upgrading from compact

[skwerl]

For every two teeth you take off the chainring, the radius reduces by 4.05 mm.
A 18 tooth difference will be 36.5 mm. I can't see a problem.

Shimano quote 16t max for a double mech and 22t for a triple. Surely that's the limit of the shift in the parallelogram. You could always put a triple mech on, it has a max ring size of 52t

 

[Dave Davenport]

The PCD on a 52/53 ring is different to a compact crank.

 

[Will1985]

The PCD on a 52/53 ring is different to a compact crank.

Not necessarily. You are thinking of the more common 130 and 135 bcd sizes for doubles, but it is possible to get 110 bcd rings as I said all the way up to 61.
The beauty of the compact crank is that it allows you to ride like a normal double as well as compact for when it gets steep. There is no shame in a compact either - even pros use them in the Alps and Pyrenees (some riders went as far as 34x29 for the Angliru last year).

 

[jimboalee]

There is only one rule as gearing is concerned, and that is that Juniors are limited to 7.93 meters development.

Choose your high gearing for the terrain.
See other threads for low gearing.

 

[yenrod]

Shimano's 52 or 53 tooth's fit compatible with their compacts? I.e. replacing the 50. Want to keep the 30 for that hill spinning ability

upgrading from compact

Congratulations !

 

[yenrod]

BTW go for a 52 !

 

[Joe24]

There is only one rule as gearing is concerned, and that is that Juniors are limited to 7.93 meters development.

Choose your high gearing for the terrain.
See other threads for low gearing.

Just as a question, im still classed as a junior arent i being 17?
The gear on my TT bike, is just under that(if i have worked it out properly)

 

[jimboalee]

Just as a question, im still classed as a junior arent i being 17?
The gear on my TT bike, is just under that(if i have worked it out properly)

I rode a 52/38 to 14 - 23 5-block on my Pug until I was Adult age,; and then put a 13 - 23 6-block on it.

http://www.jru23cycling.info/pdf/gearRatios.pdf
For sprints and tubs (700)

What was a compact?