Bottom bracket has tight spot when turned backwards

Gixxerman

Guru
Location
Market Rasen
Odd one this. I have a bike that has a bottom bracket that spins freely in the normal forward direction, but is harder to turn in reverse and has a tight spot in it whilst doing so. I have removed the chain to eliminate the free hub / derailleur as a cause. I have also spun the crank using the crank arms to eliminate a pedal issue. So it is definitely a bottom bracket issue. It is a square taper type. Never seen anything like this before. There is a marked difference in the freeness of roatation in different directions. The crank arms are not bent and neither are any of the chainwheels. The axle does not seem to be bent either as there is no noticable lateral movement of the crank arms when turning.
 

raleighnut

Legendary Member
Odd one this. I have a bike that has a bottom bracket that spins freely in the normal forward direction, but is harder to turn in reverse and has a tight spot in it whilst doing so. I have removed the chain to eliminate the free hub / derailleur as a cause. I have also spun the crank using the crank arms to eliminate a pedal issue. So it is definitely a bottom bracket issue. It is a square taper type. Never seen anything like this before. There is a marked difference in the freeness of roatation in different directions. The crank arms are not bent and neither are any of the chainwheels. The axle does not seem to be bent either as there is no noticable lateral movement of the crank arms when turning.
If it has replaceable bearings in a 'cage' then it is possible that the 'cage' has 'knife-edged' due to wear, take it apart and fit some new bearings
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DON'T TURN IT BACKWARDS! Psychologically it is very damaging to expect a bearing that has had a lifetime of running forward to reverse that habit. It won't be able to cope....

Seriously, if it is smooth forward and there is no play or roughness then leave it alone and carry on. No reason to change it at this point, unless maybe you are about to depart on a world tour.
 

Smokin Joe

Legendary Member
Seriously, if it is smooth forward and there is no play or roughness then leave it alone and carry on. No reason to change it at this point, unless maybe you are about to depart on a world tour.
I've never heard such stupid advice. The bike is scrap and the man obviously needs to replace it with a new one as soon as possible.
 
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