Bicycle Mechanics - Installation of shimano SLX crankset on LHT

I'm trying to swap out my old crankset for a a spiffy new mountain crankset. The LHT frame has a 68mm bracket, at least according to Surly (http://www.surlybikes.com/lht_comp.html). Shimano's instructions (http://techdocs.shimano.com/media/techdocs/content/cycle/SI/SI_6PZFA_002/SI_6PZFA_002_En_v1_m56577569830647029.pdf) say to put two spacers drive side and one left side in this case.

Yet doing so leaves the chainrings half a cm out from where the deraileur expects them. I can easily remove the two spacers on the right, but:

1) does this mean I messed something up?, and

2) should I remove the spacer on the left side?

Many thanks,
quester

What do you mean it leaves it half a cm out from where it's expected? Do you mean when "at rest" the derailluer isn't centered over the small ring? If so I wouldn't worry about it. As long as the derailluer covers all the rings I don't see a problem, just set the limit screw. Or switch the spacers around.

What do you mean it leaves it half a cm out from where it's expected? Do you mean when "at rest" the derailluer isn't centered over the small ring? If so I wouldn't worry about it. As long as the derailluer covers all the rings I don't see a problem, just set the limit screw. Or switch the spacers around.

Meaning that instead of the big chain ring centered under the fully-extended deraileur, it's a bit more than half a centimeter out. I took out one of the spacers and it seems fine. However, I'm a bit concerned that instead of 2 spacers on one side and one on the other, as shown in the diagrams, I now have one on each side. I could have removed the spacer on the left side, but I'm a bit duck-footed and don't mind having the extra space.

I guess what I'd really like to know is if the bike is very sensitive to the amount of space here, and if getting it wrong would be catostrophic (i.e. either the crank or my knee blowing up somehow). I THINK it's probably fine, but I just wanted to check if anyone has experience w/ such problems.

it sounds like you just need to adjust the front der.

Meaning that instead of the big chain ring centered under the fully-extended deraileur, it's a bit more than half a centimeter out. I took out one of the spacers and it seems fine. However, I'm a bit concerned that instead of 2 spacers on one side and one on the other, as shown in the diagrams, I now have one on each side. I could have removed the spacer on the left side, but I'm a bit duck-footed and don't mind having the extra space.

I guess what I'd really like to know is if the bike is very sensitive to the amount of space here, and if getting it wrong would be catostrophic (i.e. either the crank or my knee blowing up somehow). I THINK it's probably fine, but I just wanted to check if anyone has experience w/ such problems.

So the derailluer can't reach the big ring, that's what you're saying? Or are you saying the derailluer extends beyond the big ring?

If it extends beyond- limit screw. If it can't shift onto the big ring- put the spacer on the other side. 1 on the right, 2 on the left- if it'll work that way. You don't want to leave a gap there.