Help choosing a cassette
 

Hi, I live in hilly Pennsylvania where I find myself doing occasional steep climbs up mountains (1,500ft inclines) but usually on rolling hills in valleys. The question I have is regarding a bike that I am currently building. My crankset is 50/34 teeth and I'm wondering what cassette I should get that would pair well with this crank and my riding . Should I go with 10 or 11 sprockets (I want at least a 10) and how many teeth for the smallest and largest? Any help is greatly appreciated.

3x9

You really don't give enough info to expect any help. Are your wheels compatible with 11 speed? What are your shifters and derailleurs? It's been mentioned before that you should keep your questions about this prospective bike in one thread so you and others don't have to repeat themselves. Good luck!

There's some info not given (like wheel dish), but then there is also some very subjective variables that you need to work out on your own. For me and my conditioning and muscles and slow climbs that I do (sitting, in first gear), I prefer a chainring/cog ratio of at least 1.2:1. Meaning, if I were running a 34 tooth chainring, I'd want at least 40 teeth on my biggest cog.

I prefer less expensive stuff, so I'd probably run a triple in the front and an 8- or 9-speed cassette in the back. Cassettes are far cheaper, chains are cheaper, chains are wider (more durable, easier to clean, etc). The obvious downside is the additional weight of the triple crank, which is a non-issue for me. I get my 1.2:1 ratio on one bike (3x7) with a 22 small chainring and a 28 large cog. My other bike (3x8) has a 28 small chainring and a 32 large cog. It's not quite 1.2:1, but it's close. Next time I replace the cassette, it'll be with one with a 34 tooth cog.

I'd consider going with a 10-speed or 11-speed on the back only if I was going 1x, and would completely lose the front derailleur. But if I'm going to have a derailleur up front anyway, I'd go all the way and run a triple.

Agree with others, get a triple.

You can do an 11. You can got to something like 11-32 on road components and with a 34/50 that'll probably be what you need. It's just more money and you give up some tighter gearing on the rear, so always have multi-tooth jumps.

I use a 26-39-52 crank (I swapped the 30 granny to 26), plus a 13-25 9 spd. It's the same 28 gear inch low as the 34/32 combo but I get a few gears with one tooth jumps (13-14-15-16-17), which is nice on easy rolling. My stuff is Ultegra triple and shifts very well, no issues with the granny.

No reason to go to an 11 tooth with a 50 on the front.

Don't have shifters or derailiers. Figured it'd be best to get the ratio right before selecting shifters and derailures. The whells are compatible with 9-11.

this one: https://www.amazon.com/Sunrace-10-sp.../dp/B01JAICH12

and change the 50 to 46 on your cranks (46-34).

That's for a mtn bike

"Shimano Sram 10 speed Compatible"

[MENTION=463648]JakeMountain21[/MENTION], You need to learn how Gear Inches (GI) or ratios apply to your needs. For example you can compare GI of a bike that doesn't have enough bottom gear in an online calculator to what is available and compatible with your current or planned drivetrain. A 10% difference can be easily felt, but 5% maybe all that's required.

Brad

It's only for a "mountain bike" in the sense mountain/touring/multipurpose bikes usually require a larger range of gearing than a traditional road bike. It's not "mountain" for any technical reason.

So I got a shimano 10 speed 11-28. What type of derailure should I get? And are chains universal?

Cassettes with two-tooth jumps before the 19 cog are unsuitable for road riding. That makes viable combinations

11-12-13-14-15-16-17-18-19-21 10 cogs
12-13-14-15-16-17-18-19-21-23 10 cogs
13-14-15-16-17-18-19-21-23-25/26 10 cogs
14-15-16-17-18-19-20-21-22-23 10 cogs (I didn't like the extra cog changes moving from big ring to small or more frequent shifts from 39 to 50 ring)
11-12-13-14-15-16-17-18-19-21-23 11 cogs
12-13-14-15-16-17-18-19-21-23-25 11 cogs
14-15-16-17-18-19-20-21-23-25-28 11 cogs

Eddy Merckx dominated the spring classics with a 52x13 big gear, and you're no Eddy. I've always been content with a 50x13 or 52x14 big gear.

Use a triple if you want a lower gear while using those cassettes, or less shifting between rings.

I liked 50-40-30x13-14-15-16-17-18-19-21 for the Colorado Rockies (including Ride the Rockies 1997 Grand Junction to Golden with 28,000 feet of climbing in 418 miles, and the infamous Mike Horgan Hill Climb) in the 8 speed era - like a 7 cog straight block for plains rides east of Boulder, CO but 42x28 for mountain climbs. With 13-21 8 cogs discontinued and a worn out big ring I moved onto 50-34x13-23 9, but changed rings 10X as often. After wearing out more parts I went with 50-39-30x13-26 10.

YMMV. Making your own decisions will be a better idea than consulting strangers who have no idea how much power you make, how much you weigh, and how long/steep your local climbs are.

Buy a rear derailleur that is spec'd appropriately for your cassette (in terms of cog size allowance, etc) and fits your budget. You likely have Shimano-compatible shifters, so you'll probably want to stick with a Shimano derailleur.

You'll need to buy a chain specific to 10-speed drivetrains. One will cost about 25 bucks. Brand doesn't matter (to my knowledge). I tend to like KMC chains -- they make good chains at reasonable prices that wear well.