Wider, lighter crankset?
 

I have a Shimano 105 hollowtech II triple crankset that I need to get rid of and get something different. It'd take me forever to explain why, but essentially the front derailleur doesn't have enough clearance to shift the chain to the lowest chainring. With an older style crank, you could just put a spacer on the right crankarm, but with this integrated bottom bracket setup, you can't do such a thing I'm told.

So I either need a crank that has a wider bottom bracket (which would be best), or an older crank that I can shim to give the der. more clearance to move. This is a racing machine so I need it to be as light as possible. Carbon is ok, but it still needs to be a triple.

Thoughts?

My thoughts are that "racing machine" "light as possible" and "needs to be a triple" seem to be contradictory to my experience with bicycles.

Campagnolo made (still makes?) some nice light cranksets that use a square-taper bottom bracket. This style will allow you to play around with spindle lengths to get what you need.

Out of curiousity, what frameset is this on?

Ahh. Recumbent Ninja. I see why the triple. Still, if it is a recumbent you're working on, I'm kinda surprised that the design won' tallow for the use of a triple.

The racing bike I have is made in denmark. No need for a triple on the flats! I tackle a lot of serious hills and so they put the triple on when I bought it. When I changed chainrings to a set of ellipticals the shifting trouble started. Neither I nor the lbs can get it to cooperate. It IS designed to work eith a triple, but the tolerances of my particular bike seem to be too tight. I love the bike, and it's so light and fast I rarely need the small ring, but I occasionally go up some 15-21% grades, and though I CAN go up 12% hills in the 40-25, it leaves me a bit breathless to do so in the Texas summer heat and robs me of energy needed later in the ride.

http://bike.shimano.com/catalog/cycl...=1189309588146

According to this link, the octalink bottom brackets (which I think you have) are available in 4 lengths, from 113mm to 126mm. I'm not sure what size you currently have, but perhaps you can just swap the bottom bracket out, and not the whole bb/crank-arm combo. It'd be cheaper.

He has a Hollowtech II not a Octalink, but wants something different with more chainline adjustability.
That link is for a Octalink V2. That will not fit a DA, Ultegra, or 105 Octalink crank.

OP- I would suggest finding a square taper triple crankset.

That was what I figured would be best. Any suggestions for a good light setup with a wide q-factor or wide BB potential?

Care to tell us WHAT dérailleur "doesn't have enough clearance"?


YANPWDRTRMS!

Yet Another New Poster Who Didn't Read The READ ME Sticky!

it's an all 105 setup. The derailleur would have the clearance if it had room to relax all the way to it's left position. It doesn't on my bike, which is why I have to space the crank right.

Why not?

Here's the best view of the crank I could get. Essentially, when the derailleur tries to relax into position, the boom prevents it.

http://img.photobucket.com/albums/v6...icaquarter.jpg

there's your answer. if the trouble started when you went from regular round rings to the ellipticals, and you need the triple, switch back to the round rings and your shifting trouble should disappear as well. i'm guessing that the FD is too high on it's mount because of the elliptical rings and this is not allowing it to pull the chain off of the middle ring and onto the small ring. newer 10 speed FDs should have no more than 1.5mm of clearance between the bottom of the cage and the tops of the large ring teeth.

also, try to take a close-up of the FD shifted into the big ring from the side, so we can see the height of the FD cage when compared to the chainrings, and then another of it shifted to the small ring from above, so we can see if it is aligned with the chainrings, and if it is trying to pull the chain off the middle ring.

I have nothing to add except sweet ride!

You are correct - moving the derailleur higher to give clearance to the elliptical rings is what started the trouble. But I'm not giving up the rings - they give me too much extra performance and comfort to get rid of them. That's why I'm trying to find a good replacement crank I can space out.

I don't mean to offend, but people keep trying to offer ways to fix the current crankset - which Iisn't what I'm asking, since I don't think it's possible. I'm simply asking for a nice light crankset that I CAN replace this with that I can safely add a spacer to.

And thanks Brad. It's business in the front (titanium) and party in the back (carbon fiber)!

a pre-ultra torque campy record or chorus crankset might allow you to space it out, but that raises another issue, that of the BCD for the chainrings. a pre-hollowtech II shimano crank would work. or an older FSA carbon triple crank that uses either ISIS, or octalink.

honestly though, i think you'll end up either having the same problem, or a different problem, related to moving the crankset out farther to allow the FD to shift into the small ring. either the FD won't be able to reach the large ring, or it'll just pitch the chain right off to the inside when trying to shift down to the granny.

Some square taper triple cranksets to choose from.

http://www.stronglight.com/stronglig...d=impacttriple

http://www.specialites-ta.com/produi...etails1_gb.htm

http://www.specialites-ta.com/produits/crank_gb.htm

I've done it before on a different bike with similar style, so I know it can be done on a square taper, but I wasn't sure about any other style crank.

Yeah! That's one of the nicest looking 'bents I've seen!

Now to get it working perfect...

Did you use the spacers that came with the crankset?

Have you measured your front chainline? With that drivetrain it doesn't matter for shifting, but it will give us a reference point.

I'm afraid I have no idea what you're asking. I am savvy enough to replace a crank and do most of my own basic repairs. After that I'm done for!

And I wasn't aware there was a spacer with the crankset. My understanding is that with an integrated crankset you can't use a spacer of any kind since there would be less thread to catch.

chainline&spacers
 

Measure chainline from the center of your boom to the middle chainring, should be 45mm.

Your crankset should have 2 spacers, item #'s 6 and 11 in this PDF.

http://techdocs.shimano.com/media/te...9830608867.pdf

Is this a bike for the speed record type bikes, like this?

Very, very nice looking ride. How is the rear shifting? Does the long chain cause any problems?