Kappius Components: the death of the freehub?

joemmo wrote:

Chief among them is the placement of the wheel bearings, which on the drive side of the rear wheel have to be inboard of the cassette, and in many cases that means they're even inside the wheel flange: almost on the centre line of the wheel itself.

Last time I serviced my freehub the drive bearings were near the axle ends as per the diagram below so apart from the larger ratchet it doesn't sound that advantageous

http://sheldonbrown.com/k7.html

The freehub bearings aren't part of the load bearing mechanism for the axle though. They're just to make the cassette spin

Barry Fry-up wrote:

The freehub bearings aren't part of the load bearing mechanism for the axle though. They're just to make the cassette spin

On Shimano freehubs (the ones shown on Sheldon Brown), the cassette body is certainly load-bearing - that's why it needs to be attached to the hub shell via a stout 10mm or 14 mm hollow steel hex bolt, and there's no bearing between the cassette body and the hub shell. The cassette body spins on two rows of tiny balls inside the body itself. The increased distance between bearings compared to older screw-on hubs was touted as one of the main advantages of the Shimano freehubs, way back in the days when they were introduced. The other was of course easy interchangeability.

That said Campagnolo, and most hubs with cartridge bearings, have none-load-bearing cassette bodies which are held on only by the hub axle itself; half of the hub bearings are between the cassette and the hub shell, almost directly under the spokes. This basically negates half of the reason why Shimano went with freehubs in the first place.

I think the Shimano design is far superior for this reason, though it wouldn't surprise me at all if it's actually protected by patents. Now if only someone made hubs with Shimano's bearing placement plus Campag's replaceable bearing cups...

Thanks so much for all the comments! I wanted to clear up some misconceptions regarding freehubs and my design. While it's possible to place wheel bearings wider using a standard cassette spline, the common Shimano designs do not do this. The outer bearing pictured on Sheldon Brown's site is not a wheel bearing. The discussion of freehubs on that site is erroneous.

If you get a complete cross section of a typical freehub and ask yourself "What does that innermost bearing on the drive side do?" you'll understand.

Nothing in my design is a result of working around existing patents. Both Shimano and Mavic have some hub designs with wide wheel bearings, but none of them have utilized the space under the cogset as I have.

Wide wheel bearings are good. Big flanges are good. But one of the biggest pleasures of riding my hub is the quick engagement. Especially in low gear on my mountain bike, and while cyclocross racing where you start and stop pedaling a bunch.

Thanks again for the comments!

Rus

rkappius wrote:

Thanks so much for all the comments! I wanted to clear up some misconceptions regarding freehubs and my design. While it's possible to place wheel bearings wider using a standard cassette spline, the common Shimano designs do not do this. The outer bearing pictured on Sheldon Brown's site is not a wheel bearing. The discussion of freehubs on that site is erroneous.

If you get a complete cross section of a typical freehub and ask yourself "What does that innermost bearing on the drive side do?" you'll understand.

Respectfully Rus, I think you are mistaken - this is what a typical Shimano freehub looks like once the cassette body is removed:

http://sheldonbrown.com/images/uniglide-oldhub.jpg

http://www.parktool.com/uploads/images/blog/repair_help/frhub_parts.jpg

There is no "innermost bearing on the drive side". As shown in the pictures there's no bearing at all between cassette body and the hub shell. The Shimano cassette body screws onto the splines seen there, and the right-side wheel bearing cup is part of the cassette body:

http://www3.big.or.jp/~number-1/Image.ShimanoFH6401RP.gif

The cassette itself rolls on more balls inside the cassette body itself (inside part no. 11 above), but it cannot normally be disassembled. This is only Shimano freehubs though, and all other freehubs I have seen are NOT designed this way.

But now that you are here Rus, I do have two questions for you. You mentioned cyclocross, so I'm wondering how well the cut-out design of the hub sheds mud. I think a lot of us would think it's annoying to have a large amount of mud trapped in the hub shell, even if it doesn't affect the bearings.

Secondly I wonder if the choice of re-manufactured XX and Red cassettes is necessitated by the larger freewheel mechanisms in your hubs. I was just looking at the Campag cassette on my bike, and the old eye-measurement seems to say that there's simply no room in there for a 57mm freewheel mechanism if the cassette isn't hollow like the XX. Those things are over £200 a pop, and must certainly be part of the high cost of your hubs.

Thank you and keep up the great work.

Well I stand corrected! Thanks for the education - every hub I've ever dissected, including Shimano's, has had narrowly set drive side bearings, Including modern Dura-Ace:

http://techdocs.shimano.com/media/techdocs/content/cycle/EV/bikecomponen...

Knowing that some freehubs have wheel bearings outboard changes my argument, but only slightly. To me, It still seems unnatural and unnecessary to interface the inner cogs to the small diameter of the standard cassette body. Why not use that space to make the hub shell simpler and more purpose built? That's what I've done, and sized my external drive to fit comfortably under an 11-23 road cogset.

After multiple hub failures personally over 30 years of racing I sat down and drew what I thought would be the simplest and most direct hub design. I alway use as a guide Albert Einstein's Constraint: "Everything should be kept as simple as possible, but no simpler."

That's what I've tried to accomplish. Traditional freehubs seem unnatural and complicated to me.

Now to address a couple of thoughts and questions.

Regarding stiffness of the hub, and whether it can be felt. Unfortunately the flex in rims, spokes, and hubs are all additive. So yes, you can feel the stiffness afforded by large flanges and wide wheel bearings.

Cut-outs, and especially when used in cyclocross. At first blush it seems that the hub will "fill with mud." In practice it's not been a problem. The spinning spokes first deflect most debris. The debris that does get get in is forced away from the hub due to the effects of inertia. What does end up on the hub is easily washed away. In 2 years of use mostly on the mountain bike it's been a non-issue.

One thing the cut-outs do accomplish is making people take pause and think. I want people to think about hubs and the cut-outs are a great way to make that happen. They are not core to the design, and can easily be deleted.

With regard to your Campy cassette. Yes there is room for my drive under it. Think about the space between the innermost cog and the cassette body. There is plenty of room, a 23 tooth cog is 85mm in diameter. A 21 is about 78mm. But your cassette does need to change to transfer to my large drive, and the SRAM cogsets are the simplest for me to rework today.

What I've strived for is a simple, reliable, well performing hub. When I described it to Joe Breeze and compared it to the change from interior bearings on a BB to external bearings, he exclaimed "it's far more important than that!"

I hope you agree. Thanks again for the comments, Rus