Workshop: How to replace a headset
By Ian Collins, Mountain Biking UK | Wednesday, July 15, 2009 8.00am
Headsets tend to get a fair battering. They’re in the direct line of fire of everything that gets thrown off the front wheel and are subject to regular jet-wash abuse. Last month we showed you how to service a headset. This month we're showing you what to do if it's too late for that and your headset needs replacing. This guide will also help if you're fitting a new fork.
Previously, headset replacement was a bike shop job, but you can now buy an affordable headset press and do the job in the comfort of your own kitchen. Make sure you do it right, as ham-fisted fitting can seriously damage – and even write off – your frame.
Time: 40 minutes
- Headset press
- 5mm Allen key
- Slide hammer (optional)
- Teflon grease
- Headset cup remover
- Block of wood
- Crown race remover (optional)
- Large flat blade screwdriver
- Torque wrench
Step-by-step guide to replacing a headset
1 A workstand will make life a lot easier for this job. Without one it’s going to be a case of scrabbling on the floor on your knees. Remove the front wheel. Remove the front brake caliper from the fork. Remove the guide or the zip tie holding the brake hose onto the fork too.
2 Now remove the stem. If the stem has two bolts holding it onto the steerer, then loosen the bolts a quarter turn each at a time in sequence. This makes it much easier to undo the bolts and avoids the potential damage caused by overloading one of the bolts. Remove the gear cables from their slotted stops and unclip the rear brake hose. This helps to keep the bars clear of the head tube for fitting the new headset.
3 Remove the top cap while holding onto the fork so it doesn’t drop out of the frame. Remove the stem and bars as a unit and place them clear, making sure you don’t pull or kink the rear brake hose. Remove the headset spacers and withdraw the fork. The fork may need a tap on the end of the steerer with a rubber mallet to get it moving.
4 If you don’t have a headset cup remover, then it’s bodge time. Since you’re replacing the headset it’s already knackered, so it doesn’t matter if you damage it. Get a large hammer and either a length of metal bar or a large flat blade screwdriver, and knock them through. Place your bar or screwdriver on the lip of the cup on the inside of the head tube. Move a little at a time, hitting at 180 degrees to ‘walk’ the cup out.
5 If you don’t have a crown race remover, it’s bodge time round two! Place the fork upside down with the steerer resting on a block of wood. Grab a large flat blade screwdriver and hammer. Hit the crown race collar away from the fork crown. Similar to the last step, move it a little at a time, hitting at 180 degrees to ‘walk’ the collar off the steerer.
6 Clean the inside of the head tube and the fork steerer thoroughly. Once clean, apply a fresh coat of grease. Put a generous smear inside either end of the head tube where the new cups will fit, and on the entire length of the steerer. This will not only aid pressing in the new cups, but will also eliminate any creaking you may get from slight movements of the cups in the frame, or the fork within the headset.
7 Ideally fit the crown race with a slide hammer, otherwise it’s round three of bodge mania! Rest the crown of the fork on the corner of a workbench for a solid base. Slide the new crown race onto the steerer and place the old crown race upside down on top of it. Using a block of wood and a hammer, hit the crown race into place. Use the ‘walk’ technique again, hitting at 180 degrees, moving a little at a time.
8 Don’t try to fit your headset cups with anything other than a headset press. You could write off your frame by trying to bodge them in and useable ones are as little as £40, so don’t skimp. Place the cups on the headset press. Slot into position. Make sure the cups start straight, going slowly at first. Press them in tightly.
9 Now you need to grease the headset. Even if your headset has sealed bearings, a healthy amount of grease is needed. Grease inside the cups, on the crown race collar in the top cup. Fit the bearings to the cups in the frame, then add another layer of grease on top. Also, grease the cone and compression ring of the top cup.
10 Now fit the fork into the headset. If the headset has separate seals, make sure they are the right way round, and that they don’t get pinched when you slide the fork into place. Slide the headset spacers and the stem back on. If you’ve fitted a different headset, then you may need to adjust the spacing to suit. The steerer should be about 3mm short of the top edge of the stem. Leave the stem pinch bolts loose.
11 Put the front wheel back in and re-attach the front brake caliper, remembering to fit the hose into its retainer, or fit a new zip tie to hold it in place. Once you’re done, re-fit all of the cable and hoses back into their guides in the frame.
12 Re-fit the fork top cap. Use the bolt in the top of the fork top cap to adjust any play out of the bearing. Grab the front brake and rock the bike back and forth to feel for play. If there is, tighten it by 1/8th turn at a time, then re-check. There may be play in the legs of your suspension forks – put your fingers on the headset cups to detect the source of the play.
13 Once the headset is adjusted so that there’s no play and it moves freely, tighten the stem clamp bolts to the manufacturer’s recommended torque. Tighten each bolt a little at a time in sequence. When you next go for a ride, be sure to take a set of Allen keys, as it’s possible for a headset to loosen as everything beds into place.
Watch the video below on how to preload an Aheadset:
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