A little while ago I replaced the bars on my pug with some wider ones; to make this easier I also bought a quill-to-threadless stem adapter. (I then set about taping the bars with a moderate degree of success.)

The finished product looks like this, including the stem adapter:


Now, I also submitted this picture along with a review of the adapter to the website where I bought it from. I then received this email from them:
_____________________
Hello Daniel,
Thank you for reviewing your Profile Quill to Ahead converter. I noticed on your submitted image that you have a gap left just below the stem. Normally you would insert the quill section into the frame completely so that your stem rests on the top of the headset. This prevents any chance of the stem slipping down the ahead mounting point or the quill slipping down the inside of your steerer tube. I may be looking at your set up incorrectly but just wanted to be sure that you are aware of the risks. Do let me know if you need any help with this.
Thank you

Now, I'm not sure about this; I actually don't see a problem with the way it's set up. So I sent this reply:
______________________
Many thanks for your mail, I appreciate the time you have taken to write it.
However, I'm not sure your concerns are justified. The quill is no more likely to slip inside the steerer tube than a regular quill stem of the kind that was on the bike before; one of the advantages of a quill stem is, after all, that the can be raised or lowered, and then tightened into position.
I suppose it's possible that the stem might slip on the converter, but this too seems unlikely. Whilst we are used to seeing such stems resting on spacers, the primary purpose of the spacers is actually to prevent the steerer moving up and down with a threadless headset - it is the clamp action of the stem that holds the forks onto the bike (something that is done by the locknut on a threaded headset). The stem is no more likely to slip down the adapter than, say, the bars are to slip round in the stem (in fact it is somewhat less likely, given that the turning moment of the bars is on axis with the clamp, whilst for the stem would be against it, thus pressure on the bars would tend to jam the stem against the adapter).

As such, I don't think there is a problem. The quill is inserted to the 'minimum insertion' mark, so it seems it was designed to be used in this way (otherwise the 'min insertion' mark would be just under the lip of the top part of the adapter). It does look a bit odd, I agree, but that's simply because we're not used to seeing an oversize stem fitted to a narrow quill. However, I'm confident there is no mechanical risk from this arrangement, provided all the bolts are tightened to proper tolerances.
______________________

So - what do you think? Am I correct, or does the stem need to be resting on the headset locknut? It's worth noting that I actually doubt I'd be able to get the quill adapter any further into the steerer; it was a tight fit and difficult to get down as far as the 'min insertion' mark. And if I did get it lower, then the bars would be too low, unless I then bought a stem with a huge rise angle.

Anyway, I await the superior skill and knowledge of the SydneyCyclist community!

Views: 3082

Tags: advice.stem, heaset, question, quill, safe, unsafe

Comment by Bob Moore on February 7, 2010 at 3:22pm
I would say you were right if it still a quill set up, with an expander wedge thingo inside. I cant quite see what the converter does. Is it just to allow for a narrow quill to fit a larger stem clamp?

i know that with an aheadset you are supposed to leave the stem untightened until after you tighten the ahedset bolt, so the steerer is clamped by pressure down through the stem and any spacers.

Good ol Sheldon has an interesting variation, where he used another collar clamp to tighten the headset down, thus allowing adjustability of the stem up and down, and even removal of the top bolt.

Comment by Dan on February 7, 2010 at 7:31pm
Yep, it's a quill - here it is:

Comment by Doddsy on February 7, 2010 at 7:43pm
Ive seen a few quills snap and its not pretty. losing control of your body weight over the front of your bike.

Its been a couple of years since i've been exposed to them but it seemed the problems with quills was that they were all cheap, weak and garbage.

I'm not sure if people make good quality quills these days but steel is real,
Comment by Paul on February 7, 2010 at 8:51pm
Dan, I have exactly the same Quill Adapter as yourself, and I set it up exactly the same way:


I had it inserted into the steerer tube well past the minimum insertion point, and I thought this was just fine. A guy at work saw the photo and said I should push it all the way in as far as it goes. I also don't understand why the quill has a minimum insertion mark if you are supposed to push it all the way in!

Anyway, I personally don't have an issue with having it with 2cm of the narrow part of the quill sticking out. It still has plenty more of the quill down the tube.

Maybe some people are misunderstanding what this thing does. It allows the use of a standard 1 1/8" Ahead Stem on a 1" threaded headset. That is why there is a "narrow" bit on the quill, and a thicker bit at the top. This gives a much larger selection of stems and handlebars as it is almost impossible to source a quill stem with a 31.8mm bar clamp, and the available choices in 26mm bars are very limited.

Anyway, as a precaution I have now paired the quill with an Oval 710 Adjustable Stem to get the extra height
Comment by yogi on February 7, 2010 at 11:16pm
When I use a quill and I do sometimes when I wanna use risers with a road frame with a 1 inch head tube



I use a head lock kinda item too...

Comment by Paul on February 8, 2010 at 7:29am
Yogi, how does that head lock thing work? I can't see how I would attach this to a 1" threaded headset
Comment by James Gray on February 8, 2010 at 12:00pm
I'm not sure why there would be a problem, quill stems were used for decades without the stem 'resting' on the headset locknut and the reason that threadless stems have spaces is not about holding the stem up but rather allowing it to preload the headset bearings. I have the same setup on my road bike with a gap between heaset and stem.
Comment by baa baa on February 8, 2010 at 6:35pm
Is the Pug off to the Paris–Roubaix??

If not, I call safe.

I use one of those extra long 225 mm nitto technomic quills on my "gentleman’s bike" run out to the full length so if you have a problem I should really have a problem.
Comment by Ant Edwards on February 13, 2010 at 11:39am
HI Good topic.
I have a few of these converters, one in regular use on my steel road bike, and you are correct in your current set up. However an old bike pirate pointed out that the wedge needs to be orientated in a particular way inside the steerer. They are designed to load only one way and with a round upper you might have it wrong. Just copy off a quill to get the wedge where it should be.
Regards
Ant
Comment by Dan on February 14, 2010 at 1:52pm
Thanks for the comment, Ant. I wasn't sure if the orientation would matter or not, but just to be sure I put it in to match the old quill, so all is good!

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