Over the top Stronger cranksets Why?

[cnighbor1]

Over the top Stronger cranksets why?
the general trend by Shimano and Campagnolo has been to design their crankset stronger along with the bottom brackets and the method of attachment
Has any Paceline member ever tore up the old square taper crankset design for either Shimano or Campagnolo?
How about later design like Shimano Octalink?
and the new outboard design cranksets?
I ask because other than a loose Crankset I never noticed any lack of stiffness in all the cranksets I ride Superbe Delore XTR Dura Ace record Chorus

[hampco]

Just off the top of my head:

The companies are shooting for lighter weight

The new cranks are (possibly) easier to adapt to modern carbon frames

Electronic shifting requires a stiffer spider in terms of a side load, thus the new designs

Other thoughts?

[echelon_john]

I've broken 3 cranksets, all at the pedal eye.

1x old campy super record no washers
1x 7400 yes washers
1x 7800 yes washers

I'm an outlier size-wise, but am all for stronger cranks! I'd rather 50g more 'meat' between me and hitting the ground.

[berserk87]

Is "OT" for "Off Topic"? Not that it's a huge deal, but this seems very much a cycling-related discussion, unless I am missing something.

[katematt]

I'm the resident wrench for my local group. Friend brought over a cracked DA left side the other day. crack was about 1mm at it biggest spot and prevented him from pedaling without damaging the frame. I was able to break it in two once I got it. He's +200 but still for DA thought that was interesting. Crank probably has over 25k on it..

In searching around, it appears that some of those 7800 models had some issues.

[Red Tornado]

The first & last points from Hampco were the two that came to mind. Other than the need to come out with the latest "thing".
I'm like the OP and never had issues with square taper or, in my case, ISIS crank/bb's. Tools were ways very affordable as well.
Ran a Race Face Ti ISIS bb for ~10 years before the bearings failed. Still have a FSA ISIS setup on my road SS. Never was able to destroy a square taper of good quality either. The only down side to repeated remove/replace cycles might be the tapers wearing over time.
I do have Campy Power Torque on my geared road bike and I am happy with it. Just didn't want to cough up the money for tools, so take it to the shop annually for cleaning/inspection.

[FlashUNC]

I've seen torn up square tapers.

And I don't notice the difference seated, but definitely notice a difference out of the saddle.

[Mark McM]

OT Stronger cranksets why?
the general trend by Shimano and Campagnolo has been to design their crankset stronger along with the bottom brackets and the method of attachment

I think you are confusing strength and stiffness. Modern cranks/bottom brackets/frame designs are meant to be stiffer and/or lighter, but not necessarily stronger. (Remember the first rule of high performance component design: "If it never breaks, it isn't light enough!")

Whether cranks/BBs really need to be stiffer is a different question. I can't say I've ever ridden a crank or bottom bracket that wasn't stiff enough (Both older and newer designs), but I only weigh 155 lb.

Has any Paceline member ever tore up the old square taper crankset design for either Shimano or Campagnolo?
How about later design like Shimano Octalink?
and the new outboard design cranksets?

I haven't personally broken a crank or a bottom bracket (mine either wear or become obsolete first), but I've seen a number of broken cranks and BBs.

This archive of broken parts (http://pardo.net/bike/pic/fail-001/000.html)hasn't been updated in more than a decade, but there are plenty of pictures of broke parts (including Shimano and Campagnolo). Apparantly, the legendary Jobst Brandt regularly broke his classic square taper Campagnolo cranks (http://yarchive.net/bike/crank_break.html).

[merckx]

Is "OT" for "Off Topic"? Not that it's a huge deal, but this seems very much a cycling-related discussion, unless I am missing something.

"OT" is for on-topic.

:>)

[cnighbor1]

http://www.ebay.com/itm/Campagnolo-Record-Crank-170mm-52-36t-/122321622338?hash=item1c7aefd542:g:9~IAAOSw5cNYhI7 r


http://www.ebay.com/itm/Campagnolo-bullet-ultra-crankset-172-5-53-39-Super-Record-Chorus-/112280384229?hash=item1a246eb2e5:g:SV4AAOSwLEtYh9U V

[cnighbor1]

I think this it They need to go around in a straight plane or else shifting is off
''Electronic shifting requires a stiffer spider in terms of a side load, thus the new designs''

[Mark McM]

The Bullet Ultra crankset was designed for aerodynamics, not for strength or stiffness. The built in aero "fairing" adds quite a bit of weight to this crank. If it ends up stiffer or stronger, that is merely a fringe benefit.

[cnighbor1]

I am confusing strength and stiffness. Modern cranks/bottom brackets/frame designs are meant to be stiffer and/or lighter, but not necessarily stronger. (Remember the first rule of high performance component design: "If it never breaks, it isn't light enough!"

[Rusty Luggs]

Quite a few years back I saw a square taper bottom bracket spindle that had broken in service. It was steel, fractured such that crank arm came off, rider got a nasty gash from sharp end of broken spindle. As I recall he got a $ settlement out of it. Don't recall manufacturer, but not a low end component. Not like it happens every day, but nothing is indestructible.

I broke one crank arm myself at the pedal spindle ages ago. Aluminum crank, brand was Specialized. Was standing up sprinting at the time and I was on the ground sliding in a flash. Road was wet, so I actually slid pretty well, minimal road rash.

[jimwhimpey]

The worst crashes I've ever personally witnessed were due to broken crank arms mid-race. Saw one at the pedal thread but a most commonly right through the drive side crank arm. It seems like it shouldn't be possible but it happens!

[Gummee]

When I upgraded from square taper to Octalink I could really tell the difference in stiffness. Man! were those 7700 cranks super stiff!

...for about a week.

Then the 7700 crank was just another crank. Since then? Not so much.

My $.02

M

[572cv]

Cranks did break. I had a Campagnolo Record spider side crank shear while on a hard climb, many years ago, when it was basically a contemporary crank. It was my most disquieting crash ever.

I'm all for better crank design.

[beeatnik]

There's a World Famous Montrose Ride cat who can put down 1800W and he's bent 2 or 3 Cannondale Spiderrings. Not sure if this is relevant, just wanted to share.

[stephenmarklay]

I’m not sure it will every matter to me as I can’t push more than about 1000w. But I bet shifting can be more precise with stiffer drive components.

[11.4]

The shifting force of Di2 is enough to cause the front derailleur to actively crimp the seat tube on the chainset side. Some builders and manufacturers have had to beef up the tubing right there, especially in carbon, to prevent premature failure. And that's just what happens when the shifting mechanism is working and you aren't pedaling at the right rate or were already losing the chain, or whatever.

I've had plenty of square taper cranks fail. Some did so chronically. Some failed more commonly at the pedal threading. Others failed at the square taper; some of those did so because of user error -- overtorquing or mismatching tapers so that the crank arm didn't mount fully or else bottomed out (the tapers have the same ratio, just start and stop at different points in the taper). I've seen only a couple Octalink cranks fail, mostly user error. And seen a number of 7800/7900 crank arms fail. One can prematurely trash the bearings on 7800/7900 cranks but it's hard to nail the crank arm itself by overtorquing (there isn't much to over torque unless you ram the two locking bolts on the left side arm so far that you crack the arm).

Shifting definitely improves with stiffer chainrings and spiders, with mechanical and much more with Di2. Swap out a 9000 crankarm and put in an older crankset such as an old 7400 and you'll see a big difference -- you'll almost want to readjust the shifter limits because the front derailleur will push the chainring out of position and need a longer throw.

But most of all, these have gotten much stiffer, much lighter, and yet much more complicated to forge. To accomplish all of that, they've had to develop structural strength so failures don't become prevalent. And cranksets are more complicated than one might think -- consider the problems in the first couple generations of SRAM Red, both in the spiders and in the rings, plus problems in FSA crank arms, and of course numerous issues early on with the pedal threading and crank arm mounting technologies in carbon cranks, where everything tended to come unglued all too frequently.

[mike mcdermid]

Other thoughts?

the consequences of litigation recall for a big oem