So what gears have I got?

 

Typically full size road racing bikes come with a 10 speed rear cassette from 12/25 or 12/27 coupled with double chainset with 53 and 39 toothed chainrings. They have 700c wheels fitted with 700x23c tires, which gives a circumference of 2.099m when inflated to 90 to 110 psi. From this information we can calculate the maximum distance you can travel for one revolution of the bicycle crank or the gear 'development'

 

Development	=	circumference of the tire X number of teeth on the big chainring
		number of teeth on the smallest sprocket

 

Development	=	2.099m X 53
		12

 

Development

=

9.27m

 

Other common chainset fitted to full size race bikes are Compacts generally 50 and 34 toothed chainrings and Triples which commonly have 52, 42 and 32 toothed chainrings.

 

So a gear development chart for a full size road bike with a 12/27 in either compact, double or triple chainset looks like this

700	Std Compact		Std Double		Std Triple
x23	34	50	39	53	32	42	52
12	5.95	8.75	6.82	9.27	5.60	7.35	9.10
13	5.49	8.07	6.30	8.56	5.17	6.78	8.40
14	5.10	7.50	5.85	7.95	4.80	6.30	7.80
15	4.76	7.00	5.46	7.42	4.48	5.88	7.28
16	4.46	6.56	5.12	6.95	4.20	5.51	6.82
17	4.20	6.17	4.82	6.54	3.95	5.19	6.42
19	3.76	5.52	4.31	5.86	3.54	4.64	5.74
21	3.40	5.00	3.90	5.30	3.20	4.20	5.20
24	2.97	4.37	3.41	4.64	2.80	3.67	4.55
27	2.64	3.89	3.03	4.12	2.49	3.27	4.04

 

Another option available are small road race bicycles fitted with 650x23c tires, their gear development chart would look like this for a 11/28 with a standard chainset in either compact, double or triple format

650	Std Compact		Std Double		Std Triple
x23	34	50	39	53	32	42	52
11	6.01	8.84	6.89	9.37	5.66	7.42	9.19
12	5.51	8.10	6.32	8.59	5.18	6.80	8.42
13	5.08	7.48	5.83	7.93	4.79	6.28	7.78
14	4.72	6.94	5.42	7.36	4.44	5.83	7.22
15	4.41	6.48	5.05	6.87	4.15	5.44	6.74
17	3.89	5.72	4.46	6.06	3.66	4.80	5.95
19	3.48	5.12	3.99	5.42	3.27	4.30	5.32
22	3.00	4.42	3.45	4.68	2.83	3.71	4.59
25	2.64	3.89	3.03	4.12	2.49	3.27	4.04
28	2.36	3.47	2.71	3.68	2.22	2.92	3.61

 

But what gears can I use?

 

Youth A / Under 16 with the limit of 6.93m

From the gear development table for 700x23c Youth A / Under 16 riders would have the green highlighted ratios available.

700	Std Compact		Std Double		Std Triple
x23	34	50	39	53	32	42	52
12	5.95	8.75	6.82	9.27	5.60	7.35	9.10
13	5.49	8.07	6.30	8.56	5.17	6.78	8.40
14	5.10	7.50	5.85	7.95	4.80	6.30	7.80
15	4.76	7.00	5.46	7.42	4.48	5.88	7.28
16	4.46	6.56	5.12	6.95	4.20	5.51	6.82
17	4.20	6.17	4.82	6.54	3.95	5.19	6.42
19	3.76	5.52	4.31	5.86	3.54	4.64	5.74
21	3.40	5.00	3.90	5.30	3.20	4.20	5.20
24	2.97	4.37	3.41	4.64	2.80	3.67	4.55
27	2.64	3.89	3.03	4.12	2.49	3.27	4.04

 

Therefore a good choice would be a 39 tooth chainring with a standard 12/27 rear cassette. This would give a good spread of gears and only require the large chainring locking out for racing.

 

Oh but your bike hasn't got a 39 tooth chainring. Well if you get serious then 39 tooth chainrings are relatively inexpensive and readily available for compact, double and triple chainsets. Fitting requires a special tool so speak to one of the coaches and they will help you find a friendly mechanic or local bike shop to sort it out.

 

Youth B / Under 14 with the limit of 6.45m

From the gear development table for 700x23c Youth B / Under 14 riders would have the green highlighted ratios available.

700	Std Compact		Std Double		Std Triple
x23	34	50	39	53	32	42	52
12	5.95	8.75	6.82	9.27	5.60	7.35	9.10
13	5.49	8.07	6.30	8.56	5.17	6.78	8.40
14	5.10	7.50	5.85	7.95	4.80	6.30	7.80
15	4.76	7.00	5.46	7.42	4.48	5.88	7.28
16	4.46	6.56	5.12	6.95	4.20	5.51	6.82
17	4.20	6.17	4.82	6.54	3.95	5.19	6.42
19	3.76	5.52	4.31	5.86	3.54	4.64	5.74
21	3.40	5.00	3.90	5.30	3.20	4.20	5.20
24	2.97	4.37	3.41	4.64	2.80	3.67	4.55
27	2.64	3.89	3.03	4.12	2.49	3.27	4.04

 

Therefore a good choice would be a 39 tooth chainring with a standard 12/27 rear cassette with just the 12 sprocket and the large chainring locked out for racing. This setup also gives room for growth if you continue to race as the 12 sprocket can be unlocked when you become a Youth A / Under 16 rider.

 

Youth C / Under 12 with the limit of 6.05m

For this catagory we'll assume a small road race bike fitted with 650x23c tires so using that development table, Youth C / Under 12 riders would have the green highlighted ratios available.

650	Std Compact		Std Double		Std Triple
x23	34	50	39	53	32	42	52
11	6.01	8.84	6.89	9.37	5.66	7.42	9.19
12	5.51	8.10	6.32	8.59	5.18	6.80	8.42
13	5.08	7.48	5.83	7.93	4.79	6.28	7.78
14	4.72	6.94	5.42	7.36	4.44	5.83	7.22
15	4.41	6.48	5.05	6.87	4.15	5.44	6.74
17	3.89	5.72	4.46	6.06	3.66	4.80	5.95
19	3.48	5.12	3.99	5.42	3.27	4.30	5.32
22	3.00	4.42	3.45	4.68	2.83	3.71	4.59
25	2.64	3.89	3.03	4.12	2.49	3.27	4.04
28	2.36	3.47	2.71	3.68	2.22	2.92	3.61

 

Therefore a good choice would be a 34 tooth chainring with a standard 11/28 rear cassette with the large chainring locked out for racing.

 

Youth D / Under 10 with the limit of 5.45m

Road race bicycles for this catagory are generally mini or junior race bikes and come with 650c or 24" wheels. The chainssets are usually smaller and the cassettes made up of 8 or 9 sprockets. Below is an example gear development table for a 650x23c tire with a typical 8 speed cassette with either a small double or small triple chainset. The green highlighted ratios are those available to Youth D / Under 10 riders.

650	Double		Triple
x23	36	44	30	40	50
12	5.83	7.13	4.86	6.48	8.10
13	5.38	6.58	4.49	5.98	7.48
15	4.67	5.70	3.89	5.18	6.48
17	4.12	5.03	3.43	4.57	5.72
19	3.68	4.50	3.07	4.09	5.12
21	3.33	4.07	2.78	3.70	4.63
23	3.04	3.72	2.54	3.38	4.23
26	2.69	3.29	2.24	2.99	3.74

 

Therefore a good choice would be a 36 tooth chainring with a 12/26 rear cassette with the12 sprocket and the large chainring locked out for racing. This setup also gives room for growth if you continue to race as the 12 sprocket can be unlocked when you become a Youth C / Under 12 rider.

 

Youth E / Under 8 with the limit of 5.1m

Bicycles available for this age and size of rider are diverse. The coaches will help you to set up what every bicycle you have to have a go and participate at this level. However if you get hooked, then you may be able to safely ride a mini or junior race bike. So using the gear development table for the Youth Ds above the green highlighted ratios are those available to Youth E / Under 8 riders.

650	Double		Triple
x23	36	44	30	40	50
12	5.83	7.13	4.86	6.48	8.10
13	5.38	6.58	4.49	5.98	7.48
15	4.67	5.70	3.89	5.18	6.48
17	4.12	5.03	3.43	4.57	5.72
19	3.68	4.50	3.07	4.09	5.12
21	3.33	4.07	2.78	3.70	4.63
23	3.04	3.72	2.54	3.38	4.23
26	2.69	3.29	2.24	2.99	3.74

 

A sensible choice, should you get hooked, would be a 36 tooth chainring with a 12/26 rear cassette with the12 sprocket, 13 sprocket and large chainring locked out for racing. This choice allows room for growth as you move in to the Youth D catagory by unrestricting the 13 sprocket.