I’m going to be sourcing parts over summer to build a second cx bike.

I want to go 1×10 with a chain guard.

last season I raced a 2×10 with 34/46 – 11-28 (never went into 46 ring in a race though)

can I get a chain guard for a 34t ring (in a 5 bolt fitment)?

or is a 39 ring the lowest I could go?

with regards to building the crankset do I find a double I like, remove the rings and then use the spider, crank arms & bb to build my 34t setup?

or can I buy spiders/crank arms separately?

any help would be great

thanks

You’ll need a compact crank to get a 34T ring on it.

As for the chainguide, something like this will work fine.

I’d worry the chain would carry all the mud from a race through that kind of chain catcher and ultimately jam?

can I get a chain guard for a 34t ring (in a 5 bolt fitment)?

Yes, Stronglight do one, heres one at Spa Cycles

or is a 39 ring the lowest I could go?

Stronglight do a 130BCD version as well if you decide to go that route.

with regards to building the crankset do I find a double I like, remove the rings and then use the spider, crank arms & bb to build my 34t setup? or can I buy spiders/crank arms separately?

Chainsets normally don’t sell as spider only so you’re probably better off buying a full chainset and selling the outer ring. But for £20 and if you don’t mind having old school square taper then I’ve got one of these on my winter bikes and they’re not bad.

Again, from Spa (and I don’t work there, honest!)

These work well with a chainguard: http://www.billys.co.uk/english/group.php?prod=chng-js

34/11 is a pretty small top gear, have you thought of trying a smaller outer ring first, like a 42?

might move upto a 39