Cannondale BB30 bottom bracket

[Yellow Saddle]

My local bike shop has had a few Cannondale bb30 bikes come back, but plenty that haven't.

It's a known problem, so it's worth the OP having a word with the dealer.

One of the bike shop's customers got a new frame under warranty, I don't know the ins and outs of that, but the shop/Cannondale may offer some assistance.

I would be interested to know if the problem has been described by Cannondale or the dealers. In other words, what exactly is it that goes wrong? Do you perhaps know?

 

[Pale Rider]

I would be interested to know if the problem has been described by Cannondale or the dealers. In other words, what exactly is it that goes wrong? Do you perhaps know?

'fraid I only the symptom - creaking - not the cause.

I wonder if it's a batch problem with the frame or the bracket.

That would explain why some, perhaps most, users have no problems.

I had something similar with a Suntour folding pedal on which the shaft snapped.

Via the dealer, Suntour admitted a batch were weak, blaming, in turn, the supplier of the metal.

The replacement has been fine, as has the other one, and the pair of same model folding pedals I have on another bike.

 

[Milkfloat]

I have heard a couple of things.

1.) a batch of bearings with too little grease
2.) poor tolerances in frame manufacturing

It seems the first 'repair' that the stores are trying is to pack everything with grease, then if that fails they are using loctite to glue the bearing in place. I would assume that too little grease on the bearing would not be solved with loctite holding the bearing in place, but grease between the bearing and frame may temporarily stop the issue. If mind squeaks again, then I will be using loctite.

 

[Yellow Saddle]

'fraid I only the symptom - creaking - not the cause.

I wonder if it's a batch problem with the frame or the bracket.

That would explain why some, perhaps most, users have no problems.

I had something similar with a Suntour folding pedal on which the shaft snapped.

Via the dealer, Suntour admitted a batch were weak, blaming, in turn, the supplier of the metal.

The replacement has been fine, as has the other one, and the pair of same model folding pedals I have on another bike.

Thanks. I thought that perhaps Cannondale would tacitly admit that BB30 is rubbish, but the company is too stubborn to give up on its brainchild.

 

[Venod]

Fit a new bearing as a minimum. You can get specific bearing extractors, but if you've got mechanical know how, and are dead sure of what you are doing, you can tap them out (make sure any retaining circlips - if fitted - are remove

Just changed the bearings on a Cannondale caadx bb30 no special tools used, knock them out with hammer and drift, tap back in with hammer, just make sure, you keep them square and even when tapping.

 

[3narf]

Thanks. Loctite Cylindrical Parts Bonding will do the trick.

 

[EasyPeez]

I'll bookmark this thread for future reference...hopefully I won't need to refer to it, but I suspect I might.

I would be interested to know if the problem has been described by Cannondale or the dealers. In other words, what exactly is it that goes wrong? Do you perhaps know?

When the bottom bracket failed on my Boardman after a couple of hundred miles the mechanic at Halfords told me that a batch of bikes were suffering from poorly installed and under-greased bottom brackets.
They fitted another BB30. I asked if it might not be a problem with the BB30 itself rather than the fitting, and said what if it goes again, to which he replied he was very confident it was the installation at fault, and if mine failed a second time they would upgrade it to a better bracket. 600 miles later I've had no further issues, though I do detect a light clicking from the BB area when out of the saddle and peddaling hard.

I have to say, all this sounds unlikely to me given that problems with the BB30 creaking/failing have been reported from 2011 to present - that has to be a component issue rather than fitting issue, surely?

 

[Yellow Saddle]

I'll bookmark this thread for future reference...hopefully I won't need to refer to it, but I suspect I might.



When the bottom bracket failed on my Boardman after a couple of hundred miles the mechanic at Halfords told me that a batch of bikes were suffering from poorly installed and under-greased bottom brackets.
They fitted another BB30. I asked if it might not be a problem with the BB30 itself rather than the fitting, and said what if it goes again, to which he replied he was very confident it was the installation at fault, and if mine failed a second time they would upgrade it to a better bracket. 600 miles later I've had no further issues, though I do detect a light clicking from the BB area when out of the saddle and peddaling hard.

I have to say, all this sounds unlikely to me given that problems with the BB30 creaking/failing have been reported from 2011 to present - that has to be a component issue rather than fitting issue, surely?

It is a design issue, hardly at all a fitment or component (bearing) problem. The BB has a very chequered history and I'll quickly recap.
First we had cotter pin. Cotters were problematic but were eventually replaced by the square taper, which was brilliant. It allowed lightweight aluminium cranks to be securely fastened to steel crank spindles without any problems of precession and lash, both problems with the cotter. (Note that I'm referring to a British cotter, not American cotter).
Then the weight weenies came around and questioned the solid BB axle and asked for something to be make lighter. Shimano responded with the Octalink BB. It fitted into existing BSA BB shells and thus didn't require a frame redesign. However, the enlarged axle required smaller bearings so that the assembly could fit into the limited space inside the BB shell. This reduced the bearing durability. Further, the advent of MTBing meant that people now jumped their bikes whilst standing on the cranks one foot forward, one 180degrees to the back. This put huge strain on the axle and the short Octalink spines could not provide enough stiffness and the flex inside the splines caused the crank bolt to unscrew on the one crank pointing backwards. Visualise this is the bolt head moving backwards with the flexing inside the crank eye but not returning with the backlash. This caused the shallow splines to strip. In addition to that problem, the splines were blind and assembly had to be very accurate, otherwise the spindle peeled pieces of spline and ruined the spline as the bolt is tightened. Then Shimano invented Octalink II without acknowledging the mistakes of what was not suddenly Octalilnk I. Octalink II solved the lash problem but not the bearing problem. Shimano even attempted to use roller bearings in its high-end Octalink cranks but these failed prematurely as well since roller bearings don't work well in grease where the grease is pushed away from the bearing and not returned as with a ball bearing.
Then a repeat of the Betamax vs VHS story started. Shimano refused to license Octalink (or the Americans refused to buy a license) and a consortium of American companies then reverse engineered their own version of Ocatlilnk, called the ISIS spline. It had not 8 as in Shimano, but 9 splines and a different spline shape. This all to avoid patent licence fees. Octalink, Octalink I, Octalink II and ISIS is all rubbish.
Shimano then decided that it will re-invent the BB again and came up with Hollowtech. This was a two-piece crank with a 24mm spindle and an externally mounted pair of bearings. The crank press-fit into the bearings, separated by a plastic spacer between crank and bearing race. The idea was to save weight, provide a stiff spindle by going oversize and create larger bearings but place them outside of the still-standard BB shell. Unfortunately the spindle was not stiff enough and the left hand bearing now fails prematurely because the spindle flexes on the left. Remember that torque is only transmitted through the spindle from the left crank, not the right. For a long time people through their left BB cup failed because a bike is laid down on its left side and water inside the BB was damaging the left bearing. However, it was the flexing spindle that pulls the sensitive deep groove bearing to run against the sides of its grooves and bind. Also astonishingly, the bearing balls were still too small for the job. Although the bearing diameter increased, the balls stayed small and they packed more of them in rather than bulk up the assembly a bit.

A BB redesign was called for and national pride meddled with good design. Cannondale, Bullseye and some other American companies then perpetrated BB30. It had a large (30mm) spindle to prevent some of the flexing found in Hollowtech and to supposedly save the customer maintenance cost, fitted two standard industrial deep groove bearings directly into a redesigned oversized shell. This was a big mistake, especially in hindsight when frames were made from carbon. The BB shell on an aluminium bike is a fragile, highly stressed component. It is a little thin-shell transverse tube with four major welds connecting it to the top tube, seat tube and two chainstays. This welding distorts the shell. This happened with old BBs as well but now with BB30, the bearing was fitted directly into the shell by press-fit. Tolerances had to be very high if you don't want the bearing to bind because of out-of-roundness of the shell and, simultaneously you want the bearing to fit tight enough into the aluminium shell to not move and fret during hard pedaling. This is an impossible call. These bearings all move and creak. The Japanese had some wisdom in using a screw-in system and sticking with it. Further, the bearings in BB30 are not far enough outboard to prevent the aluminium crank spindle to not flex and cause lateral loading of the bearing. That's why it fails so quickly.
BB30 became an even worse idea when frames turned to carbon. Now the BB shell was too soft to accept a steel bearing directly and, cannot be machined even close enough to good enough tolerance in anyway. Out came another shell redesign and we got BB30 Presssfit. This called for the bearing to be housed in a plastic cup which is then pressed into the imperfect frame aperture. They creak like hell and wear the shell out in an oval shape. They are terrible.

And that's where we are today. Weight weenies, poor engineering and national pride gave us a system that is worse than the 50 year old (guessing here) square taper. No-one admits it, few mechanics understand it and they're all looking for solutions such as warrantee replacements bearing glue and hope.

The answer will only be found once we have a new design. Don't think BB-Right provides it either.

 

[3narf]

It is a design issue, hardly at all a fitment or component (bearing) problem. The BB has a very chequered history and I'll quickly recap.
First we had cotter pin. Cotters were problematic but were eventually replaced by the square taper, which was brilliant. It allowed lightweight aluminium cranks to be securely fastened to steel crank spindles without any problems of precession and lash, both problems with the cotter. (Note that I'm referring to a British cotter, not American cotter).
Then the weight weenies came around and questioned the solid BB axle and asked for something to be make lighter. Shimano responded with the Octalink BB. It fitted into existing BSA BB shells and thus didn't require a frame redesign. However, the enlarged axle required smaller bearings so that the assembly could fit into the limited space inside the BB shell. This reduced the bearing durability. Further, the advent of MTBing meant that people now jumped their bikes whilst standing on the cranks one foot forward, one 180degrees to the back. This put huge strain on the axle and the short Octalink spines could not provide enough stiffness and the flex inside the splines caused the crank bolt to unscrew on the one crank pointing backwards. Visualise this is the bolt head moving backwards with the flexing inside the crank eye but not returning with the backlash. This caused the shallow splines to strip. In addition to that problem, the splines were blind and assembly had to be very accurate, otherwise the spindle peeled pieces of spline and ruined the spline as the bolt is tightened. Then Shimano invented Octalink II without acknowledging the mistakes of what was not suddenly Octalilnk I. Octalink II solved the lash problem but not the bearing problem. Shimano even attempted to use roller bearings in its high-end Octalink cranks but these failed prematurely as well since roller bearings don't work well in grease where the grease is pushed away from the bearing and not returned as with a ball bearing.
Then a repeat of the Betamax vs VHS story started. Shimano refused to license Octalink (or the Americans refused to buy a license) and a consortium of American companies then reverse engineered their own version of Ocatlilnk, called the ISIS spline. It had not 8 as in Shimano, but 9 splines and a different spline shape. This all to avoid patent licence fees. Octalink, Octalink I, Octalink II and ISIS is all rubbish.
Shimano then decided that it will re-invent the BB again and came up with Hollowtech. This was a two-piece crank with a 24mm spindle and an externally mounted pair of bearings. The crank press-fit into the bearings, separated by a plastic spacer between crank and bearing race. The idea was to save weight, provide a stiff spindle by going oversize and create larger bearings but place them outside of the still-standard BB shell. Unfortunately the spindle was not stiff enough and the left hand bearing now fails prematurely because the spindle flexes on the left. Remember that torque is only transmitted through the spindle from the left crank, not the right. For a long time people through their left BB cup failed because a bike is laid down on its left side and water inside the BB was damaging the left bearing. However, it was the flexing spindle that pulls the sensitive deep groove bearing to run against the sides of its grooves and bind. Also astonishingly, the bearing balls were still too small for the job. Although the bearing diameter increased, the balls stayed small and they packed more of them in rather than bulk up the assembly a bit.

A BB redesign was called for and national pride meddled with good design. Cannondale, Bullseye and some other American companies then perpetrated BB30. It had a large (30mm) spindle to prevent some of the flexing found in Hollowtech and to supposedly save the customer maintenance cost, fitted two standard industrial deep groove bearings directly into a redesigned oversized shell. This was a big mistake, especially in hindsight when frames were made from carbon. The BB shell on an aluminium bike is a fragile, highly stressed component. It is a little thin-shell transverse tube with four major welds connecting it to the top tube, seat tube and two chainstays. This welding distorts the shell. This happened with old BBs as well but now with BB30, the bearing was fitted directly into the shell by press-fit. Tolerances had to be very high if you don't want the bearing to bind because of out-of-roundness of the shell and, simultaneously you want the bearing to fit tight enough into the aluminium shell to not move and fret during hard pedaling. This is an impossible call. These bearings all move and creak. The Japanese had some wisdom in using a screw-in system and sticking with it. Further, the bearings in BB30 are not far enough outboard to prevent the aluminium crank spindle to not flex and cause lateral loading of the bearing. That's why it fails so quickly.
BB30 became an even worse idea when frames turned to carbon. Now the BB shell was too soft to accept a steel bearing directly and, cannot be machined even close enough to good enough tolerance in anyway. Out came another shell redesign and we got BB30 Presssfit. This called for the bearing to be housed in a plastic cup which is then pressed into the imperfect frame aperture. They creak like hell and wear the shell out in an oval shape. They are terrible.

And that's where we are today. Weight weenies, poor engineering and national pride gave us a system that is worse than the 50 year old (guessing here) square taper. No-one admits it, few mechanics understand it and they're all looking for solutions such as warrantee replacements bearing glue and hope.

The answer will only be found once we have a new design. Don't think BB-Right provides it either.

That's a brilliant explanation and totally plausible.

Thanks!

 

[EasyPeez]

That's a brilliant explanation and totally plausible.

Thanks!

Indeed it is a fantastic overview of the nonsense that has gone on around BB design in recent years, and very educational. Thanks for that @Yellow Saddle

General lack of durability/poor design aside though, there must surely also be something going on here batch or fitting-wise, as a relatively large number of people (judging by internet forums) are finding their BB30s failing within 200-300 miles, but then having no problems for several thousand miles once these have been replaced. Maybe these replacements will fail too within an unacceptably short time period (indicating poor design/quality) but they are not grinding and packing up every 200 miles as those originally fitted to a number of bikes all have, so this suggests a bad batch/poor fitting.
Myself and 1 other rider in my club have Boardman Team CXs and both suffered knackered BBs within 300 miles but have had no problems with the next 700 miles (me) or 1,000+ miles (him) on the replacement BBs.

I was only aware of the problem in relation to Boardman CX bikes but as the OP has a Cannondale I guess it must be a wider issue.

 

[EasyPeez]

Incidentally @Yellow Saddle - are you aware of an alternative, good bottom bracket that could replace a BB30 or does the shell design make it inevitable that anything that would fit would just be someone else's equally poor version of the same sort of design?
Also, my other bike is fitted with one of these - are you familiar with these and if so where would they fit among your descriptions of modern BB design - I'm wondering if this is a bit of a poor man's Hollowtech but with a threaded rather than press-fit shell?
http://www.chainreactioncycles.com/fsa-bb-4000-omega-drive-mega-exo-bb/rp-prod58234
I know I tried to upgrade it to a Hope BB recently but they don't manufacture anything that would fit the spindle that a FSA Mega-Exo 4000 takes.

Cheers.

 

[3narf]

Annoying, though, isn't it? I buy the cheapest RPM square taper BBs for my singlespeed and they last 3-4000 miles completely without incident...

 

[Yellow Saddle]

Incidentally @Yellow Saddle - are you aware of an alternative, good bottom bracket that could replace a BB30 or does the shell design make it inevitable that anything that would fit would just be someone else's equally poor version of the same sort of design?
Also, my other bike is fitted with one of these - are you familiar with these and if so where would they fit among your descriptions of modern BB design - I'm wondering if this is a bit of a poor man's Hollowtech but with a threaded rather than press-fit shell?
http://www.chainreactioncycles.com/fsa-bb-4000-omega-drive-mega-exo-bb/rp-prod58234
I know I tried to upgrade it to a Hope BB recently but they don't manufacture anything that would fit the spindle that a FSA Mega-Exo 4000 takes.

Cheers.

That Mega Exo is one of the worst there is.Firstly, the spindle is 19mm. Compare that to Shimano's 24mm that's already flexing on the left. Then, it uses the problematic outboard bearing design. However, if you are prepared to sacrifice the crank, you can replace that BB with a standard square taper or even a Shimano Hollowtech (24mm).

If I were you I would cut my losses on the FSA Mega-Thing crank and go 24mm.

The best treatment you can give your BB30 is a converter that's glued inside the BB-shell. this is a sturdy aluminium sleeve that converts it from BB30 to Hollowtech (24mm). Then you can use any of the 24mm cranks such as Campagnolo or Shimano or many of the other after-market models. This conversion is easy, cheap and really effective.

Something I didn't mention in my rant above is another one of the faults of external bearing BBs such as Shimano Hollowtech, SRAM GXP or many of the other similar designs. With the bearing cups now sitting outboard instead of inside the BB shell, they don't have the support of an internal sleeve. If you look at a square taper BB you'll see that there's a spindle inside two bearings (sometimes three as with Camplagnolo) inside a steel sleeve. This sleeve adds extra strength to the assembly and any rocking of the crank now requires the entire frame to rock side-to-side. With outboard bearings the two cups rock independently of each other. Evidence of this movement is visible in the grey aluminium rouge that's evident on the thread when you remove the BB and audible through creaks and groans that quickly develop in the BB cups.

Having two individual cups press-fit into a carbon frame is possibly the worst of the worst. Someone should be sent to engineering hell.

Edit: If you want to be rally stupid you use all the poor design features in one design. Enter SRAM GXP. a 19mm spindle (perhaps 20mm?) on the left side and 24mm on the right. If anything, that should have been reversed. 300km on a GXP BB is not uncommon.

 

[Yellow Saddle]

Indeed it is a fantastic overview of the nonsense that has gone on around BB design in recent years, and very educational. Thanks for that @Yellow Saddle

General lack of durability/poor design aside though, there must surely also be something going on here batch or fitting-wise, as a relatively large number of people (judging by internet forums) are finding their BB30s failing within 200-300 miles, but then having no problems for several thousand miles once these have been replaced. Maybe these replacements will fail too within an unacceptably short time period (indicating poor design/quality) but they are not grinding and packing up every 200 miles as those originally fitted to a number of bikes all have, so this suggests a bad batch/poor fitting.
Myself and 1 other rider in my club have Boardman Team CXs and both suffered knackered BBs within 300 miles but have had no problems with the next 700 miles (me) or 1,000+ miles (him) on the replacement BBs.

I was only aware of the problem in relation to Boardman CX bikes but as the OP has a Cannondale I guess it must be a wider issue.

I doubt it is poor fitting and poor bearings. Here's why I say so. The fitting is simple - slip the bearing in and click in a circlip. There's nothing to screw up, no cross threading, no ill positioning, nothing. I suspect second time round most of the bearings are glued in with gap-filling Loctite. Second reason is because the bearings are industry-standard deep groove bearings - 6083 or 6086 IIRC. This means they could be supplied by any of several thousand bearing manufacturers ranging from SKF, FAG, Timken etc at the top end and Chinese and Indian rubbish at the low end. It's not like the industry is supplied by only one company, eliminating the bad batch theory in my view.

 

[EasyPeez]

The best treatment you can give your BB30 is a converter that's glued inside the BB-shell. this is a sturdy aluminium sleeve that converts it from BB30 to Hollowtech (24mm). Then you can use any of the 24mm cranks such as Campagnolo or Shimano or many of the other after-market models. This conversion is easy, cheap and really effective.

Sounds good. I'll do that next time I need a new BB. Forgive my ignorance, but would buying the converter and new cranks also necessitate a new chainset?

That Mega Exo is one of the worst there is.Firstly, the spindle is 19mm. Compare that to Shimano's 24mm that's already flexing on the left. Then, it uses the problematic outboard bearing design. However, if you are prepared to sacrifice the crank, you can replace that BB with a standard square taper or even a Shimano Hollowtech (24mm).

If I were you I would cut my losses on the FSA Mega-Thing crank and go 24mm.

That's my intention. I went like-for-like this time around for financial reasons (i.e prioritising new helmet & wheels!) but next time I am looking to change it. Again, would this require a new chainset too though?
Could you recommend a good square taper? I was looking at one of these but I think it has outboard bearings - best avoided?
http://www.hopetech.com/product/threaded/

I suspect second time round most of the bearings are glued in with gap-filling Loctite.

That would explain the phenomenon of the improved BB life second time around, I guess.