FarHorizon

Assuming I want to run a single chainring with a multi-speed rear, and that I'm starting with a compact triple crank, should I just attach the chainring to the spider where the original "middle" ring would have gone, or would I do better to buy a shorter bottom bracket and attach the chainring where the "large" original ring would have gone?

Thanks.

mtbikerinpa

My vote would be the middle. Logic being that the low rear gears in the large-ring position are cross-chaining. If there is no outer ring or the outer ring is replaced with a bash guard then there is no reason the chainring can't be centered on the cassette.

TLN

I would agree......without any further information (what type of cranks, what spindle length BB, etc) you should use the middle position.

roadfix

Yes, use the middle position, and don't forget to get some of those shorter BMX chainring bolts....

matheprat

Surely you should decide which gears you use most often, and use the appropriate ring. For example, if you find yourself using the smaller cogs most, put the front ring on the bigger ring mounts. If you use all the cogs equally, then I guess the middle.
Cheers