I've been meaning to write this up since I replaced my headset a little over seven weeks ago, but have been just too busy. The headset remained the only component on a bicycle I had not replaced/rebuilt/serviced. However, I wasn't too excited about the prospect of doing it with the wrong tools; As far as I was aware to properly seat a new headset you needed one of these tools (sorry, one of these).
The headset had needed replacing for a couple of years. I first discovered it was knackered when I tried to tighten it up and the star washer just rose up and up the stem. Annoyingly this had occurred at work, but I somehow managed to fudge together enough of a repair to get home. I hammered the star washer back down and of course hammered it too far which meant struggling around to find a spare bolt. The only thing long enough with the correct thread was a blind head bolt from a trampoline. The bolt had a square boss under the head so I ended up, quite literally, fitting a square peg in a round hole on a bit of aluminium bracket that deformed well enough that the bolt seated in the bracket and I could then use this "tab" sticking out the side of the bolt to tighten it up with. Of course the underlying headset bearings were still completely knackered, but this meant I could at least tighten it up properly. And then scratch my leg on this tab over then next couple of years every time I was climbing and out of my seat.
This kind of frantic fudging together of anything at hand in order to keep my bike running sums up perfectly the level of budget I'm allocated for cycling. I guess it is just fortunate I don't derive my career from cycling. No, instead I'm only utterly reliant on cycling to get to work.
I had to loosen the headset for cold winter days, so it didn't freeze up and prevent me from steering, and re-tighten when ever possible so I didn't destroy it further. But even tightened the forks would back and forth a lot. This would cause me trouble with bike lights in winter.
I only managed to get away with such a knackered headset for so long because last winter was mild enough I could use my road bike for most of it.
With the demise of my roadbike I decided to strip it and see if I could use the headset from it to replace the one in my fixed gear. When I took my road bike apart the ball bearings just fell out of the headset - I knew it was worn as well, but I hadn't realised how knackered. Plus it was an integrated headset and not an internal (semi-integrated) one. So the time had come where I finally had to splurge out £16 for a new headset. For anyone else wondering, the correct part number for a Carrera Subway Zero is a FSA No. 11N Headset 1 1/8" (Hargroves list it as just an 11, but it's definitely an 11N). I'm not sure what the equivalent part number is from FSA current line-up, or indeed if there even is one, but since a lot of Halfords Carrera brand bikes have used these headsets they still stock them if you really can't find it anywhere else. Also, if anyone wonders whether a new headset comes with the crown race for the fork, it does.
Anyway, to replace a headset in eleven frustrating steps:
- Once the handlebars and stem are off, hammering is the recommended way of removing the forks (block of wood on top, normal hammer). But this may only get you so far if everything is as rusted together as mine so...
- Use an old chisel to help prise apart and up the spacer rings, but most of all the compression ring. In an attempt the previous year I hammered the forks out so far, but no matter how hard I hammered they stuck at a certain point. My forks had brinelled over the compression ring (due to the severe rocking) and this ridge prevented the compression ring from moving up. However, with a chisel I could lever and lift the compression ring up and over this which worked far better than hammering.
- With the forks out use a chisel and hammer to prise up and lever off the crown race from the fork.
- Sand the steerer tube of the forks down with sandpaper and/or a Brillo pad (it'll do "well enough" to improve any brinelling).
- Use a chisel and hammer (again) to ease and lever out the cups from the frame.
- The good thing about internal style headsets is that the cups will take all the damage. Really they are much better than integrated headsets where if you ride the bike for too long with a knackered headset you need a whole new frame! The cups on mine were completely deformed and wrecked; In one of mine the bearing could actually no longer rotate and so had only been working dependant on the headset being loose enough and with grease between the crown race and the bearing. But the frame was fine. I just gave it a bit of a clean out with sandpaper.
- Grease these seats and the new cups and use a hammer and a block of wood to seat them. With a few good whacks this works fine! Absolutely no need for a headset press.
- I had a bit of trouble seating the new crown race on the forks. I tried to be clever and use an aluminium tube from a vacuum cleaner and some other headset bits (the old race? I can't remember) so I could hammer this down and apply equal force all the way around and seat it evenly. It didn't work. At one point I thought I was going to have to give up and just keep the old one. Eventually just whacking it directly with a screwdriver and a hammer until it seated down worked. The new compression ring went on easier with a bit of grease.
- I grease my spacers. You're not really meant to grease the steerer, but I just make sure to keep the grease away from the stem. I figure a bit of grease anywhere else is a good thing for the next strip down.
- Most important of all: seal the headset. The normal way is to use an old large diameter inner tube (like that used in a mountain bike tyre) and make a couple of tube socks that you insert over the ends of the steerer tube on the frame and then roll up/down over the headset top cap/forks after re-assembly. But I didn't have any big diameter inner tubes so I went for a different approach and just wrapped around a wide enough strip of inner tube to cover over either end of the steerer tube, and secured it with some electrical insulation tape (it's everywhere on my bike). Since inner tubes are rubber this kind of technique works great elsewhere: I use old inner tube as handlebar grips, by cutting into long strips and wrapping it tightly enough it grips to itself and you only need to secure it at the ends. This is why you need to be careful on the headset to wrap it so it's tight only on the top half of the joint otherwise it'll bind up the steering! I sealed both ends of the steerer tube. A bit of grease underneath of the lower half of each seal (to aid rotation and to provide an additional barrier under the looser half of the seal) might have been a good idea and maybe I'll do that when these seals eventually fall off.
- Ride it around for a bit (~40 miles) and then check and re-tighten the headset.
I suspect the hardest part about doing it next time will be finding the spare part.