Quill Stem Minimum Insertion
 

Hi All,

So, I'm swapping out a set of bars and also looking to decrease reach by using a shorter (spare) stem. Have read that it's paramount that the stem's expander is below the threaded section of the fork steerer. Looking at the pics, would you say I need a stem with a longer post length then? Ideally I'd need a 80mm Nitto NTC-DX 190 Technomic Deluxe Stem to replace the 100mm but, well, spares shortage etc and it doesn't look as if Nitto make the 190 anymore. NTC-DX 225 are available aplenty but would be too long - 'dead weight.'

What you're looking at in the first pic is a Nitto that's 150mm long and at minimum insertion. Second pic the NTC-DX 190(mm) at minimum insertion and the third pic is NTC-DX 190 at the height I previously had it set up at.

Cheers & look forward to your views and comments.

Hmmm. Hit a snag as I can't post the pics until I've made 10 posts. Any tips on that before I delete this then?

Your pics didn’t make it.

Dan

Yup, that's right Dan. The forum's telling me that I'm not allowed to add pics until I've made 10 posts.

Looking back I last posted (including pics) on here in 2016. Time flies :lol: New forum rules then? As, like I say, I was able to upload pics 5 years ago. The post isn't much use without the pics, eh.

I hope the time passed so quickly because you've been riding!

Riding AND collecting and building more bikes ;)

Will this work I wonder? Link to my photos album on the forum

https://www.bikeforums.net/g/album/22982792

Let's try this then...


https://cimg0.ibsrv.net/gimg/bikefor...7015b08bb.jpeg
Nitto Technomic 150 at minimum insertion

Haha..ok... :)

https://cimg2.ibsrv.net/gimg/bikefor...d7de668df.jpeg
Nitto NTC-DX 190 Technomic Deluxe Stem at minimum insertion

https://cimg5.ibsrv.net/gimg/bikefor...019fa03a1.jpeg
Nitto NTC-DX 190 Technomic Deluxe Stem (as previously ridden.)

Yes, that worked.

If you're proposing inserting the stem until the minimum insertion line is inside the steerer, I don't see an issue. If this were an older stem without a minimum line, then I aim for the expander to be below the upper headset race, and inserted to at least 2x the diameter of the quill.

Also, big news! You've finally gotten out of your probationary period!

Many thanks for your reply! And the wedge expanding into the last few threads there...Not a problem you'd say?

So long as you're below the min insertion mark, you should be fine.

That minimum insertion line is for the top of the headset if that is what you are asking.

NOPE! Those last few threads should be well below the top race of the headset, or else you risk failing to preload the bearings adequately (loose headset) and/or needing a stack of spacers that look like a roll of quarters to keep the locknut from bottoming out. Don't over-torque the stem bolt and you'll be fine.

Thanks all! I'd previously read these threads (aha - a pun!) and that's what got me thinking/worried...

https://www.bikeforums.net/bicycle-mechanics/393861-threaded-fork-how-do-you-know-what-length-steerer-use-thread-length.html

https://www.bikeforums.net/bicycle-m...line-mean.html

https://www.bikeforums.net/6273808-post4.html

"The rule is that the quill should extend down far enough so the expander is below the threaded section."

Here's a diagram, to further expand the question ((hey, I'm on a roll with these puns now)


https://cimg8.ibsrv.net/gimg/bikefor...bf4d90ccc.jpeg

As mentioned above, just don't over torque.

A roll of quarters you say? :)


https://cimg6.ibsrv.net/gimg/bikefor...27aadc172.jpeg

...and the bike in question, by the way :)


https://cimg1.ibsrv.net/gimg/bikefor...0a75e0597.jpeg
Soma Grand Randonneur V2 650B


https://cimg8.ibsrv.net/gimg/bikefor...4210cb55b.jpeg

Don't know why you couldn't use quarters as spacers. There are versatile. When the governor spring on old two stroke Detroit Diesels would weaken, the accepted fix in the commercial fishing fleet was to just add a quarter as a spacer. You were good for 3 quarters before needing a new spring. No reason they wouldn't work in application here if needed, although on dry land you have the option of getting proper parts for the job.

Mike

Is this really a thing? Has anyone actually broken a steerer because the wedge is not below the threads?
On a lot of aftermarket/replacement forks, the threaded section is fairly long (to accomodate different sized frames). It would be hard to hew to this rule.

For example:
https://www.ebay.com/itm/30420237686...UAAOxyVLNSsgEChttps://cimg3.ibsrv.net/gimg/bikefor...8a804760b0.jpg

There's a lot of info pointing that way in the links I've posted above. It'd be interesting to hear if this had ever happened, for sure.

I'm sure there is mention of steerer tubes becoming ovalized by ham-handed mechanics overtightening the stem bolt. Threads that are cut into the tubing remove material which logically weakens the tubing and it's ability to withstand the force applied by an expander wedge. Since I'm not one to try and snap or strip the stem bolt, I use a torque wrench set around 120 in/lbs and tighten the bolt carefully. If I can't turn the stem inside the steerer by the handlebars while the front wheel is between my legs, I call it good.