Changing the cassette for climbing

jon208

Hi - I'm thinking of entering the Rydale Rumble but am a bit concerned about making it up all the hills! I've got a Bianchi Via Nirone with a Veloce groupset. The chainset is a compact (50/34) and the cassette is currently a 12-25. I know I can climb a 20% gradient with this setup but not sure I'd be able to make the 33% climb that features on the Rumble. My question is would swapping to a 13/29 cassette for the event give me a significant level of help? I'm not really sure how much difference those 4 teeth would make!

Thanks in advance.
Jon

mrushton

Go to the Campagnolo site or www.sheldonbrown.com where you can enter the data into a gear calculator.

JamesB

Worth changing; even if you don`t use the 29 t spocket it is always there as a psychological bail out -- rather than feel that you`ve no lower gears left the 29t would be there if needed;
as a comparison I rode the Devils Staircase (25% +) in mid Wales on 34 / 29 fairly `easily` , could have done on a 26 t but having that extra low sprocket available was a help -- saved legs for further hills!

jon208

Thanks, the trouble is this gear inch stuff doesn't really mean anything to me. I have nothing to judge it against as this is my first road bike. Do you think the difference would be significant with the new cassette?

JamesB

You could look at it in this way:

A 29T sprocket is about 17% easier to turn than a 25T (25/29 ratio)>>> therefore if you can climb a 20% gradient on 25T you could climb a 25% gradient on 29T with same effort; so on that basis you ned a 29T for the 33%

gkerr4

make sure your frame can accommodate the 13 tooth gear as it's smallest cog.

I found to my displeasure that an S-Works roubaix SL frame can NOT accept the 13-29 - it fouls the seatstay and cuts a nice little groove with the chain!

jon208

Thanks folks, sounds like it would be a handy swap to make before attempting this ride. I'll give it a go, nice to know the extras are there even if I don't use them on the day!

cyclingvet

I run a compact 50-34 with an 11-28 cassette and on last weekend's Wyre Forest Stinger didn't have too much trouble (apart from maintaining traction on the wet muddy roads!), up several 20% and 25% climbs.

I'm entered for the Rydale Rumble and will be using the same set up.

mrushton

gkerr4 wrote:

make sure your frame can accommodate the 13 tooth gear as it's smallest cog.

I found to my displeasure that an S-Works roubaix SL frame can NOT accept the 13-29 - it fouls the seatstay and cuts a nice little groove with the chain!

This often happens on frames that are race specific. Pinarello are the same in that the largest small sprocket they can take is a 12t

synchronicity

mrushton wrote:

gkerr4 wrote:

make sure your frame can accommodate the 13 tooth gear as it's smallest cog.

I found to my displeasure that an S-Works roubaix SL frame can NOT accept the 13-29 - it fouls the seatstay and cuts a nice little groove with the chain!

This often happens on frames that are race specific. Pinarello are the same in that the largest small sprocket they can take is a 12t

Does that include the F3:13 too?

mrushton

Possibly. It's worth taking a wheel with a 13 sprocket to try with the frame. Pinarello may have changed the geometry slightly to accomodate those of us to whom small sprockets are a waste of time/energy

HarryB

mrushton wrote:

This often happens on frames that are race specific. Pinarello are the same in that the largest small sprocket they can take is a 12t

So how come my LBS has just fitted a 13-26 onto my Pinarello Prince and it works fine?

Unfortunately I didn't manage to get up the Chimney yesterday. Almost but not quite

mrushton

So how come my LBS has just fitted a 13-26 onto my Pinarello Prince and it works fine?





Pinarello may have changed the geometry slightly