[Rainbow Grease]

HI:
I want to upgrade my stock crankset with this SHIMANO 105:
http://www.niagaracycle.com/product_info.php?products_id=405844

However it says is only compatible with 10 SPD chain, does this mean
I also have to upgrade my 9SPD cassette to a 10 speed?

Here is my current config:
Crankset TruVativ Touro, 30/42/52 teeth.
Cassette SRAM 12-26 9 spd.
Rear derailer Shimano 105.
Front Derailleur Shimano Tiagra, braze-on.

And one last question: what is the performance difference between the double and triple crank systems?

Thanks in advance.::

 

[JRogers]

A 10 speed crankset will work fine with a 9 speed drivetrain. Shimano just has their own special ideas of what works. You may have to get a new front derailleur to get the shifting right, but I'd try it out first before buying one.

I switched a while back from an Ultegra triple to a Race Face double compact. I also run a 9 speed drivetrain (older Ultegra and some 105). Pretty sure I had to get a new front derailleur. Old triple shifter works fine with it.

As far as the differences, you can find lots of different opinions online if you google around a bit. Personally, once I got used to the new gearing spread, I liked it just fine. It did take a little getting used to for me. I run a 50x36 in the front and 12-25 in the back. Works fine for the rolling terrain where I am now. I tried an 11-23, but that was a bit too optimistic. I may put on a 34 front in the future as I am moving to an area with bigger mountains. You should do fine with a 34x26 low gear unless you currently find yourself in the small ring a lot on your triple- you will lose some of your lowest gears going to a compact. I switched to a compact crank because I found I wasn't using the small ring on the triple much (and I had to replace the chainrings, but it was almost cheaper just to get a new crank). You will use a bit of top end gearing, but it isn't that much. If you find it to be a problem then you can always throw an 11t small cog on, which gets you a higher gear than a 53x12. Other than a difference in gearing and probably being slightly lighter, there isn't much of a performance difference between a compact double and a triple.

Hope that helps some.

 

[Rainbow Grease]

Thanks JRogers, I just spent about 6 hours reading about gears and compatibility, think I am getting a nice understanding of the whole thing.::

 

[galmozzi]

I have a 105 drivetrain, 10 sp, and need to get a compact crank for a short term...will a 9 sp Tiagra crankset work? I don't see why it wouldn't....