Chainline issue on recumbent

Here's the issue: I built a M5 Carbon high racer recumbent with a 68 mm BB shell, MegaExo BB, and SRAM Apex compact crank. The chainrings are close to the boom, so much so that the chain contacts the right fork leg and visibly wraps around it to engage the chainrings. I can protect the fork leg, but the chainline angle causes rubbing between the small and large rings. I'm not willing to tolerate that.

I'm not wedded to the MegaExo BB, but I'd rather not buy yet another crank for this bike if I can help it. I wish to know if the SRAM Apex crank, which came with a MegaExo BB, can work with a BB30 BB or some other BB type compatible with the fixed drive side crank spindle. I need a minimum of 5 mm adjustment outboard, and in lieu of any other choices I'll have to pop for a square taper BB and a yet another crank. Any thoughts as to what BB can work with the Apex crank and allow it to be moved laterally in the BB shell would be greatly appreciated.

http://goo.gl/w30Xx5

https://www.google.com/#q=megaexo+bb+spindle&tbm=shop

Parks has advice..Shimano has variable spindle lengths.

On 3/12/2014 5:17 PM, Clayton Bigsby wrote:
Here's the issue: I built a M5 Carbon high racer recumbent with a 68 mm BB shell, MegaExo BB, and SRAM Apex compact crank. The chainrings are close to the boom, so much so that the chain contacts the right fork leg and visibly wraps around it to engage the chainrings. I can protect the fork leg, but the chainline angle causes rubbing between the small and large rings. I'm not willing to tolerate that.

I'm not wedded to the MegaExo BB, but I'd rather not buy yet another crank for this bike if I can help it. I wish to know if the SRAM Apex crank, which came with a MegaExo BB, can work with a BB30 BB or some other BB type compatible with the fixed drive side crank spindle. I need a minimum of 5 mm adjustment outboard, and in lieu of any other choices I'll have to pop for a square taper BB and a yet another crank. Any thoughts as to what BB can work with the Apex crank and allow it to be moved laterally in the BB shell would be greatly appreciated.


If you use a square taper system, most modern cartridge
bearing units include an optional spacer for use under the
lip of the right cup. There are many lengths in 2~3mm
increments. And always Phil Wood, which are not only best
quality but come in a plethora of lengths, symmetric and
asymmetric, besides Phil's infinite chainline adjustment.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971