How many spacers do I need on a Trek X-Caliber 2011?

[superkingkong]

Hi guys,

My Trek X-cal 2011 is currently using the stock SRAM s1000 crankset. I've got an XT m780 crankset with bb70 and would like to put it in.

Anyone could advice on how many spacers do I need to put it on together with the BB?

I think trek has a bb width of 73mm

Thanks in advance.

[Slash5]

If you Google "bb70 bottom bracket" the very first hit is the Shimano tech doc for the BB70 bottom bracket. It says that one spacer is required on the drive side for a 73mm bottom bracket.

[irv_usc]

I would try it according to the tech doc first. I don't know if the xcal bb is actually 73 mm or not. If you notice the stock crank set has a spacer on the non drive side even though srams manual says no spacers for 73mm bb shells..

[superkingkong]

Thank you very much for the info.

I've tried to email trek support earlier. he told me the xcal bb is 73mm. I've asked him about the bb70 and spacers needed but he didn't answer my question and asked me to check on the chain line. i don't know what is that. Hmm, I didn't notice the spacer on the non-drive side. I'll check it tonight.

[Slash5]

Don't have a tape measure or ruler?

[superkingkong]

I measured it last night. it's 73mm. This was my first time changing drivetrain. No experience at all, got freaked out when encountered a problem

earlier, I didn't think about the manual because I've read one article online, they said I need to check with the bike manufacturer when deciding how many bb spacers to put on. So, first thing, I emailed Trek but no answer, googled but nothing, so thought of asking question here.