I have an Ultegra BSA bottom bracket hosting a hollowtech crank. Does anyone know if I can replace just the bearings with ceramics? Or, do I have to go with an entirely new bottom bracket?
Well, I wasn't really asking whether or not ceramic bearings would do anything for me, and if they were worth the money. What I was asking is can I buy just the ceramic bearing cartridges to fit into the cups of the Shimano Ultegra Bottom Bracket, or do I have to buy a complete ceramic bearing bottom bracket?
As for efficacy, I have some first person reports that ceramic bearings for the derailleur pulleys and for the bottom bracket, do make a significant difference in drivetrain friction.
I *think* those bearing cartridges are replaceable, but you probably won't save much $ doing it that way either. Probably easier to just get the whole new BB. I too have first-hand observations about ceramic bearing/OSPW efficiency. The rear disk free-wheeling on my TT bike (ceramic BB and OPSWs) keeps the drive train turning for an insane amount of time. That wasn't the case with "regular" bearings/pulleys. Might only be a few watts, but I'll take them!
If they were the same price as good quality steel bearings I wouldn't buy them. As for putting them into Shimano cups, yes...it's possible. Done it w/ regular bearings dozens of times. You just have know someone that has the proper tools.
The ideal application(s) for ceramic bearings are:
High speed...thousands of rpm. Not something you'll ever encounter on a bicycle.
Pure radial load. Again, not a bottom bracket.
Clean working environment. You know what I'm gonna say.
High heat. Again...
I just think there is way to much friction in the average drivetrain. Seems more riders are addressing this with ceramic bearing oversized derailleur pulleys.
Ceramic bearings are great for jet engines, where shafts rotate at 100,000 rpm. For a bike rotating at best 100 rpm, they are a colossal waste of money. Only an easily duped moron would buy them for a bike.
There's a market for $500 power cords and $1000 speaker cables, so if that's what you want no problem. For me, if I were spending money on ceramic bearings I would probably pop for the whole BB and not have to worry about making a mistake installing the bearing.
The benefit isn't zero (unlike speaker cables) and I can prove it, everything costs something, value (or "worth it") is a personal decision. Some people just like to pimp their ride and/or want to have the most efficient (or lightest or most aero) bike possible. If you don't, that's fine too.
The benefit isn't zero (unlike speaker cables) and I can prove it, everything costs something, value (or "worth it") is a personal decision. Some people just like to pimp their ride and/or want to have the most efficient (or lightest or most aero) bike possible. If you don't, that's fine too.
GKSki...I'm older now. I train to race because I love it and am ok at it for an old ****. I look for any advantage I can. More in how to train (sleep, nutrition etc...) but I do scrutinize equipment. My Factor came stock with Ceramic Speed bearings. UNless you have a huge amount of disposable $ to spend this is just not the logical place to spend it. They make virtually no difference in performance.
Not to be a hypocrite I spend a fair amount of money on clothes looking for free speed. Point is there are other places to save watts/gain speed before ceramics...
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