Gears on new bike

johnnyc71

All going well I should be picking up my new Planet X bike tomorrow .

My current bike (hybrid) has a triple and a 9spd 12-26 fitted. The new one has a compact and 12-27.

So when using a 10spd - how far up the cassette can you move - before you get a noticeable chain crossover. Will I have to spend alot of time switiching the front chainrings?

I guess what I really need to know is how high a gear can you use on the 34 chainring and how low aa gear can I use on the 50 chainring.

feel

I would think avoiding the final 3 sprockets of max crossover would avoid any probs.

azzerb

Depends what gears you have, a lot of them have trim on the front to reduce this.

redddraggon

You can use the whole sprocket, but it all depends on how your bike is set up. I use upto about the 8th sprocket before thinking about shifting at the front.

johnnyc71

Thanks for the replies - gives me a general idea.

Never used the shimano sti's before - should be a change from my sram grip shifts

Bronzie

redddraggon wrote:

You can use the whole sprocket, but it all depends on how your bike is set up.

Chainwear is supposed to be quicker when you do use extreme chainlines as well (ie big front chainring to biggest sprocket on the rear).

redddraggon

Bronzie wrote:

redddraggon wrote:

You can use the whole sprocket, but it all depends on how your bike is set up.

Chainwear is supposed to be quicker when you do use extreme chainlines as well (ie big front chainring to biggest sprocket on the rear).

Yes, that's why "can" is italicised. 53-25 and 39-12 (or whatever) will work, but it's not necessarily the best to use as there's normally a similar ratio using the other chainring with a better chainline.

John.T

Modern chains are pretty tolerant now. I use the big 8 on the 34 ring and the small 8 on the big ring and don't think about it. I use the next cog with caution as the same gear is available on the other ring with better chain line and will use the last cog when I over estimate my abilities.
Check your gear ratios with Sheldon Brown's calculator and you can see which ones are duplicated. I would recomend setting it to gear inches unless you are used to any of the other systems. This effectively gives you the size of a penny farthing wheel that would travel the same distance for one revolution of the pedals. It is a bit old hat now but it does let you know that 50/19 and 34/13 are the same ratio (nearly).
http://sheldonbrown.com/gears/

johnnyc71

Cheers - I already have the gear inches printed out - from a few weeks ago - I find it useful for comparing gears - was just unsure of the best way to use the compact. Anyway - I should be able to test it all out in a real life scenario tomorrow morning! I hope I like the feel of a road bike.

dennisn

when you're in the 34 front ring you will probably find that you will start to get a bit
of chain "dink" if you shift onto the 2 smallest rear cogs. Not always but it can happen.
The "dink" being caused by the chain being at such an angle outward(toward the smaller
rear cogs) that it starts hitting the big front ring, "dink". This doesn't happen when in the big
ring and the large rear cog but results in a not to good chainline and shouldn't be done.

Dennis Noward

John.T

My 9sp catches but both the 10sp bikes are clear in all gears including small/small. You may be lucky or not as frames vary a little and the tolerances are very small.