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Quill stem installation question - how deep?(10 posts)

Quill stem installation question - how deep?eflayer
Dec 14, 2002 11:12 AM
When installing a quill stem, is it required that the entire wedge be in the headtube? I have 2.5 cm of spacers and with a Salsa quill the wedge would be in the threaded spacer area and not down into the headtube. I know I could get a long quill Nitto, but I like the look of the Salsa on this bike. Is it safe to have the wedge in the spacer area above the head tube?
Boy, this is confusingKerry
Dec 14, 2002 12:51 PM
Quill stem must be insterted to the line on it that says "min." or something else suggesting the minimum insertion depth. The line may not be marked with any words, just a line around the stem. Typically this is 1" or so above the top of the wedge. In other words, the stem should be inserted 1" deeper into the steerer tube from when the top of the wedge is flush with the top of the head set.

Now about those spacers. What are you talking about? I've never seen spacers used with a quill stem. The top nut of the head set threads onto the steerer tube, and the stem is inserted into the steerer tube. Maybe a 2mm washer between the adjustable cup and the top nut, to adjust for stack height, or up to a cm if you have a super low stack head set and a steerer tube cut for a regular stack height HS. But 2.5 cm of spacers? You'll have to explain this one to me!
explanationeflayer
Dec 14, 2002 12:58 PM
Chris King makes a headset that allows you to have spacers on a threaded steerer just like you would on a threadless steerer. So my question is about whether or not the quill wedge can be in the steerer tube above the top of the head tube or does it need deep enough so it is below the spacers and down into the head tube. Sounds like there is concern about whether the steel of the steerer is strong enough to handle the forces of the tightened wedge??
Two issues with insufficient insertionKerry
Dec 14, 2002 1:21 PM
- excess torque on the stem if the quill is farther out
- concentrated force on the steerer tube

The second problem is not primarily from the wedge tightening forces, but from the fact that all of the forces on the handlebar are concentrated in a very short section of the steerer tube. The first problem can be more easily visualized if you think about these forces being borne not by the full cylinder of the stem, but by a stem tube that is sliced diagonally. If your bike doesn't fit with the stem you have, then you need a new stem - you're courting disaster with your approach.
You missed the worst thing about insufficient insertion...Uncle Tim
Dec 15, 2002 3:15 PM
...She may get mad!
re: Quill stem installation question - how deep?Andy M-S
Dec 14, 2002 12:51 PM
Deep. Ideally, you want the top of the wedge below the threaded section of the fork steerer tube. That wedge puts out substantial stress, and you really do not want your steerer tube breaking.

There are a few stems other than Nitto that come with longish quills; I like the ITM Goccia these days, but I don't know if even that would be long enough for you.

Play it safe on this one. If things go wrong up front, they go very badly wrong.
Complete instructions please...Skyeward
Dec 14, 2002 2:38 PM
I'm about to install a new threadless stem. It seems pretty simple, but I would like to know the proper (detailed) precedure since, like others said, messing up in this area is bad news. It has a wedge type bolt. So do I just loosen the bolt on top of the old stem, pull it out, insert the new one to at least the minimun height, and tighten the top bolt again?

Thanks a bunch,

Skye
Threadless with a quill bolt???Rusty Coggs
Dec 14, 2002 3:09 PM
Are you talking about a quill adapter and threadless stem on a threaded system? If not,you got me.Threadless stems ,at least any I have seen, don't have a wedge bolt,they clamp to the steerer,or quill adapter if that is what you are talking about.Maybe www.parktool.com has the drill,on complete instructions. A thrreadless systen uses a star nut or some type of compression expander down in the steerer tube.the nut in the topcap of the threadless stem threades into the device in the steerer and sets the bearing preload in the HS.The stem is then clamped to the steerer with one or more bolts.
OOPS, I meant threaded...Skyeward
Dec 14, 2002 3:47 PM
Sorry for the confusion! I meant to say threaded. But I am actually installing a quill adaptor with a threadless stem on a threaded system. I assumed that the adaptor would install the same as a quill stem, so I decided to just say I had a quill stem to avoid confusion. Looks like my lack of proof reading had the complete opposite affect! Anyway, what I really need help on is uninstalling the old stem, and installing the quill adaptor.

Thanks
OOPS, I meant threaded...Rusty Coggs
Dec 15, 2002 7:40 AM
The old one comes out by loosening the center bolt. Sometimes the bolt needs to be loosened to above the level of the stem and given a whack to loosen the wedge or plug,at the base of the quill. Grease the new one. Honor the minimum insertion mark. Tighten center bolt. Tighten new stem to adapter. Tight enough is good.Too tight can cause stripped threads or broken bolts.