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PostPosted: Mon May 05, 2014 10:30 pm 
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Location: Glermsford, Suffolk U.K
The NDS bracing angle is what ios important for a wheel lateral stiffness not the DS. The move to 11 speed makes the DS bracing angle on the DT Swiss hub comparable to others but the NDS angle is still very low. this little deatil is very imporant and is often overlooked. If the DT hubs are combined with a stiff rim then all can be well. I use DT Swiss hubs from time to time but given there price there appeal is limited. I sell more royce hubs than DT Swiss.

Flange failure occur on various hubs and they tend to occur for a reason. With DT Swiss hubs excessively high tension is a likely culprit in a vain attempt to compenate for the low NDS bracing angle forgetting of course increasing spoke tension does not increase wheel stiffness but I have gone into that already.

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Posted: Mon May 05, 2014 10:30 pm 
  • 0.20 € (including 19% VAT)
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PostPosted: Tue May 13, 2014 6:16 am 
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Posts: 473
uraqt wrote:
Why held in such contempt?

Very hard to beat DA and Campy.
I agree, and it reminds me of one my standard and awesome rants: :D
:thumbup:

As others have said, the main gripe with DT 240s and Zipps is that they are way overpriced.

Almost all cartridge bearing hubs are a total ripoff, because there's no tech in them; they're just a shell that houses the sealed bearings that are made for not much dosh by someone else. Most of the tech is in the bearing, which are almost always mass-produced and very cheap.

I can't see why Zipp, et al, should be barely any more expensive than Novatech hubs, apart from higher labour costs (are Zipp made in the U.S.?), and if Zipps include ceramic bearings, then that would obviously bump up the price.

Below is a Zipp rear hub. That's all it is: a shell, a few seals, 4 cartridge bearings, the cassette body, axle and locknuts -- pretty much the same as a Novatec hub. I used to own some Flashpoints, and the first time I pulled the rear hub apart, I couldn't believe how basic the design was. Sure, the Flashpoints have Novatec internals, but it's still fundamentally the same design.
Then I couldn't believe how cheap the bearings were to replace. I went to my "local bearing shop", and paid $60 for 4 SKF bearings for the rear Flashpoint hub, and that was full 'sucker' retail; not mate's rates or Ebay or nothin'. So, I thunk to meself: "if there's only 60 bucks worth of bearings in there, how to companies charges hundreds for cartridge hubs?!"

And what the replacement cost for a Zipp replacement cassette hub body??! Crikey! All that dosh for 2 bearings that they didn't make, an aluminium 'can', and a few pawls

Image

Having said all that, I'd say that Chris King hubs should be singled out, coz it looks like they've got some slightly more intricate stuff going on; either that, or I've just been seduced by the roller bearings and the shininess :D


Image


Last edited by User Name on Tue May 13, 2014 7:54 pm, edited 1 time in total.

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PostPosted: Tue May 13, 2014 10:48 am 
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Location: Islip, NY
Cartridge bearing hubs may be simple, but insisting on a certain level of tolerance in the machining does raise the cost. Some cheap hub tolerances are horrible. This can be reflected in bearing life. I know from discussing tolerances with a few hub manufacturers that it can go wrong very easily.

Sent from my DROID RAZR HD using Tapatalk

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PostPosted: Tue May 13, 2014 5:30 pm 
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User Name wrote:
Almost all cartridge bearing hubs are a total ripoff, because there's no tech in them; they're just a shell that houses the sealed bearings that are made for not much dosh by someone else.

Cup and cone hubs differ how? They're still just a shell with pressed in races and loose balls purchased from someone else...


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PostPosted: Tue May 13, 2014 5:56 pm 
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jooo wrote:
Cup and cone hubs differ how? They're still just a shell with pressed in races and loose balls purchased from someone else...

Yeah, but at least, for eg, Shimano has designed and machined the cups and the cones themselves (or one of their consolidated subsidiaries has), and that's what makes the hub fast or slow. So, the stuff that makes it good or bad is made and designed by Shimano.
What's "Zipp" about a Zipp hub? What "Zipp" makes one of their hubs run well? Not much at all :D It's the 20 bucks worth cartridge bearings they've shipped in from somewhere


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PostPosted: Tue May 13, 2014 6:01 pm 
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ergott wrote:
Cartridge bearing hubs may be simple, but insisting on a certain level of tolerance in the machining does raise the cost. Some cheap hub tolerances are horrible. This can be reflected in bearing life. I know from discussing tolerances with a few hub manufacturers that it can go wrong very easily.
Ok, that's a good comment, and something I forgot about. :D
However, isn't that one of the drawbacks of cartridge hubs?
Then there's the whole issue of replacing the bearings dead straight.
I once had some bearings replaced, and I reckon the guy did it slightly off, because there was some rhythmic drag. I took it back, but the bike mechanic said it he didn't feel anything, and basically told me to forget about it.


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PostPosted: Tue May 13, 2014 6:56 pm 
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Location: Islip, NY
For me, I prefer a well designed cartridge bearing setup. Well designed means that they can be adjusted so there is no play and no drag from clamping the hub into the bike. Also as previously mentioned, the tolerances need to be high.

I have these so bearing replacement can be done correctly and to preserve the bearing bores. The bores can definitely be botched up if extracted or pressed in without the right tools. However you can botch up cone/cup hub if they aren't adjusted properly as well.

Image

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PostPosted: Tue May 13, 2014 7:55 pm 
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Crikey!! Is that from NASA?!! :thumbup:
That stuff is awesome


Last edited by User Name on Wed May 14, 2014 3:40 pm, edited 1 time in total.

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PostPosted: Tue May 13, 2014 9:25 pm 
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Location: Islip, NY
That's how you professionally service bearings. It's worth the investment for hubs that are $600 a set.

To the left is the complete rebuild for 1st gen. Alchemy hubs. I've used some of those parts for other service so I still get use out of them.

To the right are the Chris King Classic service tools. Best/worst part about those tools is I've had them for over a decade and only used them once. Even then, customer's hubs didn't really need it. I felt had to use the tools at least once!

In the middle you have all the presses for most bearings and above that, proper bearing extractors.

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PostPosted: Wed May 14, 2014 5:48 am 
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I've never seen a sexier bunch of bike tools.


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PostPosted: Wed May 14, 2014 6:29 am 
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Location: London, UK
jooo wrote:
User Name wrote:
Almost all cartridge bearing hubs are a total ripoff, because there's no tech in them; they're just a shell that houses the sealed bearings that are made for not much dosh by someone else.

Cup and cone hubs differ how? They're still just a shell with pressed in races and loose balls purchased from someone else...

They differ in the way the balls are supported. Cartridge bearing hubs have support in a vertical plane only, whereas cup an cone have side support too. This means the bearing is supported better and with less rolling resistance.

Here's Shimano's illustration of why cup and cone are superior in their opinion
Image


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PostPosted: Wed May 14, 2014 6:54 am 
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^ Yeah, I agree. :thumbup:

Zipp's counter to that is the following, but I don't buy it; well, I don't buy all of it. To be fair, it's a pretty old article. Are the cartridges they use deeper-grooved than regular?
I suppose one obvious comment to make is that there have been a billion pros winning races on these hubs at a billion mph for many years, so they can't be all that bad. :thumbup: But that's got nothing to do with maintenance and reliability.

------------------------------

Radial Contact instead of Angular Contact

One area that we feel strongly about with our hub design, that is not shared by any other manufacturers in using
radial contact bearings with ideal ball location. This means that we utilize deep groove cartridges, but confine
their location to be optimal for friction and life, and do not allow them to be preloaded or adjusted by the
consumer. Why are we so adamant about this design? And what does that mean for you, the consumer?

First, radial contact bearings much better handle the loads seen in a bicycle hub, and nearly ½ the manufacturers
out there are using them. The radial ball loading better distributes the load fed into the hub, and can handle
higher loading using lighter weight bearings that generally spin smoother than cup and cone type setups.
Granted, that cup and cone bearings can be carefully adjusted to feel near perfect in your hands, but once the
wheel is on the bike, the loading of the cup and cone bearing actually results in higher ball friction and reduced life.

The key to notice in the Radial vs the Cup and Cone design is that the force Fn is the Normal (vertical) force fed
to the bearing through the weight of the rider. In the radial bearing design, Fn is the same force resisted by the
ball, but in the angular contact situation, the normal force is only one component of the ball force, since the ball
contact line runs 45 degrees to the force line, the ball must generate √2 times more force (and a lateral force
component represented by FL). This means that Factual is 1.41 times greater than Fn, so the ball in the cup and
cone scenario sees 41% higher load than the radial ball bearing. This higher ball load results in higher friction,
decreased ball and race life, and increased wear of the internal components meaning that the hub will have to be
adjusted more frequently.

The reason for the cup and cone design is quite simple, it is much less expensive to machine and assemble since
the components are adjusted for preload by the consumer. This means that the bearing race diameters can have
nearly twice the tolerance, and there is little to no need to axial tolerances in the assembly as any slop can be
accounted for in the adjustment of the cone. Contrarily, the radial ball situation, requires exact dimensional
control of both bearing bore diameter, as well as axial length of both hubshell and center spacer, as well as
requiring bearing planes to be exactly coplanar to each other. One design variant now becoming popular is to
utilize radial cartridge bearings but to use an adjustable cone design, allowing for user adjustability for bearing
preload, but this essentially negates the gains to be had in using radial cartridge bearings (other than the better
seals). The precision necessary for a perfect radial cartridge hub is on the order of +/- 0.0002” in 3 axes, this is
simply unachievable in Asian production, and is not even achievable in most types of CNC equipment, so it is
very, very expensive to obtain. However, with proper machines and fixuturing, the Zipp hub is manufactured to
these exacting tolerances and specifications, the only hub in the world to do so. The result is a hub that spins
with as much as 1 watt efficiency improvement over competing designs! What’s 1 watt mean? Well, that’s
roughly 2-3 seconds in a 40k time trial, and it was all achieved through design and process control measures.

http://www.zipp.com/_media/pdfs/technology/hubs.pdf


Last edited by User Name on Wed May 14, 2014 9:16 am, edited 1 time in total.

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PostPosted: Wed May 14, 2014 9:12 am 
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Last edited by Causidicus on Wed Jun 18, 2014 1:12 am, edited 1 time in total.

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PostPosted: Wed May 14, 2014 3:38 pm 
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I'll call bull**** on them too - Asians can produce anything...

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PostPosted: Thu May 15, 2014 3:34 am 
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Joined: Sat Dec 11, 2010 2:25 am
Posts: 148
Location: MN
I have a very hard time believing that +/- .0002" is necessary for a hub. But, if that is in fact what they're holding their parts to it is very impressive. To put it in perspective for the non manufacturing folks; I used to machine the moving parts of mechanical heart valves to their final size. Tolerances for those, which if they fail results in death in under four minutes, were +/- .0005", 2.5 times what Zipp claims.


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Posted: Thu May 15, 2014 3:34 am 
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