Anyone got a valid reason for the High Torque settings on the brake rotor?

[mgardiner2673]

I apologize beforehand if this question has been asked before. But I'm looking more for an explanation than general specs.
I've worked on bikes for many years and have a number of friends who are bike mechanics, including one who has worked on bikes for 40 years. Nearly everyone I've asked tells me that 63 lb/ft of torque on a brake rotor bolt sounds extremely excessive and they can't see a reason for it. I have been told that 40 lbs is about the top for most bikes for a rear rotor bolt. Can anyone give me a valid reason for such a high torque rating on the Spyder?

Please don't answer and tell me that is just what Can Am requires. I want to know what is the mechanical need for that torque level?

Secondly, is there any real reason that they require new bolts on everything when you remove and replace the rear wheel. They say absolutely nothing that I can find that says all of their bolts are torque-to-yield and that is the only reason you would need new bolts.

I appreciate anyone's attempt to enlighten me on these issues.


2018 Spyder F3-S
19,000 miles and just purchased.

 

[Mikey]

Sometimes they like to cover their #@%! Don't over think this, use your head, and do what you have been doing all these years. I only take the torque wrench out for the lug nuts! Now if I was putting the head back on the engine or something like that, it would also likely come out. :dontknow:

 

[Bfromla]

:agree: butt coverage & course lil extra part$ will add the PRESS MODE functionality is also just butt coverage disclaimer So attempting adding up to BUTT Load:dontknow:opcorn:

 

[mgardiner2673]

Mikey,
Common sense. I like that. Thanks for the reply and your common-sense approach to a questionable specification. I'm going to do the same thing. It hasn't let me down all of these years and I don't think it will do so now. Still, it is comforting to know others look at a problem the same way.

Mike
Raymond Ms.

 

[Jetfixer]

I don't have a problem reusing those bolts as long as the threads are not damaged and you clean out all the old thread locking compound. Also not a bad idea to run a tap through the holes to clean the mating threads out also.

 

[djh3]

So I'm not sure about which bolts exactly, but a guess would be bolts holding rotor to wheel? At 64 ft lb the chart I find they would have to be a 10mm diameter and a 12.9 grade bolt. Last grade 12 metric I remember was a head bolt or caliper mount on a car and it was probably a 12mm diameter.

 

[pegasus1300]

If you really want to know the "why" of the high torque you will need to ask the engineer who wrote that spec. Nobody here knows what was in their mind. As to the bolt replacement, I have heard that since there may be a possible stretching issue, they want new bolts to avoid that. Having removed the rotor to have a tire shop put a new tire on the rear rim I brought them, I used neither new bolts nor that much torque.

 

[mgardiner2673]

Thanks to all that responded. I feel the same way as you do. I'll just use my experience and do what I think is right.