Technical FAQ with Lennard Zinn: Removing headset top caps, seatpost creaking, and more solutions to mystery creaks
Is it OK to ride without a headset top cap?
I noted a pro mountain biker who ran his fork without a top cap and bolt. When you think of it, the top cap is essentially a headset adjustment tool; once the headset’s tight, and the bolts are pinched on the stem, then you’re carrying around extra weight that you’re highly unlikely to use until the stem is loosened. Does the top cap perform any support function beyond its adjustment duties? I’m thinking of carbon steer tubes in particular?
No, it does not. Once you have your headset in adjustment, you can remove the top cap, bolt, and any spacers above the stem without experiencing a drop in performance or longevity. But of course, if you want to adjust your headset, you’ll have to replace those parts.
Creaking seatpost — solved! But why?
I have an issue with a creaking seatpost. My setup is a 2007 Look 585 size L, and I have been using the carbon Ergo Post provided by Look. My saddle is a Specialized Alias. While riding the bike in the early spring I had no problems with creaking. Not a peep. I decided to get a set of Speedplay pedals, and, during the fitting, I lowered my saddle significantly. This is when the creaking began. Anytime I put force to pedals, even minimal force, the seatpost would creak.
I tried a number of fixes like lubing the saddle’s rails, greasing the seatpost bolts, even a new seatpost (Al), etc. Nothing worked. And then one day while playing around with the saddle height, I noticed that the noise went away when the saddle was about 1″ higher than I normally would have it. I decided to cut the Aluminum seatpost down to its minimum insertion point, which took off about 4 inches of post. Miraculously, the noise has gone away.
Can you shed some light on why this is?
Yes, I can. There is only a section of the upper seat tube that fits tightly around the seatpost, and, below that, the tube flares out and has a larger inner diameter. If the seatpost extends much beyond that smaller-ID section, there will be movement of the end of the post inside of the seat tube, and that is what was causing the noise. Remove some length, and the noise goes away.
More creaking from all over
I posed a question to you a couple weeks ago regarding creaking coming from my Basso carbon bike. You suggested a shorter seatpost. A friend loaned me a short, aluminum Campy post and the results were immediate and positive. I rode for two days (not solid) with absolutely no creaking.
However, I’ve started to hear it again. Now I’m hearing it while both on and off the seat. I believe some of it is coming from the bottom bracket or crank area. This is a new creak. But, I also think the seat area is beginning to creak again. Certainly not as bad as before the short seatpost. And to make this more perplexing, these creaks seem to come and go with the weather. Morning rides are quieter than afternoon rides. Some days are better than others. It is still improved, but seems to get worse daily.
I’ll be looking into removing the seat tube sleeve and re-attaching it as you suggested. I love the ride of this bike, but the noise is a bummer. It hardly makes one feel lean and mean when your bike is crying for help.
There are a lot of possible causes. I’ve discussed bike creaks and noises many times in this column. In particular, if you don’t find a fix for your creak in this column, then look at the note below from a former warranty manager, and if not either of those places, write back.
More creaking explanations (and a few cures)
As a former warranty manager for a well known bike company we experienced two other culprits concerning mystery creaks especially with extremely thin-walled aluminum bikes:
- A good number of thin walled aluminum bikes have vestigial down tube shifter posts/cable guides that were neither welded or bonded to the frame but instead consisted of a fairly elaborate series of nuts and bolts so if any part of this system was loose it would resonate throughout the frame.
- Integrated headsets. We take for granted that these things are going to be installed and aligned properly from the factory. Wrong. Not only had I seen a good number of frames that had some gobby welding flashing left in the head tube but that additional flashing would either cause the headset cups to list one side or another and not cause the bearings to align properly or on the other hand cause a stress riser and eventually crack the entire head tube.
- External seat clamps. Yup, they move. Grease them collars because they move too even on road bikes. Just a dab will do you.
- Ti rail saddles. Creak.
- Open-face stems. Creak. Especially single-bolt pattern open-face plate stems.
- Minimally spoked bladed wheels. Creak. A lot of Shimano’s prebuilt wheels spokes would rub together and make a pretty nasty noise and that holds true for a lot of their clones from the Far East.
- Ti quick releases. Creak.
- Carbon headset spacers. Creak.
- Double check with your stem and steer tube interface especially with bikes that have a full carbon steer tube. I’m working as a wrench again and I’ve seen a lot of people try to jack up their handlebars by adding spacer after spacer under their stems in order to make them higher. The problem is that when you exceed the maximum height requirements on a lot of these forks that the top portion of the steer tube is not supported and can be easily crushed even while using a torque wrench. Secondarily with stems like some of Ritchey’s designs (not to unduly single them out but since they are common they will have to do) that are essentially hollow and have a big gaping space between the steer tube clamping mechanism and where the stem is the steer tube will take the path of least resistance and will be forced into that cavity. (OK, just look inside there boys and girls, I’m a bike mechanic not an English major).
- Your bike may not be made properly to start off with. Gasp! Sorry to burst your bubbles but there are some just poorly made frames out there. Most come from factories, not individual craftspeople. Sometimes there just aren’t any ways to see that until they break.
Readers can send brief technical questions directly to Zinn.
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Technical writer Lennard Zinn is a frame builder (www.zinncycles.com), a former U.S. national team rider and author of numerous books on bikes and bike maintenance including the pair of successful maintenance guides “Zinn and the Art of Mountain Bike Maintenance” – now available also on DVD, and “Zinn and the Art of Road Bike Maintenance,” as well as “Zinn and the Art of Triathlon Bikes” and “Zinn’s Cycling Primer: Maintenance Tips and Skill Building for Cyclists.”Zinn’s regular column is devoted to addressing readers’ technical questions about bikes, their care and feeding and how we as riders can use them as comfortably and efficiently as possible. Zinn’s column appears here each week.