Author Topic: Taper bearings  (Read 1596 times)

Offline Sesman

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Taper bearings
« on: March 15, 2021, 08:18:12 AM »
Has anybody used the taper head bearings from DS?. The QMP product includes a spacer, but no instructions. I presume the spacer is used on the lower yoke, under the bearing, but do I also need to use a seal of any kind which is not included in the kit.

I’ve trawled the site, but there doesn’t appear to be any definitive guidance on this specific topic.

If anybody could help I’d be grateful.

Cheers.

Offline Sesman

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Re: Taper bearings
« Reply #1 on: March 15, 2021, 10:12:29 AM »
No seal apparently..hay ho. :-\

Offline Bryanj

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Re: Taper bearings
« Reply #2 on: March 15, 2021, 10:43:44 AM »
Check the thickness of the washer, if its more than 1mm you will be short of threads for the top nut

Offline Sesman

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Re: Taper bearings
« Reply #3 on: March 15, 2021, 12:46:22 PM »
Wow. 1mm depth will render me short of threads? Why is there a spacer at all. I’m missing something here?

Thanks for the reply by way.

Offline Bryanj

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Re: Taper bearings
« Reply #4 on: March 15, 2021, 01:36:12 PM »
Without a spacer the bottom yoke rubs on the frame before the bearing inner and outer engage properly.
The taper bearings are taller than the ball races which causes the problem

Offline Sesman

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Re: Taper bearings
« Reply #5 on: March 15, 2021, 02:40:03 PM »
Hi, Bryant. I get that, but 1mm. Can that be correct?

Offline Sesman

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Re: Taper bearings
« Reply #6 on: March 15, 2021, 02:57:44 PM »
The spacer is deeper than the width of a pound coin (can’t find my micrometers) by the way. Looks like a return to DS is in order.

Offline Sesman

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Re: Taper bearings
« Reply #7 on: March 15, 2021, 04:11:42 PM »
Hi, Oddjob.

Woe is me, old bearings are on their way to landfill. Didn’t think a well established swap out would be so difficult. Naively I assumed our man DS would,only sell stuff that fitted. :-\

Was trying to avoid the test fit hammering and swearing method.

All balls...here I come


Online McCabe-Thiele (Ted)

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Re: Taper bearings
« Reply #8 on: March 15, 2021, 04:24:10 PM »
Hi, Oddjob.

Woe is me, old bearings are on their way to landfill. Didn’t think a well established swap out would be so difficult. Naively I assumed our man DS would,only sell stuff that fitted. :-\

Was trying to avoid the test fit hammering and swearing method.

All balls...here I come

I am assuming you are replacing ball bearings with tapper rolers if that is the case and you have thrown the old ones away look on e-bay for original ball bearing fitments. Most actually give the replacement bearing thickness, ID & OD. Then just measure the height of the bottom replacement and subtract the original ball bearing thickness that should give you the thickness spacer you need. If your bottom yoke is 30 mm in diameter where the bearing sits I have a small selection of laser cut strong steel ones spare. I have them in 1mm, 2mm & 3mm thickness. MP me if they look like the right diameter.
« Last Edit: March 15, 2021, 04:26:12 PM by Macabethiele (Ted) »
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Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html

Offline Bryanj

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Re: Taper bearings
« Reply #9 on: March 15, 2021, 04:28:34 PM »
No point sendind DS back and buying all balls they are all the same bearings. You can get 1mm thick 30mm(i think) id shim washers on ebay for not much, i did and have some spare you can have at cost if you want.
EDIT
1mm thick 30mm bore 42mm od still on ebay at £4.02 for two, i bought 10 costing £8 so £0.80+ stamp+envelope = £2 to you if you want 1.

By the way i know it fits as i have2 bikes on the bench with them in
« Last Edit: March 15, 2021, 04:37:16 PM by Bryanj »

Offline Sesman

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Re: Taper bearings
« Reply #10 on: March 15, 2021, 04:41:46 PM »
Thanks Bryant. Live saver. I’ll pm you later if that’s ok.

And thanks for the tips Oddjob and Ted.

Just finishing some rattle can painting then it’s beer o clock.

Offline Bryanj

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Re: Taper bearings
« Reply #11 on: March 15, 2021, 04:56:21 PM »
Wont be able to get at it till friday as they are in my mates garage, measure yours first as if its 1mm you wont need one from me

Offline Sesman

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Re: Taper bearings
« Reply #12 on: March 18, 2021, 03:56:03 PM »
Hi, Ted.

Shim arrived...perfect fit. Thanks again and donation made.

Cheers.

Offline Sesman

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Re: Taper bearings
« Reply #13 on: March 18, 2021, 05:03:00 PM »
Now, if the challenge is to match the combine depth of the original fully assembled lower ball race, then I’d wager the correct shim is the 4mm job by supplied with the DS taper rollers.

I could have this completely wrong, though cos that’s my specialty.


Online K2-K6

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Re: Taper bearings
« Reply #14 on: March 18, 2021, 05:30:16 PM »
I think you're right there regarding dimensions.

But it's complicated by the top taper bearing bearing thicker than the original ball race,  hence the concern arises of threads left to complete assembly on the stem.

What it seems to need is to "pinch" enough height at the bottom, while still getting clearance for the fork to turn, which then leaves some small room for compensation at the top.

If you get the total stack height of both bearings together, then compare to original to give more complete picture.

 

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