Triaxtremec

I have a Sirrus Sport 2010 and was curious of the benefits of upgrading the crankset as well as what crank to choose?

nfmisso

Benefit: separates you from your money; enriching the supplier and manufacturer.

Why do you want to change it? Are the gear ratio not to your liking? The wrong color?

Triaxtremec

I feel like I'm shifting constantly, kinda drive me nuts sometimes, other than that works great but doesn't look as cool as others. I'm not going to buy a new one just based on looks. I guess I just don't understand why some can be $40 and other $400 and the benefits of them.

NukeouT

Sometimes teeth wear down, which can cause bad shifting. They should be flat instead of pointy.

You can also get damage on your square-taper cranks from putting them on too tight or riding on them when they are too loose. This often also warrants a replacement.

Aside from that sometimes you want to change amount of teeth or crank length. I moved from a 165mm crankset to a 170 standard and it made a positive difference for me.

Some cranks also come with an outer chain guard to protect your pants from getting eaten.

Others are newer so they are simply lighter in weight.

Some new high-end cranksets out there like SRAM can measure the torque you put into them.

Some may be needed for special drive-trains and chains, although I know little about this. I mainly stick to vintage parts.

nfmisso

why are you shifting constantly? just can't find the right gear - what you really want is between two that you have?

you have not really defined the problem well, nor not adequately stated what you currently have to provide anyone enough information to suggest any solutions.

Information needed:
* number of teeth on every sprocket of your cassette/freewheel.
* number of teeth on each chain ring.
* tire size
* terrain the you ride.
* front and rear combinations that you are currently using, and under what conditions when riding.

For example; on my commuter:
14 - 16 - 18 - 20 - 22 - 24 - 34
40/52
32-630
mostly flat, one underpass and one over pass in 12 mile one way commute.
On the level I start off in 52/24, and shift up to cruise in 52/16; 52/18 if there is a mild head wind and 52/14 with a strong tail wind. For the over/under passes I get down to the 52/22 if I do not have to stop due to traffic. I do not use the 40T chain ring during my normal commute.

I am planning on changing to 13,15,17,19,21,24,28 in the near future, mainly for the smaller jump between 24-28 compared with 24-34 which is tough on the knees.

AdelaaR

Glad to know I'm not the only hybrid rider staying on his 52 chainring nearly all the time

OP, as nfmisso said, you should clearly state your problem otherwise it is impossible to suggest anything.

qmsdc15

Triax, shifting a lot is good. If the shifting is working well, and the chain is running smoothly, don't change anything. I usually stay in my middle ring until I need something bigger or smaller.

My theory is if you change your chain often enough you should never need new chainrings, but in practice no one changes his chain that often and eventually rings wear out. Most bikes these days come with chainrings riveted together rather than bolted, so when you've worn out one of the rings, you need to replace the whole crankset.

I've purchased a crank with Hollowtech bottom bracket for when I need to replace the crank on my MTB. It's a lot lighter than the stock crank/BB. It was on sale and I figure I'll need it sooner or later.

JonathanGennick 

At the very low end, you tend to get stamped rings, riveted-together sets in which the rings cannot be changed, steel rings instead of aluminum, old-style bottom-bracket choices such as square-taper.

As you move up the price scale, you tend to see more CNC machining on the rings (improves shifting), stronger alloys, alloy rings instead of steel (less weight), bolts instead of rivets, so that you can replace individual rings, hollowed out crank arms (on many Shimano models), etc.

You do get to the point of diminishing returns. For my mountain bikes, I've been buying either the Shimano LX cranks from Jenson at $89, or SLX cranks when on sale for less than $150. A racer might benefit from spending more to shed a few grams, but I prefer to stay in the middle zone and focus on bang-for-the-buck.

qmsdc15

The LX from Jensen USA is the one I bought for my MTB. The 44t big ring maybe too small for a hybrid but with 11t small cog, 108 gear inches, not bad. I need to get my BB shell faced before installing that, right?

JonathanGennick 

Getting the shell faced is the gold-standard, yes. I will confess that on my latest build, that I just slapped the chainset on without facing. But the "best practice" is to face the bottom-bracket to ensure that the two sides are square with each other.