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Bottom brackets and headsets
Being fairly averse to change, I've not kept up with the developments
in Bottom Brackets and headsets. I've tried a Favourite Search Engine to look for a summary of what's what, but don't seem to have the right search terms. Can some kind soul summarise what the latest deal with bottom brackets is - the kind with the bearing outboard - and why they're so good. How are the bearings attached to the bike? Bear in mind I think square tapered cranks are a New Thing. And then a similar thing with head sets. I'm a Stronglight A9 man myself, and have trouble even considering a threadless steerer. AIUI integrated headsets do away with headset cups and the bearing press directly into the headtube. Doesn't seem that smart a move to me. What are the advantages? Or have I got it wrong (again)? Tim |
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Bottom brackets and headsets
"Tim Hall" wrote in message
... And then a similar thing with head sets. I'm a Stronglight A9 man myself, and have trouble even considering a threadless steerer. AIUI integrated headsets do away with headset cups and the bearing press directly into the headtube. Doesn't seem that smart a move to me. What are the advantages? Or have I got it wrong (again)? Opinion is divided on integrated headsets, mostly people saying they're a bad thing since the hole in the frame can grow and make the entire thing sloppy. But I did rather like the fact that I could fit one without tools - the bearing isn't pressed into the tube. cheers, clive |
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Bottom brackets and headsets
Tim Hall wrote:
Being fairly averse to change, I've not kept up with the developments in Bottom Brackets and headsets. I've tried a Favourite Search Engine to look for a summary of what's what, but don't seem to have the right search terms. Can some kind soul summarise what the latest deal with bottom brackets is - the kind with the bearing outboard - and why they're so good. The whole combination of cranks and bearings is claimed to be lighter and stiffer. Drag is higher, though, apparently. How are the bearings attached to the bike? Bear in mind I think square tapered cranks are a New Thing. Have a look at the diagrams on the manufacturers websites. Different makers do it in different ways. I haven't bothered to learn a lot about them yet because Campag don't make triple versions. And then a similar thing with head sets. I'm a Stronglight A9 man myself, and have trouble even considering a threadless steerer. AIUI integrated headsets do away with headset cups and the bearing press directly into the headtube. Doesn't seem that smart a move to me. What are the advantages? Or have I got it wrong (again)? Again they're supposed to save weight, also enable low stack height and neat appearance. There are variations, some less crazy than others. ~PB |
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Bottom brackets and headsets
Tim Hall wrote:
Can some kind soul summarise what the latest deal with bottom brackets is - the kind with the bearing outboard - and why they're so good. How are the bearings attached to the bike? Bear in mind I think square tapered cranks are a New Thing. The bearings screw in: http://www.wiggle.co.uk/images/shima...20b%20cups.jpg Outboard bearings are an attempt to combine the following: - larger diameter axle for stiffness / reduced weight - decent size bearings (the larger axle means you can only fit tiny bearings inside the shell, hence sticking them outboard). - something other than a square taper interface If you're happy with square taper I don't think there's any compelling reason to change. Personally I never got on with square taper cranks (they always started creaking), so I quite like the outboard bearing ones. And then a similar thing with head sets. I'm a Stronglight A9 man myself, and have trouble even considering a threadless steerer. AIUI integrated headsets do away with headset cups and the bearing press directly into the headtube. Doesn't seem that smart a move to me. What are the advantages? Or have I got it wrong (again)? The main advantage is easier assembly. Here, OTOH, are some disadvantages: http://www.chrisking.com/tech/int_he...explain_1.html Anthony |
#5
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Bottom brackets and headsets
in message , Tim Hall
') wrote: Being fairly averse to change, I've not kept up with the developments in Bottom Brackets and headsets. I've tried a Favourite Search Engine to look for a summary of what's what, but don't seem to have the right search terms. Can some kind soul summarise what the latest deal with bottom brackets is - the kind with the bearing outboard - and why they're so good. How are the bearings attached to the bike? Bear in mind I think square tapered cranks are a New Thing. I too think that square taper cranks are a good thing. However, there are reasons why the new systems /may/ be better (I still use square tapers). Firstly, the actual bearing races are further apart, which means that they can resist the rocking action of the bottom bracket spindle better. Second, the bearing races are larger diameter; third, the spindle is larger diameter which means it can be stiffer with less material, and consequently lighter. The cups screw into the ends of a conventional bottom bracket shell (except on some Cannondales, which have oversize BB shells). Consequently the new systems can be fitted to conventional frames. And then a similar thing with head sets. I'm a Stronglight A9 man myself, and have trouble even considering a threadless steerer. AIUI integrated headsets do away with headset cups and the bearing press directly into the headtube. Doesn't seem that smart a move to me. What are the advantages? Or have I got it wrong (again)? You're wrong. With the standard threadless headset, the head tube is just a plain tube, and the bearing sits outside it. With newer, 'integrated' threadless headsets, the inside of the tube is shaped to accommodate the whole bearing inside it, but it isn't pressed in and you can disassemble it without tools (the lower cup still has to be pressed onto the forks). What was good about the old type over threaded headsets was just that they were a lot simpler. The new integrated ones are neater, but aren't yet standardised so lose some of the simplicity benefit. -- (Simon Brooke) http://www.jasmine.org.uk/~simon/ ;; I can't work yanks out...... ;; Why do they frown upon sex yet relish violence? ;; Deep Fried Lettuce |
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Bottom brackets and headsets
Simon Brooke wrote:
The cups screw into the ends of a conventional bottom bracket shell (except on some Cannondales, which have oversize BB shells). Cannondale are encouraging other people to adopt the same standard: http://www.bb30standard.com/ http://www.bikebiz.co.uk/news/24323/...bottom-bracket The "COMPANIES WHO'VE ADOPTED THE STANDARD" links page still only lists Cannondale though. The new Trek Madone has an oversize shell too, 90mm wide so the bearings end up in the same place as in external cups on a standard shell, apparently. http://www2.trekbikes.com/madone/technology/efficiency/ http://www.velonews.com/tech/report/...s/12366.0.html http://neilroad.blogspot.com/2007/06...ost-about.html What was good about the old type over threaded headsets was just that they were a lot simpler. The new integrated ones are neater, but aren't yet standardised so lose some of the simplicity benefit. The Madone also has 1.5 inch lower headset bearings. http://www2.trekbikes.com/madone/technology/strength/ Both changes seem to make some sense, but whether they will become a new standard or be specific to one model from one manufacturer remains to be seen. |
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Bottom brackets and headsets
Quoting Alan Braggins :
Simon Brooke wrote: The cups screw into the ends of a conventional bottom bracket shell (except on some Cannondales, which have oversize BB shells). Cannondale are encouraging other people to adopt the same standard: Don't tell me; it's a _different_ outsize BB to the one used by BMX one-piece cranks? -- David Damerell Kill the tomato! Today is Second Brieday, June. |
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