Bottom bracket on its way out?

[Brandane]

Just noticed this on my Tricross. You can grab hold of either crank, and when you pull it from side to side, i.e. away from the frame, there is some noticeable movement. Not a lot, maybe about 3 or 4 mm.. I am assuming that my bottom bracket is worn, and will need replaced? Replacing it is not a problem; I have the correct tools as I upgraded the standard stuff to Tiagra components a couple of years ago. Since then the bike has done somewhere around 5000 miles, so I suppose I can expect stuff like the BB to be worn by now.

Just looking for confirmation that this is the most likely problem before I spend money with ChainReaction!

 

[numbnuts]

With BB I think it down to how you ride your bike, I only sit and spin and mine lasted 10000 miles, but if your one of those that honks out of the saddle most of the time I think it will wear out faster

 

[HLaB]

Just noticed this on my Tricross. You can grab hold of either crank, and when you pull it from side to side, i.e. away from the frame, there is some noticeable movement. Not a lot, maybe about 3 or 4 mm.. I am assuming that my bottom bracket is worn, and will need replaced? Replacing it is not a problem; I have the correct tools as I upgraded the standard stuff to Tiagra components a couple of years ago. Since then the bike has done somewhere around 5000 miles, so I suppose I can expect stuff like the BB to be worn by now.

Just looking for confirmation that this is the most likely problem before I spend money with ChainReaction!

Doubt it (its not a valid comparrison but my Kinesis has done over 20,000 miles and the BB was replaced (maybe prematurely) at 12 or 14k miles) it'll be more likely to be the cranks, the chainrings or something needing tightened up.

 

[MontyVeda]

i think my BB is going every few months... but it always turns out to be the cranks coming a little bit loose.

Bike gets daily use, current BB has been on for a good 8 years and it's replacement has been sitting my tool box for 18 months now.

 

[Brandane]

With BB I think it down to how you ride your bike, I only sit and spin and mine lasted 10000 miles, but if your one of those that honks out of the saddle most of the time I think it will wear out faster

I am also a "spinner" but only on the flat. Unfortunately we have some substantial hills around here, where I have no choice but to "honk out of the saddle" . Or, perhaps a better description would be to stand on the pedals and struggle up the hills, half a crank revolution at a time.

 

[Brandane]

i think my BB is going every few months... but it always turns out to be the cranks coming a little bit loose.

My crankset is fixed on the chainring side, and the other side is tight. The BB is the only other component which is why I am thinking along those lines. It is one of these types of BB:

The axle (fixed to the crank) from the drive side goes through the cups then the other crank fastens onto it.

 

[User6179]

If you mean the cranks are rocking 3-4mm then it will be the bearings but if you mean you can slide the crank from side to side then it could be you need a spacer, just fitted one myself and forgot to put the spacer in, also check the bb shell around the welds for cracks as when my cranks started to wobble it was because the frame had cracked .

 

[Brandane]

If you mean the cranks are rocking 3-4mm then it will be the bearings but if you mean you can slide the crank from side to side then it could be you need a spacer, just fitted one myself and forgot to put the spacer in, also check the bb shell around the welds for cracks as when my cranks started to wobble it was because the frame had cracked .

Yes, it rocks rather than slides. Just taken it apart, and thankfully it is not a cracked frame. The bearings on the BB cups are rough as old boots and a lot of rusty grease inside the BB.. Since it is the cheapest option, I have ordered a new BB from ChainReaction.. This time an Ultegra part rather than Tiagra. Allegedly it is better sealed against water ingress, and better quality bearings. For the price difference it is worth a go; we shall see!

 

[mrandmrspoves]

Hollowtech external bearings don't seem to last very long. I have known them to need replacing after about 3,000 miles - so I would be pleased with 5,000.

 

[mrandmrspoves]

When you remove the old unit - take careful note of where the spacer washers (if any) are and ensure you replace them in the same position. I think spending a few pounds more for the Ultegra is a good call - on the basis that they MIGHT last a little longer.
I find that Shimano tend to be very sparing on the grease and every time I have had to replace one of these external bearings it has been dry as a bone - so now I add a little extra grease on assembly.......time will tell if this makes a difference.

 

[addictfreak]

Had the same problem with my MTB recently. Changed BB, sorted no problems.

 

[Shut Up Legs]

I plan to replace my BB sometime soon, on the Vivente tourer I use for commuting. Wish me luck: it will be my first ever BB replacement, as my bicycle mechanical competency is still a work in progress. So I read this thread with interest.

 

[Brandane]

I plan to replace my BB sometime soon, on the Vivente tourer I use for commuting. Wish me luck: it will be my first ever BB replacement, as my bicycle mechanical competency is still a work in progress. So I read this thread with interest.

If I can do it, anyone can. What type of BB is it? You might need the proper crank pulling tool to get your pedal cranks off, then the proper spanner or key for loosening the bottom bracket (one side has a right hand thread, the other left hand). With the proper tools, it is easy! No doubt there are clips on YouTube to show how it is done.

 

[Shut Up Legs]

If I can do it, anyone can. What type of BB is it? You might need the proper crank pulling tool to get your pedal cranks off, then the proper spanner or key for loosening the bottom bracket (one side has a right hand thread, the other left hand). With the proper tools, it is easy! No doubt there are clips on YouTube to show how it is done.

It's the same as the one in your previous post, and I probably have the correct tools in the Park Tools AK-37 tool box that I bought last year. I have viewed the Park Tools online video, but have yet to take the leap of actually doing it.

 

[Crankarm]

If I can do it, anyone can. What type of BB is it? You might need the proper crank pulling tool to get your pedal cranks off, then the proper spanner or key for loosening the bottom bracket (one side has a right hand thread, the other left hand). With the proper tools, it is easy! No doubt there are clips on YouTube to show how it is done.

I have a sneaking suspicion the hollowtech 2 bb bearing cups need changing on my MTB. I need to buy a spanner just for removal of the FSA Mega Exo cups and FSA chainset as it is a bit worn (10k commuting miles - new rings are the cost of a complete new chainset incl beaing cups) then probably another spanner for the bearing cups of the Shimano Deore Hollowteh 2 chainset I intend to replace it with. ££££. But I won't be paying for any extortionate LBS labour costs.