How to pick gearing for a time trial when using a fixed gear?

[Woofer]

Obviously if I could preride the courses repeatedly with different gearing this would be the optimal method for picking gearing. However I live a couple hours drive from the two flattish out and back time trials I plan on doing this year. The area in which I live in has no flat spot that lasts more than a couple of minutes at most - there being traffic lights or hills and mountains interspersed here and there. What method or methods have other folks used? I was thinking of going with 90 inches.

 

[tomdavis80]

Obviously if I could preride the courses repeatedly with different gearing this would be the optimal method for picking gearing. However I live a couple hours drive from the two flattish out and back time trials I plan on doing this year. The area in which I live in has no flat spot that lasts more than a couple of minutes at most - there being traffic lights or hills and mountains interspersed here and there. What method or methods have other folks used? I was thinking of going with 90 inches.

My best recommendation would be to do a TT without using a fixed gear bike and take note of your average speed and cadence and then find the appropriate gear that will match your preferred cadence and average speed. Try using Analyticcycling.com, they'll help with those calculations. Also, if you can average 25 mph for a 20k TT on a regular bike, I'd go with probably around a 48-16 which sounds about right, or maybe 48-15.