How to check Front Derailleur fit?

[1FJEF]

So I have to change my E-type bottom bracket, which means I have to change my bottom pull, top swing FD. The BB is a 68x110mm. It'll be a UN-55.
It's a late '90s Specialized Expedition Elite MTB, 21speed 35mm seat tube. Triple front rings, biggest is 42 tooth. I can check the other ring sizes if I need to.
I hate to put something cheap or crappy looking on it, the Acera on it seems to be better made & nicer looking than current offerings in that range.
The one that surprised me (seemed nicely made & looked good) was this lower line cheapie.

ALIVIO FD-M413


So how do I tell if it'll work/fit with a 42T ring? How do I make sure the angle of the seat tube is OK? Do I check this angle from plumb to a line in the seat tube center, or from the chain stay to seat tube c-t-c?
What's Hyperdrive?
Will it work with a 7 or 8 speed cassette and chain?
Do I have to worry about chainline compatibility?
Should I just shut up, buy it, try it, toss it in the parts box if it's a no go?
Do you have a better suggestion?
Sorry, I'm ignorant. I can't check at the LBS, they have cheap junk & crazy scary expensive.
When I've changed them in the past I've used the same model as whatever was OEM after a wreck or mishap.

[nfmisso]

Hi Jeff;

I put one of these on my GT Triple - really nice unit, very easy to set up and adjust. I had to make a collar for it as it was intended for a 34.9mm seat tube (vs 28.6) I bought a foot of 6061 T6 aluminum alloy tubing; 1.375" OD, 1.125" ID - used this solution on both the SR and the GT.

It is a very smooth FD, I purchased a couple more from Crosslake Sales on ebay - at $0.99 it is an incredilble deal, at $10- it is still a good choice.

According to Shimano, the M413 will work with chainrings up to 48T max (would probably do 50T in a pinch); 42T is no problem.

http://techdocs.shimano.com/media/techdocs/content/cycle/SI/Alivio-Acera/FrontDriveSystem/SI_6KFFB/SI-6KFFB-002-ENG_v1_m56577569830750020.pdf
http://techdocs.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/FD/EV-FD-M413-2674B_v1_m56577569830728361.pdf

[1FJEF]

1) The techdoc specifies a BB 13mm wider than my existing. Is that because the doc refers to Alivio crankset install too?
2) The tech doc shows the M413 as a top pull, and I can't see in the picture where it would work as a bottom pull. Can you look at yours & confirm, I think your green bike has one & it looks like a bottom pull cable.
3) I guess FD angle is center line of the chainstay & seat tube. Your green triple triangle looks about the same angle as my Specialized.

[1FJEF]

I goofed. There are clearance issues as the existing FD is an E-type & when it moves to the inner chainring it (the fd body) almost touches the seat tube. I believe I am incorrect & will need a bottom swing as I have interference with something mounted to my water bottle braze-ons. A bottom mount or (bottom swing?) is going to have clearance issues when it moves to the smallest front ring, I think the inner side of the FD mechanism will hit the seat tube as it tries to move in. I'll have to take pics & post again. Sorry guys.

[nfmisso]

Hi Jeff;

1) tech doc is referring the Alivio crankset.

2) The M413 can be used as either a top or bottom pull - great to have one model that works either way

3)......

next - on my GT, the FD is mounted between the bottle screws - I need a spacer there to use that mount.