Headset bearing question

Discuss light weight issues concerning road bikes & parts.
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UpFromOne
Posts: 723
Joined: Wed Apr 08, 2009 5:23 am
Location: Olympic Nat'l Park, WA

by UpFromOne

Does anyone make a thin-section integrated headset bearing with an OD that fits a 1 1/8" head tube, but an ID that fits a 1 1/4" fork crown race?

1 1/8" bearings are typically 40.8 or 41mm OD, and 1 1/4" bearings typically have an OD of 43.8mm, so I am thinking it is at least possible, as they are so close to begin with.

On the IDs, 1 1/8" are typically 30.15mm, where 1 1/4" are 32.4mm.

So this would be a bearing that has an OD of 40.8, and an ID of 32.4.
Granted this would be a thinner section than normal (i.e., OD less ID), but would still be 4mm+ of material on each side, enough for this size to function.

I do intend to query a couple of bearing manufacturers directly, but before I do I just wanted to see if any of you have ever heard of such a bearing.

Valbrona
Posts: 1504
Joined: Fri Oct 28, 2011 3:25 am
Location: United Kingdom of Great Britain and Northern Ireland

by Valbrona

For inch + eigth:-

41.8 OD
30.2 ID
45 x 45


But ther is also:

41.8 OD
32.8 ID
45 x 45
6mm high

(Inch + quarter = 31.75mm).

What you trying to do? Get fork with inch + quuarter steerer in head tube meant for inch + eiight?

by Weenie


UpFromOne
Posts: 723
Joined: Wed Apr 08, 2009 5:23 am
Location: Olympic Nat'l Park, WA

by UpFromOne

Yes, that is the goal, a 1 1/4" tapered fork in a straight 1 1/8" head tube. So I am only conerned with the bottom bearing.

I understand that some Giant bikes use a straight 1 1/4" steerer, such that this size bearing might exist to fit those into a 1 1/8" head tube, at least on the top side. But I haven't seen any yet.

Do you have a model number for that second bearing you mention?

Valbrona
Posts: 1504
Joined: Fri Oct 28, 2011 3:25 am
Location: United Kingdom of Great Britain and Northern Ireland

by Valbrona

Not sure of bearing number, but maybe just put measurements in internet to find it.

Likely that the diameter of the crown of the fork may not match the OD of the head tube at the bottom.

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