help ??/ Suntour Microlite BB and xt fc m730's compatible?

[Lord_fowl]

hi RBer's
hoping i could get some help here with a BB issue. Could anyone tell if a suntour Microlite BB can be used with old XT cranks/?
My BB is a suntour grease guard Microlite Microdrive 73 mm x 119 spindle.The treads are english and the square taper is 2 degrees
The cranks i want to use are xt FC M730 also with a square taper but i cannot find any info on the number of degrees.
This contraption has given me a rough chain line of 51mm with none of the parts for the BB or crankbolts are fully tightened, just hand tightened.
The bike is a merlin with a 34.9 seattube and sheldon browns website tells me fatter seattubes on Ti bikes can have chainlines near 50 mms
the way i have it now there is a 2.5 mm space on the drive side cup of the 73 mm BB which is somehow been fit onto a 68 mm BB shell.
So does anybody have any idea or do you want pictures?
any help is greatly appreciated
Lord_fowl
Booookkkkk

 

[mynchiboy]

Hmm..The usual recommended BB length for M730 cranks is 122.5mm so you may have clearance issues on the inner ring at the very least.

I'm sure there may be other opinions though...watch this space

 

[euphras_1]

Depends highly on the given frame and the chainrings installed. On my ´88 Rockhopper i run a Suntour XC LTD crank with 46-36-26 and 113 mm Ultegra BB. The taper should be OK if you only mix vintage japanese parts.

 

[FluffyChicken]

They are classed at VX taker as do their crank arms, whatever that means.
You will need the 2.5mm spacer on the 68mm shell.
For 50mm chain line and m730 you are up in the 127.5mm lengths.

But give it as go you may get away with it.

119 is a funny length, 118 was the 73mm shell with MicroDrive cranks at 50mm chainline setup iirc.

 

[DoctorRad]

Re:

119 is a funny length, 118 was the 73mm shell with MicroDrive cranks at 50mm chainline setup iirc.

I measured 119mm on the two axles I have in the spares archive.

FWIW, I tried running an M730 crank with the 125mm SunTour BB axle and run into chainsuck jam problems on my On-One Inbred Barry White. Ended up using a 127.5mm UN-52, and that's on a 68mm shell.