[CreeP]

I don't know if you noticed but the whole darn bike world seems awash with BB sizes, you've got your different length spindles for mtbikes, your three different 'euro' shells (two widths and a threading annomaly from italy just to mess things up) Cannondale has been putting out what they call their 'system integration' or SI setup which uses a completly different everything short of chainring mounts and pedal boss, Pinnarello is doing something practically the same only, different. Then of course there's truvativ with their oversized version of the isis/euro idea. And we haven't got into the ****storm in bmx. What you haven't heard? there are now four differnt shell designs competing for supremacy over the now effectively passe euro and american.

So what do you do? What if you want to make an intergrated system?

 

[Changleen]

The Spanish BB by Fly Bikes rules What do you mean by integrated? Like Saint?

 

[CreeP]

no, integrated like cannondale.

 

[Repack]

Not really sure how the C-Dal works, but I wouldn't be surprised to see the s-storm settle with a press-fit/Shimano 2-piece crank design. Something like the old Klein BBs. I just bought a set of new Shimano LX cranks and was blown away by how stiff they are. The only drawback is that the chainline is a little wider than before. Doesn't make a difference in shifting, but it seems like the drivetrain could wear a little faster becasue of it.


Does anybody know if there are any significant patents regarding the Shimano design that would prevent someone from copying it? Its not like their octalink- 2-piece cranks with pinchbolts have been around on BMX bikes for years.

 

[CreeP]

can you tell me any more about the Klein?

 

[Repack]

can you tell me any more about the Klein?

"Normal" bb shell other than that is wasn't threaded. A bearing pressed in from either side and then the spindle pressed into the bearings. It was held together with loctite so no Profile-style spacer was needed. I think that its downfall was that you needed shop tools to service it. Worked in a similar fashion to an integrated headset- another feature of old Kleins. The tool kit installed and aligned the 2 bearings and spindle symultaneously. I only worked on a few and didn't hear any complaints. I think the design went away when Trek bought them. The full Klein tool kit was huge $ though.

 

[bballe336]

i personally think its great. it means that now when you buy a set of cranks you get the whole bb with it. i think its better. in the end its less expensive and the new integrated/outboard bottom brackets are much stronger than isis.

 

[CreeP]

oh sure but when will all the experiments end? Or will we end up with brand specific cranks everywhere?

 

[recidivist]

As much as we'd like peace and love and stable BB standards, companies do this sort of thing because they think they'll make money off of it. Sometime it's done with a bit of collaboration (like the ISIS consortium which was was formed so small crank manufacturers could cash in on splined BBs without paying Shimano's licensing fees), sometimes its done without (Shimano splined). Sometimes there's a good engineering reason (i.e. outboard-bearings get around the problems with conventional splined BBs with their teeny-tiny bearings), sometimes they don't (Pinarello's proprietary BB standard, SI, the old Merlin system).

In the end, vote with your dollars. If you think BB proliferation is dumb, don't buy it. If you think a given design (i.e. ISIS) is great, buy it and convince all your friends to buy it.

And on a last note, just remember that Camagnolo, what with all their Italian style and carbon cranks, still uses square tapered BBs, the same BBs they've made for decades and decades....

 

[CreeP]

well obviously but what do you do if you're designing a frame or crankset these days? Or more accurately which standard would be the best to side with, they're all valid if approached properly but what are frames or cranksets going to be designed around in the future? Will all these recent ones blow over?

 

[draco]

Cannondales SI crankset is ONLY available for their SI bottom bracket standard. IT was only created and used on team bikes to reduce wieght and increase stiffness... too expensive to bring to a market. So in a sense, you can eliminate that as a "Standard" as only ONE crank works for it.

Euro BB's.. man thats a mess. some used in BMX, but the bearings get too small and explode. oh wait, that happens in mountain bikiing too. lets put them outside and call it X-type... oh but now the bmx kids wont run that, even tho its within 2mm of it working with a million cranks. dont forget that isis overdrive or whatever... its like almost the size of an american shell - but its threaded. wierd. because ths pindle is still tiny. which still bends.

there's the MID BB - one of the best options for bmx and other right now IMO. take the good sized bearing from a 19mm spindled bmx crank, and press em right into the frame. sweet. as light as a euro shell, with bearings that last.
Now available for 22mm cranks too!

fly's spanish BB is just tiny, and works under the same principle of pressing in bearings, but they had to have some crazy bearings manufactured... so limited options there.

What I have noticed and would like to see, is that most of the X-type BB's are all using the 6808 bearing (i think its 6808)... and that could be pressed into a frame, reducing chainline issues with the bearings sticking out.

but a lot of riders are lame, and wouldnt pay attention to/care about a loose crank issue until they wreck a frame.


euro for road bikes. very few problems there.
american for hefty mtn, bmx
mid for anyone!
spanish for no one!
gigapipe or overdrive or whatever for NO ONE EVER.

who knows man. its one easy thing to change in the industry apparently.

 

[bighitfsr]

I think the X type (outboard bearing) system is taking off.
I'm pretty sure that truvative/shimano/raceface outboard BBs are the same its just the spindle interface thats different (shimano using pinch bolts and others using various splines). It seems the obvious solution is for frame designers to compensate for the chainline issues by matching 68/73mm BB shells with 150mm dropout spacing.

IMO an oversized BB shell is a bad idea as with many suspension designs its going to interfeer pivot placement (concentric systems, konas, FSRs ... etc).

It would be lighter to press bearings directly into the frame but the X type system solves the current problems so I cant see there being much motivation to change this.

 

[Repack]

.....

What I have noticed and would like to see, is that most of the X-type BB's are all using the 6808 bearing (i think its 6808)... and that could be pressed into a frame, reducing chainline issues with the bearings sticking out....

Thats what I was getting at. I see X-type m(incl Shimano) as a sort of stop-gap meassure. The 2-piece cranks are hugely strong, have big bearings, but the chainline is a little off. Sooner or later some frame company is going to offer a bb shell that will enable the user to press bearing right into it and forget about the bb that comes with the outboard bearing style cranks. Like a reincarnation (sp?) of the Klein system that I mentioned and the Merlin system that somebody else mentioned. One cool thing about the Merlin BBs is that they had grease ports for the bearings on the shell. The bb used standard bearings, but you would pull the seal off of whichever side ended up being the inside side. There was a flange or somehting on the inside if the shell that directed the grease into the bearings. Given the price of cart bearings I think that the system might have been a bit of overkill, but it was still cool. Its the fixation on Euro-sized shells that has everyones panties in a bunch. Since outboard bearings have now gone mainstream, bigger shells will come along shortly. It makes perfect sense. Just my .02.

 

[dhpimp]

And on a last note, just remember that Camagnolo, what with all their Italian style and carbon cranks, still uses square tapered BBs, the same BBs they've made for decades and decades....

Campagnolo only uses Square Taper because there is no patent on it and they don't have their own REAL R&D (not rip off and duplicate) department...

Shimano and Cannondale are two companies that actually DO R&D .. Because there is no patent on Shimano's Hollowtech 2 design (the first to popularize the outboard bearings), everyone jumped on board. That crank/BB style was actually first used in the 80's by Bullseye and Sweet designs.

BB's and Cranks SHOULD be designed to go together.. not be two seperate units that you mix and match. Systems engineering (like Cannondale's SI crank - the stiffest crank out there) is what pushes the limits of how well something perform/holdup.

Remember that Mountian Biking is still in it's infancy - it's only about 30 years old! We are enjoying a very young sport - and one that pushes the limits of the bicycle in general.

 

[Repack]

Campagnolo only uses Square Taper because there is no patent on it and they don't have their own REAL R&D (not rip off and duplicate) department...

Shimano and Cannondale are two companies that actually DO R&D .. Because there is no patent on Shimano's Hollowtech 2 design (the first to popularize the outboard bearings), everyone jumped on board. That crank/BB style was actually first used in the 80's by Bullseye and Sweet designs.

.......

on Campy.
But don't forget the CDale Magic crankset: Slef-extracting, hollow cranks, hollow al spindle, splined, AND outboard bearings.

 

[CreeP]

the magics had outboard bearings?


-ooh the magical 666 posts!

 

[draco]

as for pressing in the bearings, I think the only issue is that the spindles are wider... ie - can you make a better chainline with existing stuff, or do you need a spindle? Because I am making my trail frame and am considering this as a solution.

 

[CreeP]

ya, you'd need a new spindle, which race face could help you with perhaps as they do do a special one for bikes with 100mm shells they also seem to be the only guys doing a non-welded and non-cryo fit for the spindle which means they're the only setup that allows you to change the spindle and keep the arms. Alternatively you could retain the original spacing and in so doing retain the advantage of the really widely spaced bearings. Only problem is that RF's bearings are i think integrated into the aluminum external cup. I'm not 100% on that though.

 

[Repack]

the magics had outboard bearings?


-ooh the magical 666 posts!

I'm all but positive. I could be wrong but I don't think so.

 

[-BB-]

The Spanish BB by Fly Bikes rules What do you mean by integrated? Like Saint?

You use spanish fly?

you must be desperate. :nuts:

 

[zedro]

Sooner or later some frame company is going to offer a bb shell that will enable the user to press bearing right into it and forget about the bb that comes with the outboard bearing style cranks.

i was thinking of that if i do another frame; not hard since i'm obsessed with CNC-everything anyways...

I think i good approach would be like zero-stack headset design; a harder 7075-T6 cup/reducer pressed into the BB shell housing the bearing, and the option of conversion cups to the old Euro shell (which of course wont work as well). Evil/E-13 could make the initial cup versions just to make people go gaga over the idea....