Is a 52 tooth big ring and a 14 tooth small cog alright for junior racing. Where can you buy a 14x27 tooth cog. I checked colorado cyclist and they dont have any. Thanks

Yes a 52x14 is okay for Jrs. Having just finishing rolling out ALL of the Jrs at Jrs Natz, it is better to go 'smaller' than larger. In other words, it's better to come in under the 26', than to push the limit and possibly go over.

In the USCF rulebook, rule # 2.2.024 explains the gears needed, and different ratios that you are able to use.

Looking at the chart given, the 52x14 is the largest, legal, gearing you can use. As an official, I also recommend just getting a Jrs cassette. Go to your local shop, and they can help get you set up with the correct gears. Once you have them, just ride'em, that way you know how they feel, and what you can do with them. Don't block your gears out, by having the cassette, you can use ALL of your gears.

If you have questions, send me a message and I'll reply.

Also, the gear ratio that will put you right on the limit, is a 45x12. Just an FYI. I still don't recommend being right on the limit, it's too easy for problems to arise.