Q&A: What gearing should I use on a singlespeed mountain bike?

Ed. – This question came in from a reader who needs some advice. If you’ve got an answer and/or opinion, please leave it in the comments. Also, if you have a question you’d like answered, email diggers@commutebybike.com.

From Anthony:

I’m going to give commuting a go and need some advice.

I’m a singlespeed mountain biker and do not have any geared bikes. I test drove my route today and it’s 12 miles with essentially no hills. The only hills are highway overpasses, so I’m sire I can push a big gear over with no problems since they are short, plus I will have a rolling start. The bike I’m going to use for commuting is a GT 9’r (Ed. a 29 inch singlespeed mountain bike) and is currently set up as 32×18 with Schwalbe Big Apple slicks. I don’t even want to try commuting with 32×18 because I will never get there… It took me 30 minutes to drive the route today and with 32×18 it would probably take over 2 hours.

I need a taller chainring, so this is where I need some advice. I can either get a new set of road crankset or just a bigger chainring for my current mtb cranks.

Jensonusa has a clearance on Shimano 105 cranks, which are 53×39 for $45. I don’t need anything highend, so this seems like a killer deal.

If I get a mtb chainring I will go with the big ring, which should be a 44t.

So, my question is if I go with road cranks is it unrealistic to try commuting on 53×18? I have some 20T cogs, so I could do a 53×20. I know once I’m rolling I can push this gear, but I’m concerned about starting. Is it too tall?

Or, should I just go with 44×18?

I know this is subjective, but I’m looking for some general advice so I can get started.

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