SethL

Hi, Currently I have a BB30 50/34 crankset. I never thought of replacing it but a buddy of mine has a FSA 52/36 that is all carbon fiber that is free never been used.. Since they are both BB30 will it be easy to install? I have 11 speed will it affect the gears and chain? Will it make that much of a difference? I think my currrent one is gossemer, all aloy.

Eric F 

With the BB is the same on both, it shouldn't be an issue. The front derailleur will need to be repositioned for the new larger chainring size, which also might require a new cable if there isn't currently enough length to accommodate the new derailleur position. I would also expect that you will need a new chain.

If this was my bike, I would also consider replacing the cassette (depending on how old the current one is) for a complete drivetrain refresh. I would also plan on new cables and housing.

Soody

Unless you live somewhere flat and are very strong I think it will make a small negative difference because of the gearing change.

cpach

If the carbon crank has 10 speed rings you can potentially have some shifting problems with an 11 speed drivetrain. This is technically out of spec though in practice it often works OK. Also, to be honest, 10 speed era FSA rings don't shift as well as their 11 speed ones, they've made real improvements in that area. If you can I would probably switch the old rings onto the new crank. Honestly a 52t ring isn't terribly useful for riders who do not race, and you'll loose some low gearing.

Mechanically, the switch isn't very hard at all. You'll drop a modest amount of weight. I strongly doubt you'll notice anything else about stiffness or whatever. In-of-itself it's probably not super noticeable, but it'll look bling and it's a fair amount of weight savings for a single component (without really any downsides) for what it's worth.

SethL

Thanks, it sounds like I should look for a 50/34 lighter carbon fiber crank set. I have no problems with the gears and don't want to change my chain or have to adjust anything.

alcjphil

My guess is that the weight saving will be insignificant and unnoticeable.

cpach

You could just swap rings like I suggested.

SethL

So after reading this, I am deciding to keep my same size crank. My chain and cassette are brand new and I have no problems with the 50/34 size. I do think the crank rings or the crankset need to be replaced as the bike is 10 years old and the teeth are warn. Replacing both chain rings would be the same cost as getting an entirely new cranket, used and there are ones like the one below for dirt cheap.

(5) Marketplace - FSA K Force Light Crankset | Facebook

1. How can you tell if these have warn teeth? Kind of hard to see in the photo but there is not an ounce of grease on it.
2. For the install job, should it be done by a bike mechanic? The youtube videos make it seem easy but I have found those to be somewhat deceiving.

70sSanO

So let me get this straight. You have a chance to get a free carbon crankset from a friend that will fit on your BB, but instead you are taking advice from people who have no clue how you ride not to take it. They don’t even know what cassette you are using.

John

SethL

I have not taken any advice as I have not purchased or changed anything yet. After hearing I would have to move my gears and replace a new chain if I increased my teeth on the big ring I did not want to do this, especially since i don't have a problem with the gears on the 50/34. There is a great aftermarket exchange on bike components and I am wanting advice before making any decisions. I have loved these forums so any help is great.

70sSanO

I understand. But if your chainrings are worn, you might want to use a new chain anyway.

The reality is that you need to run the gearing by gear inches and even determine speed at a certain cadence to determine the effects of a 2 tooth change from your current setup. The quick and dirty method is to know how much you use the 34t/lowest cassette cog and maybe the 50t/highest cog. If you struggle with the 34t and never spin out with the 50t, then you probably should pass. That is the rationale approach before making any gearing change.

John