BB, RD and FD for Shimano crank fc-m543?
I have this crank and I want to put it on a bike, but I don't have the bottom bracket for it. I think it came off a hybrid. it's a triple with 26-36-48 rings and I want to use it with a top-pull FD and a 12-28 8-speed cassette. the frame is an old Bianchi Boardwalk steel lugged hybrid and has a 68mm bb shell. it will only work with a top-pull FD or some sort of pulley system.
what BB will work with this? should I go after a Shimano road BB or mtn BB? does it matter what level?
will I need a short, medium, or long cage RD?
can I use a mtn FD for the 48t ring, or do I need some sort of larger FD? if I need a larger one, I may have trouble finding a top-pull FD that facilitates this size ring.
The crank requires a Hollowtech II, so any from the Shimano MTB range will do, when bought retail these come with a BB; stick with MTB.
For the FD, would either look at the cable routing, or find a picture of a compete built Bianchi Boardwalk, and copy this, although a lot of FD's can now be used as bottom or top pull, you will also need to check the seat post diameter for this. For chainring sizing, FD's only come on one size, just the seatpost diameter which differs.
For the RD, simplest is to go with a long cage, as this covers all options.
are you certain that FD's made for road 50t+ chainrings are the same size as FD's made for smaller mtb chainrings?
Originally Posted by jimc101
FD's come in triple or double; they do care about the number of T difference (10 for road, 20 for mtb, unless you are using say a 53/22, which would be unusual), but not a max; you can use road on an MTB or Vice versa, if you know this, why are you asking.
The crankset you have is from an MTB / Touring groupset, why not just get somthing like Alivio, works well, and is cheap.
sorry jimc101, but I think you are incorrect here. there are absolutely different FD's for mtb and road because the shape of the cage is different. You should go with a MTB FD of some sort as opposed to a road FD, what are you planning to use for shifters?
With a 48/38/28 crankset, you can go either way with the front derailler, road or MTB. I've done both and they both work fine. What will actually force your decision is the type of shifters you decide on. If you are using road shifters, you must use a road front derailler. If you are using MTB shifters, you can use either a MTB front derailler or a road front derailler designed for use with flat bar shifters, like this: http://www.universalcycles.com/shopp...1&category=696
Having looked at a road (SRAM Rival) and mtb (Deore XT) I have lying aroung, cage shape wise, they are almost identical, the XT one is a triple, and is more beefy than the Rival which is a double, if fitting to a double crankset, both would do the same job. as the OP has a triple, he is limited to a small number of road FD's which are produced as triple compatiable, and a better option would as previously suggested to go with an mtb FD
Originally Posted by motobecane69
the arc on a road FD seems to be a lot wider than the arc on a mountain FD. or is that an optical illusion do the the lower inside edge of the cage? so there may be some issues with compatibility, but I think the matter of FD's made for triple rings vs. double rings may be more important.
anyways, I am using bar-end shifters and they are all friction, so indexing is not a problem. my main concern is what BB to buy for this crankset.