mike868y

I don't mean to dig up an older thread, but I have a question regarding junior gearing. All the examples use a 52 X 14 setup. however, I've got a 50t front chainring on my bike, yet the smallest cog is 11t, is this legal? I'm guessing no, but just wondering...

umd

pretty sure not

mike868y

damn. So what cog size would be legal with a 50t front chainring?

efficiency

14t

mike868y

Thanks for the help... 50/14 seems like a really crappy setup though, especially if there is a lot of descending/really fast sections...

Rosso Corsa

FYI today I got away with 53x14 and 21c tubular tires. But only just.

mike868y

Wait, I was just thinking, shouldn't I be able to run something smaller than a 14? The rule book quotes that 52 X 14 is legal, so if I have a 50t front ring, shouldn't I be able to get away with 13 or 12 in the back?

Psimet2001 

Read the rulebook. Do the math. Do a rollout.

PhillyRoadie

I was in a break of three in a road race yesterday, one of which was a junior rider, and I think his gear restriction might have screwed him over a little bit. A couple laps in a row I was spinning out my 53/11 pulling down a long descent on the backside of the course, and he just ran out of gears. We'd suck him along for awhile, but the poor kid was light, too, so we'd always get some separation and then he'd have to chase back on at the bottom and burn an extra match or two

YMCA

No to your question.
50x13 is too big for rollout. It is the same as ~ 55x14.

Either by a 52t chainring, or buy a 45t and match it with a 12.
52x14 = 45x12
Those are your options.

Some juniors get away with a 53x14, but it depends on crank length and tire width.

mike868y

So if I upgrade to SRAM rival in the future, would I be better going with the std. or compact crank? As far as I can tell only 50t chainrings are available for the compact, so I assume it would be better to get the std. adn go 52 X 14?

umd

You should make the decision based on what you want your small ring to be...

mike868y

In that case, I'm pretty sure the compact is the better choice. Its pretty hilly around here, and climbing is my "specialty."

YMCA

You can put a 52t on a compact crank.
But like I said earlier, go with a 45x12, so you can get a normal cassette.
This way you never have to lock out/waste gears and don't have to search out cssettes that start with a 14.

mike868y

I can't seem to find any 45t SRAM chainrings though. I know I could use something like FSA, but the shifting quality will be compromised...

umd

Shifting will be pretty much the same. Put down the kool aid.

mike868y

Even so, I'm having trouble finding 45 tooth 110 bcd chainrings, can someone hook me up with a link? Why is junior gearing such a cluster F*&#

zzzwillzzz

crank length won't affect rollout, one revolution is one revolution whether the cranks are long or short. i know you know, that's why i'm so surprised you made the mistake.

YMCA

Thanks for the vote of confidence, but I assumed a 165mm crank would roll a bit shorter than a 180mm crank.
Still makes sense to me. Am I missing something?

Jynx

how would crank length have any effect on the rollout of a bike? 1 revoltion with a 100mm crank and 1 revoltion with a 200mm crank will turn the rear wheel the same amount in the same gear. You just need to look at gear ratio and tire size for rollout.

YMCA

guess I was brain farting
happens now and then

kudude

I call bs. I don't like rutnick's tone, but if you've ridden a mtn bike much, you know that gear selection and spinning up steeeeeep stuff like a madman is the only way you don't end up walking. 5 sec at 140rpm seated sounds like a good skill to have on an XC course

snoboard2

I disagree with the rule the way it's written for a few reasons:

1. Jrs can race in open fields, but are using restricted gears. As most of us posting in this thread can sprint in a pack to speeds well above 35, this is a distinct disadvantage, crippling in slightly downhill sprints.

2. Those cassettes are hard to find and it's extra money you have to spend

3. The majority of jrs don't cruise Z2 at 30mph. This being true, 52x14 is 17.5 mph at 60 RPMs which we'd all agree is mashing (what the rule is designed to prevent)

4. I have yet to hear of an example of any knee injury caused by a low cadence alone. Improper fit or adjustment yes, low cadence, no

5. locking out 2 or 3 of the gears really defeats the purpose and expense of 9-10 spds

6. Roll-outs after races take a lot of time and volunteers that could be helping out with other things or just enjoying the other races and are just one more thing race promoters have to worry about.

Until I come across examples of a low cadence damaging young knees, there is no logical reason for the rule.

Even if I was shown case studies of cadence related knee injuries, the rule as it stands allows for some serious mashing at cruising speed anyway.

A stronger jr is going to beat a weaker jr even with the gearing restriction in place.

I don't know about you guys, but i've done extensive power testing on sprinting scenarios to determine how I can produce the most power, and mine comes between 110-120 rpm, not 140+

Truly, it does more harm than good, if it does any good at all. I believe it should be removed, or at least allow jrs to run unlimited gearing in open races and leave the gearing restrictions for jrs only races.

merckx89

Just for reference, we have a junior on our team that regularly won sprints in the 3s on junior gears hitting above 40 many times. It's not hard to do and it is a good skill to develop. Said junior now races in the 1/2s and may not be able to win the sprints there, but is in the running and can pull off top 10s, and that's at speeds closer to 45 and up.
Junior cassettes, while sometimes harder to find if you don't want to run a 45 tooth chainring which would solve the problem right there, are no more expensive than any other cassette, and most of the time cheaper because only the lower end models are made with a 14 tooth cog as the smallest.
You can't control what someone is going to do when they're training, but I see plenty of people racing and sitting at 60-70 rpm.
Roll outs take all of 5min max and are done by uscf officials, or at least are supposed to be done by them so it puts no extra time commitment on the organizers. Less time if it's a cat 1/2/3/4/5 instead of a pure junior race.
And I'm too lazy to go look up the knee thing. I'm sure someone on here will.

snoboard2

Good example, however some people produce more power at 120 rpm than 150 rpm, myself included.

I don't know of any bikes that come standard with either a 45 tooth outer chainring or an XX-14 cassette. It's an additional expense if you want to have use of all your gears. The debate as to the usefulness of 10 gears as apposed to 7 is a separate issue.

Also, I never said the jr cassettes are more expensive, but they are an additional $75 expense that a jr paying his own way could use for race entrance fees or something else. There were weekends I couldn't race when I was a jr because I was $20 short for entry fees or my gas tank was empty.

That's the aim of this rule. They're claiming to control jr cadences. So what's the point of the rule if there are still enough gears to mash? Why not limit them to 39x17 so their cadence is 90+ at entry level cruising speeds.

A jr field of 25+ will take a significant amount of time. Even a smaller field takes time. If officials didn't have to roll-out jrs, that's one less thing for officials to worry about.

I agree some of the points I make have more of an effect on some than others, however they're valid. Having rules just to have rules is pointless.

You forgot to mention why you think this rule is justified.