Integrated headsets and bottom brackets not good design...
The problem as Chris King and several other manufacturers have pointed out over the years is that integrated bearings in headtubes and in bottom brackets (BB30) inherently put undo stress directly against the frame itself. The outside race of the bearings are usually made of a very hard material such as high carbon steel or or high carbon stainless steel. In a world were we are putting extremly high amounts of load on cranksets and headsets (think impact force not constant force) one of the two materials at a junction such as a bearing to mating surface is going to see some sort of distribution of friction (even with great bearings) and or some sort of cohesion or distribution of high levels of "rubbing" if you will. When you have a soft or low hardness material such as carbon fiber fighting against a hard or high hardness material such as the outside of a bearing= ultimately the bearing is going to win the battle it is only a matter of time. This is why several bike manufacturers have stepped away from BB30 or integrated headset frames or have all together never made frames with integrated headsets or BB30 bottom brackets. If you read Park Tools explanation, Chris Kings, Moots, Specialized and so on most people agree that having an interface of direct contact on the frame with the bearings is a recipe for long term failure. However there are several great alternatives. For instance with Bottom Brackets you can still have the benifits of oversized 30mm spindle but have the bearings rest within a cup such as PF30 just like Niner uses on the Jet9 RDO. And in the case of headsets you have the internal versus the integrated. Having some sort of cup that can take the friction, cohesion, linear momentumand collision forces (no matter how small these forces are) is a good idea when mating a very hard material such as a bearing against something with such a low hardness and friction rating such as carbon fiber. Why do it, why take the risk? when you can simply put something between the bearings and the frame. The answer comes from the road frame world were there is a never ending quest to one up the other guys by making a bike a few grams lighter than the next manufacturer. As some manufacturers have said is it reduces the weight how ever slight it may be, and in the never ending quest to have the lightest frame on the market taking out a small amount of aluminum (or steel in the case of some headset manufacturers) saves some weight. Remember not all things that trickle down from the road world is necessarily a win win for the mountain bike world as well.
Originally Posted by PeopleForScience
You may be able to generate several hundred ft. lbs of constant torque with your leg against a lever (your crank arm) as you push down on it with all your weight. However unlike in the roadie world in the Mountain bike world a simply jump and landing off something as small as even a one foot jump can generate exponentially much more force. For instance a simple 150lb runner who is jogging generates roughly 1200lbs of impact step after step!
Now just imagine how much force you and your bike are generating on your headtube juntion and bottom bracket junction everytime you hit a bump, take a jump, etc. I have read that some mountain bike manufacturers have seen numbers as high as 7000 to 8000 lbs of impact force from a simple xc racer on a xc race course on the bottom bracket and headtube. Now imagine how much force all mountian, free ride and downhillers generate! remember a jogger is taking a simple stride and not actually getting there foot much more than 4 to 10 inches off the ground. Impact Force is a big reason several manufacturers such as Chris King, ect simply refuse to make integrated headsets or bottom brackets.... its only a matter of time before your frame will wear down in these highly stressed spots as the bearing has to wear on something...
yes that article I posted from Chris King may have been written in 2002 but too my understanding the laws of physics we are talking about have not changed since 2002?
Headset worry = maintenance is your friend
In response to the guy said "Nothing against king but it sure seems like companies like niner have their **** together." Really? Niner has repeadtly changed their designs to try and keep up with what is the most current. But more often than not gone back to what is tried and true ie. the new RIP9 RDO has a regular english thread bottom bracket. Furthermore over the years Niner has had a couple "oh oh" momments and had recalls and or "free" frame replacements due to errors. I am in no way bashing Niner, in fact I love Niner. I'm a Ninerd and own a WFO and and JET9 RDO. I think their suspension design is one of the best on the market if not the best. They build one hell of a strong and robust frame. (I have ridden many bikes in my 20+ years of mountain biking and I have never ridden a stiffer frame, that still pedals as efficiently and is still so plush of a ride!
But... Niner is not perfect, no one is! The point I am getting at is, Niner at least stands by their mistakes, and takes care of their clients, much better than most companies in my opinion.
More importantly, everything I have said is just my opinion, I am not an expert, and furthermore I am human so no matter how hard I try I will have some bias in my opinions, based on past experiences. Just like everyone else on these forums, all comments are just opinions, some more educated opinions than others, but all the same just opinions.
So point being, take everything you read on these and all forums with a grain of salt!
it doesn't matter what type of headset you end up getting- integreated, inset, etc. the main thing to do, is check your headset regularly, with your regular maintenance and you should be fine.
Maintenance is your friend! and your bike will reward you for it!