Hi everyone and thanks in advance if you can help me out. I'm installing a shimano 105 triple crankset into a Chris King external bottom bracket on a surly pacer with a 68mm bb shell. And I can't get the thing to work. I'm following all of the steps... I've included the spacer on the left side crank arm that it calls for on the triple, and there are no spacers on the BB, but when I get it all put together the drive side crank arm is about 4mm further away than the left side, and the left crank arm is not fully seated on the spindle. I've been racking my brain and all that I can come up with is that maybe I need a smaller spacer on the drive side (there is a 6.5mm spacer that was on the part when I received it) to make the whole thing centered correctly. It seems like I need to bring the drive side closer to the frame, but I can't figure out how I would do that.

I can't find anything online and I thought I'd post something here before going to the shop. Has anyone else encountered this? Am I doing something wrong? Thank you

is the BB the correct spindle length for you model of 105 triple? your frame straight?

Maybe I missed something here, but why the left arm is not fully seated? This is a FC-5603 with the integrated spindle, right? When the left arm is properly installed with the correct preload, the drive side crank will be pulled up against the DS bearing. If you're using the correct [supplied] spacer, and the bottom bracket hasn't been faced measurably below 68mm, there shouldn't be any slop.

Yes, I'm making some assumptions, and no, I haven't used a King BB.

A Shimano external BB can be used with 73mm (MTB) shell OR 68mm (road) shell, IF YOU USE the right spacers. I am assuming you have a 68mm shell, since 105 are road components. If the King BB is the same width as the Shimano BB, then it should work. I'm NOT sure about any spacer you should be putting on the spindle, though. Especially if the left arm will not fully seat on the spindle. Try to assemble it without the spacer, and see if the left arm fully seats.

I just had something like this when I put an XT crankset with external BB on my touring rig. Turned out I had not fully seated the right (drive) side cup--only out a little, but caused the left arm to make the assembly 'drag' when I fully seated it. After removing the left crank and closely inspecting everything, I found the right cup out a little. I removed it, ran a thread chaser through the BB shell, and VIOLA--right cup threads all the way in, everything snugs up, and SPINS freely. I knew it should spin freely without a chain installed, because I went to the added expense of installing ceramic bearings in the BB cups. That made me VERY suspicious about it not turning freely!

You might check again to see if the BB cups are FULLY seated, then assemble without the spacer, and see if the left arm fully seats.

That's the problem...the left arm is not fully seated because the spindle on the crankset almost seems too short. the bb cups are on, tourqued to the manufacturers spec, and I'm setting it up exactly as the directions are telling me to do. that spacer on the crankset was on the spindle when i got it, and it snugs right against the bb cup. if i removed that then the crankset would be too close to the frame, but i feel like that piece needs to be smaller.

I think my next step really is just to take it to a shop and see what they think because it's driving me batty.