Wider Q-Factor Cranks?

[Epicus07]

Hey guys,

Just finished building up a stunning Serotta Legend Ti that I acquired from a fellow forumite (will post pics soon!) I stripped my Campagnolo Centaur 10 speed group off of the Roubaix to build it up. The cranks have a narrow Q-factor of 140mm. This has the tightest clearance between the front derailleur cage and the crank arm that I have ever seen. It only just works. Even the slightest shift of the derailleur limit screw will lead to crank arm contact.

I had a fitting done with this bike and my fitter suggested going to a wider Q-factor. We talked about adjusting my cleats further inwards or longer pedal spindles to widen my stance but given the FD clearance, I'd like to look at a wider q-factor.

It looks like most modern campy are 145.5, shimano is ~147 and sram is between 145.5 and 150 (supposedly).

I'm running a 10 speed set up but understand that if its just the crank, I can get away with a lot.

Do you guys have any recommendations ~148 that would be relatively affordable and look good with the campy group?

It seems too sacrilegious for me to run a shimano crank.


Cheers

[AngryScientist]

white industries VBC is a pretty handsome crank and pairs well with campy, with the added bonus of tons of chainring combination options. Q factor is right around 150 i believe.

https://instagram.fewr1-2.fna.fbcdn.net/t51.2885-15/e35/20766838_270743553410003_777357022940102656_n.jpg

[Kontact]

I doubt your front derailleur is aligned correctly for this to be an issue.


Aside from cleat placement, washers between the pedal spindle and crankarm is the normal way to increase Q.

If you have your heart set on a different crank, I'd look for an original C-Record or Chorus, but I have no idea if those have much larger Q than yours. Otherwise, almost anything will work with modern chainring. I have a Speedlight crank I quite like, but no idea what the Q is for that, either.

[Epicus07]

white industries VBC is a pretty handsome crank and pairs well with campy, with the added bonus of tons of chainring combination options. Q factor is right around 150 i believe.


That could be a great option. Thanks ! Are you running square taper or MR30?

I doubt your front derailleur is aligned correctly for this to be an issue.


Aside from cleat placement, washers between the pedal spindle and crankarm is the normal way to increase Q.

If you have your heart set on a different crank, I'd look for an original C-Record or Chorus, but I have no idea if those have much larger Q than yours. Otherwise, almost anything will work with modern chainring. I have a Speedlight crank I quite like, but no idea what the Q is for that, either.

I wish it was that simple. Unfortunately it is correctly aligned and the FD is new and straight.

[AngryScientist]

That could be a great option. Thanks ! Are you running square taper or MR30?


i am running square taper. nice phil wood BB on this particular bike too. i doubt i will ever kill it.

[Ralph]

What length PW square taper axle?

[ColonelJLloyd]

Can you not using the existing crank with a wider spindle?

[Kontact]

That would mess with chainline.

[ColonelJLloyd]

That would mess with chainline.

Yes, but you could have more offset on the NDS depending on the spindle and that's approximately the same as the difference in using the 4th cog versus the 5th cog (worst case scenario). I suppose it could actually cause issues, but I'd be more inclined to say you'd never notice unless you're someone who rides a whole lot in the smallest cog.

[Epicus07]

Can you change spindle length on modern cranks like campy power torque ?

[ColonelJLloyd]

Can you change spindle length on modern cranks like campy power torque ?

No. My apologies. I thought your crank was square taper.

[kingpin75s]

white industries VBC is a pretty handsome crank and pairs well with campy, with the added bonus of tons of chainring combination options. Q factor is right around 150 i believe.

https://instagram.fewr1-2.fna.fbcdn.net/t51.2885-15/e35/20766838_270743553410003_777357022940102656_n.jpg

Looks like you are running the ENO (mountain) cranks with VBC rigs instead of the White Industries road VBC cranks. 160mm Q on the ENO cranks and 150mm Q on the WI road VBC cranks.

[Ralph]

I have two bikes with last generation Campagnolo square taper crank sets. One a 2006 Centaur like you say you have, and one a 2004-6 Chorus. The Centaur uses the black 111 BB, with 2 bearings on the drive side, just like the 102 BB for Chorus and Record. Both great BB's, and both cheap from Ribble.

Both have been on and off a few times, so while I am careful not to over Tq them, they both probably go on a little further than when new.

Campagnolo says both have a 45.5 MM chainline, and the Chorus has a 145 MM Q, but....when I measure the Q, the Centaur with 111 BB has closer to 150 MM Q, while the Chorus with it's 102 MM BB has closer to the advertised 145 MM Q. That leads me to believe if your Centaur measures 140 MM Q, something is not right. If your Centaur arms have been on and off so many times they go on too far.....you could use the Centaur 115.5 black BB. it's a good BB. It may fit just right. Phil Wood also has different lengths in ISO tapers.

[Ralph]

No. My apologies. I thought your crank was square taper.

Me also.

[steveoz]

interesting discussion on Q factor- anybody use a wider Q factor crank to alleviate knee pain? My LBS has fitted spacers under the right pedal..it's better (the knee) but it's not ideal....

[Kontact]

interesting discussion on Q factor- anybody use a wider Q factor crank to alleviate knee pain? My LBS has fitted spacers under the right pedal..it's better (the knee) but it's not ideal....

I've seen pedal washers used in fitting, but it is rarely to combat just knee pain but for more complicated issues.

All road bikes have "unnaturally" wide Q factor. We don't walk or run with our feet that far apart.

[Mark McM]

I've seen pedal washers used in fitting, but it is rarely to combat just knee pain but for more complicated issues.

All road bikes have "unnaturally" wide Q factor. We don't walk or run with our feet that far apart.

While most people can adopt to a range of Q factors, there are some for whom too narrow a Q factor can cause knee issues. A production called Kneesavers (http://www.kneesaver.net/) has been around for a few decades, for those who prefer a wider Q factor.

I'm just the opposite - I prefer as narrow a Q factor as I can find. While a wider Q factor doesn't cause me knee pain, I find it feels less natural, and even a bit awkward. I haven't done any testing, but I suspect that I'm a bit more efficient with a narrow Q factor as well.

In addition to a narrow Q factor, I also prefer a narrow U factor (the width of the cranks at the spindle). I'm a little duckfooted (i.e., my feet angle outward), so a narrow Q factor doesn't help me unless there is an even narrower U factor for ankle clearance. (And yes, that also means I sometimes have clearance issues between my heels and the chainstays.)

My preference for narrow Q factor/U factor is yet another reason I am not a fan of disk brakes - the ever increasing rear hub/axle width is leading to wider rear triangles and wider chainlines, which leads to wider Q factors/U factors.

[Kontact]

While most people can adopt to a range of Q factors, there are some for whom too narrow a Q factor can cause knee issues. A production called Kneesavers (http://www.kneesaver.net/) has been around for a few decades, for those who prefer a wider Q factor.

I'm just the opposite - I prefer as narrow a Q factor as I can find. While a wider Q factor doesn't cause me knee pain, I find it feels less natural, and even a bit awkward. I haven't done any testing, but I suspect that I'm a bit more efficient with a narrow Q factor as well.

In addition to a narrow Q factor, I also prefer a narrow U factor (the width of the cranks at the spindle). I'm a little duckfooted (i.e., my feet angle outward), so a narrow Q factor doesn't help me unless there is an even narrower U factor for ankle clearance. (And yes, that also means I sometimes have clearance issues between my heels and the chainstays.)

My preference for narrow Q factor/U factor is yet another reason I am not a fan of disk brakes - the ever increasing rear hub/axle width is leading to wider rear triangles and wider chainlines, which leads to wider Q factors/U factors.
Wanna buy some DA 7410 cranks in 170? ;)

[cp43]

Just a thought, but I think that q-factor isn't really the measurement you're after. Q-factor is an outside to outside measurement. It doesn't really tell you anything about the center line of the bike to the inside of the crank arm dimension that you need to solve your FD issue. I don't know how to get this second dimension, and it is likely to be related to q-factor, but it will also be affected by the crank arm thickness.

Good luck with the search!

Chris

[AngryScientist]

white industries publishes this kind of stuff, but you need to extrapolate a bit based on what chainrings you choose.

https://static1.squarespace.com/static/53cd4a66e4b0216897ed1b86/t/5575e09ae4b0dbb60c7a60f6/1433788607354/?format=1500w

[Kontact]

Just a thought, but I think that q-factor isn't really the measurement you're after. Q-factor is an outside to outside measurement. It doesn't really tell you anything about the center line of the bike to the inside of the crank arm dimension that you need to solve your FD issue. I don't know how to get this second dimension, and it is likely to be related to q-factor, but it will also be affected by the crank arm thickness.

Good luck with the search!

Chris

The inner crank dimension is not one anyone should normally have to worry about. Campy, Shimano, etc knows they need to leave enough room for the front derailleur, regardless of how narrow they try to make the Q. The OP's problem shouldn't be happening considering he is using a Centaur group that was designed to pair that crank and derailleur.

As consumers, we shouldn't need to know why everything is compatible, just that they are or are not.

[Kontact]

white industries publishes this kind of stuff, but you need to extrapolate a bit based on what chainrings you choose.

https://static1.squarespace.com/static/53cd4a66e4b0216897ed1b86/t/5575e09ae4b0dbb60c7a60f6/1433788607354/?format=1500w

It would be hard to extrapolate from this diagram. It is almost certainly drawn or dimensioned wrong if the 45mm chainline goes beyond the 108mm spindle length as shown.

[ColonelJLloyd]

Ha.

"bottem"
"clearence"

[Rpoole8537]

interesting discussion on Q factor- anybody use a wider Q factor crank to alleviate knee pain? My LBS has fitted spacers under the right pedal..it's better (the knee) but it's not ideal....

I have to use wider cranks or pedals to alleviate knee pain. I have several pair of the old Look CX - 6 pedals that can be adjusted up to 5mm. They work fine for me. They are not made anymore, so when they are completely toast, I'll have to find another solution. My two bikes with triples are not a problem.

[kingpin75s]

It would be hard to extrapolate from this diagram. It is almost certainly drawn or dimensioned wrong if the 45mm chainline goes beyond the 108mm spindle length as shown.

Took me a minute to figure out what you were getting at but yes, probably useful to know at least one more fact about White Industries VBC and ENO cranks to use this chart correctly.

The chain line they are referring to in each case is the single speed chain line and not that of a double. If running a double then need to adjust chain line as being between the 2 rings and not on the big ring.

So yes the diagram of C spacing should probably go to about the middle of the spline shown and not to the far edge of it.

For the OP, the ENO cranks Angry is running seemingly would address both the wider Q desired as well as ENO cranks never have issues with FD cages. Things do get tight on low-Q cranks as I well know as a low Q guy. Ritchey Logics are low Q and you really have to feather that FD in there.

[Mark McM]

Wanna buy some DA 7410 cranks in 170? ;)

Yes, the DA 7410 cranks were narrow, but they weren't the only ones. Stronglight Speedlight cranks were similarly narrow (use the same 103 mm BB as DA), and so were the Campy Record & Chorus cranks of the same era (used a 102 mm BB).

When crank/BB manufacturers moved to external bearing BBs, they nearly universally increased their crank U factors. The one major exception is Campagnolo, who maintained the same 128 mm U factor from their (narrow) square taper cranks on almost all their Ultra-Torque and Power-Torque cranks.

[Kontact]

Yes, the DA 7410 cranks were narrow, but they weren't the only ones. Stronglight Speedlight cranks were similarly narrow (use the same 103 mm BB as DA), and so were the Campy Record & Chorus cranks of the same era (used a 102 mm BB).

When crank/BB manufacturers moved to external bearing BBs, they nearly universally increased their crank U factors. The one major exception is Campagnolo, who maintained the same 128 mm U factor from their (narrow) square taper cranks on almost all their Ultra-Torque and Power-Torque cranks.

I think they started to get wider with the splined cranks, like Octalink. Maybe that's why Campy stuck with square taper until they went to external bearings?

I had always just heard that the 7410s were king. Without any concern for Q, I happened to replace the 7410s with Speedlights.



Actually, digging into this I found Q listings for Shimano cranks, and the 7402 was even narrower than the 7410, despite the 112mm spindle. I think the 7410 had more ankle clearance, though.

[Mark McM]

Actually, digging into this I found Q listings for Shimano cranks, and the 7402 was even narrower than the 7410, despite the 112mm spindle. I think the 7410 had more ankle clearance, though.

Yes. 'Classic' cranks like Campagnolo Nuovo Record had even narrower Q factors, (around 138 mm), but their straight arms gave them roughly the same U factor as their Q factor, so they had less ankle clearance. In the era of 120 mm rear axles & 5 speed freewheels, chainlines were narrower, and front derailleurs were narrower (they didn't have flared cages yet), so Q factors could be narrower despite using longer BBs.

But now, everyone has to have 11 (or more rear sprockets), disk brakes, and super wide carbon BB shells, so chainlines are getting wider and Q factors and U factors have been growing.

[Kontact]

Yes. 'Classic' cranks like Campagnolo Nuovo Record had even narrower Q factors, (around 138 mm), but their straight arms gave them roughly the same U factor as their Q factor, so they had less ankle clearance. In the era of 120 mm rear axles & 5 speed freewheels, chainlines were narrower, and front derailleurs were narrower (they didn't have flared cages yet), so Q factors could be narrower despite using longer BBs.

But now, everyone has to have 11 (or more rear sprockets), disk brakes, and super wide carbon BB shells, so chainlines are getting wider and Q factors and U factors have been growing.

Well, chainline hasn't changed on standard road bikes since standard 6 speed came out with 126mm rear spacing - even 11 speed.

If disc road bikes have a different chainline, that's because road bikes are using MTB hubs in symmetrically spaced frames. That could have gone differently.

[Mark McM]

Well, chainline hasn't changed on standard road bikes since standard 6 speed came out with 126mm rear spacing - even 11 speed.

I actually started riding when 120 mm and 5 speed freewheels were the norm. :)

If disc road bikes have a different chainline, that's because road bikes are using MTB hubs in symmetrically spaced frames. That could have gone differently.

Yes, it appears that disc brake road bikes will have wider chainlines. For example, the Campagnolo H11 disc brake group has increased the chainline offset by 2.5 mm. The rear axle width has been increased from 130 mm to 135 mm, and all the extra space is on the left (to make room for the disc), which means the cassette (and chainrings) have been offset 2.5 mm to the right.