BB replacement or Service

[River Rat]

Thanks JB, I agree its not optimal but at least my dog ain't ugly!

[greatwhite]

@Bos: I said nothing abount the BB lying in the muck - it seems I was unclear:

 

My comment continued from JBs earlier comment that all the crap that collects inside the BB shell (rain getting down seat post etc) that has no chance to drain, will inevitibly run to the left, because bike are usually put down on the left side.

 

While my explination seem relatively inplausible, no plausible explination has been offered. The JBs comment about torque possibly being the cause holds no water (pun intended) to me, the forces on the right (chain side) bearing will always be greater and I don't believe underloading of the left bearing will be the cause

[Johan Bornman]

@Bos: I said nothing abount the BB lying in the muck - it seems I was unclear:

 

My comment continued from JBs earlier comment that all the crap that collects inside the BB shell (rain getting down seat post etc) that has no chance to drain, will inevitibly run to the left, because bike are usually put down on the left side.

 

While my explination seem relatively inplausible, no plausible explination has been offered. The JBs comment about torque possibly being the cause holds no water (pun intended) to me, the forces on the right (chain side) bearing will always be greater and I don't believe underloading of the left bearing will be the cause

 

Aha! Slap to the forehead and all that.

 

I think you have something here.

[greatwhite]

Can I have a photo of that slap to the forehead?

 

Getting back to the original question:

A new octolink BB will be the cheaper solution, otherwise a full new Deore or SLX crank set with external BB might be an option. This will also provide new chain rings, eliminating that future headache (note: often a complete set of 3 rings will cost approx the same as a complete new crankset)

[Flowta]

Can I have a photo of that slap to the forehead?

 

Getting back to the original question:

A new octolink BB will be the cheaper solution, otherwise a full new Deore or SLX crank set with external BB might be an option. This will also provide new chain rings, eliminating that future headache (note: often a complete set of 3 rings will cost approx the same as a complete new crankset)

 

Another option is get the new crank, put the old chainrings on (provided they fit and/or can be removed from the crankset). Ride those till it is time to replace and then you put the new original chainrings back on.

[River Rat]

Guys thanks for the replies and insights. But a bit more info for the guys that were sceptical of how the LBS was capable of greasing a sealed BB unit.

 

Well I was doing some research on the Cannondale website as to what size BB to order and I noticed a supplementary manual for my Rize 5. This document notes that the Rize 5 has BB shell that is compatiable with BB30 standard and I did some research on how to replace this type of BB and noticed this from the following website:-

http://www.parktool.com/repair/readhowto.asp?id=162

 

The BB30 is a threadless bottom bracket shell system using two pressed cartridge bearings. These bearings are replaced when they wear out. However, it is possible to lift the bearing seal while the cartridge bearings are in the shell to clean and grease bearings inside. So I suspect this is how the LBS serviced it albeit for a temporary repair.

 

I am still confused as to what to replace my BB with and have emailed Cannondale for some guidance.

[Flowta]

Guys thanks for the replies and insights. But a bit more info for the guys that were sceptical of how the LBS was capable of greasing a sealed BB unit.

 

Well I was doing some research on the Cannondale website as to what size BB to order and I noticed a supplementary manual for my Rize 5. This document notes that the Rize 5 has BB shell that is compatiable with BB30 standard and I did some research on how to replace this type of BB and noticed this from the following website:-

http://www.parktool.com/repair/readhowto.asp?id=162

 

The BB30 is a threadless bottom bracket shell system using two pressed cartridge bearings. These bearings are replaced when they wear out. However, it is possible to lift the bearing seal while the cartridge bearings are in the shell to clean and grease bearings inside. So I suspect this is how the LBS serviced it albeit for a temporary repair.

 

I am still confused as to what to replace my BB with and have emailed Cannondale for some guidance.

 

Is it possible for you take some picture and post them, so we can get a better idea of what is there.

[River Rat]

Will do Flowta. However, I will only be able to post on Wednesday as I am travelling on business at the moment.

[greatwhite]

BB30 is almost a pressed in version of an external BB see http://www.bb30standard.com/index.html . It's Cannondales wet dream that they are trying to get folks to buy into. It has some good technical merit, but also has some drawbacks.

 

As far as you are concerned, if you have octolink, then you don't have BB30

[Johan Bornman]

After all that, you tell us you have a BB30. Different animal althogether. With that you just replace the two cartridge bearings. Simple, cheap, effective.

 

You need a hammer, a pin punch and some savvy, that's all.

[Johan Bornman]

BB30 is almost a pressed in version of an external BB see http://www.bb30standard.com/index.html . It's Cannondales wet dream that they are trying to get folks to buy into. It has some good technical merit, but also has some drawbacks.

 

As far as you are concerned, if you have octolink, then you don't have BB30

 

 

GW, I quite like BB30. What do you consider to be the drawbacks?

[River Rat]

My apologies to all. It goes to show what happens when you take the manual at face value. I was unaware of the supplementary manual until yesterday. I guess I should add a crank extractor to your tool list JB.

[greatwhite]

I recon the upside of the BB30 is the replacement cost of bearings, the larger (read stiffer/lighter) crank shaft is also a plus. For me, the down side is the press fitting - putting extra strain onto the already highest stressed part of the bike and if it is too loose, you get creep instead. For the short term and as long as everything is made to correct, tight tolerances, it should be fine, but regular bearing changes could lead to problems.

[AndreZA]

I just don't know why they did not develop a system as simple as the modern headset. You have the two cups, being it pressed in or integrated, the two bearings and the the races on the crank arms. You preset the tension the same way as you would a headset and tighten the pinch bolts like on the current cranks and stems.

[Johan Bornman]

I recon the upside of the BB30 is the replacement cost of bearings, the larger (read stiffer/lighter) crank shaft is also a plus. For me, the down side is the press fitting - putting extra strain onto the already highest stressed part of the bike and if it is too loose, you get creep instead. For the short term and as long as everything is made to correct, tight tolerances, it should be fine, but regular bearing changes could lead to problems.

 

GW, I don't understand why a pressfit bearing puts more strain on the BB shell? Or are you not referring to the shell? I also don't think the neccessary number of bearing changes (if not botched) would make a difference. We heard the same arguments with headset cups when frame makers started making them part of the frame. We never saw those predicted failures other than on abused bikes ridden with completely loose headsets.

 

I think the pressfit gets rid of all the problems of a threaded fit and comes with no new problems. I've had a look at some BB shells on BB30s when I replaced the bearings and saw no noticeable rouge, indicating fretting between bearing and shell.

[greatwhite]

@JB: Maybe you are right. In many respects it is a cost effective, simple design. I'm just concerned about longevity. The fact that there is relatively little adoption is either a function of others saying the same or everyone playing wait and see (not wanting to be the bleeding edge early adopter). You make a valide point about is being similar to the headset. Which leads me to:

 

@Moegoe: The BB30 system is quite similar to a modern headset