Goodbye carbon stays and integrated headsets...



On 5 Dec 2005 05:49:49 -0800, "Qui si parla Campagnolo"
<[email protected]> wrote:

>Agree but my point is that standard dimensions of a frame, like the ID
>of the headtube and threaded portion of a BB shell is a much better
>idea than a ton of unique to that frame HS and BB dimensions, like
>Klein, Merlin and many frames with IH.


Well, we appear to be violently in agreement then. OTOH, if someone came
up with an IH that took industry-standard-sized bearings (rather than
rolling (no pun intended) their own, custom, unlikely-to-be-stocked-much-
longer-than-it's-sold-new bearings), I'd applaud them. Motorcycles seem
(from watching Orange County Choppers, at least) to use that style a lot,
actually, 6003 or similar bearings pressfitted into the headtube, and then
a bolt through there that links the upper and lower parts of the crown
assembly thingy.

Of course, I don't really think it's viable to use industry bearings with
an industry-standard steerer diameter, so. Maybe for a manufacturer that
makes its own shock forks.

But still, the BB variant of it? *So* in favour of it.


Jasper
 
Jasper Janssen wrote:
>
> Motorcycles seem
> (from watching Orange County Choppers, at least) to use that style a lot,
> actually, 6003 or similar bearings pressfitted into the headtube, and then
> a bolt through there that links the upper and lower parts of the crown
> assembly thingy.


Most of the motorcycles whose head bearings I have serviced use Timken
tapered roller bearings or similar multi-piece angular contact ball
bearings.

My current motorcycle, a 1992 model weighing something like 1100 lbs.
with me on it, uses tapered roller bearings on a 25.0mm steerer. With
no part replacement and one repack, the head bearings have gone about
60,000 miles without issues.

> Of course, I don't really think it's viable to use industry bearings with
> an industry-standard steerer diameter, so. Maybe for a manufacturer that
> makes its own shock forks.


The B500 series of aircraft control type bearings are suitable for use
in headsets. I believe that's what the American Classic headset used,
and I know that's what Klein put in the Attitude MTB's headset.

http://www.nationalprecision.com/bb11a.htm

They are not as free-running as Conrad type bearings, but they have
load ratings per weight that are an order of magnitude higher.

I put a pair of the 3/4" size in an eccentric BB I made for my custom
Bohemian MTB, and so far they are holding up well to heavy-duty use. I
paid $17 each for two of them from National Precision Bearing.

Chalo Colina
 
On Tue, 06 Dec 2005 15:15:32 -0800, Chalo wrote:

> Jasper Janssen wrote:
>>
>> Motorcycles seem
>> (from watching Orange County Choppers, at least) to use that style a
>> lot, actually, 6003 or similar bearings pressfitted into the headtube,
>> and then a bolt through there that links the upper and lower parts of
>> the crown assembly thingy.

>
> Most of the motorcycles whose head bearings I have serviced use Timken
> tapered roller bearings or similar multi-piece angular contact ball
> bearings.
>
> My current motorcycle, a 1992 model weighing something like 1100 lbs.
> with me on it, uses tapered roller bearings on a 25.0mm steerer. With
> no part replacement and one repack, the head bearings have gone about
> 60,000 miles without issues.
>
>> Of course, I don't really think it's viable to use industry bearings
>> with an industry-standard steerer diameter, so. Maybe for a
>> manufacturer that makes its own shock forks.

>
> The B500 series of aircraft control type bearings are suitable for use
> in headsets. I believe that's what the American Classic headset used,
> and I know that's what Klein put in the Attitude MTB's headset.
>
> http://www.nationalprecision.com/bb11a.htm
>
> They are not as free-running as Conrad type bearings, but they have load
> ratings per weight that are an order of magnitude higher.


These might be what's in my Quantum Pro frame, which has an odd, 1 1/16"
steerer. The B541DD listed seems to correspond -- it's the same size as
the steerer, which is pressed into the bearing. I guess the 2200# thrust
rating is enough... is it?

I'd still rather see a tapered roller bearing, or angular contact ball
bearing in a headset (as is traditional).

I don't hear of these things failing in Klein frames, but OTOH there's a
company (Reset Racing) in Germany making retrofit cups for Klein frames,
so standard headsets can be used. There must be a reason.

It's good to know what's probably in my frame though, so thanks.

Also, I wonder what kind of bearing Chris King uses. I've heard it's a
tapered roller bearing from somewhere on a helicopter, but I've heard
otherwise too. In any case, CK headsets seem dead reliable.

> I put a pair of the 3/4" size in an eccentric BB I made for my custom
> Bohemian MTB, and so far they are holding up well to heavy-duty use. I
> paid $17 each for two of them from National Precision Bearing.


Well, these are perfect for a BB because the load is radial, especially if
you've beefed up the spindle.

We've had 5 different steerer sizes in the last decade, for no
reason at all. Somehow the bike industry managed to change almost
overnight, just to follow fashion. The BB could actually benefit from a
larger shell, but no one dares to try. Why not?

Matt O.