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Should brake disc float radially - 2015 V7 Stone

TimmyTheHog

TimmyTheHog

Cruisin' Guzzisti
GT Contributor
Joined
Jan 26, 2017
Messages
234
Location
Surrey BC Canada
Hi all,

okay, as I was getting ready to go home yesterday and undoing the front disc lock, I noticed my front brake disc rotor moved...

as curious as I was, I decided to move the disc a bit...I understand they are floating disc so they should move Axially.

However, I also noticed they move RADIALLY by a bit and clunk in the process.

I measured the radial play and it is about 1mm for all the bobbins.

There is the video of my clunking the disc



Does this sounds normal???

I only have 4700 KM on this bike

Thought I should mention I didn't notice any pulsing, vibrating, or clunking noise during normal operation...

Only hurt the clunk when I move the brake disc and by moving the bike around parking lot
 
Good questions, and being the curious sort I googled your question, and found the pdf at the link below.

https://zodiac.nl/docs/instructions/235474.pdf

Seems that they are designed to move both in axial and radial directions. Assuming your bike had been at rest for a few hours as you were "... getting ready to go home yesterday and undoing the front disc lock ..." the radial movement in your disk rotor is conceivably normal, expected behaviour.

Since the recommended tolerances on the V7 Stone may be different I'm going to keep watching this thread, and advise you to do the same There are numerous members on this site that will, I hope, weigh in and provide technical and rational explanations why the floating rotors are mounted this way and exactly how much tolerance there should be.
 
blakbird said:
Good questions, and being the curious sort I googled your question, and found the pdf at the link below.

https://zodiac.nl/docs/instructions/235474.pdf

Seems that they are designed to move both in axial and radial directions. Assuming your bike had been at rest for a few hours as you were "... getting ready to go home yesterday and undoing the front disc lock ..." the radial movement in your disk rotor is conceivably normal, expected behaviour.

Since the recommended tolerances on the V7 Stone may be different I'm going to keep watching this thread, and advise you to do the same There are numerous members on this site that will, I hope, weigh in and provide technical and rational explanations why the floating rotors are mounted this way and exactly how much tolerance there should be.
Click to expand...

Well, it was sitting maybe after about an hour or so? I was running around doing errands...so it wasn't overly long when it did sit in a hot sun.

As for the reading on other site...let just say I read too many and they all sort of contract each other but since they are other makes of bikes, I am not sure if the rotors were made the same.

So far there are not braking issues...but this "situation" is ticking me in the way that I don't like...lol
 
TimmyTheHog said:
...
So far there are not braking issues...but this "situation" is ticking me in the way that I don't like...lol
Click to expand...

I'm glad no braking issues have cropped up so far. Until now it never occurred to me to check the rotor for movement. About once a month or so I do a visual check for chips, cracks, discoloration, grooves etc.

Until today and since I'm working from home and the bikes in my garage have been sitting for at least 8 hours I took the opportunity to pull on a few floating rotors.

A very unscientific, unmeasured experiment. All 6 of the floating rotor in my garage move radially to some degree, some more than others. My sons FZ07 moving the most, and clunking the loudest. My California move less, with less clunking than the FZ07. My 96 Sort 1100 barley moves at all, and not a click to be heard. :whew:

I can't wait to hear from the experts on this. I wonder what factors the engineers that design these things have to account for ???.
 
My opinion on why it has play has to do with the rotor spinning between the brake pads.

If the rotor was in a completely fixed position, and the brake pads were not lined up 100% to the rotor then the rotor would be rubbing against the pad with more force, essentially braking.

I think the play in the rotor prevents this in case the wheel or the caliper is not true and straight.

I have done no research on this but just me thinking about why this may be so - I can very well be wrong.
 
I just checked my V7 II 8500ks and it has very little movement.
I'm thinking maybe check them when hot with gloves on of course and see if the slop is less.
 
Carlos Rivera said:
My opinion on why it has play has to do with the rotor spinning between the brake pads.

If the rotor was in a completely fixed position, and the brake pads were not lined up 100% to the rotor then the rotor would be rubbing against the pad with more force, essentially braking.

I think the play in the rotor prevents this in case the wheel or the caliper is not true and straight.

I have done no research on this but just me thinking about why this may be so - I can very well be wrong.
Click to expand...


This is why you want rotors to "float" if they don't you may feel a pulsing when braking as if the disk is warped. If you feel this, cleaning up the buttons usually cures the issue. Conversely when you detect too much wear on the buttons to disk interface the rotors should be replaced.
 
I don't know if my disc are hot enough to expend that much to make a difference...

however, when I check them, it usually are:

@just before work (cold)
@right about to go home from work (somewhat cold but hot sun beaming down)
@right when I got home (warm with moderation using of brake thru traffic)

I don't see the movement changes...they all about total 1mm or so in radial (or rather front & rear movement)...

So far all my bobbins rotates okay and I have no issue (as I know of) with the braking...

Maybe just me being too curious and too nosy at things :p...

I might try to warm up the disc by slowing from a higher speed...hopefully the slop will decrease to almost none...?
 
I noticed this on my 2013 V7 Stone 24K miles, and came here to post a question, but found this thread first. I'm going to assume the play in mine is normal as it's very similar to what you show in that video.
 
So far it seems so

I have my bike @ the dealer doing some services right now as I am currently away from the country.

Will update once I get back...but so far I had been reading regarding to this as being within spec
 
So just an quick updates for those who are interested.

Just got the bike back from the dealer for some other works so had him check out the rotor as well.

He said between the scale of 1(excellent) to 10(shit show), I am about 1.5...which is acceptable with these floater style.

normally they do get "tighter" due to the brake dust/crud gets in the bobbins.

My ,for some reason, had been cleaning off by themselves and with me playing with them, they got cleaner.

so, this is another case of "me wondering and noticing things but were not sure"...learning curves :p
 
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