Hey everyone,

I have an older fillet brazed Jamis Diablo (1988) that I'd like to rebuild from a rigid mountain bike into a dirt drop/commuter setup. It has a threaded, rigid fork, and Tioga headset.

I assumed that the quill stem post (where it inserts into the steerer tube) diameter should be 22.2mm. When I got out the dial caliper and measured at multiple points, I am getting exactly 22mm - if I open my caliper to 22.2mm I definitely have a minute amount of play between the caliper arms and the stem.

Is this typical? I know some older French bikes like my Motobecane take a 22mm stem, but was suprised to get a 22mm reading on a late 80s mountain bike. Do stems vary by a couple tenths of a mm typically?

I am getting measurements of 22.0mm stem diameter and 25.4mm clamp diameter for the stem (which makes sense).

I'd prefer to get a nice 22.2mm Nitto dirt drop stem with a 26mm clamp size to fit the Nitto Dirt Drop bars, but if I really have to go with 22mm options I'll be stuck with a threadless adapter.

Thanks for any insight!

Is there no marking on the stem? And do you have another stem to try? Because that would be weird if it were specced as 22.0mm.

Unfortunately I don't have another 22.2 quill stem lying around I could try. The stem has no markings other than "Jamis" on the neck and the marks for the minimum insertion depth.

Have you measured the ID of the fork? Maybe there is space for a 22.2mm quill but the OEM stem is just undersized.

^I hope this is the case - I had just repacked the bearings and correctly tensioned the headset and locknut when I decided to actually measure it before ordering parts last night. I couldn't get a good measurement of the ID of the fork steerer with the locknut installed as there is a rubber washer in there to prevent grime from getting in. I am unsure if the ID of the locknut is the exactly the same as the ID of the fork as well. I guess I'll have to pull it apart and check that next. I was wondering if maybe it was common for 22.2 quills to measure closer to 22.

Another possibility is that some early MtB bikes used the "American" (these days I should really say "USA") 21.15mm stem diameters, a left over from decades of US bikes and Wald/Schwinn like products. (Ross was another who used this spec). With a simple caliper the measuring is easily drifted a bit from the actual. This is why afterr the thousand of assumptions and the one measurement, a trial fit tells all. Andy

another possibility is that the caliper is not 100% accurate?

Agreed. The cheap calipers tend to have a bunch of slop in their movement. Additionally don't forget that if you ask 10 people to measure something with the same device it's often that you end up with 11 different claims Andy

I've seen the odd bike with a 22.2" steerer tube but with a top lock nut from a 21.5 headset.

Cheers

Yes so have I. But when one says they measured a steerer ID you have to hope that they know the difference between the steerer and the top nut Andy

I've seen far to many who measure at the top lock not and assumed it was the same as the steerer tube. I NEVER assume what people might do when it comes to working on a bicycle.

Cheers

Yes, My reply was a tad tongue in cheek. I should have added more then a smile to indicate that. Andy

since this thread came up in my search, i'll tag on to it.

i just measured my Raleigh (1983 super record mixte) stem and got .860" / 55/64" for stem diameter. used a carbon infused General brand dial caliper.

internet conversion table tells me it's 21.844 mm.

anyone suggest a short reach stem to fit this steertube

anyone suggest a dropped randonneur bar around 17" to fit it?

thanks

Something is screwy there. Old Schwinns and Ross bikes had 0.833" stems, which is 21.15mm or so. Old french bike had 22.0mm. The Raleigh should have the standard 22.2mm.
Try to stuff a standard 22.2mm stem in there and see if it fits.

the man @ Modern Bike told me to measure the steer tube inside diameter. then helped me navigate to their quill stem page.

this has become tomorrow's project!

stay posted . . .

It might help to know thsy Jamis is only a brand label, and has no factory of their own.

They source bikes and put their labels on them. So, assuming you measured correctly, it implies that this bike was made in France. Or that it's a replacement fork made in France.

The other possibility is that a prior owner replaced the stem with a French one. Check the steerer ID to confirm and follow through accordingly.

Necropost - the person who revived it is not asking about a Jamis ... why does anyone think it's a good idea to do this?

I HATE ******* ZOMBIES!!!

So, re. the Raleigh.

It's reliably 7/8" (22.2,mm)

This is so reliable that you could use it to check the accuracy of your calipers. The fork is 1"OD with a 1/16" wall thickness, so also 7/8".

If you come up with anything else, either your caliper is off, you're not using it correctly, or your bike has non original parts.

because some other inmate will come out with the statement "use the search function".

so i did, and this is what you got.

you can only satisfy so many people in life. you are not on my short list.

anything helpful to add?

i'm getting mixed messages here.

your hate is so great, yet you still find compassion to help. hmmmm .........

well, since this is really all about me,

thank you for the help.

Yes the search function is for finding out if someone earlier had the same issue, and a solution was posted.

However, if you don't find a useful answer, and wish to post, then you're better off starting a new thread rather than waking up a zombie.

So you found a years-old post that wasn't actually relevant to your question, yet thought it was helpful to revive it, tacking your own query on the bottom where many people won't see it because they answer the OP's question, not yours? When an apparently new post arrives in the "recent activity" list most people won't look at the date, they'll just assume it's new and read the subject line, and if they're interested they'll read the first post in the thread, perhaps answering it. So a significant proportion, perhaps the majority of responses you see will not be answering your question. You've reduced the quality of responses you receive, and annoyed at least some of the people who were actually trying to be helpful. If you think that's a smart way to conduct yourself then by all means carry on.

too long; didn't read