Tripleshot Cycling

Does anyone have a definitive answer on gear ratio limits for junior riders?

Here's my situation:
My son (12 years old) is riding a small frame bike - 24" wheels and 152 mm cranks. He is very small and the bike frame fits him well.
His current setup is a 42-tooth front, and 13-tooth rear, giving him roughly a 5.7 metre "gain ratio"

He's very frustrated that he tops out on speed quickly in his top gear, and can't do anything on downhills.

I'm wanting to increase his gear ratio by changing his set-up, if possible, but I don't want to spend the money if I'll be putting something on that will take him over the allowable - or safe - limits.

I'm thinking of putting a 50 on the front, which would get him up to about 6.8 metres, and probably be cheaper than adding a whole new rear cassette.

Does anyone have any advice here?

Thanks!

You might be surprised at the cost the one chain ring can be as expensive as a whole set of cogs. Adding a big front chain ring will also make it more difficult to shift and might require a longer cage rear derailleur to take use up the extra chain. If he has no trouble climbing I would try a new cog set first, less pain to change as well.

Hugh

Thanks, Hugh. That's really helpful.

So do people think a 42-11 set-up might get some decent power?? It looks like it could get him up to about 6.7 m; pretty close to the 50/13 set-up.

Thanks again.

Again, if anyone has info on limits, that would be great.

As we discussed Dave, go with the 11 tooth top gear. How many cogs on his cassette? You'll need to know that to buy a cassette. I have an 11-? tooth cassette in 9 speed if he uses that. And the biggest cog should be no bigger than 28 or maybe 29 to work with his derailleur. 27 is the max published by shimano for their short cage derailleurs, though some have made 30s work.

The 7.9 meter junior maximum is quite big. 18 year olds at junior worlds use that. Also in the track sessions former national coaches Kurt Innes and Houshang Amiri have been emphasizing spinning. So no need to go bigger I think.

Thanks Lister. His current rear cog set-up is an 8-speed "V": 13-14-15-17-19-21-23-26

Apparently there is an 8-speed "R/ah": 11-12-14-16-18-21-24-28... Perhaps that would be the best bet for him...

What do you think?

Thanks again for all the help.

I would go with that and remind him that his spin is an advantage. Axel Merckx told one of our stronger juniors at the youth development weekend, "You are very strong, but you don't know how to pedal. Ride more track. "

L

Here is a link to the Aussie roll out calculator. Absolutely invaluable if you are trying to match chainrings, cassettes and wheel diameters for junior racers.

http://www.cycling.org.au/?Page=9497
Rob

Oh, and the U13 roll out limit is 5.5m.
I know it was a big adjustment for Alex to go to junior gearing when she first entered races with junior gear restrictions.

That gear restriction is not enforced in most provinces. The cadet limit was enforced in Quebec for the cadet stage race that VAC's Joel Taylor attended. It wasn't in BC's axel merckx series however.

Ontario publishes it this way:
http://www.ontariocycling.org/web_doc/g ... icle_3.pdf
Special Note for Younger Riders
The CCA Rule Book states that gear restrictions may be applied to younger riders as follows:
Under 17: 6.94 m or 52 X 16
Under 15: 6,00 m or 45 X 16
Under 13: 5.60 m or 42 X 16
These restrictions will not be enforced in Ontario at this time. Riders entering races in other
provinces may find that these restrictions are enforced there. This is especially true for cadets (U17) who travel to Quebec for major races as part of OCA development projects. If you plan to race outside of Ontario make sure you find out if gear restrictions are enforced, and that you have the correct equipment on your bike.

It should be noted that the gear teeth are misleading. Smaller wheels change which size cogs make up the allowed development.

And finally, it depends what other riders a u13 rider trains with. Unless all have the gear restrictions, it's kinda hard to do the ride with others on bigger gears.