|   Paging næstep re: German mag crank comparison | race frehley
Nov 26, 2003 1:29 PM | | Your German bike magazine crank + bottom bracket comparison links were brought up in this thread race frehley "Which Cranks?" 11/26/03 12:51pm
Do you know how the "S" number was arrived at? Is it force required for x amount of deflection? Are the weights actual or claimed? I assume the "SGI" is weight/force, so it's a measure of strength per gram but in reverse, i.e. lower number means stronger. Sound right?
On the '03 chart, the blue/yellow highlighting must mean stiffest, and the red highlighting must mean lightest... what's the orange highlighting mean?
After looking through that it seems that the '03 LX is currently the best cost/performance ratio by a long shot. My only concern with these cranks is the stories of creaking and loosening.
Any comments you may have would be very much appreciated, thanx. |
| Couple of things... | næstep
Nov 26, 2003 3:28 PM | | 1. The tests were posted by one of the weight weenies in their forum. I don't want to take credit where none is due. I just link to them in 'My Profile' (" because they're so useful.
2. 'S' is the number of newtons of force required to deflect the crank + bottom bracket spindle one millimeter. I can't be more precise than that because I don't speak German. But the torsional stiffness of the bottom bracket is just as much a part of the test as the crank arm itself, and that is reflected in the ISIS tests where the Truvativ Gigapipe turns "flexy" cranks into contenders.
3. 'SGI' is comprised of stiffness, weight, and I believe price. I best I can determine, the orange square indicates the value leader. Perhaps Nino can answer in more detail.
næstep |
| It seems to me, that one must consider that these tests may...... | Bikeless Rider
Nov 27, 2003 6:33 PM | | ...be set up to test ONLY crank and BB flex, meaning what they're mounted to may be stationary. If this is the case, the only outboard bearing crank there, being the XTR, may be misrepresented, as wider bearing placement is less likely to create frame flex. |
| Just the fact that it's a static load test... | næstep
Nov 27, 2003 9:11 PM | | ...makes it not entirely representative of the forces encountered on a bike. I'm sure the deflection is being measured in only one direction, around the axis of the spindle. It would make sense that they are measuring this by "locking" one crank arm in a jig of some sort, then applying the load to the opposite crank arm and measuring deflection vs. the "locked" crank arm.
The reality of it? I only use it to point out how equal the majority of today's cranks are, and how the bargin LX stacks up against the more expesnive stuff.
The real reality? I'm a clyde, and I still ride square taper cranks on some of my bikes that score anywhere from 30% to 40% less stiff than the Octalink cranks on my other bikes, and I can't tell the difference. Yes, splined is stiffer than square, but in a blind test I couldn't tell you which was which.
næstep |
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