I just had a set of rotors installed and i think they were installed wrong. I checked the regulation point with them installed and with the right crank arm straight up and down the triangle is way below the regulation points. It doesnt feel any different than regular cranks. And judjing from the simulator on the website there should be a lot more angle at the top crank arm.
you’ve likely answered the question. they seem clearly wrongly installed.
if you want to make sure, post a picture.
heres a pic.
if this is what they look like when the right crank is perfectly vertical then they are definitely not well installed
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Yep, they appear to have slipped. The 2 triangles should be pointed at each other, or off by no more then the second lines on either side. maybe they forgot or failed to use Loktite on the bb threads.
Slippance!
Or, they didn’t do it right to begin with.
Thanks guys. I figured as much but wanted an expert opinion before i went back and claimed they were wrong. I should have known better but the guy I bought them from said this bike shop knows how to install them so i went there instead of my regular shop.
thanks again
Yes, they likely slipped, make sure you torque the left cup to 55lbs and use a thin layer of blue thread locker on the bottom bracket shell threads, should look like:
If using on a Ti or Mg frame, you should use a primer that allows the thread locker to dry overnight, otherwise allow your frame to dry overnight if it is Al or CRMO.
As everybody mentioned already, they aren’t installed correctly. Did you receive them from the bike shop in that exact condition? Also, don’t ride them too early. Wait one or two days after installation.
Gary, for some reason I’ve always had trouble visualizing what moving the regulation point does. Where these rotors have the regulation point in, would that make the slowest spot occur closer to six o’clock by however many degrees are seperating the default regulation point marking and the current marking? Where would one want to set the arrow to get the slowest part of the stroke happening at 3 o’clock?
Hmmm…My only guess would be that it should point AT 3 o’clock, or exactly perpendicular to the crank arm when it’s perfectly vertical. Yes, no, maybe so?
Sojo wrote: Gary, for some reason I’ve always had trouble visualizing what moving the regulation point does. Where these rotors have the regulation point in, would that make the slowest spot occur closer to six o’clock by however many degrees are seperating the default regulation point marking and the current marking? Where would one want to set the arrow to get the slowest part of the stroke happening at 3 o’clock?
Hmmm…My only guess would be that it should point AT 3 o’clock, or exactly perpendicular to the crank arm when it’s perfectly vertical. Yes, no, maybe so?
I’m not Gary, but, YES, You’ve Got It! Exactly as you said, the arrow on the inner ring points to the area corresponding to the slowest part of the downward-moving crankarm. As this fellow’s Rotors are situated, that would be at 6:00…which makes sense if they slipped…this would be the area the Rotor would tend to settle in a slippage condition.
These cranks seems like Saunier Duval UCI Cycling Team Cranks
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Thanks for the continuing help Titan. Anyway, what seems to make the most sense to me, based on rotorcranks power model on their website that shows where peak power is made, is that one would want the slowest part of the stroke to correspond with the peak power, which shows to be at exactly 3 o’clock. So, I’m a little confused why the default regulation point is pointing to about 4 o’clock.
Wouldn’t this guys slow point be coming in at about 4:45 or so, not 6 o’clock?
your thinking sounds right to me, Joe.
your thinking sounds right to me, Joe.
Gary, if you’re checking this out, could you help me out with this? I realize you are pretty tied up with other things, but if you could refer Pablo C. to this thread that would be cool to hear why he picked the default regulation point to be where it is, right around 4:00 I think.
I will have Pablo reply, probably by Monday (Spain is ahead of us, so they will not be back at the factory until Monday)
And the saunier duval chainrings were developed for the Pro team for races last season, pretty cool collector’s item, one of the first of our AERO version chainrings
- g
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They are saunier duval cranks. I got them from a friend. I took the bike back to the shop today and they fixed the problem. Thanks again everyone for the help.
“Anyway, what seems to make the most sense to me, based on rotorcranks power model on their website that shows where peak power is made, is that one would want the slowest part of the stroke to correspond with the peak power, which shows to be at exactly 3 o’clock. So, I’m a little confused why the default regulation point is pointing to about 4 o’clock.”
If 3 o’clock is when normal people make their maximum force, makes sense that the maximum of the “variable chainring size effect” that comes with Rotor happens near 4 o’clock. This is because the applied force goes not only against the resistance; it goes also to accelerate the bike, this is, to win inertia.
As at 3 o’clock is when the acceleration is maximal, seems logic that the gearing is not maximal yet.
Even at “constant speed”, the instantaneous speed varies like a sine type function, not so much for flat pedaling, but it is very clear climbing. And so the acceleration is always there, every downstroke.
I suppose that my words are difficult to understand, more for my difficulty to explain in english than for the concept itself. Really all is in the equation:
F(applied)=F(resistance)+M·Acceleration
“Anyway, what seems to make the most sense to me, based on rotorcranks power model on their website that shows where peak power is made, is that one would want the slowest part of the stroke to correspond with the peak power, which shows to be at exactly 3 o’clock. So, I’m a little confused why the default regulation point is pointing to about 4 o’clock.”
If 3 o’clock is when normal people make their maximum force, makes sense that the maximum of the “variable chainring size effect” that comes with Rotor happens near 4 o’clock. This is because the applied force goes not only against the resistance; it goes also to accelerate the bike, this is, to win inertia.
As at 3 o’clock is when the acceleration is maximal, seems logic that the gearing is not maximal yet.
Even at “constant speed”, the instantaneous speed varies like a sine type function, not so much for flat pedaling, but it is very clear climbing. And so the acceleration is always there, every downstroke.
I suppose that my words are difficult to understand, more for my difficulty to explain in english than for the concept itself. Really all is in the equation:
F(applied)=F(resistance)+M·Acceleration
Bummer, that doesn’t quite resonate with me. Hmmmm
I’ll have to meditate on this a bit more, and when I get another set of Rotors I’ll probably be best served just experimenting with them as I see fit. Since I have a powermeter, it should be pretty easy to get some good data from the experimentation.
I’m still left wondering why you picked the default regulation point to be where it is. WAs there any specific formula you used? I imagine it’s not just an arbitrary point a little past 3 o’clock.
Thanks for addressing the post though, and your English is just fine. Certainly a lot better than my Spanish. You could always type in Spanish if you’d rather, that’d be interesting to read, because there would be no filter to your thoughts.
How do you measure torque on a BB? I have a standard torque wrench that fits my ratchet set - but how the heck does that help with the BB wrench? Is there a specialized cycling tool that I can only get for megabucks? Thanks.