thick after reaming , they tend to be quite heavy but I’d rather lose a few grams then a few teeths…

My thought on custom stems

  • They are great to get the handlebars exactly where you want them

  • they look good (depend on the type of bike of course )

  • Versatility : you can mix handlebars and steerer size without any shims for a proper look
    for example ,I made a while back a quill stem for a vintage Peugeot to get a more upright position and use an OS drop bar with less drop ( Nitto )

  • You can get really creative with clamping features and additional things you want to put on them ( bells,phone mount…)

  • You can paint them to fit your frame ( but you could actually do that with any stem…)

  • They don’t really look MTB’ish, maybe using PMW stems parts could solve that

  • They end up much more expensive than any stem if you want to sell them

  • They have to be dead straight

What’s your feeling on custom stems? How light would you go? Do they have there place in MTBing/ heavier riding type?


I want a 44 Bikes Ti stem once he gets it tested and available.
I do think they are super cool

Ive done a couple. Mostly use 4130 and same, shoot for around 1.5-1.6mm for the clamps. Down to 1.2mm on the extensions on a road bike.


I did a few for myself/friends over the years but decided to stop bothering because what I was making was objectively inferior to a $15 Kalloy. Never sold one to anyone because I calculated out I’d have to charge $300+ to make it worth my time.

The look is cool but looks aren’t really my thing.

I have done (unfortunately no pics) bar/stem combos for kids bikes a few times (for my own kids) so that they can fit a bike for longer/bigger reach initially (ie, zero length “stem” setups).



When making a quill stem, what size tubing do you use for the part that goes into the steerer, seeing as they have to be 22.2 mm? Do you get really thick 23mm to mill down to 22.2?

22.2mm = 7/8"

If you can source Imperial sized tubes in Europe no machining is required.

I know, the imperial sizing is the whole problem :slight_smile: I can seem to easily find these measurements in tubing, and if i can most of the time it is thin walled for things like chain stays or seatstays


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$300 is what I charge and people still want them!

I build one or two a month, they’re a nice quick-ish project to crack out between frames or when I’m burnt out on whatever I’m supposed to be doing.


Yeah I charge Aus$450 stand alone or Aus$300 with a frame for the road ones.



If I had nothing else to do, maybe I’d build some. In my whole time in business I’ve never had any involuntary downtime/empty queue, though, so it’s never been something I pursued much.

I’m also a bit gunshy about making a clamp that’s safe for carbon.



I also should note that having little projects to do was always super good for me. I used forks for that purpose - if I was having a rough time with a bigger (usually frame) project, or just needed to change gears for a bit, I’d whip out a fork and give myself a 90 minute change of pace.

Stems could serve the same purpose, good stuff.



Is there a consensus on the maximum height for a tall-boy stem? Say for example you have a road bike with a full carbon fork that is cut short for a slammed stem, could you build a stem with 20, 40, 60mm extra height? More? Hypothetical question.

I’ve seen goosenecks that have to be 100+mm tall.

Not sure I’d put one on a carbon steerer, though.


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My friend gave me a nice chunk of aluminum, and my fatbike needed a new stem, so an evening of playing in the machine shop led to this. Very rough, but I learned a bunch, so it’s a win. It also hasn’t broken after 3 years of riding, so that’s a plus.


One of my favorite old MTBs uses a 1-1/8 threaded steerer for a 1" quill stem, but I wanted to use some modern wide drop bars on it, so I made this, possibly the only 1" quill for 31.8 bars in existence?

There was a tiny bit of distortion on the clamp part despite my best efforts to keep the heat even, so I will have to address that either with files and a lot of checking, or if I can find someone with a reamer that will do 31.8. Neither of the local shops I have checked with had an adjustable reamer that would go that big.


Made this one for myself. But the extension tube is to thin… so now it’s super flexible. Not the best characteristics for a track bike stem. Maybe i have to replace the tube.
I think it was about 1,00mm.


I copied Alex Meade’s stem fixture and started making my own stems.


I have a bunch of vintage bikes that work well with a nice fillet brazed quill stem so I did a batch of 4 with one ahead style.

I use .065 tubing and turn down the quill to 21.5mm to make room for paint and ream the clamps to fit correctly. I didn’t like how much .058" walled clamps closed up on a slightly undersized steerer or bar.


yesterday I tried to build a road stem with an integrated clamp. i split the tube for the steerer tube to create a squeezing effect. I soldered the binder in the extension tube with silver and put fillets on the inside for reinforcement. However, the test quickly showed that it does not work that way. any tips?