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[2020_SRS_Commuter]

Hello, I did not reply back for a long time because a project kept me from changing the disk on my bike. It sat on the bench until finally I got around to it... I just kept riding with the warped one.

Anyway, I was all jacked to finally have non pulsing brakes and was dismayed to find on my first commute to work that it still had a slight pulsing in it.

When I got home, I inspected and found the OTHER disk also has problems, but of a different kind. There are several cracks in the disk, big enough to feel with a dragged fingernail, and it had a gruesome scraping sound as it went through the calipers. I did not notice this before, and the dealer didn't point it out either if you look at what I wrote in the beginning of this thread. The cracks go from one drilled hole to another in some places.

ANYWAY... I ordered a replacement and the damn thing had to sit for weeks waiting for the new disk. It arrived today and I put it on. Finally my front brakes work normally.

So that's two crap tastic disks out of two. One was bad from day one, the other didn't make it 9000 miles.  Not good. I noticed something on the defective disks... they have a minimum thickness of 4.5mm stamped on them, but that's the thickness, essentially, of a new disk! The replacement disks are stamped minimum 3.5mm as you would expect. Also both the new disks have a circular marking added next to the part number that the old ones did not.

I suggest you check your bike and see if you have front disks with the incorrect minimum thickness markings on them.  If you do... keep an eye out for them failing.
 

[NervEasy]

New brake rotors for SR/F and SR/S have 5mm thickness from factory and a minimum thickness of 4,5mm.

[2020_SRS_Commuter]

The ones I received from AF1 as factory replacements say 3.5mm.

Where did you get information that it should be 4.5mm thickness minimum?

It seems to me that 4.5mm minimum spec ought to be incorrect, and the 3.5mm is correct. I'm basing that on two things;
1) The replacement disks have the spec 3.5mm etched onto them
2) On another motorcycle I have that I have ridden for 20 some years, a 98 Honda Superhawk 996, its front disks are essentially the same size and serve a similar sized bike, and are also a little over 4.5mm new, and they are stamped minimum thickness 3.5mm. I've changed those disks twice over 150000 miles, and the first, second, and third sets all had that spec.

[2020_SRS_Commuter]

Here's one of the faulty disks the bike came with.

[2020_SRS_Commuter]

Replacement disk part number with 3.5 spec, this part number has a circle added.

[2020_SRS_Commuter]

Original disk part number, a disk with the 4.5mm spec . This part number has no circle marking

[lunarx]

Interestingly my 21 SR/S (w/ 600mi) has these stampings;

• Circle "O" with Part#
• Min = 4.5mm

However actual Rotor Thickness is 5mm.
How thick are the disks w/ Min = 3.5mm?

[2020_SRS_Commuter]

Both of my new disks are 4.9x mm. They have about 1000 miles or less. To be clear they have the circle marking.
I just measured them using a cheap digital OriginCal caliper set from ebay so the 100ths is variable. IDK why but my Mitutoyo will not power up and changing the battery didn't help. I hope it didn't die.

That spec is absurd.... Imagine replacing disks for a .5mm reduction in thickness. And its absurd that they are sending out parts with differing specs. I wonder if these are produced by Zero themselves or J Juan provides them as well as the calipers.

I'm going with the 3.5 spec because it makes sense and matches my other bike. Based on what I've seen so far the minimum thickness may be irrelevant.  They may well fail again before they wear out. Not impressed. Not at all. 

[karlh]

On page 6.13 of my 2020 SR/S Owner's Manual, under Brake Disc Inspection, the minimum thicknesses are listed as 4.5 mm front, 4.0 mm rear.

For what it's worth, 0.5 mm wear seems to be standard.  The front discs on my 2007 BMW are 4.5 mm thick when new and marked with a minimum thickness of 4.0 mm.

[2020_SRS_Commuter]

Oh boy.
The new right disk I put on at around 9000 miles or so is now warping again, at 11000 miles/ It lasted two months and 2000 miles. Unreal.  UN REAAL.

The left side one I replaced for cracking in several places is still holding up.

If this keeps up I will have to sell this motorcycle.  I cant recommend anyone buy one at this point. I was sold a brand new bike with two disks that failed in 9k miles, and now the first of the replacements has already failed again. It has a warp that is about 90 degrees of its rotation. 

And in case you're wondering.... I hardly use the brakes at all. This is used to get back and forth from work along the exact same route every time that consists mostly of  slowdowns to a stop   by regen. The brake lever is used to engage the switch on it, so it will change to the braking regen setting. Thats all.

[2020_SRS_Commuter]

I'm ordering another disk from AF1. Not giving up yet but my patience is running out. I tried contacting Zero support where you have to enter your VIN and all that, and it wont accept it. When I click "submit" is says "This content isnt available. Contact the owner of this site for help." 

Hey ZERO can you help a customer out here? I spent 24 grand on this bike and the disks last 2k miles.
Here's what I wrote to them, in case some Zero lurker is reading this forum. That has happened before, because one of them private messaged me.
------------------------------------------------------------------------------------------------------------------------------------------
Both front brake disks on my srs failed by 9k miles. One had cracks in it, one had a bad warpage. I replaced both using what are supposed to be factory parts from AF1 in texas. After only 2k miles the right side one is warped again. Morever, these new disks have a minimum thickness stamped on them 3.5mm, where the original ones said 4.5mm. I want to keep this bike but I cannot afford to keep buying disks. I hardly even use the disks, its mostly regen for stopping. What's going on with these parts?

[TheRan]

Are you sure there's not something up with your wheel? That seems more likely to me than having such terrible luck with multiple rotors, especially with them warping so soon and with such light usage.

[2020_SRS_Commuter]

I considered this and looked closely at the assembly of them. I observed that on both disks, each point where the disk touches the wheel for a bolt was in full contact, so no way it could be warped from tightening down to the wheel. ( I checked this BEFORE putting any bolts in, and tried several different rotated positions, disk relative to wheel to double check )  I could see no warp or wobble initially in either of the new disks, tested visually by spinning the wheel on the forks, without the calipers attached, and placing a nail as close to the disks as possible to look for a change in distance there. 

I did notice that the disk bolt holes have holes that are large enough, relative to the disk bolts, that you can actually put the disk a bit off center, so it would be slightly off balance when rotating. There is a bit of an art there. You have to do your best to center it. But this would not contribute to warpage. This slop  also allows for a bit of rotation relative to the wheel, so I placed it resting against the bolts in the direction it would apply force when you brake.


Once the new disks were on, it actually worked properly. There was no pulsing. It was perfect. So if there was a problem with the wheel I would expect it would not work right from the start. I cant think of anything, maybe there is. For about 2k miles I had no pulsing. Then last week I noticed.... uh oh. And every ride it seemed to be more obvious to me.

Its my opinion that these disks are made poorly. The metallurgy is wrong, or the way they are assembled causes some weird loading in the floats. That's another thing I've noticed about these  J Juan brakes that I've never seen on any of my other motorcycles... the disk float is enough that it actually makes a little cracking sound moving around in the float points. Standing beside it, I can roll the bike back and brake, then roll the bike forward and brake,  and literally hear the disks adjust in the floats.

IDK man but I'm furious about this. This should not be happening. I paid 24 grand for a bike and this elementary crap that works on beater Suzuki's  doesn't work  on this bike. Like giving a track runner some hobo's shoes to run in with the heel coming off.

[Crissa]

Maybe you should just replace the brakes if you put them under more stress than Zero expected?

I mean, you'd replace the shocks or tires if the stock ones were unsuitable to your use, right?

-Crissa

[2020_SRS_Commuter]

If that was the case, yes. But I probably use the brakes less than most people do.
90% of my braking is nothing more than pulling the brake lever just enough to switch to braking regen ( 100% for me ) .
I rarely ever really use the brakes to stop. Just to hold my position at a stoplight or whatever.