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General Category => General Discussion => Topic started by: earemike on November 09, 2015, 10:06:35 PM

Title: Chance of worn wheel bearings or a warped rotor? LM2 Linked Brakes
Post by: earemike on November 09, 2015, 10:06:35 PM
Hi all,

a LM2 with linked brakes found it's way to my shed & the discs 'felt' warped.

Under medium braking with the rear pedal there's a slight pulse. Similar braking with the front lever results in pulsing through the lever & really bad pulsing as I pull up.

Putting the wheel on my balancing rod I can detect where one part of both discs appears to deviate from straight. Thing is if I carefully watch the tyre it also seems to 'wobble' slightly at one point. Thinking about it I should have marked the 2 discs & tyres to see if it occurs at the same place for all three points.

Will dodgy wheel bearings give me a firm pulse through the lever?

I'm asking more as a learning exercise & will still try some new wheel bearings, your advice will confirm/refute the possibility and push me to order replacement discs earlier rather than later if necessary.

Cheers,

Mike
Title: Re: Chance of worn wheel bearings or a warped rotor? LM2 Linked Brakes
Post by: Wayne Orwig on November 09, 2015, 10:09:57 PM
If there is a spot on the disks that is contaminated, they can grab at that spot. Cleaning the surfaces may be all that is needed.
Title: Re: Chance of worn wheel bearings or a warped rotor? LM2 Linked Brakes
Post by: Scorpione on November 09, 2015, 10:37:36 PM
I have an LMII with linked brakes which also had this problem (but not as exaggerated as you are experiencing though).
I purchased and fitted a Tarozzi fork brace and never had the problem surface again. It also upped the handling quality a bit (added bonus).

Not sure if same issue, but putting it out there just in case FYI.
Title: Re: Chance of worn wheel bearings or a warped rotor? LM2 Linked Brakes
Post by: Turin on November 09, 2015, 11:01:40 PM
I've had worn wheel bearings give a similar result. If you have the wheel off and don't know the service history, you might as well change them. They're cheap enough and available at napa.
Title: Re: Chance of worn wheel bearings or a warped rotor? LM2 Linked Brakes
Post by: Arizona Wayne on November 10, 2015, 12:10:23 AM
Never heard of original iron discs actually warping.  I have a `81 CX100/LM II  with over 100K miles on it.   Neither the wheel bearings or the discs have ever been replaced.  If any moister gets on the  iron discs from rain/lack of riding/washing the discs then need to be ridden to make them 100% smooth again. They rust REAL quick !  Some times they get stuff on them you can't even see/feel and until you ride and use them enough they are not real smooth again.  I'll bet this is your situation.  I've owned my CX for 30 years.  :smiley:
Title: Re: Chance of worn wheel bearings or a warped rotor? LM2 Linked Brakes
Post by: Stevex on November 10, 2015, 12:49:14 PM
I felt my LM2 original discs were warped and a dti appeared to confirm this, but after a vernier gauge check they were worn to minimum recommended thickness anyway.
I de linked them, fitted stainless discs and carbon ceramic pads. With PS15 MC up front and a PS12 at the back, they are a considerable improvement. I have had problems with the front caliper pistons being pushed back into their bores on bumpy roads but I'm hoping a fork brace will cure this trait.