Advice on cassette choice needed!

Smig1985

Hi guys, just looking for a bit of advice on choosing a new cassette. I'm upgrading from an aluminium bike (Shimano 105) to a carbon one (Sram Force), with the new one weighing a little over a kilo less than the old - so that'll definitely be a factor going uphill. I'm a light rider in any case (c. 63kg) and would consider myself a good climber - currently running a compact up front (50/34) and an 11-28 cassette. I rarely if ever use the 34-28, and usually find myself with a gear or two to spare even on longer, tougher climbs. What do you reckon would be a good set-up...11/26 maybe? My new cassette will be a Sram one and I believe their ratios are somewhat different to Shimano ones. Any info/advice would be greatly appreciated, thanks!

niceonetom

At that weight, on a compact, in this country, 11-23.

Smig1985

Really? Bearing in mind I'm a spinner and not a masher! Do you run that ratio yourself?

manwithaplan

You definitely don't need anything bigger than a 25. If you're planning to race, the closer ratio of 11-23 would be best.

Smig1985

Sorry manwithaplan, could you elaborate a little more on why an 11-23 would be better for racing? I'm pretty clueless when it comes to this techy stuff!

Dermot Illogical

manwithaplan wrote: »

You definitely don't need anything bigger than a 25.

+1 on that.

manwithaplan

I'm about 72kg. I have a standard double (53/39) with a 11-25 cassette on my race bike. I race A3 and would be considered a reasonably good climber. I have gone over most of the Wicklow climbs on that fairly comfortably, although I would probably prefer my training bike, which has a compact on it, for something like Slieve Mann.

Edit - just saw the question about racing. 11-23 would be better because the tighter cassette (with mostly only one tooth of a difference between cogs) gives smoother changes and less 'clunkiness'. Also, most races don't involve super steep hills so I can't see you needing 34-25 in a race. Actually, I have only used the small front chainring a handful of times this season in racing. Should also say that quick acceleration through the cassette doesn't matter that much outside of a race, so you could go with 11-25 in that case.

lennymc

id suggest going out on your current setup, seeing what gear you can ride on, work out the gear inches or gear ratio (sheldon brown gears) of that gear and then see what that would relate to on a 39/2x

so, if you are comfortable on a 34/26 on the current bike, that equates to a gear inches of about 35. The equivelant gear on a standard chainset would be a 39/30

For comparison, your current lowest gear is about 32.8 gear inches, and a 39/23 is about 45.8 gear inches which is about a 40% difference. 39/23 would equate to about 34/19 on your current gearing.

Explanations are available on that page linked above

macnab

I am also 63kg but not a great climber. I have an 12-28 with a compact chainset on my 2nd bike. I would tend to use that on spins around Wicklow and often use the 34/28. Some of the ratios have more than 2 teeth of a difference so that is quite a jump when sprinting, more so if you are out of the saddle. Cadence is not as constant.
My good bike also has a compact chainset but I have an 11-23 on the rear. This setup is perfect for my Meath/Kildare spins which are relatively flat. On the occasion where I encounter a climb I tend to sprint as much as I can as 34/23 is a tough gear for me to sustain for any longer than 500m if the climb is over 7%.
Again I am not a good climber so bear that in mind. I suggest you borrow an 11-23 cassette and try it out for a while, or buy a cheap or 2nd hand one.

Smig1985

Great, thanks for all that guys. Well, as I don't intend taking up racing anytime soon I think I'll go with an 11-25/11-26. What are your opinions on buying 2nd hand cassettes? I've been using the same cassette for quite a while and have run two new chains on it without experiencing any major problems with poor shifting etc. It seems to me that as long as the cassette isn't badly worn to begin with and you partner it with a new chain you should be fine. Any thoughts?