Bearing angles

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lloyd_e
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Bearing angles

Postby lloyd_e » 9 Jun 2020, 9:28pm

Hello all, I'm new here.

I have a Scott CX1 Compo that I am putting new headset & crown bearings on for a friend. I ordered 2x replacement bearings, as measured by myself, to find they are a standard 30.15 x 41 x 6.5 with 2x 45 degree angles. When they arrived, the headset bearing fitted well, but the crown bearing left me with a larger gap between forks and frame than looked acceptable, so I have ordered a 36/45 degree bearing. This got me thinking... how would anyone measure the angle on these bearings? My son-in-law used his maths skills to try and work it out but the measurements are so tiny with a calliper that it becomes inaccurate.
Surely workshops don't just guess, or try another bearing with a different angle, do they?
I should say that the bearing was very rusty, and there are no sizes visible.

We look forward to any possible answers :D

jb
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Re: Bearing angles

Postby jb » 9 Jun 2020, 10:59pm

Have you a picture of the fork with the bearing on?
Cheers
J Bro

Brucey
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Re: Bearing angles

Postby Brucey » 9 Jun 2020, 11:19pm

you could use one of these;

Image

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Marcus Aurelius
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Joined: 1 Feb 2018, 10:20am

Re: Bearing angles

Postby Marcus Aurelius » 10 Jun 2020, 5:27am

Integrated headsets have either 36 or 45 degree ACBs. 36 has been obsolete for ages, so it takes any guess work out.

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Bearing angles

Postby Brucey » 10 Jun 2020, 6:14am

Marcus Aurelius wrote:Integrated headsets have either 36 or 45 degree ACBs. 36 has been obsolete for ages, so it takes any guess work out.


isn't that exactly the kind of logic which has resulted in the OP having to buy a second set of bearings?

FWIW a good trick for determining bearing angles is as follows;

- get something with a good straight edge (e.g. drill bit shank, allen key) mounted horizontally in a bench vice, sticking out to one side
- offer up the bearing chamfer to the straight edge and hold it in position
- assess if the opposite side of that chamfer is vertical or not

If the opposite side of the same chamfer is vertical then that bearing chamfer has a 45 degree angle. If the opposite side of the same chamfer is inclined 18 degrees from the vertical, then the chamfer is 36 degrees.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Bearing angles

Postby Brucey » 10 Jun 2020, 7:41am

in a similar vein if you have couple of old lengths of spoke and some elastic bands (cut from an old inner tube?) then you can assess the bearing angles like this;

Image01698.jpg
'X' marks the spot


cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

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fausto99
Posts: 638
Joined: 19 Sep 2011, 10:06am

Re: Bearing angles

Postby fausto99 » 10 Jun 2020, 8:18am

Brucey wrote:you could use one of these;

Image

cheers

Very nice - what's it called and who sells them?

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lloyd_e
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Joined: 27 May 2020, 2:27pm
Location: Pagham

Re: Bearing angles

Postby lloyd_e » 10 Jun 2020, 8:50am

Well I’m amazed at the informed and prompt response, having never used a forum before, thank you. Brucey, what a interesting piece of kit, and looks like something every good mechanic should have, as others have asked, what’s it called?

I did read that the 36 degree bearing was obsolete elsewhere, so I am only guessing that it is the fix for my problem. All the ideas given are excellent, and as I am about to begin my Cytech 2 course, I look forward to joining to hopefully helping others on this forum. I will post some pictures of my issue later today, after I’ve been for a cycle :D

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Bearing angles

Postby Brucey » 10 Jun 2020, 8:58am

https://www.bikester.co.uk/bicycle-equipment/tools-assembly/workshop-equipment/13619.html

there is another gauge which you need (as well I think) if you want to do 1-1/4" headsets and 1-1/2" headsets.

BTW you may be wondering why the 45 degree internal gauge has notches in the sides of the gauge. I think this is because one type of bearing has a lip on it which otherwise fouls a plain (notchless) angle gauge.

cheers
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fausto99
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Re: Bearing angles

Postby fausto99 » 10 Jun 2020, 11:20am

Brucey wrote:https://www.bikester.co.uk/bicycle-equipment/tools-assembly/workshop-equipment/13619.html

there is another gauge which you need (as well I think) if you want to do 1-1/4" headsets and 1-1/2" headsets.

BTW you may be wondering why the 45 degree internal gauge has notches in the sides of the gauge. I think this is because one type of bearing has a lip on it which otherwise fouls a plain (notchless) angle gauge.

cheers
no longer available :(

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Bearing angles

Postby Brucey » 10 Jun 2020, 11:34am

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lloyd_e
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Location: Pagham

Re: Bearing angles

Postby lloyd_e » 10 Jun 2020, 12:15pm

Ive just ordered the last one from SJS, thank so much! Here are some pictures....
Image Attachments
5.jpeg
A larger gap with the NEW bearing
4.jpeg
The NEW bearing sat on the crown forks
3.jpeg
The OLD bearing sat on the crown forks
2.jpeg
Forks in place to the frame with the OLD bearing
1.jpeg
This is the old and new bearing

Marcus Aurelius
Posts: 1635
Joined: 1 Feb 2018, 10:20am

Re: Bearing angles

Postby Marcus Aurelius » 10 Jun 2020, 12:55pm

Brucey wrote:
Marcus Aurelius wrote:Integrated headsets have either 36 or 45 degree ACBs. 36 has been obsolete for ages, so it takes any guess work out.


isn't that exactly the kind of logic which has resulted in the OP having to buy a second set of bearings?

FWIW a good trick for determining bearing angles is as follows;

- get something with a good straight edge (e.g. drill bit shank, allen key) mounted horizontally in a bench vice, sticking out to one side
- offer up the bearing chamfer to the straight edge and hold it in position
- assess if the opposite side of that chamfer is vertical or not

If the opposite side of the same chamfer is vertical then that bearing chamfer has a 45 degree angle. If the opposite side of the same chamfer is inclined 18 degrees from the vertical, then the chamfer is 36 degrees.

cheers

No “logic” involved, that’s the way it is.

From here.

https://www.parktool.com/blog/repair-he ... ion-system

“In years past, there were two different standards for the bearing contact angle for the integrated system, which were the 36-degree and 45-degree contacts. The 36-degree standard is now considered obsolete and the current standard is the 45-degree contact. Because the 36-degree frames are not being produced, the angular contact is not called out and is assumed to be 45-degrees for new headsets. Integrated headsets in the SHIS system are abbreviated as “IS.”

If there’s an issue with fit, it’s due to wear and tear in the head tube.

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Bearing angles

Postby Brucey » 10 Jun 2020, 12:59pm

I find it is rarely a better idea to assume something than it is to measure up carefully. It seems a bit odd to advise someone that their headset ought to have a given chamfer angle when they appear to have already discovered that it doesn't....?

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~