Chris King Threadless Headset Keeps Loosening

[PaulE]

The 1-1/8 inch Chris King threadless headset keeps loosening on my HSG with S-3 fork. I tighten it up using a torque wrench to 7 NM and everything is good for a few rides and then it starts to get a little loose.

This is a list of everything in the headset/steerer tube:

Chris King 1-1/8" threadless headset and stem cap.

Internal Expansion Plug similar to those sold by Aspire Velotech that accepts a Chris King stem cap.

3 Serotta Carbon Fiber spacers - 2x1 cm + 1x0.5 cm between headset and stem.

Deda Zero 100 Servizio Corse stem.

The Deda Zero stem says the maximum torque for the steerer tube clamp is 8 NM. I know that is the maximum torque for the stem bolts, not the carbon steerer tube of the fork, so I've been tightening it to 7 NM.
I'm wondering if one of the following may be the reason my headset keeps loosening:

Maybe the carbon spacers are not such a good idea and I should switch to aluminum spacers.

Maybe I should move the 0.5 cm spacer on top of the stem.

Maybe I need to make the expansion bolt a little tighter and the stem cap a little tighter.

Maybe I should tighten the stem to 8 NM.

Maybe the Deda stem is not the best for clamping this steerer tube and I should switch to another stem.

I bought the frame, fork and headset used with extremely low miles and the headset was installed by a professional. The stem was brand new when I installed it.

Thanks in advance for any tips on helping me keep my headset tight for more than 100 miles at a time!

[tuscanyswe]

Im guessin your expander is slipping, just seems most likely.

[David Kirk]

As long as the steerer is a few millimeters shorter than the headset/stem/spacer stack (so the steerer is recessed a few mm below the spacers on top) the only thing that matters is that the stem firmly clamps the steerer.

The top cap only sets the headset preload - it's the stem that maintains it. The spacer material will not matter at all.

So what you have happening is that the stem slides up the steerer just a bit allowing knock in the headset. Are you using a carbon paste between the stem and steerer? If not, you should be. It will take care of it 99.9% of the time.

Carbon paste and correct steerer length/spacer count and you should be all set.

dave

[tuscanyswe]

Davids post makes more sence ;D

Those times i thought i tighten the expansion and fixed the problem i prolly just reinstalled the stem with more torque aswell.

[dave thompson]

Move the 5mm spacer on the top of the stem. Bet that will cure it.

[PaulE]

I'm going to give try carbon paste first. The top of the steerer tube is a few mm's shorter/recessed a bit from the stem and spacers. I have carbon paste but so far have only used it to stop the seatpost in my CSI from slipping. (It works for that too!)

[Mike748]

Move the 5mm spacer on the top of the stem. Bet that will cure it.

I second this idea and do it on all (both) my threadless bikes. It allows the full length of the stem to clamp the steerer. Also less likely to crush the open end of the steerer.

[sbparker31]

I was having a similar problem on my bike (same setup by the way, S3 fork, Deda stem Chris King headset). I didn't have the expansion bolt tight enough, and it was slipping up. I just reinstalled everything, tightened the expansion bolt a bit more, and no more problems. I think reinstalling with carbon paste is a good idea as well.

[David Kirk]

I'm going to give try carbon paste first. The top of the steerer tube is a few mm's shorter/recessed a bit from the stem and spacers. I have carbon paste but so far have only used it to stop the seatpost in my CSI from slipping. (It works for that too!)

IMO everyplace where carbon is clamped by something there should be carbon paste. It dramatically lowers the amount of torque needed to hold stuff in place. I for one can not think of a single downside to using it.

Brake levers to carbon bars, seatpost in frame, bars in stem all get the paste.

dave

[11.4]

Here are the things that can cause problems:

1. The insert inside the steer can slip. Old star-nuts rarely slipped but the new o-ring models and such do so all the time. And as forks get lighter, the wall thickness of the steers is shrinking so you can't tighten up the internal nut as much.

2. The stem isn't tight enough. Carbon paste helps a lot.

3. The stem clamps on the top of the steer and the top of the steer collapses slightly, allowing the stem to creep up on the steer. This is solved by making sure the steer actually sticks up higher than the stem by a few millimeters.

4. The spacer(s) can be badly cut. I find this all the time. I basically just go with the ridiculously priced Chris King spacers because the facing surfaces are perfectly co-planar, all the time. I see big problems with carbon spacers. What happens is that one side of the stem fits tight against the spacer while the other side of the stem is loose, so as you ride, you end up levering the stem up slightly.

5. Is your crown race down all the way? I often end up with a new bike that has a crown race that wasn't seated all the way. With weight on the bike, it does settle down, but each settles, it loosens the headset.

6. Your stem is helped by the top cap bearing down on it. Now if you clamp the stem onto the steer but the top cap ends up bearing down on the steer rather than on the top of the stem (or on a spacer that bears on the top of the stem), you can tighten all day long and the stem itself is bearing the full load of any stresses on the steer-stem connection. Be sure your top cap bears down directly through to the top of the stem proper.

[dave thompson]

I have to put in a plug (sorry for the pun) for the Specialized Steerer Expander Plug. These things really work! Almost 2 inches long, further strengthening the steer tube/stem junction area, knurled surface for excellent grip, completely self-contained including a top lip to protect the edge or your carbon steer tube and best of all.....$10 MSRP!

I use the Specialized plugs in all my bikes, simple and easy to use.

http://www.specialized.com/us/en/bc/SBCEqProduct.jsp?spid=56854

[cfox]

Your problem, I'm guessing, is the Zero 100 stem. I love Deda products, but I have had horrible luck with that model stem. I have had/seen a few examples where it wasn't possible to keep that thing in place, even with carbon paste. There seems to be a wide range of tolerances for the bore. I have had 2 where the stem could rattle around very loosely on the steerer before tightenting.

Also, 7nm is an awful lot of torque for a carbon steerer. If a stem requires any more than 5 to 5.5nm to stay put, esp. with carbon paste, I'd say the stem is a problem. The 8nm printed on the stem is the max the stem bolts can take before stripping, not the recommended torque for the steerer tube.

[oldpotatoe]

The 1-1/8 inch Chris King threadless headset keeps loosening on my HSG with S-3 fork. I tighten it up using a torque wrench to 7 NM and everything is good for a few rides and then it starts to get a little loose.

This is a list of everything in the headset/steerer tube:

Chris King 1-1/8" threadless headset and stem cap.

Internal Expansion Plug similar to those sold by Aspire Velotech that accepts a Chris King stem cap.

3 Serotta Carbon Fiber spacers - 2x1 cm + 1x0.5 cm between headset and stem.

Deda Zero 100 Servizio Corse stem.

The Deda Zero stem says the maximum torque for the steerer tube clamp is 8 NM. I know that is the maximum torque for the stem bolts, not the carbon steerer tube of the fork, so I've been tightening it to 7 NM.
I'm wondering if one of the following may be the reason my headset keeps loosening:

Maybe the carbon spacers are not such a good idea and I should switch to aluminum spacers.

Maybe I should move the 0.5 cm spacer on top of the stem.

Maybe I need to make the expansion bolt a little tighter and the stem cap a little tighter.

Maybe I should tighten the stem to 8 NM.

Maybe the Deda stem is not the best for clamping this steerer tube and I should switch to another stem.

I bought the frame, fork and headset used with extremely low miles and the headset was installed by a professional. The stem was brand new when I installed it.

Thanks in advance for any tips on helping me keep my headset tight for more than 100 miles at a time!

Headtube prepped? Faced?

[Louis]

Does anyone know if these Specialized plugs would also work in an Alpha-Q fork in place of the glue-in insert that comes with the fork?

If so, I'd much rather use that than permanently glue the Alpha-Q sleeve in place.

TIA
Louis

I have to put in a plug (sorry for the pun) for the Specialized Steerer Expander Plug. These things really work! Almost 2 inches long, further strengthening the steer tube/stem junction area, knurled surface for excellent grip, completely self-contained including a top lip to protect the edge or your carbon steer tube and best of all.....$10 MSRP!

I use the Specialized plugs in all my bikes, simple and easy to use.

http://www.specialized.com/us/en/bc/SBCEqProduct.jsp?spid=56854

[dave thompson]

Does anyone know if these Specialized plugs would also work in an Alpha-Q fork in place of the glue-in insert that comes with the fork?

If so, I'd much rather use that than permanently glue the Alpha-Q sleeve in place.

TIA
Louis
One of them should. Black expander is 23.4MM, the red is 22.3MM/ Measure the i.d. of your steertube and order accordingly. I've found that the Specialized dealers usually have these things. If not, they can get them quickly and easily.

[tuscanyswe]

Im sure you can get an expander to fit into the alpha fork I wouldent use an alpha without the glue in insert but thats just me. It was designed with the insert in mind and may even have a strenghtening effect on the steerer itself i dunno.

Maybe they made the steerer thinner cause they know it will have an insert glued in anyways?

[cfox]

Maybe they made the steerer thinner cause they know it will have an insert glued in anyways?

I believe this is the case...aplha q's are thin. I'd glue in the spacer.

[djg21]

I second this idea and do it on all (both) my threadless bikes. It allows the full length of the stem to clamp the steerer. Also less likely to crush the open end of the steerer.


I agree, and also think the carbon spacers are silly. I prefer the machined Chris King spacers.