So chain guards are, as my handy neighborhood mechanic tells me, badly out of fashion (this being the reason he offered for why the shop doesn't carry them). But I'm a commuter, and try as I might, I can't completely avoid some schmutz on my pants from the chain. Hence my desire for a chain guard. My chain ring is 42t, and I found this chain guard for a 44t. Would it fit, do you think?