ryda wrote:ok so you tell me..
why if they are so good a monocrome bearing BB lock up after 1 x 24hr race and once we freed it up it was a rough as so we binned it yet a CK so far has lasted 1 x24hr 2 x12hrs 2x 6 hr 2 x 4hr 1x 5hr races countless miles of training and is still running sweet ?

personaly I wouldn't run any but CK's now

Note both 24hr event where very wet, as were the 6hr events

yet we have el booto's pic of a very very dead ck

personally I think ALL externals are crap and Hope stainless are merely the least crap - now ask me how many THOUSANDS of wet kms my stainless skf isis has done and is still perfect (roller bearings and proper labrynth seals ftw)

danose wrote:

ryda wrote:ok so you tell me..
why if they are so good a monocrome bearing BB lock up after 1 x 24hr race and once we freed it up it was a rough as so we binned it yet a CK so far has lasted 1 x24hr 2 x12hrs 2x 6 hr 2 x 4hr 1x 5hr races countless miles of training and is still running sweet ?

personaly I wouldn't run any but CK's now

Note both 24hr event where very wet, as were the 6hr events

yet we have el booto's pic of a very very dead ck

personally I think ALL externals are crap and Hope stainless are merely the least crap - now ask me how many THOUSANDS of wet kms my stainless skf isis has done and is still perfect (roller bearings and proper labrynth seals ftw)

But marketing tells me that an external is way much stiffer.
Actually - engineering tells me that this is true. But stiffness is worth diddly squat if your bearings are rooted.
I can see a shitload of merit in Dougal's (Shockcraft) 'storm drains' concept. Let that shit out of thurrrrr.

Conners wrote:I can see a shitload of merit in Dougal's (Shockcraft) 'storm drains' concept. Let that shit out of thurrrrr.

yep - last external I killed was full of rust - this was after the horrendously wet hanmer 12hr (shortened to 8hr) - water had got in down the seat tube, past the poxy inner sleeve seals and then in thru the inner seals of the bearings). Even if I'd ditched the inner sleeve and drilled a drain hole in the BB shell, the stupid raceface cups have an inner lip, so any water that gets to the bearings is trapped - storm drains would definitely have helped!!!

I'm too light to notice any stiffness diff between my externals and isis

ryda wrote:ok so you tell me..
why if they are so good a monocrome bearing BB lock up after 1 x 24hr race and once we freed it up it was a rough as so we binned it yet a CK so far has lasted 1 x24hr 2 x12hrs 2x 6 hr 2 x 4hr 1x 5hr races countless miles of training and is still running sweet ?

personaly I wouldn't run any but CK's now

Note both 24hr event where very wet, as were the 6hr events

Bearing failure, like any other failure is statistical. Some will fail early on, some will last for a very long time.
All the Monocrome bearings are covered by a 6 month no question asked warranty for this reason. It covers our customers for failures not only caused by the bearings but also caused by installation, corrosion or any other reason.
Part of the 6 month warranty is returning failed bearings so they can be stripped and the reasons for failure identified. If it's a manufacturing fault and it's found more than once we can start isolating and testing batches of product. If it's an installation problem, then we replace the bearings and inform the customer so the next set fares better. If it's a corrosion problem then we replace the bearings and give the customer options to manage or eliminate the problem in future.
If a product is binned, then the customer misses out on warranty and we miss out on finding and remedying the cause of failure.

All Monocrome BB's are fully servicable and every single part is available as a spare. If the BB in question can be found and returned, then I will warranty the bearings. Regardless of the cause.

BTW, any bearing once locked up is damaged and will never run smoothly. There's no point trying to unseize them. If time is tight then we have loan BB's which are couriered out so you can keep riding while we sort out your original item.

danose wrote:

Conners wrote:I can see a shitload of merit in Dougal's (Shockcraft) 'storm drains' concept. Let that shit out of thurrrrr.

yep - last external I killed was full of rust - this was after the horrendously wet hanmer 12hr (shortened to 8hr) - water had got in down the seat tube, past the poxy inner sleeve seals and then in thru the inner seals of the bearings). Even if I'd ditched the inner sleeve and drilled a drain hole in the BB shell, the stupid raceface cups have an inner lip, so any water that gets to the bearings is trapped - storm drains would definitely have helped!!!

I'm too light to notice any stiffness diff between my externals and isis

I have had so many rust up that I brought some bearings with SS races and ceramic balls. Problem solved. Water that gets in doesn't damage the bearing.

Dougal wrote:

ryda wrote:ok so you tell me..
why if they are so good a monocrome bearing BB lock up after 1 x 24hr race and once we freed it up it was a rough as so we binned it yet a CK so far has lasted 1 x24hr 2 x12hrs 2x 6 hr 2 x 4hr 1x 5hr races countless miles of training and is still running sweet ?

personaly I wouldn't run any but CK's now

Note both 24hr event where very wet, as were the 6hr events

Bearing failure, like any other failure is statistical. Some will fail early on, some will last for a very long time.
All the Monocrome bearings are covered by a 6 month no question asked warranty for this reason. It covers our customers for failures not only caused by the bearings but also caused by installation, corrosion or any other reason.
Part of the 6 month warranty is returning failed bearings so they can be stripped and the reasons for failure identified. If it's a manufacturing fault and it's found more than once we can start isolating and testing batches of product. If it's an installation problem, then we replace the bearings and inform the customer so the next set fares better. If it's a corrosion problem then we replace the bearings and give the customer options to manage or eliminate the problem in future.
If a product is binned, then the customer misses out on warranty and we miss out on finding and remedying the cause of failure.

All Monocrome BB's are fully servicable and every single part is available as a spare. If the BB in question can be found and returned, then I will warranty the bearings. Regardless of the cause.

BTW, any bearing once locked up is damaged and will never run smoothly. There's no point trying to unseize them. If time is tight then we have loan BB's which are couriered out so you can keep riding while we sort out your original item.

I bined it ages ago

FYI - the problem was the seals failed to do their job, 48hrs after the event when I got to do the maintance on the bike I found the Non-drive side had siezed, with the Crankset out I couldn't spin the bearing by hand, the dive side wasn't much better. I removed the BB and found 2/5th's of SWA water in the frame so storm drains wouldn't have helped, Removed the bearing from the cups, then hooked the seals out, cleaned out as much of the crap as i could, filled bearing with pentrating lube for 48hrs, still no luck tried warming but still had to tap the bearings with a punch to get it to free

I bined it on the fact that it performed no better than a std deore one

BTW while I know once damaged they will never run 100% smooth again, I have freed up a seize bearing suffecient enough to re use (short term) but wasn't going happen in this case

I stick with the 5 yr CK warranty, but thanks for your offer anyway

wpp1 wrote:I have had so many rust up that I brought some bearings with SS races and ceramic balls. Problem solved. Water that gets in doesn't damage the bearing.

Correct that it doesn't damage the bearing, but it does ruin the grease. You will still have to clean and regrease them regularly to get good life. The other problem is the stainless steels which are hard enough to make bearings from will still rust. Not as badly as chromium steel bearing material, but they will rust if water is left pooling inside.
The third problem is, stainless steels cannot be made as hard as chromium bearing steels, you miss out on about 3 points on Rockwell C scale. This softness eventually leads to sub-surface fatigue failure like the photos above.

If you can keep the water out, a chromium steel bearing will outlast a stainless steel bearing by a big margin. A stainless bearing has to outlast many chromium steel bearings to be economic. In the end it comes down to doing your own maintenance vs paying someone else. If you do it yourself then bearing cleaning/regreasing usually comes out best. If you pay others to do the work then bearing replacement is the usual outcome.

It should also be noted that water doesn't enter an external BB through the frame. It enters along the BB axle with the expansion and contraction of the air within the BB. I have performed experiments using bikes with sealed BB shells and moisture test strips.
Once inside an external BB it cannot get out and ends up in the water-trap which exists in every external cup against the bearing seal. Here water sits until it can corrode it's way under the seal and into the bearing.

ryda wrote:I bined it ages ago

FYI - the problem was the seals failed to do their job, 48hrs after the event when I got to do the maintance on the bike I found the Non-drive side had siezed, with the Crankset out I couldn't spin the bearing by hand, the dive side wasn't much better. I removed the BB and found 2/5th's of SWA water in the frame so storm drains wouldn't have helped, Removed the bearing from the cups, then hooked the seals out, cleaned out as much of the crap as i could, filled bearing with pentrating lube for 48hrs, still no luck tried warming but still had to tap the bearings with a punch to get it to free

I bined it on the fact that it performed no better than a std deore one

BTW while I know once damaged they will never run 100% smooth again, I have freed up a seize bearing suffecient enough to re use (short term) but wasn't going happen in this case

I stick with the 5 yr CK warranty, but thanks for your offer anyway

Water doesn't enter external BB's through the frame. It comes in along the BB axle. It's not possible to seal a BB completely due to the large air cavity within and the expansion/contraction of this air.
Once inside that water can't get out. If your BB didn't have storm drains (presuming it didn't, I don't know your real name to check our records) then the same failure mode is experienced with all external bearing BB's. The water sits agains the bearing, corrodes it's way in and if left to sit will seize the bearing. If kept rolling it will stay free but continue to get noisier and rougher.

The photo attached is a typical failure, I'd expect yours to be identical.


This is why I invented CNC Storm Drains. They drain the water-trap behind the bearing to prevent water entering the bearings from the back side. I recommend these for anyone in wet conditions, for those who originally bought BB's without, it's an easy retrofit at the same cost with any bearing replacement. The results are speaking for themselves.

If you have any other BB issues I can send you a Monocrome with CNC Storm Drains to test out. We like our customers to be satisfied, but it can be difficult when not given the chance to check things out and find the cause of a problem.

Dougal wrote:

wpp1 wrote:I have had so many rust up that I brought some bearings with SS races and ceramic balls. Problem solved. Water that gets in doesn't damage the bearing.

Correct that it doesn't damage the bearing, but it does ruin the grease. You will still have to clean and regrease them regularly to get good life. The other problem is the stainless steels which are hard enough to make bearings from will still rust. Not as badly as chromium steel bearing material, but they will rust if water is left pooling inside.
The third problem is, stainless steels cannot be made as hard as chromium bearing steels, you miss out on about 3 points on Rockwell C scale. This softness eventually leads to sub-surface fatigue failure like the photos above.

If you can keep the water out, a chromium steel bearing will outlast a stainless steel bearing by a big margin. A stainless bearing has to outlast many chromium steel bearings to be economic. In the end it comes down to doing your own maintenance vs paying someone else. If you do it yourself then bearing cleaning/regreasing usually comes out best. If you pay others to do the work then bearing replacement is the usual outcome.

It should also be noted that water doesn't enter an external BB through the frame. It enters along the BB axle with the expansion and contraction of the air within the BB. I have performed experiments using bikes with sealed BB shells and moisture test strips.
Once inside an external BB it cannot get out and ends up in the water-trap which exists in every external cup against the bearing seal. Here water sits until it can corrode it's way under the seal and into the bearing.

I clean and regrease every month or more depending on how wet it has been. I agree the water enters along the BB axle so the plastic tube supplied with most BB's only makes the problem worse as it holds the water, so I don't install the plastic tube. I modified some Shimano cups to be 1mm deeper so that I could still use the shimano seals and spacer and use 7mm x 25 mm x 37mm bearings. my current setup has done 5000km's on my commuter and the bearings still run smooth.

Not disputing the water ingress via the bottom bracket axle theory at all, but water can get in via the seat and head tubes as well - some frames are definitely worse than other for this - and once it does it will pool at the lowest point of the frame, the bb.

By the way, it's good to see you again Dougal.

Oli wrote:Not disputing the water ingress via the bottom bracket axle theory at all, but water can get in via the seat and head tubes as well - some frames are definitely worse than other for this - and once it does it will pool at the lowest point of the frame, the bb.

Water can certainly get into the BB shell, but to get into a Monocrome BB it's got to squeeze between two machined aluminium parts which are o-ring sealed. It is a joint that's not going to leak with the 1psi you'll get if you fill a bike frame completely with water. It was an easy choice to make going with the machined and anodised centre-sleeve over the plastic part. The intent is major parts which last through multiple changing of the service parts (bearings and top-hats or gaskets). The plastic part would have saved 10g (thats grams, not grand).

Some other brands are using moulded plastic centre sleeves which can have a step in the moulding line. Some brands even have a centre-sleeve with seals that don't actually meet the cup when installed. Reverse engineering the competition shows some scary stories.

Ah, sweet. I misunderstood what you meant about the water getting in. Your bottom brackets sound like the business.

Oli wrote:Ah, sweet. I misunderstood what you meant about the water getting in. Your bottom brackets sound like the business.

Cheers, we have road versions too.

Besides the complete spares availability, we can offer these with pretty much any bearing choice you can think of. Monocrome 6805, Monocrome Big Steel, Enduro Big Steel, Enduro Big Ceramic Hybrid, bearings to fit a 3/4" BMX crankset, bearings to fit a 22mm BMX crankset, reducers to fit GXP cranksets. We've even got some angular contact Enduro bearings if anyone wants to try them. I don't see the advantage though, the loads on a BB are vertical/horizontal so the bearings should take load best in that direction.

One of these days I need to crank out a BB identification and parts guide. It's confusing enough already and every year it's getting worse. BB86/BB92, BB90/BB95, BB91/41 vs BB91/42, BB30 vs PF30 vs GXP and adapting systems to make cranks from one fit into the other.

TELL me about it!