HOW TO FIX A LOOSE HEADSET

Troy's Tech Talk

RBA’s lead Tech Editor Troy Templin answers your questions.

Q: My bike’s fork and headset seem to come loose every few rides. What could be the problem, and is there a way to fix it?

A: There are a few things to consider when your headset seems to be coming loose. First and foremost, you need to have a steerer-tube compression plug (for a carbon steerer) or a star nut (metal steerer) installed. Sometimes when a steerer tube gets cut, the plug gets installed incorrectly or even missing if it was still in the portion that was cut off.

Once you have that sorted, then it is time to check your headset. Make sure you have the correct bearing contact angle. This is normally specified by the manufacturer and between 36–45 degrees. If this is incorrect, then the bearing will not fit in the frame correctly. Along with this you need to ensure the correct top and bottom bearing races are installed, too.

Next, you need to ensure there are enough headset spacers to elevate the top cap (by about 2mm) over the steerer tube so it doesn’t bottom out against the compression plug or steerer material. If you have a compression plug, make sure it is far enough in the tube that it works correctly.

Once everything is ready, install your stem and spacers in the order that fits your needs. Make sure the stem bolts are still loose and install the top cap. Slowly add tension while ensuring that the bearings are completely seated. In some rare cases the bearing’s top bearing cone/cap can rub on the frame and a small shim may be needed. To make sure things are seated, I like to have the bike on the ground and I hold the front brake while rocking the handlebars front to back. Then lift the front end and rotate the bars back and forth making sure there is no friction.

“If you still can’t get it, head to your LBS and tip them, because they will normally do it for free.” 

With everything set and tension on the system, it’s time to align your stem and torque the bolts down around the steerer tube. Once that is done, it will effectively hold things in place, so don’t tighten the top cap anymore.

In a few rare cases the compression plug is positioned too high and the stem isn’t clamping around it. This can cause the steerer to compress just enough that the stem moves a tiny bit. If possible, make sure the compression plug is in far enough that the stem clamps around it, this might mean cutting the excess
steerer tube off. Another problem is when you have a few spacers between the headset and stem, and they are very thin or lightweight.

Over time they compress, leaving slop in the headset. If you have more than one spacer and are over 10mm between the bearing and stem, then ensure they are substantial spacers. Alloy spacers normally offer the best results, but the correct carbon ones are fine, too, just stay away from the very thin ones that you can flex between your fingers before putting it on.

Last thing to remember is to loosen the stem bolts before trying to add tension to the top cap. If you don’t, the tension is not transferring to the headset; it’s just stopping at the top of the stem. With a lot of bikes adding internal routing through the headset or other widgets, make sure you check your manual for your specific bike, because it could have a proprietary system.

 

Q: I purchased a used bike during the pandemic as a way to get some exercise. It had clipless pedals, and I want to swap them for flat pedals to start, but I can’t get them off. What am I missing?

A: There are a few things that could make this difficult, but the main one is most people put their pedals on like they are Thor. They don’t need to be that tight. Many also install them without a pedal washer and grease, making things worse. This can make them very hard to remove later. On top of that, the left-side (non-drive side) pedal is also reverse thread, so you might have been tightening it if you didn’t know this. 

You will most likely need one of three tools—an 8mm or 6mm Allen wrench or a 15mm open-ended wrench. Some pedal systems will fit the 15mm, as well as the Allen, so it comes down to preference.

Allen-only pedals have to be tightened or loosened on the inside of the crankarm. As an extra safety precaution, make sure the chain is on the big ring to protect against shredding knuckles and forearms on the exposed teeth.

I always orient the pedal I want to remove near the bottom of the stroke and try to position the tool parallel with the ground. Then, you can carefully press or step on the end of the tool with the least amount of risk of hurting yourself.

If that doesn’t do it, carefully apply a bit of penetrating fluid to the spindle as close to the crankarm as possible. Try to not get any near the pedal itself, as it will get in the pedal bearings. I will normally do it on the inside for the least risk. Let that sit for a bit then start over. When installing your new pedals, make sure they are on the correct side. Both sides should spin forward to go on. If you still can’t get it, head to your LBS and tip them, because they will normally do it for free.

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