I have a MTB frame that I want to put a compact road crankset on. Actually it is a Cannondale Bad boy (stupid name, I know) that is a kinda sorta hybrid. I found that external bearing cranksets have a limitation that I didn't know about: it doesn't appear that you can do any tricks with the chainline. If you buy a road crankset, you will get the chainline, usually 43.5mm, that is inherent to the design. A MTB outboard bearing crankset has spacers, but they are only there to compensate for a the differences between 68mm and 73mm shells. Due to the design of the assembly, it doesn't look like there is a way to play with the chainline at all. I would love to hear that I am wrong on that subject.
So, like many other MTB frames, the 43.5mm chainline on this bike comes too close to the chainstays for comfort. I haven't actually tried it yet, but I really don't want to learn the hard way. Cannondale tech said they didn't think it would work and my measurements haven't been encouraging. The other option which looks like it may work is to use an Octalink or Isis crankset and instead of using the 108-109mm BB for doubles to get the 43.5mm chainline, use a 118mm BB designed for triples to get the chainline back to about 48mm. Opinions?
I have a MTB frame that I want to put a compact road crankset on. Actually it is a Cannondale Bad boy (stupid name, I know) that is a kinda sorta hybrid. I found that external bearing cranksets have a limitation that I didn't know about: it doesn't appear that you can do any tricks with the chainline. If you buy a road crankset, you will get the chainline, usually 43.5mm, that is inherent to the design. A MTB outboard bearing crankset has spacers, but they are only there to compensate for a the differences between 68mm and 73mm shells. Due to the design of the assembly, it doesn't look like there is a way to play with the chainline at all. I would love to hear that I am wrong on that subject.
Nope, you are right.
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So, like many other MTB frames, the 43.5mm chainline on this bike comes too close to the chainstays for comfort. I haven't actually tried it yet, but I really don't want to learn the hard way. Cannondale tech said they didn't think it would work and my measurements haven't been encouraging. The other option which looks like it may work is to use an Octalink or Isis crankset and instead of using the 108-109mm BB for doubles to get the 43.5mm chainline, use a 118mm BB designed for triples to get the chainline back to about 48mm. Opinions?
On cross frames also-using an outboard bearing, road crank...makes for chainring interference with the chainstay. How about a square taper crank/BB, the spindle which comes in lots of lengths, to make the clearance and chainline as good as possible.
On cross frames also-using an outboard bearing, road crank...makes for chainring interference with the chainstay. How about a square taper crank/BB, the spindle which comes in lots of lengths, to make the clearance and chainline as good as possible.
I thought about square taper, but there aren't very many options for compact. Campy makes a few very expensive ones, Centaur and Chorus carbon, but that is more than I wanted to spend. Other ones I've seen I had never heard much about them. Any recommendations?
On cross frames also-using an outboard bearing, road crank...makes for chainring interference with the chainstay. How about a square taper crank/BB, the spindle which comes in lots of lengths, to make the clearance and chainline as good as possible.
I thought about square taper, but there aren't very many options for compact. Campy makes a few very expensive ones, Centaur and Chorus carbon, but that is more than I wanted to spend. Other ones I've seen I had never heard much about them. Any recommendations?
Sugino makes excellent, inexpensive cranks for square taper BBs. They're widely available too.
There's nothing wrong with using an older crank either.
On cross frames also-using an outboard bearing, road crank...makes for chainring interference with the chainstay. How about a square taper crank/BB, the spindle which comes in lots of lengths, to make the clearance and chainline as good as possible.
I thought about square taper, but there aren't very many options for compact. Campy makes a few very expensive ones, Centaur and Chorus carbon, but that is more than I wanted to spend. Other ones I've seen I had never heard much about them. Any recommendations?
How about something like a Sugino XD? It comes as a 110/74 triple, but you can fit the rings of your choice and just leave the inner ("granny"😉 ring off. Nice stuff, available for under $50 with steel rings (which you won't be using). Sugino also makes a "compact double" version (i.e., no 74mmBCD inner ring mount for more money.
On cross frames also-using an outboard bearing, road crank...makes for chainring interference with the chainstay. How about a square taper crank/BB, the spindle which comes in lots of lengths, to make the clearance and chainline as good as possible.
I thought about square taper, but there aren't very many options for compact. Campy makes a few very expensive ones, Centaur and Chorus carbon, but that is more than I wanted to spend. Other ones I've seen I had never heard much about them. Any recommendations?
One of the reasons I muck with this NG-Campag makes aluminum compacts starting with Mirage at about $115, Veloce at $130 and Centaur at $170...110mm BCD, very nice and with a $30 BB, very economical.
Mirage is Veloce but bl;ack, Veloce is Centaur with less expensive rings, Centaur is Chorus quality rings but aluminum.
One of the reasons I muck with this NG-Campag makes aluminum compacts starting with Mirage at about $115, Veloce at $130 and Centaur at $170...110mm BCD, very nice and with a $30 BB, very economical.
Mirage is Veloce but bl;ack, Veloce is Centaur with less expensive rings, Centaur is Chorus quality rings but aluminum.
Thank you, that is great information. I haven't recently seen anything other than carbon compacts from Campy, but an aluminum Centaur crankset would be very cool. I could special order one if need be. The next question is: what is the spindle width for the typical 43.5mm chainline? 'Cuz what I need to do is get one that is 8-10mm wider to get an MTB style chainline. Am I correct in assuming that most square taper BB's will work? If Campy has one in the length I need, that would be great, but I could be persuaded to spend a few extra bux on a Phil Wood.
One of the reasons I muck with this NG-Campag makes aluminum compacts starting with Mirage at about $115, Veloce at $130 and Centaur at $170...110mm BCD, very nice and with a $30 BB, very economical.
Mirage is Veloce but bl;ack, Veloce is Centaur with less expensive rings, Centaur is Chorus quality rings but aluminum.
Thank you, that is great information. I haven't recently seen anything other than carbon compacts from Campy, but an aluminum Centaur crankset would be very cool. I could special order one if need be. The next question is: what is the spindle width for the typical 43.5mm chainline?
111mm ISO taper
'Cuz what I need to do is get one that is 8-10mm wider to
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get an MTB style chainline. Am I correct in assuming that most square taper BB's will work? If Campy has one in the length I need, that would be great, but I could be persuaded to spend a few extra bux on a Phil Wood.
To get 5mm more length of the BB-see Phil Wood. 'Most' BBs will work but not ideal.
