Restrictions on gear ratios - Youth

[Schulla]

With the change of UCI/CSA age categories could someone please advise on the new gear ratios for U17, using a 50T chainring. The new regulation states equal to and not more than 6.94 metres measured by one full revolution of the chain wheel set.

 

I take it there should be some calculation that could determine this rather than having to test the options. Thanks.

[gtr1]

If you convert the 6,94 meters to inches to can then check what gear ratio fits in with that.

[TheKaiser]

With the change of UCI/CSA age categories could someone please advise on the new gear ratios for U17, using a 50T chainring. The new regulation states equal to and not more than 6.94 metres measured by one full revolution of the chain wheel set.

 

I take it there should be some calculation that could determine this rather than having to test the options. Thanks.

Measure the diameter of the 50T chain ring. Multiple that by pi (3.1415926...) and whammy - you have the circumference.

 

So.... Circumference = Pi x diameter.

[gtr1]

That won't work. It's not circumference of chain ring. It's how far the bike travels wit 1 turn of pedal.

 

So front ring/back cog x wheel circumference. So work on smallest cog on cassette. That will tell you distance of travel wit 1 revolution. So wheels usually meadured in inches eg 27. But if you measure wheel in centimeters will get a meter measurement.

[NordicElf]

With the change of UCI/CSA age categories could someone please advise on the new gear ratios for U17, using a 50T chainring. The new regulation states equal to and not more than 6.94 metres measured by one full revolution of the chain wheel set.

 

I take it there should be some calculation that could determine this rather than having to test the options. Thanks.

 

Use this awesome tool to do the calculations for you: http://ritzelrechner.de/

[Donovan Le Cok]

 

From the CSA 2017 National champs "bible" You can download it here - https://www.cyclingsa.com/s/20170109_2017-SA-ROAD-TIME-TRIAL-RACE-BIBLE-MB_MP.pdf

 

 

 

 

[Frosty]

Attached are the CyclingSA rules - on their website

 

3.3.3.5 The regulations regarding the restrictions on gear ratios have been

amended to conform to international standards. With effect from 1

January 2017, the following gear restrictions as measured by one full

revolution of the chain wheel set will apply:

3.3.3.5.1 Under 11: Equal to and not more than 5,66 metres.

3.3.3.5.2 Under 13: Equal to and not more than 5,66 metres.

3.3.3.5.3 Under 15: Equal to and not more than 6,10 metres.

3.3.3.5.4 Under 17: Equal to and not more than 6,94 metres.

3.3.3.5.5 Under 19 Equal to and not more than 7.93 metres.

 

The next page shows the following:

3.3.3.6 In order to enable Youth / School cyclists to change gear components,

compliance with the amended rules relating to the restrictions on gear

ratios will not be enforced during the period 1 January 2017 to

31 December 2017 and the following gear restrictions as measured by

one full revolution of the chain wheel set will be tolerated during that

period:

3.3.3.6.1 Under 11: Equal to and not more than 6,227 metres.

3.3.3.6.2 Under 13: Equal to and not more than 6,227 metres.

3.3.3.6.3 Under 15: Equal to and not more than 6,626 metres.

3.3.3.6.4 Under 17: Equal to and not more than 6,897 metres.

3.3.3.6.5 Under 19 Equal to and not more than 7.93 metres.

 

 

A quick Google search - here's a table showing the rollout distances for each gear combination.

British Cycling Road and Track gear restrictions.pdf

20161125_00.3+Cycling+SA+-+Rules+of+Cycling+PART+3+16.11.19.pdf

[Schulla]

Thanks all for the replies. Nicely cleared up.

[TheKaiser]

That won't work. It's not circumference of chain ring. It's how far the bike travels wit 1 turn of pedal.

 

So front ring/back cog x wheel circumference. So work on smallest cog on cassette. That will tell you distance of travel wit 1 revolution. So wheels usually meadured in inches eg 27. But if you measure wheel in centimeters will get a meter measurement.

Ooooooooohhhhh...... guess i should read the full post 

[Zeffer]

Important to note that the change in gear ratios are only effective from 2018!

[Zeffer]

Schulla, you should have realised by now that you cannot get a perfect ratio with a 50T... you will need to roll short for U17... or change the big chainring...

[Schulla]

Hi Zeffer, that's correct. Will go with the 52T chainring. Thanks

[FC&P2C]

The ages has not changed, they just call it different. Used to be 10 and under and now its under 11.

With regards to the new gear restrictions as from 2018 I see that the little dudes are much lower than what it used to be namely

12 and under was 78" and now 71"

13 and 14yo was 84" and now 76,4"

15 and 16yo was 88" and now 87"

 

Not so much of a drop for the u16 but the younger kids basically 10% lower than what was already very low. 

Old track records will also have to be scrapped as it would be an impossible goal with 10% lighter gear ratio.

 

Or just stick to bmx and mtb as there you can ride whatever gear you like. 

[Pure Savage]

With the max 52-18, would it not be better to run a 1x11 block, run a smaller chain ring on front?

[Slowbee]

  there is only so much maths a bloke can handle and this thread exceeds the monthly limit so I am going to go straight back to bed ... after a glass of wine to calm my nerves down.

 

*interesting reading tho' never knew they had limits*

[Super_mil]

Out of interest, what is the purpose of limiting the gear ratios?