Good Morning forum,
So, after wearing down my rear rim after a little over a year of use on my commuter bike, I was thinking that I would like to change out my brake setup. I was going to have the rear wheel rebuilt with a nexus 8 hub and roller brake and leave the front canti in place. The idea being that I would use the roller brake for braking and both the front canti and rear roller brake for braking really fast. I've decided not to go with the Nexus 8 but still want at least one non rim brake. So, I was thinking about replacing my front fork with a disk brake ready unit. One of my local bike shops has a guy with a carbon front fork with disk and cantilever bosses on his cross bike that he is thinking of selling. The idea being that I could put the disk up front and leave the cantilever in the rear. I believe some call this a mullet. This way I can put the fork on and when the front rim wears out, build a new one with a disk hub and install the disk hardware.
What I want to know is this;
Are carbon forks suitable for commuting and some light touring? (no front panniers)
How are they for durability compared to steel?
How does carbon feel compared to steel?
Are there any other considerations I should make?
I'm using cable actuated drop bar handles, are BB7s still the way to go?

The first issue is does the different fork match the old one's fit WRT to frame. Is the steerer the same diameter and headset fit? Will the new fork work in the frame/headset.


Second is how the new fork will change the handling, or not. Is the axle to crown race seat the same? Is the rake the same?


Third is if the new fork can accept the same accessories as the old did. Fenders, racks, lighting.


Nothing wrong with mixing brakes types on the same bike. But some brakes require a greater cable pull amount then others do. Canti brakes usually are paired with levers that pull a short amount of cable. Hub brakes (including many disk) require a longer cable pull. There are devices to translate cable pulls (The Travel Agent as example) but many feel that this solution is either overly complicated or not as effective as just getting a well matched system. What is a problem is when trying to run two brakes off of one lever. This is when the matching of cable pulls is really important. Even then this type of set up can be less effective then only having one brake on the lever. (Tandems come to mind)


Carbon forks tend to be very strong as far as how much stress they can handle but they also will fail in a catastrophic manor sometimes. They also can suffer from bonding issues, I've seen drop outs come loose as example. But these speak more to the build quality then the materials in play.


There are so many factors that contribute to the "feel" of one fork to another. When actually riding one can't separate out the fork's stiffness from the air pressure or profile of the tire, as example. Changes of A-C dimension and rake (and the resulting trail change) can't be separated from the change to the bike's front center. But do be assured you will feel some difference, just that exactly what that will be is hard to anticipate completely. Andy.

Maybe learn to use your front brake predominantly and to not drag your brakes.

This was my first thought. You shouldn't be able to destroy a rim in a year.

I didn't think I would destroy a rim that fast either, but I live in an area with some pretty steep hills, there was construction on my route to and from work, so there was lots of grit and mud all over the place, and I live in the pacific north west, so it's wet all the time if it's not June, July, or August. Actually, I ride a lot of back country roads, so there is always some sort of dirt or grit from all the logging trucks. My rims, when wet, just sound dirty when I brake after riding for 15 minutes.

Others have written and will continue to provide good info on the fork swap. I just want to commend you on choosing against the 8 speed Nexus with roller brake. I had a bike with that setup and it was not good. The hub was a love/hate situation. The brake was just stupid, nothing to like.

The first cut is the relative size of the donor bike frame vs. the recipient bike frame.

Unless the donor bike is a larger frame size it's likely not going to work.