Author Topic: Lateral movement (fork bearing)  (Read 3722 times)

jul

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Lateral movement (fork bearing)
« on: June 08, 2019, 11:13:14 am »
Hi the specialists,

Since i bought my Nomad, i noticed a lateral movement on the upper fork bearing (around 1/2 to 1 mm). I can feel it only when stopped, if i brake from the front only.
I don't like that, i tried to tighten my screw strongly, but the lateral movement is still existing    :-\

For information my bearings are from origins.

And about your Nomad ? thanks

PH

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Re: Lateral movement (fork bearing)
« Reply #1 on: June 08, 2019, 01:06:24 pm »
Before you tightened the screw, did you loosen the stem and anything else connected to the steerer?  The top cap screw is only there to pre load the bearings, once that's done and the stem is tightened it served no purpose, tightening it without loosening the stem won't do anything to the adjustment.
Plenty of online guidance, I use Park Tools as my default (Adjustment half way down the page)
https://www.parktool.com/blog/repair-help/threadless-headset-service

If you follow that and you still have play, there's a problem with the headset, though that isn't the usual failure mode, are they turning freely? I'd probably drop the forks out, and check the cups.

jul

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Re: Lateral movement (fork bearing)
« Reply #2 on: June 09, 2019, 12:00:52 pm »
Hi PH,

Yes i did of course, i have loosed stem and Bar T extension before  tightening.

It's strange because i bought my bike almost new (2500 miles), and the lateral movement was existing.. 

PH

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Re: Lateral movement (fork bearing)
« Reply #3 on: June 09, 2019, 01:34:54 pm »
Hi PH,

Yes i did of course, i have loosed stem and Bar T extension before  tightening.

It's strange because i bought my bike almost new (2500 miles), and the lateral movement was existing..
OK, though you saying you've tightened the screw strongly shows something isn't right.  The pre load of the bearings doesn't need the screw to be very tight, so it seems to be something else happening when you turn the screw.  Two possibilities I can think of:
The stem or spacer above it is not higher than the steerer, take the top cap off with the stem clamped tight, there should be a gap of a few mm
The star nut is not far enough down the steerer and the screw/bolt has come to the end of it's thread before exerting enough force.
In either case adding a spacer above or below the stem will cure it.

My apologies if I'm stating the obvious, sometimes the answers are obvious to everyone but ourselves, happens to me all the time...

jul

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Re: Lateral movement (fork bearing)
« Reply #4 on: June 09, 2019, 05:51:38 pm »
I have to check all that, but in september, i'm currently on a business trip.
Crazy i ride like that since 15000 kms without worrying  :o
Probably, the cups did not appreciate...

However, i'm not stupid in mechanics   :-\

I will leave a feedback, thank to you

As well, my fork bearings turns freely even if i tighten the screw strongly.
« Last Edit: June 09, 2019, 06:06:26 pm by julio »

PH

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Re: Lateral movement (fork bearing)
« Reply #5 on: June 10, 2019, 10:49:15 pm »

As well, my fork bearings turns freely even if i tighten the screw strongly.
Again, that suggests you’re not loading the bearings when you tighten the screw, if I did that on any of my bikes the steering would stiffen up long before I’d consider the screw tight.

Dave Whittle Thorn Workshop

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Re: Lateral movement (fork bearing)
« Reply #6 on: June 11, 2019, 08:57:27 am »
Is the frame an S&S coupled one?

Danneaux

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Re: Lateral movement (fork bearing)
« Reply #7 on: June 11, 2019, 09:04:53 am »
Quote
Since i bought my Nomad, i noticed a lateral movement on the upper fork bearing...
Julien,

Is it possible the headset might have been misassembled by the previous owner? If it is an Orbit XLII, then it should go together like this:
https://www.thorncycles.co.uk/sandbox/thorncycles/fsa.pdf

Might be worth checking if it doesn't adjust as expected or in case you do take it apart and need a reference for reassembly.

Best,

Dan.


jul

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Re: Lateral movement (fork bearing)
« Reply #8 on: June 11, 2019, 10:27:32 am »
Dave,
No it isn't

Dan,
Thanks, i will check this properly..

But I'm not sûr the first owner disassembled the fork, he reversed only the stem..

As well, now i understand why, always my plastic seal came out of its housing... there is something wrong from the beginning.
http://thorncyclesforum.co.uk/index.php?topic=12993.0
« Last Edit: June 11, 2019, 10:34:19 am by julio »

macspud

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Re: Lateral movement (fork bearing)
« Reply #9 on: June 16, 2019, 01:13:53 am »
These videos shows the problem caused by insufficient gap between the the top of the steerer and the top of the stem (top of your spacer stack in your case)  https://www.youtube.com/watch?v=TihBJNn0Bck & https://www.youtube.com/watch?v=84xF6TN97pE  This can be caused by a missing spacer or possibly because the headset has been misassembled.


jul

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Re: Lateral movement (fork bearing)
« Reply #10 on: June 16, 2019, 08:06:42 am »
Thanks for videos, now it's very clear.   

I'll send a feedback later.