From: jobst.brandt@stanfordalumni.org
Subject: Re: Thin washer with new cassette?
Newsgroups: rec.bicycles.tech
Message-ID: <c_Tva.13748$JX2.831096@typhoon.sonic.net>
Date: Mon, 12 May 2003 21:03:04 GMT

Ryan Cousineau writes:

>>> I just bought an HG-70 (105) 8v 13-26 cassette. It included a very
>>> thin washer or spacer (I didn't measure it, but think 0.1 mm or
>>> so) which was between the lockring and the 13t cog.

>>> What is this? Am I actually supposed to leave it there when I put
>>> this cassette on?

>> Washers are to prevent the bolt (=lockring) from loosening itself
>> due to vibration.  That's the purpose of this one too.  Why would
>> you leave it out?

> I've never seen a cassette with such a washer (between the lockring
> and the small cog) before.  Both the lockring and the small cog have
> very distinctive teeth cut into them, and it looked like the washer
> would interfere with the mating of those teeth.

The same question occurred to me when I changed the sprockets on a
cassette hub.  The washer is made of soft steel and deforms only
slightly if the locknut is tightened forcefully.  I tossed it out
because it negates the function of the face spline on nut and last
sprocket.  Retention of the locknut is reduced by this washer and I
suspect that was the intention, because people could not remove the
locknut, many not having the special tool to do so.  Using a
screwdriver to do this is possible with the soft washer in place.

I found the splined lock nut a great invention when it was introduced,
removing the need for great force with an ungainly "chain whip" to
unscrew the smallest sprocket that formerly acted as locknut.

Jobst Brandt
jobst.brandt@stanfordalumni.org
Palo Alto CA