BB Mounted Front Mechs

Does anyone have experience with the above?? Looking for a front mech for my build and considering getting a BB mounted one, any pro's and con's to this idea? Would I be better off sticking with a traditional post mount one??

Are you talking about an e-type front mech? (google them)
If so generally there are 2 mounting points, 1 is putting the BB through the mech and screwing it into the frame, then there is a small hole above the BB mount. You put a bolt through that hole and screw it into the e-type mount on the frame.
If you don't use the top bolt the derailluer will flex alot and not change properly.
If your determined to use an e-type front mech on your non e-type frame you can use one of these instead.
http://www.chainreactioncycles.com/Mode ... odelID=745

It's what I used on my partners bike, it could only use an e-type front mech, but the e-type bolt mount had been ground off.

I shall more than likely be using a top-pull e-type front mech, with the adapter in the link, on my other cro-mega as I'm fitting Maguras and will have a spare cable-stop...

isitafox":1zi0avai said:

Does anyone have experience with the above?? Looking for a front mech for my build and considering getting a BB mounted one, any pro's and con's to this idea? Would I be better off sticking with a traditional post mount one??

Click to expand...

I think generally yes, unless your frame is designed for it. I have one on my 98 E4, but I notice that most 98 E4s owners have fitted standard fms.

Remember that you need an E bottom bracket as well, because a standard bb would be skewed outboard, and position the cranks further out than the centre of the mech's operating range.

Anthony":2iz7pj7e said:

isitafox":2iz7pj7e said:

Does anyone have experience with the above?? Looking for a front mech for my build and considering getting a BB mounted one, any pro's and con's to this idea? Would I be better off sticking with a traditional post mount one??

Click to expand...

I think generally yes, unless your frame is designed for it. I have one on my 98 E4, but I notice that most 98 E4s owners have fitted standard fms.

Remember that you need an E bottom bracket as well, because a standard bb would be skewed outboard, and position the cranks further out than the centre of the mech's operating range.

Click to expand...

You can combat the BB issue by using a 73mm BB, putting the right spacers in the right place, and then getting the right length axle to suit. I have done this sucessfully, but my mate owns a bike shop and quite happy for me to go in there and try out half a dozen BB's to get the right one

Ah right, didn't realise you needed a specific frame to fit as they look so convenient to use! Cheers for the info guys!

FST4RD":18bx56qi said:

Anthony":18bx56qi said:

Remember that you need an E bottom bracket as well, because a standard bb would be skewed outboard, and position the cranks further out than the centre of the mech's operating range.

Click to expand...

You can combat the BB issue by using a 73mm BB, putting the right spacers in the right place, and then getting the right length axle to suit. I have done this sucessfully, but my mate owns a bike shop and quite happy for me to go in there and try out half a dozen BB's to get the right one

Click to expand...

Yes, that works on the drive side (but only if your bb shell is a 68 ), but I'm not so sure whether the adapter would work properly, and I can't get my head around whether a 68 or a 73 adapter would be better

...though there's a very easy way to find out

We_are_Stevo":18v6hegm said:

...though there's a very easy way to find out

Click to expand...

Easy yes, but not necessarily pain-free. It hasn't happened to me, but my trusted LBS adviser said if the adapter isn't located properly onto the bb, there can be enough joggling about to damage the threads on the drive side of the frame. He could have been exaggerating I suppose, but I wouldn't risk it myself.

Anthony":3ilas6l0 said:

We_are_Stevo":3ilas6l0 said:

...though there's a very easy way to find out

Click to expand...

Easy yes, but not necessarily pain-free. It hasn't happened to me, but my trusted LBS adviser said if the adapter isn't located properly onto the bb, there can be enough joggling about to damage the threads on the drive side of the frame. He could have been exaggerating I suppose, but I wouldn't risk it myself.

Click to expand...

What's to do wrong?

You have a f*ck off big curved mounting bracket for the derailleur that you bolt up to the BB shell with your E-type BB ( http://www.ebay.co.uk/itm/Truvativ-Squa ... 19cceaa49a ), you bolt your Problem Solver ( http://www.chainreactioncycles.com/Mode ... odelID=745 ) to the seat tube and bolt said curved bracket to it - job done, n'est pas?

Assuming everything lines up correctly of course...