Rotor Dilemmas

[maxcruiser]

Alright, I need some help trying to figure out some issues that I am having with my rotors.

I have changed front rotors 2 times and back one once due to warping them, or atleast at the time that's what I thought. So to say the least, I am very confused as to why and if they were/are really warped.

I have bled the brakes more times than I would like to admit, took the calipers apart twice and the masters once. Checked if front wheel is warped or if any component in the front end is out of whack and all looks good.

The rotors themselves have no bluing or irregular grooving. My conclusion is that there is nothing obviously wrong with my wheels, calipers, etc... either.

I did notice one thing, the rotors seem to be very tight at the rivets (ones that hold the 2 rotor pieces together) There is absolutely no play at all, as if it's was a single piece rotor, rather than a 2 piece floating rotor.

Could it be that the buttons (rivets) are seized up causing the rotors to feel as if they are warped? Is this even possible?

The bike is an 06 with 32,000 miles.

Any thoughts on this would be appreciated.

Mike

 

[KJShover]

Could it be that the buttons (rivets) are seized up causing the rotors to feel as if they are warped? Is this even possible?

Yup, its more common than you think, as with many floating semi-floating rotors, the buttons are prone to get crap in them. If this is possibly your situation, just hit the buttons with some brake clean then smack them with a rubber mallet. Then lube the buttons with some graphite.

Here is a similar issue of sticky calipers.
http://www.vmaxforum.net/showthread.php?t=17926&highlight=brake+rotor+seized

 

[Rusty McNeil]

Mine have never been able to be moved by hand or to visibly see that they "float". Since bought at 9300 miles or at 45,000

I thought it was normal? In any case never had any problems with them.

You never really said what your symptoms were??

 

[bazwell]

The rotors are "semi floating", they they don't move a lot.

What are the actual symptoms you had?

 

[wildweasel_pt]

They are not supposed to be able to be moved by hand. They move "slightly" when under pressure from caliper braking. If the rotors get abused in a regular basis the freeplay tends to increase due dilation cycles. It depends on what kind of rotors you are using. Racing rotors are looser than regular semi floating due to heat dilation when operating. You can even get a rattling noise when riding on older roads (cobblestone by instance). What symptoms are you getting? Any issues on braking? I think you are being overly concerned about it...

 

[naughtyG]

I installed chinese wavy rotors on my '86 a couple of years back, and while the breaking improved greatly (larger diameter / wavy surface) they always felt a little 'bitty' for lack of a better word, like if they weren't 100% flat.

I checked everything, found the buttons to be very tight also (no way they could be moved) but as it all worked right and the pad wear was normal I just left it.

Don't think there actually was any problem to speak of, even if it still felt slightly jittery at very low speeds or when coming to a stop.

 

[maxcruiser]

Stock rotors and symptoms are that there is a pulsation felt when applying the brakes - fells as if they are warped.

I checked out one that I took off that had these symptoms. Put it in the vise and checked for movement at the buttons and nothing. put a pair of vise grips on the end of the buttons and tried turning it, very very tight and difficult to turn.

I will try to clean it tonight with brake clean and lube them with graphite to loosen them up.

Just strange that I have had this happen 3 times last year and never happened before.

Mike

 

[bazwell]

Well, my heart tells me you are on the right track there. Makes sense, rotor off line a bit and won't self centre.

Still, the logical part of me says that the only thing that hasn't been touched is the hoses. I don't know how that could cause the symptom though.

"difficult to turn" is enough movement. They don't have to move very much at all. So I guess they would be quite easy to bind up too.

Maybe you have changed to a different brake pad? Different pads make different dust...

Just thinking out loud.

 

[bazwell]

I just checked on my brand new rotors. I can't turn the buttons by hand at all.

 

[wildweasel_pt]

Is your tire in good condition/pressure? How about the forks? Properly set? Same pressure on both stanchions and oil? Are the rotors properly fastened to the rim? Are you using stock rotor bolts? Is your rim straight and true?

To check for warpness you have to use one of these...

 

[gamorg02]

how about true-ness of the mouting flanges for the rotor? my rear wheel at one point had one 'post' that was lower than the rest. wasn't noticable with a stock rotor but once i put a galfer on it it actually bent the galfer down and that was the only way i could tell. maybe worth a look.

 

[maxcruiser]

Is your tire in good condition/pressure? How about the forks? Properly set? Same pressure on both stanchions and oil? Are the rotors properly fastened to the rim? Are you using stock rotor bolts? Is your rim straight and true?

To check for warpness you have to use one of these...

Tires used, need replacement now, but was near new 1st time it happened - 38 lbs pressure - radial tires

Forks properly set - yes - no air pressure in them, ricor intiminators and Progressive springs - 5 wt oil - same amount in each

Rotors - all torqued to same spec - stainless bolts

Rim is '85 rim, measured with dial indicator as in your pic and is within yamaha spec straight and true

Rotor is showing warp on dial indicator at one spot on rotor.

Mike

 

[naughtyG]

What kind of rotors are they?

Also, which pads are you using - HH I assume?

You said it happened three times - does that mean this is your third pair of rotors?

And, out of interest, are both rotors warped, and if yes do they show warping in the same place?

 

[maxcruiser]

how about true-ness of the mouting flanges for the rotor? my rear wheel at one point had one 'post' that was lower than the rest. wasn't noticable with a stock rotor but once i put a galfer on it it actually bent the galfer down and that was the only way i could tell. maybe worth a look.

Ok, this is something that I did not think of - the rim was new to me from last year and was powdercoated, so I guess it maybe possible that the rotor is not sitting flat on the rim. I will have a look at this tonight. But the funny thing is that the "warping" did not show up until sometime after it was installed. This issue would show up on the first ride after rotor install.

Mike

 

[maxcruiser]

What kind of rotors are they?

Also, which pads are you using - HH I assume?

You said it happened three times - does that mean this is your third pair of rotors?

And, out of interest, are both rotors warped, and if yes do they show warping in the same place?

Stock rotors, EBC HH pads, Braided lines.

The third one "warped" is on there now. This issue does not show up right away (after replacement) it happens after a few thousand kilometers. The first two times I replaced both rotor with used stock ones off ebay.


Kinda went like this, first time it happened, oh well shit happens and replaced both of them, second time, well that's strange, checked everything out, than changed both, third time, when it first started, bled brakes, took calipers apart, etc....

 

[naughtyG]

Checking the rim may be the best so far - just maybe the powder coating isn't quite flat/true and that's what's causing it?

 

[gamorg02]

Ok, this is something that I did not think of - the rim was new to me from last year and was powdercoated, so I guess it maybe possible that the rotor is not sitting flat on the rim. I will have a look at this tonight. But the funny thing is that the "warping" did not show up until sometime after it was installed. This issue would show up on the first ride after rotor install.

Mike

shit man thats the rim i sold u too? sorry about that.

the machine shop near me charged like $25 to fix it(leveled all the other posts to match)

 

[maxcruiser]

shit man thats the rim i sold u too? sorry about that.

the machine shop near me charged like $25 to fix it(leveled all the other posts to match)

Do sweat it Garrett, so far only a possibility of being the problem. It just blows my mind that of all my years of riding and building bikes, that I have run into this streak of bad luck with rotors. To be honest, my buddies up here have had a laugh at my bad luck, not just on my bike, but I have had a string of bad luck with brakes, on my car changed rotors and pads than caliper seizes 1000 kms later and smoke to caliper and rotor. On my SUV, change rotors and pads and later the wheel bearing goes and ruins to rotor and pads, etc, etc, etc.... In one year, I have ruined brakes on just about everything I own.


Mike

 

[gamorg02]

Do sweat it Garrett, so far only a possibility of being the problem. It just blows my mind that of all my years of riding and building bikes, that I have run into this streak of bad luck with rotors. To be honest, my buddies up here have had a laugh at my bad luck, not just on my bike, but I have had a string of bad luck with brakes, on my car changed rotors and pads than caliper seizes 1000 kms later and smoke to caliper and rotor. On my SUV, change rotors and pads and later the wheel bearing goes and ruins to rotor and pads, etc, etc, etc.... In one year, I have ruined brakes on just about everything I own.


Mike

jezus that is some bad luck! well if it ends up being the wheel let me know and we'll see if we can work something out?

 

[naughtyG]

Think it's time you let your hair down and bought a dirttrack bike?

No brakes on those.. lol