Yet Another Cycling Forum
General Category => The Knowledge => Topic started by: velosam on 12 October, 2015, 01:47:01 pm
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So as usual I have no idea what I am doing.
I am fed up of the gearing on my bike, so am getting a triple chainset for it (ignoring the fact it may not fit because of the chainstay, but keeping my fingers crossed on that one)
Unfortunately its to square taper bb, which is not as easy as hollowtech (in fact I can see why people like hollowtech, because even a numpty like me can swap cranksets around).
I am pretty sure the bb width is 70mm, but there does not seem to be any standard on what the length of the spindle should be for a triple rather than double.
My searching (blame the lack of parliamentary questions) - has lead me to the fact that I need a 125mm spindle (which doesn't seem to be in stock at spa)
So has anyone done a swap from double to triple and if so what spindle length do I need.
thanks
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It depends entirely on the cranks. Campag used the same BB length for both their double and triple cranks in recent times.
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It depends entirely on the cranks. Campag used the same BB length for both their double and triple cranks in recent times.
Veloce triple - currently on chorus cranks (double)
Jan Heine suggests this, which means an easy swap??
Campagnolo
- Chorus (before 1995): SKF ISO taper 111 mm
- Racing Triple: SKF ISO taper 111 mm
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125mm seems awfully long. What chainset are you hoping to fit? Campag or other brand
IIRC Campag triple BBs are 115mm. I may be wrong here but it's definitely a lot shorter than 125mm.
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Campag square-taper chainsets and BBs:
Shell width is 68mm for British thread, 70mm for Italian. The taper is basically ISO.
Modern (~2000+?) Chorus and Record triple cranks were designed for Chorus and Record Triple 111mm asymmetric BB only. However, the amount of asymmetry is slight and some users are happy with symmetrical versions. Modern Chorus/Record doubles were designed for 102mm.
All other Campag triples (at least in the cartridge era) are designed for 111mm symmetric like doubles by default, or 115.5mm on bikes with fat (32mm+) seat tubes to give the front mech more room. Filing a bit off the mech is an (unofficial!) alternative, though sometimes even this is not required for 111mm with 32mm seat tube. I recommend the black-version Centaur BB for these groups, which is near Chorus quality with three bearings; can be fitted with a cassette tool. Drag can be reduced by fitting the left cup with threadlocker and less than maximum torque.
Older/lower Campag cartridge BBs need a different tool and have only two bearings: probably no longer available. Campag-compatible BBs from other makes are available.
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Sorry, vintage Chorus double cranks could be on 111mm.
I will re-write my posts. I have re-written my posts.
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Sorry, vintage Chorus double cranks could be on 111mm. I will re-write my posts.
Depends on vintage I guess, mine are around 1990, not sure how I tell without taking them off or doing some weird measurement.
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Come over one evening after 20:00 and we'll pull the cranks and refit them.
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Sorry, vintage Chorus double cranks could be on 111mm. I will re-write my posts.
Depends on vintage I guess, mine are around 1990, not sure how I tell without taking them off or doing some weird measurement.
They'll be what I'm calling vintage, so will be on 111mm, which will indeed be suitable for your triple cranks (if seat tube not too fat - see my first post for details).
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Come over one evening after 20:00 and we'll pull the cranks and refit them.
We have to catch up, you dont know the half of it.
Anyway maybe tomorrow or thursday depending on what works for you.
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Whenever you like.
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Sorry, vintage Chorus double cranks could be on 111mm. I will re-write my posts.
Depends on vintage I guess, mine are around 1990, not sure how I tell without taking them off or doing some weird measurement.
They'll be what I'm calling vintage, so will be on 111mm, which will indeed be suitable for your triple cranks (if seat tube not too fat - see my first post for details).
Seat tube runs a standard 27.2 post, lets assume not too fat.
Just got to find a derailleur now and reasonably priced cranks
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We have spare triple Campag front mechs.
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As a way of an update, LWaB very kindly measured my spindle and it came in at 113mm which means a triple will fit strong on.
I just need to work out whether a campag or stronglight is a better buy
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Actually an asymmetric 115mm cup and cone BB. I expect that a Campag triple crank will fit fine. A Stronglight would likely require a new BB, as it is almost certainly JIS, rather than ISO.
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As a way of an update, LWaB very kindly measured my spindle and it came in at 113mm which means a triple will fit strong on.
I just need to work out whether a campag or stronglight is a better buy
Different tapers, I'm afraid. Campagnolo uses ISO, Stronglight JIS.
You may find that a Stronglight triple plus decent (eg Shimano) BB comes in at less money than a Campag triple. Not that there's anything wrong with the latter but I for one prefer the lower gearing that chainsets like the Stronglight offer due to the smaller PCD (hence smaller rings).
edit@ cross post with LWaB
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cheers will just get the campag triple and live with it, I really wanted the bottom gear
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The small ring can be easily changed down to 24t but will work better around 26-28t.
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another option is four bolt mtb chainsets, plenty of choice. q-factor is about 1cm wider in comparison to road cranks, but i can't say i notice it. aesthetically doesn't look right on a road bike, but perfect on hybrid. i use 48/38/28 rings which i find a great combination all kinds of riding, except racing.
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Having used all these options I find stronglight triples with big choice of rings to be really good---jis taper---make sure you get a decent shimano BB as stronglight BBs v. poor. I use 113mm axle length---but that may not necessarily be right for you (as above)
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I had to do some research on this some time ago for my Raleigh. This bike has a 70mm Bottom bracket and now has a 5T crank axle/spindle fitted. Here is a link to what I wrote up.
https://docs.google.com/document/d/1dAoNa9qNlHfHv8rUl75NFZEBuyedvI0HBCpmvDmgBaU/edit?usp=sharing
Comments/ corrections welcome.
PM.
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I had to do some research on this some time ago for my Raleigh. This bike has a 70mm Bottom bracket and now has a 5T crank axle/spindle fitted. Here is a link to what I wrote up.
https://docs.google.com/document/d/1dAoNa9qNlHfHv8rUl75NFZEBuyedvI0HBCpmvDmgBaU/edit?usp=sharing
Comments/ corrections welcome.
PM.
70mm would seem to indicate Raleigh bb and therefore Raleigh bb threads which are not the same as BSC (and which IIRC have no shoulder and a slight taper on the rhs cup, which can be a bit difficult to shift sometimes. I can't remember if the cones on the spindle are the same width apart as BSC or larger ( and not to be confused with french which also have 70mm shells but different spindle and cup dimensions to the extent that some combinations work, some have too much play and some simply don't go together at all, BTDT)
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see
https://sheldonbrown.com/bbsize.html (https://sheldonbrown.com/bbsize.html)
and/or
https://law.resource.org/pub/in/bis/S13/is.1131.2006.pdf (https://law.resource.org/pub/in/bis/S13/is.1131.2006.pdf)
which shows that 5* spindles have shoulders 55mm apart vs 3* spindles which have 52mm shoulders instead.
There are various options for assembling a BB to go in such a frame. Quite a good one is to retap to BSC, and then to use a shimano cartridge BB that is meant for use with a chaincase bracket that is trapped behind the RH cup; these fit into 70mm BB shells quite well.
cheers