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-   -   Minimum insertion length for nitto technomic (https://www.bikeforums.net/classic-vintage/984054-minimum-insertion-length-nitto-technomic.html)

himespau 12-02-14 11:47 AM

Minimum insertion length for nitto technomic
 
Odd question for you all. How far up from the bottom should a nitto technomic stem be inserted into the head tube? I picked up a stem at a good deal, but it appears to have been too long for a previous owner who cut it shorter. The angle looks like a good match for the expander, but the top of the angle of the cut is slightly above the minimum insertion line. So how much higher than that should I make my new minimum insertion? Any ideas? I don't have a technomic handy that I can just measure from the bottom to the minimum insertion line (would that be a sensible idea if I did have one?).

rootboy 12-02-14 12:04 PM

Odd problem indeed. If it were mine, I think I would make sure the expander wedge was just below the threaded portion of the steerer. Or maybe more if you have enough to work with. Do you feel the mod that has been done to this stem still makes it safe?

Ciufalon 12-02-14 12:08 PM

Does this help at all? You might also look at the last question and reply at the bottom of this page.

himespau 12-02-14 12:08 PM

Since the angle matches up, I think it looks safe still (unless the bottom has more reinforcements that I don't know about and are lacking here). I'm not sure why one would do this mod and not just go with a smaller/lighter stem. At least I think it's a mod. It turns out it wasn't the minimum insertion line that I saw (really faded), but the notation saying "For 26.0" that's right at the bottom of the angle and almost cut off. Was there a shorter version of the technomic that I'm not aware of?

The Golden Boy 12-02-14 12:11 PM

Interesting question. If it looks like it's cut well, I'd imagine it would be the same distance as any ordinary stem with the same expansion bolt/wedge system.

I had a big tall Dirt Drop- and even when it was slammed down, it was just too tall. I ended up using a regular Dirt Drop and I believe that big one worked out really nice for someone here.

himespau 12-02-14 12:12 PM


Originally Posted by Ciufalon (Post 17356558)
Does this help at all?

Well, that says they're about 240 mm total height (for some reason I'd been thinking 220), and mine is ~195 mm at the longest, so that's a difference of 35 mm. It also says there is ~160 mm above the insertion line, so I could estimate that I could have ~125 mm above the minimum of where I should insert it, but I'm thinking rootboy's suggestion of holding the stem up to the fork and drawing a line where the expander would be below the threads and calling that my minimum insertion height would be the way to go (assuming it is still tall enough for what I need).

Velocivixen 12-02-14 12:18 PM

I've got multiple Technomics but they're all in the bikes! I'd venture to say 2-3" should be in the head tube or at least that's where the mark is up from the wedge.

Ciufalon 12-02-14 12:20 PM

Here is another link I just added. See last question/answer at the bottom of the page.

ham 12-02-14 12:34 PM

Just measured one I have laying around and the min insertion mark is 75mm from the bottom.

brian3069 12-02-14 12:36 PM

I have a Technomic stem, from the minimum insertion line to the bottom is 65mm.

himespau 12-02-14 01:08 PM


Originally Posted by ham (Post 17356651)
Just measured one I have laying around and the min insertion mark is 75mm from the bottom.


Originally Posted by brian3069 (Post 17356659)
I have a Technomic stem, from the minimum insertion line to the bottom is 65mm.

gracias. good to know my estimate was in the right ballpark.


Originally Posted by Ciufalon (Post 17356601)
Here is another link I just added. See last question/answer at the bottom of the page.

Hmm, so there was a 190 mm technomic deluxe. That'd be roughly the right size for what I have but this isn't more shiny than another technomic that I used to have (though I suppose wear could have removed the finish over time).

due ruote 12-02-14 01:40 PM

I think, like rootboy said, getting the expander below the threads is the generally accepted principle to follow.

I can see the need to cut a Technomic if you have a small frame, need the height of the stem, but not all the available height. Slamming the stem all the way down could result in putting the expander in the butted portion of the steerer, which isn't a good idea. The obvious solution would be to shorten the stem.

Hands Up (Or Down)! Adjusting Handlebar Stem Height on Your Bicycle

AZORCH 12-02-14 04:36 PM

I just read this somewhere yesterday - Sheldon, maybe? -anyway, minimum is 2 inches.


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