Hey guys, should be a quick question. Thinking about buying a used Ultegra 6503 crankset, which is a triple. Want to just take off the inner ring. Would that end up being complicated or a really easy procedure. I already have 105 double STI's but I'm running an old Biopace set up I finally want to replace. Thanks a lot!


Picture: https://www.bikepartsplace.com/discou...egra-fc-65031/

Taking the inner ring off should be easy, but it's probably not a great way to go, since you'll have iffy chainline - the rings will be shifted outboard relative to a real double. You can get an NOS 5500 double crankset for probably about $70 shipped, and a bottom bracket for less than $50.

When I ride a triple, I use that middle ring about 90-95% of the time. I can't think of a single good reason to remove it.

I believe he is removing the inner (smallest) ring, not the middle ring. Ignoring the technical complications of havig no middle ring and the jump from smallest to biggest, I think most people would thing removing the middle ring is a weird idea.

The middle ring of a 6503 is a 42, significantly higher than the more common 39 used as the middle ring on most Shimano triples or the inner ring on most standard doubles.

Ah. Well, there are a lot of people buying compacts these days.

Keep shopping. You would also have to buy an octalink bb and they are not inexpensive. You can get a modern lower range Shimano crank with bb for under $100. Tiagra or Sora. Will work fine.

The octalink bb would come with it. For 50$, I think I will do it and live with the iffy chainline for now. And yes I do plan to just drop the inner ring.

Anyway I'm running a 42/52 with the biopace set up right now, and have already lived with some not-so-great shifting using a 10 speed chain with chainrings designed for a 6 speed chain.

The 6503 requires an Shimano Octalink bottom bracket. What do you have now?

I have a square taper but the BB will be included with the crankset