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[Specter]

Question:
Applying the front brakes, it's surging a tiny little bit like a pad is a bit grabby or the rotor is slightly warped.
Can't see HOW this could be a worn out rotor as I use regen for probably 80 percent of my braking, but then again, yah one real hard stop could do it.

The thing is though, this is at higher speeds, and the surge is like every half second or so? for just a bit, in other words, if it was a warped rotor you'd feel it every rotation Id think but what I am feeling would be like every 3rd or 4th rotation kind of.

Am I possibly feathering the brake and not noticing it and im feeling me giving it a slight extra squeeze or something?  Not sure what this is, just noticed it recently.

Edit: IM breaking in my new track gloves, so maybe Im not fully attuned to the full feel between the bike and my fingers and am grasping it a bit, the gloves are a bit stiff yet.

Reason I am asking is, if something is starting to go bad, I want to know, if it's technique, ill need to fix that too but hardware issues are more important on this IMO at this point.  If someone else has experienced something similar maybe?

Thanks
Aaron

[jotjotde]

Feeling something from the brake every 3rd or 4th rotation is really odd. I have no explanation for this.

Currently I have something like a bad patch on one of my front rotors, so I can actually feel every rotation of the front wheel while braking.
My theory is that this is a patch corroded last winter when I drove on dry but salted streets and over night the air humidty crept under one brake pad and stayed there for a longer time causing a corroded area at this spot.
It is noticeable at low speed brakes and at high speed braking there is noticable vibration. But as long as the braking performance is not compromised I will wait until I change the rotors.


What you can try is to clean the floaters of the discs. Good chance that solves your problem.

Refer to this post: https://www.electricmotorcycleforum.com/boards/index.php?topic=12671.0

[SBK74]

I have exactly the same issue as @jotjotde but stopped annoying myself, first world problem... For who is interested:

Situation:
bike was new in July 2021, I bought in May 2022 with 8000km as a demo. I noticed later that year that the rotors were extremely out of true, like really excentric. Also it had brake judder. Dealers noticed as well, but there was no guarantee on wear parts from Energica. Dealer sold me 2 new rotors and made a deal, we both took cost.

New rotors from Jan 2023:
Not so much out of true, but I noticed vibrations at 100km/h under light braking. I brought to a specialist and he measured 0,45mm swing in the left rotor, he correted to <0,12mm. Vibrations were less, but still there is an issue of uneven braking, specially with warm brakes, constant brake force, it seems that there is a grippy part on the rotor. You would almost think the rotors' thickness is uneven.

I am really disppointed that Energica are accepting this level of quality from Brembo. I hear lots of complaints about uneven braking and brake judder. Also de demo Experia that we had in the friends group in September displayed that behaviour according 2 BMW GS drivers who took turns on the bike. Energica are using the OEM single brake rotor from the Ducati Scrambler (I think to get 330mm diameter due to the weight of the Energica). In defense or Brembo: I notice that braking does get better when the bike is driven hard, typically EVs don't always apply the brakes that frequently.  Anyway, my next replacement will be a Brembo ORO 78B408B2.

 
 

[Pard]

Just some thoughts...

Could be some buildup on the brake pistons leading to the seals getting hung up when retracting.  I would clean the pistons and seals while they are still mounted with a good brake cleaner spray, and lightly sand the rotors with red scotchbright pads, before replacing any hardware.

If you are using a light touch, the pistons will have some force both pushing them on and pulling them off the rotors.

If you feel that pulse with firm pressure against the rotors, then piston retraction is not at play.

[wadejesu]

What happens when you turn ABS off

[SwampNut]

What happens when you turn ABS off

Bingo, that's the first thing I'd test.  Let's do the math on a rotor issue.  You said high speed, and that's relative, so let's call that 70 mph.  You didn't say what bike you had and it's not in your profile, assuming it's got a normal sport tire that's 23" around, and travels 72 inches per rev.  That's 1100 RPM or 18 rotations per second.  Logically this should be able to cause a problem every half second, right?

Or maybe I did the math wrong, it's way too early and I'm barely into the coffee.

[SBK74]

I will try the Scotchbrite suggestion. Rivets are nicely loose.

[SwampNut]

I will try the Scotchbrite suggestion. Rivets are nicely loose.

I personally prefer medium sandpaper.  In either case though, removing the pads and running them over some sandpaper on a flat surface has done a lot for me in some cases.  I have experienced a good doubling of braking effectiveness by doing both, because the pads/rotor had clearly glazed or burnt.

[Specter]

I have not tried the ABS but will.  I am not braking at a level that would being me even near abs activation when this happens.  At least I don't think so.  That kind of jitter jutters anyways when it activates though right, not  a pulse?  Ill try it.

Pard, ill give stuff some cleaning and see what I can find.  One goofy thing I have done in the past with other equipment is XRF it, just a slow CW beam sweep and watch the numbers, if you find a big spike, you know you hit a spot with some crap on it, in it, heavier oxidation etc etc.  Geeky, just something else to take a look at 'things' and how they are.

Cleaning though, again, it comes down to, a rough spot / crap on pads-rotors should hit EVERY rotation, which as pointed out by earlier math, should be several a second, not one a second or so.

I ride a Ribelle, and this is noticeable at slower speeds, more specifically when slowing down at a light or intersection in a situation where you KNOW regen is absolutely not going to stop you, so you are not emergency braking but applying a bit of force and letting it up a bit of course, as you slow and get to your final stopping spot.  I'll say 25 to 30 mph and below?

I'll have to keep a keener eye / feel and try to get more accurate info on when its happening so I can report back.

Thanks everyone.
Aaron

[SwampNut]

I have not tried the ABS but will.  I am not braking at a level that would being me even near abs activation when this happens.

My thought process is that maybe ABS is doing something it shouldn't.  At this point, since you have excluded the more obvious things, it's time to just start grasping at straws and see what happens.  The cleaning, also makes no sense, and also should be tried.

I just helped a friend with a very weird noise on his 4Runner, which would come and go.  There was a lot of head scratching and checking things.  It turned out to be a bent axle, and the noise would happen when the caliper would decide to bind instead of sliding, but then would go away when it did slide with the bend.