22.2 mm. stem into 25.4 mm steerer?

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lettersquash
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22.2 mm. stem into 25.4 mm steerer?

Post by lettersquash »

Hello people,

I'd like to change my stem in Meg, my Marin Eldridge Grade to something with more height and less forward extension. I happen to have a nice one with a short uplifted angle on my old bike, but it's 22.2 mm diameter and I think Meg's is 25.4.

I see that one way to do this seems to be to buy a shim, something like this https://www.ebay.co.uk/itm/122260478281
Any thoughts, recommendations? Anyone used this sort of remedy? Or would it be better to buy a whole new stem?

Also, if I do it this way, I'm thinking these aren't rocket science and I could probably make one from a suitable tube with a cut - anyone done that? It should only need to be flexible enough and pad the requisite difference in size - it's not under any great strain, mostly just compression.

The old stem is all in one - the vertical part is welded to the forward extension - by the way.

Cheers
mattsccm
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Re: 22.2 mm. stem into 25.4 mm steerer?

Post by mattsccm »

You could.
I have. Make sure everything is damn tight though.
Biggest problem will be those who worry about you and tell you it is a bad idea.
I wouldn't bother again though. It looks messy.
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lettersquash
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Re: 22.2 mm. stem into 25.4 mm steerer?

Post by lettersquash »

mattsccm wrote: 14 Aug 2022, 7:43pm You could.
I have. Make sure everything is damn tight though.
Biggest problem will be those who worry about you and tell you it is a bad idea.
I wouldn't bother again though. It looks messy.
Thanks mattsccm. That one's cheap on eBay, so I might just go for that and save the messing about.

Edited to add: I think I saw somewhere that you shouldn't actually tighten the stem/steering tube connection too much, both to avoid it damaging the tube and because you might want the bars to twist in a crash rather than stay rigid (maybe Sheldon Brown). It suggested still being able to turn them round with a good bit of effort holding the wheel between your legs.
cycle tramp
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Re: 22.2 mm. stem into 25.4 mm steerer?

Post by cycle tramp »

lettersquash wrote: 14 Aug 2022, 4:37pm Hello people,

I'd like to change my stem in Meg, my Marin Eldridge Grade to something with more height and less forward extension. I happen to have a nice one with a short uplifted angle on my old bike, but it's 22.2 mm diameter and I think Meg's is 25.4.

I see that one way to do this seems to be to buy a shim, something like this https://www.ebay.co.uk/itm/122260478281
Any thoughts, recommendations? Anyone used this sort of remedy? Or would it be better to buy a whole new stem?p

Cheers
The 22.2 stem is usually fitted to a fork with a threaded headset. It's usually an older frame. The wedge of the stem and the stem itself fits inside the steerer tube of the fork.
The 25.4 stem is usually used by a fork without a threaded headset. Usually a more modern frame, and the stem clamps onto the steerer part of the fork.
We can only be really sure if you would be kind enough to send photos if the two frames.
However if I'm right, what you're proposing may not work because of the star fangled nut already wedged into the fork steerer of the Marin and the way the bearings are tightened - so I'd be looking to purchase a new stem to fit the Marin..
It's time to go :-)
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lettersquash
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Re: 22.2 mm. stem into 25.4 mm steerer?

Post by lettersquash »

cycle tramp wrote: 14 Aug 2022, 9:22pm The 22.2 stem is usually fitted to a fork with a threaded headset. It's usually an older frame. The wedge of the stem and the stem itself fits inside the steerer tube of the fork.
The 25.4 stem is usually used by a fork without a threaded headset. Usually a more modern frame, and the stem clamps onto the steerer part of the fork.
We can only be really sure if you would be kind enough to send photos if the two frames.
However if I'm right, what you're proposing may not work because of the star fangled nut already wedged into the fork steerer of the Marin and the way the bearings are tightened - so I'd be looking to purchase a new stem to fit the Marin..
Thanks, I'll post some pics tomorrow.
rjb
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Re: 22.2 mm. stem into 25.4 mm steerer?

Post by rjb »

There was a short time when 1, 1/8 forks with threaded steerers were being made. Ive got them on my Dawes discovery tandem. Spares like threaded headsets and stems are getting increasingly difficult to source in this size. Im using a 22.2 mm stem with a shim ( 1/16" wall thickness). :wink:

Stems here from SJSC
https://www.sjscycles.co.uk/stems-1-18- ... +ascending

or a shim.
https://www.sjscycles.co.uk/stems/humpe ... 254-mm-od/
At the last count:- Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin X3, Raleigh 20 stowaway, 1965 Moulton deluxe, Falcon K2 MTB dropped bar tourer, Rudge Bi frame folder, Longstaff trike conversion on a Giant XTC 840 :D
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lettersquash
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Re: 22.2 mm. stem into 25.4 mm steerer?

Post by lettersquash »

Photos: (Sorry I can't figure out how to turn them round the right way!)

The Marin headset (from 1995) - yes I know it needs cleaning!
20220815_102051.jpg
20220815_102106.jpg
The stem has threaded bolt and expander:
20220815_102133.jpg
The donor bike (1983-ish Marinoni Special) and its 22.2 stem.
20220815_102231.jpg
20220815_102310.jpg
Actually the rise is similar on the stem top, but I'm hoping I can fit the donor one higher up in the steerer. The Marin Lite stem is at/beyond its safe fitting limit, and I'd like to gain a bit of height on the bars.
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lettersquash
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Re: 22.2 mm. stem into 25.4 mm steerer?

Post by lettersquash »

rjb wrote: 14 Aug 2022, 10:57pm There was a short time when 1, 1/8 forks with threaded steerers were being made. Ive got them on my Dawes discovery tandem. Spares like threaded headsets and stems are getting increasingly difficult to source in this size. Im using a 22.2 mm stem with a shim ( 1/16" wall thickness). :wink:

Stems here from SJSC
https://www.sjscycles.co.uk/stems-1-18- ... +ascending

or a shim.
https://www.sjscycles.co.uk/stems/humpe ... 254-mm-od/
Thanks rjb. I'm pretty confused about all these standards, to be honest. I measured the stem diameter on the Marin at 1" which is 25.4 mm. I see this as standard in many instances, as well as 22.2 mm. I measured my racing bike's stem and it's 22.2 mm. (As far as I can tell with calipers against a ruler.) But I've also seen this other standard, 1 and 1/8". That equates to 28.575 mm., not 25.4 mm., but I do see those given together as if synonymous sometimes - as your examples do. Is this just for the expansion of the stem, and the inner diameter of the headset is 1 1/8" while the stem is 1"?

That shim description is very confusing when is says: "Outer Diameter: 25.4 mm (1 1/8 Inch)".

I'm still hoping to get clarification of whether a shim like that would work in my case, but it looks like the sizes are ok. I don't know what the difference is between the threaded system and other ones, or which mine is.
rjb
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Re: 22.2 mm. stem into 25.4 mm steerer?

Post by rjb »

Your pics show a 1,1/8 system which utilizes a steerer with a 1,1/8 external diameter and a 1" internal diameter. Hence your confusion. The sjsc shim I linked to should suit your needs to accommodate the difference in diameter to enable you to use your 22.2 mm (7/8") stem. :wink:
At the last count:- Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin X3, Raleigh 20 stowaway, 1965 Moulton deluxe, Falcon K2 MTB dropped bar tourer, Rudge Bi frame folder, Longstaff trike conversion on a Giant XTC 840 :D
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531colin
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Re: 22.2 mm. stem into 25.4 mm steerer?

Post by 531colin »

You have to be sure the shim is in the bit of steerer tube where the stem wedge tightens.

The free solution is to scrounge an old pair of forks with a one inch steerer and use (some of) that steerer as your shim....leave just enough thread at the top so you can fit the old headset locknut, and cut a slot in the shim where the stem wedge goes to just under the locknut.....maybe with 2 hacksaw blades in the saw frame.

Its such a pity that generations of people have been deprived of our engineering heritage by a fashionably forward-looking education system.
A one inch steerer has walls one-sixteenth of an inch....so the hole in the middle is seven eighths of an inch....."converted" to a daft 22.2mm
Inch and eighth steerer with the same one sixteenth walls has a hole in the middle precisely one inch, so an inch steerer will telescope into it.

Guess what? Steel, Ali and even titanium tubing is still made in imperial (inch) sizes.....thats why we talk about ridiculous metric measurements.....why in the name of sanity would anybody deliberately set out to make handlebars 31.8mm diameter at the clamp?
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lettersquash
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Re: 22.2 mm. stem into 25.4 mm steerer?

Post by lettersquash »

rjb wrote: 15 Aug 2022, 8:01pm Your pics show a 1,1/8 system which utilizes a steerer with a 1,1/8 external diameter and a 1" internal diameter. Hence your confusion. The sjsc shim I linked to should suit your needs to accommodate the difference in diameter to enable you to use your 22.2 mm (7/8") stem. :wink:
Excellent - thanks for clearing that up. Although my confusion was partly due to the illogical spec of that shim, giving the impression that the number in parentheses was the same measurement, when they refer to different parts of the blumin' system!
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lettersquash
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Re: 22.2 mm. stem into 25.4 mm steerer?

Post by lettersquash »

531colin wrote: 16 Aug 2022, 1:06pm You have to be sure the shim is in the bit of steerer tube where the stem wedge tightens.
Yes indeedy.
The free solution is to scrounge an old pair of forks with a one inch steerer and use (some of) that steerer as your shim....leave just enough thread at the top so you can fit the old headset locknut, and cut a slot in the shim where the stem wedge goes to just under the locknut.....maybe with 2 hacksaw blades in the saw frame.
Hmmm, interesting idea - I hadn't thought of that. I was thinking I might make a shim out of a sheet of aluminium or steel, or I might even have a suitable tube knocking about (have to check thickness is about right)...or buy one of the shims for sale for the job (checking the position of the expanding part, as you say, or adapting it).

So I think I understand that the donor forks' locknut would then sit on top of my bike's locknut as a stop? I see the shims aren't just a split tube, but have a flange to locate them. I might try that. It's tempting to use the road bike's forks that the donor stem is from (or that I had used last in it), but the whole frame and forks might be worth too much to do that despite the condition, being a hand-built '80s racer by Guiseppe Marinoni. Time to hang around at the tip or go begging at bike shops!
Its such a pity that generations of people have been deprived of our engineering heritage by a fashionably forward-looking education system.
A one inch steerer has walls one-sixteenth of an inch....so the hole in the middle is seven eighths of an inch....."converted" to a daft 22.2mm
Inch and eighth steerer with the same one sixteenth walls has a hole in the middle precisely one inch, so an inch steerer will telescope into it.

Guess what? Steel, Ali and even titanium tubing is still made in imperial (inch) sizes.....thats why we talk about ridiculous metric measurements.....why in the name of sanity would anybody deliberately set out to make handlebars 31.8mm diameter at the clamp?
I agree, although the benefits of going metric outweigh the downsides, IMO. Luckily, the conversion is exact to a decimal place, but it would make sense to still use the imperial measures for things that are/were originally imperial. My dad was a mechanical engineer heavily involved in metrication coming in at the Central Electricity Generating Board.
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531colin
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Re: 22.2 mm. stem into 25.4 mm steerer?

Post by 531colin »

https://www.metalmaniauk.com/Stainless- ... ished.aspx
There you go...polished stainless....a pity to put it inside the steerer!

ID stated as 22.4mm .....probably best to put a vernier on your stem to check if its 22.2 or less!

They also have mild steel tube with the same stated dimensions.....the cynic in me wonders if it is actually the good old imperial inch tube with 1/16" wall gauge.

https://www.metals4u.co.uk/materials/mi ... ube/2321-p....not sure you need 3 metres!
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lettersquash
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Re: 22.2 mm. stem into 25.4 mm steerer?

Post by lettersquash »

Well, as a follow-up, I tried making a shim, but without great success, and decided to switch approach and change the bars instead. This is probably a better solution to the problem I was having - too great a reach to the bars, they're too short (about 25 cm wide) and straight, putting a strain in my wrists. The "new" one is slightly higher, longer, swept back and angled more, so it'll do the job. It's an old heavy rusty lump, but if I like the position I can get something similar in ally. The next problem is that it's made the short cable outer to the front brake even worse, so I'll have to replace that, but it could have done with it anyway. Thanks for you help everyone.
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