did I lose anything? stupid question?

[beungood]

I am not sure if this qualifies as a stupid question but here goes..

When I bought my spectrum beam it came with a 13/23 rear cog and 53/39 up front. I was worried at first not having an extra climbing gear (my Allez Comp Cro-mo has a 12/25) but found the Geometry of the Spectrum beam seemed to make much more effiecent allowing me to climb some hills with 23 when I usually needed a 25. I found though that I could spin out out on some down hills with the 13. I got a great deal on a campy 12/25.

My question is did I lose anything or waste my money taking of my 13/23 (13,14,15,16,17,19,21 and 23)

and installing the 12/25? (12,13,15,17,19,21,23 and 25)

I am rather confused by gear inches and all the tech jargon. I am about to take it out for a run through the Blue Hills Res on my loop to see how it rides and compares to my Allez as I write this..

[yeehawfactor]

i dunno. if you really liked a particular gear that your old cassette had that your new one doesn't, then yes. if not, then i'd 'spect not

[Sandy]

If you look at the cogs on each cassette, you will see that 6 are identical:

13,15,17,19,21,23

That leaves 2 cogs different on each cassette:

On the 12/25: 12 and 25, not found on the other cassette
On the 13/23: 14 and 16, not found on the other cassette

So the 12/25 gives you both a bigger gear (12) and a lower gear (25) than the 13/23. That is good, as the 25 will help you climbing steep hills and the 12 will allow you not to spin out as quickly on hills.

The 13/23 has a closer sequence of gears from 13 thru 17:

13,14,15,16,17 versus 13,15,17 of the 12/25 (as the 14 and 16 are missing). That means that as you shift gears from 13 thru 17 there will be no 2 cog jumps, which gives a more linear shifting with closer gears and 2 more choices. Some cyclists really like the 16. With the extra 2 gears, one might more easily find a gear that he or she prefers.

To me the choice of 12/25 versus 13/23 would be simple. I would choose the 12/25 as you have a larger and smaller gear than on the 13/23.


Shimano Shifting Serotta Sandy

[beungood]

You guys were right, I gained alot more than I lost with the switch. I still have to adjust deraiiluer due to some jumping back and forth in the middle of the cog, but, the new gearing seems to make my bike jump when I mash. It out accelerates my Allez. and makes it real easy to stay in the mid and high 20's through most of my loop. Even after William's 3 hour torture session I knocked off minutes from my loop and upped my top speed a few miles an hour. I can't wait to do it fresh... Anyone seen the Skunkbird around?

[Sandy]

You and possibly a different bike makes the difference. Certainly not the gearing. A max speed going down a steep hill might be higher as you wouldn't spin out as quickly, but a higher average speed seems very unlikely because of a gear change as you described.

Give yourself and the bike the credit, but not the cassette.


Looking for credit,



Sandy