BB30, am I the only one that doesn't think it's the best?

[madcow]

Here's something I'd like to discuss. Why does it seem like so many people are hot for bb30? What does it really offer over more conventional setups.

yes, I know the claims that it's stiffer and lighter, but is it really better? Velonews recently did a test of bb30 cranks, and also they seemed a little bit under-whelmed(not that I'm one to be terribly influenced by Velonews, I'm also not one to disagree with them simply because they are Velonews)

I like the idea of a 30mm spindle, all cranks should go that direction, but not with the bb30 standard.

I have to agree with Trek on this one, the current bb30 standard while it does offer some advantages isn't really all it could be. A bb30 standard with something like an 80mm shell could be much better.

bb30 is a stiffer crank, at least the potential is certainly there to make it stiffer. However my understanding is that frames flex far more at the bb than a crank. Having a wider shell allows for wider downtubes and seat tubes which can reduce flex far more than a smaller tube with a bb30 crank.

bb30 is lighter, perhaps. But an 80mm shell means tubes on the frame can be stiffer and lighter, is this enough to offset the savings by not having a threaded insert?

bb30 certainly takes a more skilled mechanic to properly install it. The result of a slightly botched installation is far more drastic than on other systems. Push in a bearing crooked and you can end up ruining your frame.

Am I the only one that feels the bb30 standard falls short of it's real potential. I want to like bb30 I really do. However it almost feels to me like this was a push by Cdale to validate their existing design rather than get together with other industry people and really make a new standard which really addresses all the issues with crank/frame design.

Most of the engineers I know that work in the industry and work with carbon think that if carbon spindles such as what THM/Storck/Ax are doing are to really become all they can be, it will take a spindle diameter of at least 40mm. So in my opinion by accepting bb30 we are actually slowing progress in crank/frame design.

[tommasini]

What I don't look forward to with BB30 is how the frame becomes the sole housing for the bearings. WIth the outboard bearing designs (and Shimano's BB86 system) there is still a "disposible" cup (either threaded or press in) for the bearings to seat in. WIth those you can take the bearings in and out for cleanings/relube/replacement and you still haven't put added wear and tear on the actual frame. In fact Campy's UT arraignment relys heavily on the idea that you will should pull the bearings from time to time for cleaning/relube - so if they wanted to design a BB30 crank they'd likley have to move away from the bearings pressed onto the axles and instead have them pressed into the frame or into frame mounted bearing cup (as most others do).

I also wonder what the differnce is between seal drag of a bearing for a 30mm spindle vs 24mm spindle......

[mythical]

madcow, i've been saying this for years. I do think that BB30 is fantastic if you press in cups. It allows for even bigger axles than 30mm and we've seen what Look did with their proprietary frames and Zed cranks. 80mm does go a long way and, all things being equal, it'll allow for even bigger downtubes thus making the BB area stiffer.

A good point was frame builders. 68mm is very narrow and it suits carbon frames more than it does welded ones. Welded causes distortion of the BB shell, especially when the downtube and chainstays are so close to the outside of the BB, although mostly this will be corrected with boring and reaming. Luckily, this is where BB30 makes it easy as it's straight through the shell and a consistent diameter. I bet that if BB shells were made wider, distortion would become slightly less of an issue with welded frames and yes, crankset manufacturers would have to adapt. It's not really such a big issue, except crankset manufacturers force BB dimensions onto frame builders and this should be more in a 2-way interaction.

I think it would be great to see more frame builder team up with crankset manufacturers to come up with proprietary frame/crankset setups.

@ tommasini: Drag implies aerodynamic resistance, but if you mean seal friction, this is negligible between a 24 and 30mm axle. It's rather an issue of what type of seal is used and how many seals. For example, you can reduce seal friction by removing the inner seals of your bearings. This is a trick Campagnolo a.o. uses with their Ultra-Torque BBs.

[2002SaecoReplica]

bb30 certainly takes a more skilled mechanic to properly install it. The result of a slightly botched installation is far more drastic than on other systems. Push in a bearing crooked and you can end up ruining your frame.

If you can install a Chris King headset(viewed as the best in the world, and rightfully so) you can install BB30 bearings.

[prendrefeu]

If you can install a Chris King headset(viewed as the best in the world, and rightfully so by many, but not a majority, who also think that the differences between headsets - something that gets very little turning/action when compared to other bearings on a bicycle - is really that significant to justify spending that much more money on it) you can install BB30 bearings.

here, I fixed it for you.

[daj]

I think the biggest problem is that every manufacturer tries to create a new standard. They should just stick with one, but no manufacturer is going to give up his own standard that easily.

[CharlesM]

I think the different manufacturers playing with this is actually a good thing simply because BB30 is a reasonable starting point to developing a better bottom end.

There are sompanies complaining fo a lack of standard and companies like Cannondale that actually made a progression.


Is it the ultimate? Plainly No. But they lets talk headsets and drive spacing while we're at it... BB30 is the "current better-more commonly available"...



Part of me likes standards. Part of me likes companies that make the commitment to "see your standard and raise you"...

[GZA]

I think that BB30 is a fine design, but new better ones will comes along once marketing (the route of all evil) get bored of them!

[Menkalist]

I think BB30 is the way to go, but i had assumed that a wider BB shell was part of the re-design ...I didn't realise it was still 68mm! 75 or 80mm does sound better from a stiffness point of view as it would still be less than the current external bearing arrangement and reduce the Q-factor.

My question is how stiff is stiff enough? Every manufacturer typicaly claims their frame, cranks, wheels etc are 10, 15, 20% stiffer than last years, but does this actually equate to forward motion improvements or is the current stuff already sufficiently stiff to make further stiffness increases pointless?

[prendrefeu]

But, it's always going to be stiffer and lighter than what you just bought and are using today.
ALWAYS.

Honestly, I've already found that in terms of frame design, I like stiff... but I don't need ultra-stiff. I'm a climber, not a sprinter. I'm 150lbs at my heaviest, not a clydesdale.
So..... cranks? Stiff would be nice, but at a certain point I wouldn't be able to tell the difference except for my wallet being lighter.

[jediknights]

bb30 is really not hard to take apart and clean, in fact i think its much faster then pulling other systems apart. the barrings really dont have to be pulled out of the frame. your not supposed to take the barring apart. all you have to do is take the drive side off tap the axial out and clean the surface of everything good and lightly grease the system again. if you ride a lot witch most of us do you should have a bb over haul every 2-3 months bb30 or not.
my opinion on whether its the best or not is, well i think the whole package of what you get with the frame technology and cretin cranks are much better then standard systems. lighter and stiffer, who can complain? i wouldnt ever purchase the sram crank system though, just not a fan of sram.
sure if your not mechanically savvy or inclined the system is different and needs special tools to take apart, but just like the standard out board barrings we have now they need a special tool to take apart the system too.

my vote is for bb30 if i can have it i wouldnt pass it up, especially if it has the special letters saying CANNONDALE down the side.

peace

[Tomx]

What if you want to install a BB30 cranck on a non BB30 bracket? I know there are adaptors that should make it possible. Anyone has experience with this? I heard someone say it is not easy.... Im thiking of buying an Cannondale Hollowgram cranck, but am not sure if I will get a BB30 bracketed frame from my team next year. Should I do it or not? Where can I get the adaptors?

[Tomx]

I quote the Bicycle.net Cannondale Hollowgram SI SL Review. On the buttom someone asked more or less the same question:


Can you use the Hollowgram crank set up with non-Cannondale frames that have the BB30 set up? If so which ones?

“The quick answer is yes. It will work on any BB30 bike. You can also use it on a non BB30 BB using a adapter”.

Too bad they dont tell how you could install it on a non bb30 BB.

[Bikey]

There is a rare adapter floating around that can be used to adapt Cannondale BB30 cranks to standard English bottom brackets. Without this, you cannot use a BB30 crank on a non-BB30 frame.

[madcow]

What if you want to install a BB30 cranck on a non BB30 bracket? I know there are adaptors that should make it possible. Anyone has experience with this? I heard someone say it is not easy.... Im thiking of buying an Cannondale Hollowgram cranck, but am not sure if I will get a BB30 bracketed frame from my team next year. Should I do it or not? Where can I get the adaptors?

Yes and No. Yes this can be done with the Cannondale crank only because it's a 3 piece. It cannot be done with new 2 piece designs. The problem with using the cannondale setup and the adapter is that it pushes the q-factor out to 160mm. There's no reason for a q-factor to be that large on a double ring setup. It seems like the q-factor would negate any advantage that the crank had.

I guess my main problem comes down to bb30 being stiffer. The problem I have is that what good is making an already stiff crank stiffer if the real flex is coming from the frame. If the frame can be made stiffer it's going to have a bigger impact than making a crank stiffer.

I really want to like bb30, but I just can't seem to figure out why I should.