Colorado

For those in the know, is there any difficulty in switching a triple Ultegra crankset to a double crankset on a road bike. Currently using Shimano 105 shifters. Bought the bike when i wasn't really in the know and now i'm starting to race well and realize that the triple isn't really doing anything for me anymore. thanks a lot for anything you can tell me.

sydney

To make it like a factory job,you need a crank,BB, front and rear derailer.Not a bit of difficulty if you have a BB removal tool and know what you are doing.

marcusbandito

Why not just take the small chain ring off and call it quits? That makes it a double.

Point

I'll agree. just take off the small ring and you've got a double. Always have the option to put it back on. Could just leave it on and not use it. The weight penalty is negligible.

Of course, if you want a compact double, that's another story.

marcusbandito

Now I'm curious about the performance of a double vs. triple rear derailer. I would think the shorter pully cage would give quicker shifts, but would it be really noticable?

53-11_alltheway

It's not the same. THe chainlines will be different.

I've heard people say that you can take the small ring off, swap in a double BB and double FD and call it quits though. (never tried it myself though)

john5211

I couldn't say about the RD, but on a double front derailluer you can trim the derailleur, whereas with a triple you cannot (at least I can't trim mine ).

oldspark

Just race the triple, beating the guys with doubles will drive them wild.

53-11_alltheway

triple rear derailleur will be fine.

Dchiefransom

I can trim my front derailleur on my triple, but only for the small and middle rings.

suntreader

What if you took off the granny ring, then inadvertantly shifted to the absent ring while riding? Wouldn't your chain fall off?

DinoShepherd

No, you set your shifters up so the low gear on the shifter, (most slack in the cable) is the (old)middle, (now the low) ring. When you shift to what the shifters think is the middle ring, you are actually in the big ring.

The deraileur stops will prevent you from overshifting out of the big ring.

Simple.

-Z (Wrench-Dog Spot)

sydney

Only in appearacne..The small ring wil be a 42 rather than the typical current road 39 and the chainline will be all wrong for a double.

sydney

BS...Consider chainline while you are at it, and the 42 ring.

sydney

An ultegra front shifter will have trim when set up right with a double.It also has trim when used as a triple. If yours is ultegra, it isn't setup right.

sydney

Heard of limit screws?

sydney

And you won't have trim for the big ring,and the chainline will be all wrong for a double. Do it the right way and at least get get the shorter double BB. Simple enough.

Dchiefransom

Will the front triple derailleur work, or is there a problem with that?

alraicercsu

you can keep the triple and adjust the fd so you block out the small ring and have a lot of trim in your gears or you can get a new bb and crank and fd, you might be able to go with a triple fd.

Colorado

thanks for all of that. what i'm going to do if the bike shop can do it i think is just switch to an actual double, maybe an FSA carbon crank and see what else i'd have to replace. although it is fun outsprinting the double guys.

Colorado

if it helps at all for the technical aspects, i have a 105 fd an ultegra BB and triple crank and an ultegra rd

john5211

*light goes on*

No, it's setup fine ... I'm just an idiot. When I got the bike a couple of weeks ago I asked the guy who did the final adjustments/fit about trimming and he told me that it's not possible to trim a shimano triple. So naturally I've been fiddling around with the front derailleur wondering why I can't get it to shift crisply ever since I got the bike.

But yeah, if I account for trimming on the small and medium chainring then everything works perfectly.

Doh!!

DinoShepherd

Syd -

Hey, we heard you about the chainline. Nobody cares. If the chainline was fine with a triple it will be fine with a double. It won't be optimal, but it will work. He can change the BB when it needs it. Get over it, dude.

I was responding to the question about overshifting. His concern was having three clicks in the shifters, but only two chainrings to shift to. I told him how to tune his front der. so his triple shifters would shift like double shifters. Of course you could just adjust the trim stops, but then you still have the third position to potentially click into.

-Z

sydney

No it won't be fine dude. Think about it. The big ring is further out and trying to use the bigger cogs results in excessive cain angle. Even the small ring in the middle ring position will result in excessive chain angle when in the big cogs. A BB is cheap enough. Do it right or don't do it dude.

Waldo

You failed to mention that most triples feature either a 50T or 52T (more common of the two) big ring, as opposed to the 53T we know and love on our doubles.
The 42T v. 39T is most likely a more significant issue for the average rider, but here in the flatlands the downsizing of the big guy is hardly trivial.