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upgrading to a triple crank...(6 posts)

upgrading to a triple crank...grannygear
Sep 8, 2002 7:33 AM
has anyone had experience with upgrading ultegra (1999) to a triple? if i understand correctly i'll need a new bottom bracket to accomodate the triple, new derailleurs and shifter indexed for a triple. am i missing anything? is it really neccesary to replace both derailleurs?

thanks...
I have good news and bad news.Spoke Wrench
Sep 8, 2002 9:05 AM
The bad news is that you really do need to replace both derailleurs. The short arm version of the rear derailleur doesn't have enough chain wrap up for the triple chainring.

The good news is you don't have to replace your shifter. The STI shifter costs way more than a rear derailleur so you are better off than you thought.
partial bad news.....Rusty Coggs
Sep 8, 2002 12:12 PM
Having to replace the rear derailer is not always the case, as it depends on the tooth spread in the rear, and it really doesnt matter that some of the smallest cogs in the rear may be unusable in the granny as it it just a bailout for most riders anyway.
Well, you have a point.Spoke Wrench
Sep 8, 2002 1:45 PM
You have 29 teeth of chain wrap to work with and the front chainrings use up 22 of that. That leaves you with seven teeth of chain wrap for the cassette. That would allow you to use the granny gear with the four or five largest cogs. More than that doesn't make any sense anyway.

That's the kind of thing I might do on my own personal bike, but I wouldn't want to do on a customer bike. That's the kind of thing that comes back to you later.
Certainly........Rusty Coggs
Sep 8, 2002 2:58 PM
Wrap capacity is often conservative too. I'm running a 13/23 in the rear and an 8 speed short cage 600/ultegra will wrap it all. No real point to it though.Coming back depends on how knowldgeable a customer might be and how well the concept is explained. Maybe best to play to the moron intelect though.
The damage is the story they tell to other people.Spoke Wrench
Sep 8, 2002 3:48 PM
I had a guy bring a tweeked wheel to me to straighten. I told him very clearly that I could pull it straight but I couldn't make a good wheel out of it and it might taco the very next time he hit a bump. Well, he absolutely has to ride the next day so he was good with that. He made an informed decision to take that chance. I didn't even charge my full wheel trueing fee.

Guess what! Next thing I hear is not from him but from one of his buds. His wheel tacoed, exactly like I said it might, only now its my fault.