"Proprietary bottom bracket"

[GregL]

Originally Posted by bicycletricycle

Certainly some ideas or features do require custom components to execute but putting bearings in a frame these days should not require a new standard.

Agreed!

Greg

[weiwentg]

Originally Posted by rain dogs

I may be the voice of the minority but I don't see a huge problem with this BB other than I would prefer it be threaded, but as Matt pointed out:

1. The more Gravel bikes trend toward the Mountain spectrum, the less we're going to see 68mm wide BB shells. Want more clearance and double?... no free lunch

2. Hollowgram cranks are already A+++ cranks and they'll play nice with the system, so no one is suffering by using the Hollowgram crank system. Some would say you're using some of the best (strongest, lightest, most modular) cranks available.

3. The Wheel dish is a bit annoying, but unless you're swapping wheels between bikes it's one and done.... build a sweet pair with the correct dish y voila.

That said, I wouldn't buy it, but the BB isn't the make-it or break-it issue for me.

James Huang at Cyclingtips relayed Cannondale's rationale for the BB as part of his review of the Topstone (emphasis mine):

The Topstone Carbon uses Cannondale’s BB30-83 Ai bottom bracket shell, which is similar to standard BB30 in that the bearings press directly into the frame. Already used on the Synapse, SuperX, and F-Si hardtail, BB30-83 Ai is an asymmetrical shell that’s 5mm wider on the non-driveside than than driveside, and 83mm-wide overall. According to Cannondale, this provides more space for the chainstays to move outward for increased tire clearance.

Also borrowed from the F-Si and SuperX is Cannondale’s Ai, or asymmetric integration, concept. This offsets the entire drivetrain outward by 6mm, which creates even more room for tires and drivetrain bits.

Downsides? Well, the wider bottom bracket shell requires a longer spindle, which then increases the Q-factor relative to standard road bikes. Granted, narrower Q-factors aren’t universally better for everyone, but nevertheless, many riders will likely be bummed to see this.

And while the rear end uses standard 142mm-wide hubs, the rim has to be dished over to the non-driveside to keep it centered in the frame. This actually improves wheel strength by evening out the spoke bracing angles, but it also means that off-the-shelf wheels won’t work without modification (which won’t always be possible). And then there are all the proprietary parts required, such as the custom bottom bracket spindle and custom chainring spider.

I'm not a fan of proprietary standards either, though.

[oldpotatoe]

Originally Posted by weiwentg

James Huang at Cyclingtips relayed Cannondale's rationale for the BB as part of his review of the Topstone (emphasis mine):


I'm not a fan of proprietary standards either, though.

Ya left out the last sentence..

Consider it the price of progress, I guess.

[steamer]

The bike industry creates new stuff for the primary purpose of suckering people into buying new stuff to supplant their not-yet-worn-out older stuff. Because new stuff is obviously always better, right?

[Jeff N.]

Originally Posted by steamer

The bike industry creates new stuff for the primary purpose of suckering people into buying new stuff to supplant their not-yet-worn-out older stuff. Because new stuff is obviously always better, right?

In the bike industry, I'm afraid necessity is NOT the Mother Of Invention. It's just change for the sake of.....change. For the most part, anyway.

[oldpotatoe]

Originally Posted by bicycletricycle

I am a product designer / engineer. I make things for a living. I know about the role of creativity. In my experience Solving a difficult problem with custom made proprietary parts is more often a workaround or a marketing ploy than some real move of creative genius. Certainly some ideas or features do require custom components to execute but putting bearings in a frame these days should not require a new standard.

What he said..this isn't a new way to put a camera on a ball bearing swivel in the next Mars explorer, it's a bicycle...

[charliedid]

Here's your new bike. Get in Line. Here's your new bike. Get in ...

[Mark McM]

Originally Posted by weiwentg

James Huang at Cyclingtips relayed Cannondale's rationale for the BB as part of his review of the Topstone (emphasis mine):

Cannondale's explanation doesn't hold water. Tire clearance and brake disc clearance issues are not unique to the Topstone. MTBs have already dealt with the issue and come up with standard solutions, so Cannondale could have just adopted already existing components and solutions for the Topstone, without having to do a completely proprietary re-design of the rear triangle/drivetrain. As far as the Q-factor differences between MTBs and road/gravel bikes, SRAM already has narrow Q-factor (156mm) MTB cranks that have a wider chainline and work fine with standard BBs.

[sg8357]

Originally Posted by bicycletricycle

Nobody cares how easy manufacturing and maintenance is if they cant get the gearing they want or can't find parts to repair their bike 10 years from now.

Geez, in 10 years the bikes will be 187% stiffer, 132% more compliant,
who would want to ride an olde timey bike.
(Numbers from the 2029 Cannondale press packet)

[yinzerniner]

Originally Posted by Mark McM

Cannondale's explanation doesn't hold water. Tire clearance and brake disc clearance issues are not unique to the Topstone. MTBs have already dealt with the issue and come up with standard solutions, so Cannondale could have just adopted already existing components and solutions for the Topstone, without having to do a completely proprietary re-design of the rear triangle/drivetrain. As far as the Q-factor differences between MTBs and road/gravel bikes, SRAM already has narrow Q-factor (156mm) MTB cranks that have a wider chainline and work fine with standard BBs.

As an engineer though, do you find Cannondale's rationale sound for the AI concept? Benefits seem to include:
-More even spoke tension
-Better hub flange angles
-Less need for asymmetric rims on rear wheel
-Shorter chainstays per given tire clearance without adding bulk (ie dropped chainstays)

Just looking at the benefits it seems like maybe rear wheels should have been dished like AI from the beginning, although that's really only been feasible since the advent of carbon construction and/or advanced titanium and alloy tubing since the chainstays being asymmetric adds complications of their own with regards to frame construction

As a consumer I think it's total b.s. - as stated, solutions that stray far beyond what has already been developed to combat the problem just for the sake of being different. But the benefits (mostly) seem to be there.

[Jaybee]

I also think it's a little unfair to say that there isn't a point to the AI engineering. 415mm chainstays are insanely short for the tire clearance, and you can still fit a 50-34 double. You have to do something to get there, whether that is AI, dropped chainstay, elevated chainstay, some kind of yoke for metal bikes. For comparison, some gravel bikes that do some kind of non-symmetry in the chainstays. :

Allied Able: 420mm, can't fit a double with the elevated chainstay
Trek Checkpoint: 425mm
Open UP: 420mm,
Salsa Warbird: 430mm,


You can decide if you think the Cannondale approach of super short chainstays and longer front centers is geometry that works for you on gravel, but it's pretty clear that if you want that, AI gets you there.

[Mark McM]

Originally Posted by yinzerniner

As an engineer though, do you find Cannondale's rationale sound for the AI concept? Benefits seem to include:
-More even spoke tension
-Better hub flange angles
-Less need for asymmetric rims on rear wheel
-Shorter chainstays per given tire clearance without adding bulk (ie dropped chainstays)

Just looking at the benefits it seems like maybe rear wheels should have been dished like AI from the beginning, although that's really only been feasible since the advent of carbon construction and/or advanced titanium and alloy tubing since the chainstays being asymmetric adds complications of their own with regards to frame construction.

The first rule of engineering is, "don't re-invent the wheel." As noted before, all the features you mention have already been accomplished with previously standardized components and systems, so the Cannondale system creates more problems than it solves. For example, they have created a proprietary asymmetric 83mm BB shell, when an asymmetric 86mm BB shell already exists (called BBRight). And the BBRight system was designed to work with already existing standard BB cups, bearings and cranks, whereas the Cannondale system does not. How is that progress?