Shimano headsets

[Garry Booth]

How much 'better' is a 600 headset than a 105? And where does the 500 I see advertised on ebay stand in comparison? The 600 I have on my 80s rebuild needs replacing and so I'm looking at alternatives? (The rest of the group is 105.) Is it best to buy a new/NOS. Is it risky to buy another 2nd hand one? Suggestions welcome.

[Brucey]

there are several different versions of both 600 and 105 headsets so it isn't possible to provide a definitive answer. But typically (for non-cartridge ball-bearing versions) 600 headsets are built like Dura-Ace (but lacking the finishing touches) whereas 105 are built like the cheaper headsets, but better. At one point both 105 and Exage 500 headsets had steel races with plastic covers over them. This was a reliable arrangement but for one detail; the plastic covers can get broken. Later versions have cartridge bearings in them.

If you buy used then there is no guarantee that your purchase will be any different from the one you have at present.

My advice is to at least try rebuilding the extant headset with loose balls and to see how that works for you. This often works very well (even with self-centring headsets which have little dents in the races from being adjusted badly with clipped balls in) because

a) the dents don't have to line up with one another (esp if you remove and refit the lower set race) and
b) the loose balls don't line up with the dents anyway because they are spaced differently from the clipped ones.

Just be careful when you adjust the headset; the correct adjustment is achieved in two steps

1) when you tighten the locknut and there is a little play, then
2) you adjust the threaded race a tiny bit more, retighten the locknut and the play is gone for the first time.

You may well find that the headset works fine once it has been fitted with loose balls and set up properly as described.

cheers

[Graham]

Garry, have you encountered the "low-stack-height" problem ?

When I tried to replace a Shimano 600 headset (original in 1990) all the decent local bike shops were unable to provide a replacement 600 or 105 or anything suitable from Shimano.
Here begins a looooong story.

[rjb]

Tange Levin headsets like this one have a similar low stack height.
https://www.sjscycles.co.uk/headsets/ta ... d-headset/

[Brucey]

Tange Levin headsets like this one have a similar low stack height.
https://www.sjscycles.co.uk/headsets/ta ... d-headset/

IIRC some shimano models have (had) a stack height about 8mm smaller than that.

cheers

[Garry Booth]

What is the 'low stack height problem' I should be looking out for? (That SJS headset looks like good value for money - not sure I trust myself rebuilding the old headset... )

[Graham]

Hello Garry,

What is Stack Height ? Well I wish I could find a brilliantly easy explanation with diagrams. . .
Best diagram so far . . . .
https://en.wikipedia.org/wiki/Headset_% ... 9#Threaded

Here a quick version from Chris Juden posted on this forum . . . .
viewtopic.php?f=5&t=84460&p=759611&hilit=measure+stack+height#p759611

[pwa]

What is the 'low stack height problem' I should be looking out for? (That SJS headset looks like good value for money - not sure I trust myself rebuilding the old headset... )

The problem is that Shimano managed to make their headsets lower than just about anyone else, which made them very good if you felt you wanted to lower your Cinelli stem a little further than other headsets allowed. But then you saw off the excess threaded steerer. Great. Then eventually you need a replacement headset and Shimano ones are harder to get. And the other brands seem too tall to fit on the threaded steerer you have left......

[Brucey]

- not sure I trust myself rebuilding the old headset... )

rebuilding one and fitting one are not much different to one another. A rebuild avoids having to remove the races from the frame (although you might want to lift and turn one of the lower ones if they are indented) but does add a slight complication if you use loose balls vs clipped balls.

Loose balls are far superior in most headsets so the slight faff of sticking them in position with grease is easily worth it IMHO.

cheers

[Garry Booth]

Thanks Brucey, maybe I'll get one of my more able pals to watch over me while I attempt it!