From: pauls@icecreambar.css.itd.umich.edu (Paul Southworth)
Subject: Re: HEADSETS - stack ht, diameter
Reply-To: pauls@umich.edu
Organization: University of Michigan
Date: Tue, 8 Sep 1992 17:34:27 GMT

Eric Praetzel writes
| In article <1992Sep8.095418.1@mscf.med.upenn.edu>  
ross@mscf.med.upenn.edu writes:
| >	I need to replace the headset on my Specialized Hard Rock bicycle.
|   Good luck.  Specialized is well known for using "non-standard" forks  
back
| then.  Look at your bike carefully and decide what you want to do.  Like  
mine
| it is probably heavy and if you use 2" tires there will be _no_  
clearance.
|   Pull the fork off the bike and use a micrometer/calipers to measure  
the
| diamters of the fork and the headtube.  Unfortunately I don't remember  
what
| was non-standard about the ones that they were using.

Most Specialized ATBs used the JIS 27.0/30.0 standard headset.  Finding  
one should be easy.  Clearance for the tire is related to the fork, not  
the headset, unless the HT angle is so steep that a large tire doesn't  
clear the downtube, in which case a fat headset would help.  On a  
mass-produced recreational mountain bike though, the headtube will  
undoubtedly be quite slack.

| >	- Ordering a new headset.  I would like to buy a decent sealed
| >bearing headset to replace the piece of crap headset that the bike came
|   There are no sealed headsets that I am aware of.  But any good headset
| will probably be better than the cheap steel thing that came on the  
bike.

Chris King makes a sealed bearing headset that is quite nice.  They are a  
little stiff, but bombproof and require very little maintenance.  Bearings  
are pressed in and not too tough to replace.  The unit usually goes for a  
little over $100.  Two heights are available--standard (somewhere around  
40mm stack) and short (made to replace those ridiculous Shimano headsets,  
stack around 33-34mm).  Both were same price last I checked.  Silver or  
Black.  Cash, check or charge?

IMHO, you can get a very fine headset without going to a sealed *cartridge  
bearing* style.  If you are looking for high quality steel headsets, I  
recommend the newer Shimano DX & XT headsets that have 1/4" bearings.   
They are very tough, much better than the old short ones with the rubber  
doodad over the top.  They have rubber/plastic seals that seem to help  
keep the trail out of your headset a little better.  You might also look  
into putting a rubber boot over the lower cup assembly.  A 1.5" long chunk  
of 2.0" inner tube will fit the bill.  

Another good one for low $ is the Tange Levin or Tange Falcon -- they have  
ground steel races, unlike the one that came in the Specialized -- usually  
around $20 - $25.  Versions with and without the rubber seals both exist,  
so check before you buy.  Stack height around 37mm.

In alloy, take yer pick.  You'll hammer most alloy headsets in a mountain  
bike quicker than a cheapo steel one.  Shimano 600 Ultegra is one of the  
shortest-lived out there.

|   About cutting the fork down if the stack hight is too high. No  
problem. I
| did that when I built my Klein.  Make sure that your cut is good and  
debur
| the edges to make sure that it does not cut into the stem.

Definitely don't cut the fork below what is required to accommodate a 40mm  
stack height or you'll be sorry later.  A mitre block of some kind will  
greatly assist you in making a clean cut.  Even if you don't have one, be  
sure to take the old upper threaded cup from your dead headset and thread  
it way down on the fork, so that after you cut, you can screw it off to  
help clean the threads if you can't get access to a proper die.  You can  
also take two old threaded cups, thread them down the fork until the upper  
face of the upper cup is even with where you want to cut.  Then take two  
headset wrenches and lock the two cups together so they don't spin.  Cut  
level with that face and you'll get a flat cut.

| >	- Tools.  How many, what type of tools are needed to remove the  
old
| >headset.  I know I have to remove the stem (no problem) and then loosen  
the
|   Well you could do it the low-tech way.  Some wooden dowels, blocks of  
wood
| and a small hammer with lots of time.  Or you could make yourself a  
puller.
| If you can machine the parts it is easy enough to make one but its  
probably
| a lot faster to carefully push them out with a hammer and dowel or  
hammer
| and slot screwdriver on the outside.

A big flat-blade screw driver will usually suffice for the whole removal  
process.  To install the new headset, I recommend you don't hammer the  
cups in or you may deform the cups or the head tube.  You can make a  
headset press (that works for one-piece bottom brackets too) by getting a  
chunk of threaded rod about 18" long, along with two nuts and two large  
thick washers (washers' outside diameter at least as large as the head  
tube).  You can also use a vise to press them in if the jaws will open far  
enough.  Be very careful if you install an alloy headset--you don't really  
want to put lots of pressure on the outer part of the cup, since you can  
mush it and the bearing races will move slightly, making the headset have  
tight and loose spots when adjusted.  To press the new crown race onto the  
fork, you need a piece of pipe that will accommodate the steer tube so you  
can slide it on after the crown race and hammer that sucker down.  Make  
sure you get no gaps between crown of the fork and the crown race or you  
will have tight and loose spots, as well as future loosening of the  
headset.
Newsgroups: rec.bicycles.tech