Hollowtech cranksets
-liam-
Posts: 1,831
Can someone please explain these to me in a manner of which a 2 year old could understand?
Not sure I understand the sizing of bottom brackets full stop. I believe the size of mine is 68mmx110 or something like that lol. I'm thinking about buying this...
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... SIMPLEITEM
....but have no idea if it would fit
Bike is a kona fire mountain btw.
Not sure I understand the sizing of bottom brackets full stop. I believe the size of mine is 68mmx110 or something like that lol. I'm thinking about buying this...
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... SIMPLEITEM
....but have no idea if it would fit
Bike is a kona fire mountain btw.
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yeah mate will fit no problemo, you just need to use a spacer or 2 in your BB they come with the set and there is instructions in there too that can be read by a 2 year old!!!Go big or go home!!
dmr exalt
fitbike team park bmx
both my custom jobbys
:D
http://www.pinkbike.com/photo/2915789/0 -
yup, will fit as already stated above. the instructions will probably say that you should have your frame faced before fiting to maximise the life of the bearings. your local bike shop should be able to do this for you but i have no idea how much that would cost (not much though i would imagine)0
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sheepsteeth wrote:yup, will fit as already stated above. the instructions will probably say that you should have your frame faced before fiting to maximise the life of the bearings
That to provide a clean face to provide a clean sealed surface I guess ?
I'm a machinist by trade.....but I still reckon I'll get the bike shop to do it just in case I screw it up lol !
Cheers chaps, most helpful.0 -
if you brought this to where i work we would charge you £15 to fit it all.
Just incase that gives you a rough idea of price0 -
-Liam- wrote:sheepsteeth wrote:yup, will fit as already stated above. the instructions will probably say that you should have your frame faced before fiting to maximise the life of the bearings
That to provide a clean face to provide a clean sealed surface I guess ?
I'm a machinist by trade.....but I still reckon I'll get the bike shop to do it just in case I screw it up lol !
Cheers chaps, most helpful.
Nope to provide mounting faces that are Parallel to each other and perpendicular to the axle axis."Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0 -
it is to ensure that both cups run perfectly square to each other.
im a soldier by trade but as a royal engineer i chose to be a machinist as one of my trades. i have spent so little time doing it that i would definately get a bike shop to do it for me for the same reason as you!!0 -
15 quid sounds very fair and it only needs doing once!!0
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sheepsteeth wrote:it is to ensure that both cups run perfectly square to each other.
that is only half of it.
"Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0 -
nicklouse wrote:-Liam- wrote:sheepsteeth wrote:yup, will fit as already stated above. the instructions will probably say that you should have your frame faced before fiting to maximise the life of the bearings
That to provide a clean face to provide a clean sealed surface I guess ?
I'm a machinist by trade.....but I still reckon I'll get the bike shop to do it just in case I screw it up lol !
Cheers chaps, most helpful.
Nope to provide mounting faces that are Parallel to each other and perpendicular to the axle axis.
There's always one smartarse
Thats what I meant. If it wasn't parallel then it wouldn't seal
Why would the original machining of the manufacturers not be considered adequate then ?0 -
Why would the original machining of the manufacturers not be considered adequate then ?
good question, especiqally when loads of modern bikes come fitted with external BB but dont appear to be faced from the factory0 -
no sealing has nothing to do with it.
Seating has all to do with it"Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0 -
The way I understand it, if the cups aren't parallel and perfectly aligned the bearings will run at an angle on the axle and wear a hell of a lot quicker...hence the frame facing.
Or am I talking out of my arse?=========================================
Dot 4 in the eye hurts. Trust me0 -
So how does your average bike shop face the frame ? I've not seen the workshop of a bike shop with a milling machine in the corner recently.
Probably just clean them up with a file and a bit of emery cloth lol.0 -
Your LBS will use a bottom bracket facing tool , you don’t need a milling machine to do it.
Better to be thought a fool, than open your mouth and prove it.0 -
the tool used looks like a couple of shell mills bound on an axle and sprung (the spring provides a small amount of pressure) together on either side of the BB, the tool is rotated by hand and both cutting tools turn and shave a tiny amount of metal and paint to square the bb shell up.0
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Facing tool
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£375 or £600 if you want the thread chasers as well."Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0 -
should be able to knock one up for about 20 quid though if you are a machinist!0
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So if you bike already has a hollow-tech BB, would you still need to get it faced if replacing with a new one?0
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good question, i suppose if it hasnt been faced already then yes you should but f there was a real need, the manufacturer would have done it in the frst place.
for the sakes of 15 quid it is probably worth doing if it makes the BB last longer0 -
Bargain !!
Got me a deore hollowtech for 32 quid plus postage. I love ebay
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 02589627050 -
I've never had a BB shell faced on a bike and I've never had a problem with bearing wear (several Hollowtech 2s, MTB and road). I've always just slapped them in.
If you're buying decent modern frames, surely it's expected that they'll end up with an external bearing BB in, and will be built and finished accordingly? It seems to me that they are.0 -
chriskempton wrote:I've never had a BB shell faced on a bike and I've never had a problem with bearing wear (several Hollowtech 2s, MTB and road). I've always just slapped them in.
If you're buying decent modern frames, surely it's expected that they'll end up with an external bearing BB in, and will be built and finished accordingly? It seems to me that they are.
sure is right :roll: it is amazing how many modern frames that are expected to be used with external bearing bb are totally out.
the last one that come to mind is an expensive carbon road frame that was very out.
each to their own."Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0 -
my Orange came fully faced and prepared from the factory.......... another benefit of home grown quality? (runs for cover)
however on previous frames I did not have them faced and did not have any problems so would echo the fact that it is maybe not as important as is made out.0 -
Nicklouse, I've fitted H2 to a Cannondale and Marin alu, Scott and Planet X carbon and they've all been fine. If you do buy a frame that's 'very out' then of course getting it faced makes sense. I'm saying that I don't default to spending £15 on BB facing cos it's never been necessary in my experience.0
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-Liam- wrote:nicklouse wrote:-Liam- wrote:sheepsteeth wrote:yup, will fit as already stated above. the instructions will probably say that you should have your frame faced before fiting to maximise the life of the bearings
That to provide a clean face to provide a clean sealed surface I guess ?
I'm a machinist by trade.....but I still reckon I'll get the bike shop to do it just in case I screw it up lol !
Cheers chaps, most helpful.
Nope to provide mounting faces that are Parallel to each other and perpendicular to the axle axis.
There's always one smartarse
Thats what I meant. If it wasn't parallel then it wouldn't seal
Why would the original machining of the manufacturers not be considered adequate then ?
It's so the bearings run concentric to eachother.
The BB shell will be near enough correct, the tolerances aren't that great when they're made but they are suffice. But you might have a dodgy one that slipped through the manufactures quality control, you never know, so it's worth doing.
The reason it's a good idea to get it done is to clean off any paint/laquer of if there are any small marks in the surfice will will throw up a lip.
This just helps to ensure there is an equal amount of pressure on each bearing. Also if the bearings bugger up in the future you know it wasn't down to the shell.0 -
My Chris Boardman roadbike has suffered from a slightly stiff crank from new compared to my other bikes. Finally removed one BB cup to find factory had not faced the shell as it is still painted. You could see as screwing in the cup the BB shell is a tiny fraction out of square. The factory had massively over-torqued the cup as well (perhaps in an attempt to overcome the irregularity caused by the paint).
Have complained and Halfords have offered to pay for another shop to face the BB shell for me and give me a new BB (I'm, concerned that after 1000km the original bearings will have suffered excessive wear)._______________________________________________
Trek hardtail
My new Beastie, a custom build Yeti 575
And Chris Boardman Road Bike when I feel the need for speed instead of mud0 -
<pedant>
Fitting Hollowtech cranks and a BB doesn't generally require the shell being faced.
Fitting Hollowtech II cranks does.
Hollowtech is the name for Shimano's method of making hollow cranks. It's been around for ages.
Hollowtech II is the name for Shimano's method of attaching the right hand hollow crank to the BB axle and using external BB bearings.
</pedant>0
