Good Afternoon. After my bike was stolen a few years ago I've finally decided and am in a position to get a new one. I'm currently planning to get a vintage miyata 912 and convert it to single speed. I'd like to use a Shimano Dura-Ace Fc-R9000 55 tooth chain ring and a 13 tooth surly single speed cog. I'm not entirely sure how to go about such a thing and any and all advice would be welcome. and yes I know the chain ring is as much as the bike.

I run a 90's Shimano 600 crankset with a 3/32 chainring and 1/8 chain and cog and have never run into issues. Just make sure your chain line and tension are tight and you'll be good to go.

I ride a Miyata 312 converted to fixed gear, 1989 model year. One of my favorite bikes for several reasons. You'll have fun on the 912.

There is so much more to unpack in your post but I'd simply like to congratulate you on your ambition - 110+ Gear Inches is a helluva gearing to start with after not riding for a few years.

Have fun - good luck...

+1
That's close to the highest gear on my 20 speed, and much higher than the 42 x 14 used by a very strong fixie riding friend.

A massive thank you to both of you! I had thought a higher gear ratio meant it would be easier to peddle the bike. The parts I'd chosen would have the opposite of the effect I wanted. Back to the drawing board for now and thanks for the replies

My knees hurt just reading this.

Smaller in front.
Bigger in back.
Easier pedaling, lower top speed.