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[NervEasy]

Hi,

(2020 SR/S - 4200kms)

My front brake is pulsing when coming to a slow stop and when braking when speed is above 100km/u. At that speed the bike is shaking when braking.

I tried organic pads (no joy)
I tried freeing up the buttons as they where completely stuck. Now they spin free (still no joy)
I tried sanding the rotors slightly with scotch brite pads, this was dealer recommendation (no joy)

Anyone have some tips to fix the issue?

[princec]

Your discs are warped. There is no fix apart from new discs. Don't buy OEM, get EBC, Galfer, or Braking. They are far higher quality than OEM.

OEM discs shouldn't really warp like this, but because they're a disposable "service item" part, good luck arguing about warranty replacement. In any case they'll just replace them with more shitty OEM discs... so basically, just bite the bullet and put decent new ones on instead.

Cas

[Richard230]

I have had issues with a warping front disc (always when there is just one disc, it has never happened with a wheel with two disc brakes) on both my 2005 Triumph Bonneville and my 2009 BMW F650GS. On both bikes I had two original discs warp and I eventually replaced them with a name-brand aftermarket disc. After doing that I had no further problems. If you replace the disc, don't forget to install a new set of brake pad too. I like H-H friction pads, which provide the best stopping power.

[NervEasy]

Ok, How do I know what kind of aftermarket rotors I need? The J Juan rotors do not come with an EBC part number

[Richard230]

Ok, How do I know what kind of aftermarket rotors I need? The J Juan rotors do not come with an EBC part number

That is a good question and one that I can't answer as my Zero's brakes are still working as intended.  Perhaps check with EBC and Braking and see what they say. J Jaun is apparently major brake parts manufacturer in Spain so i would think that the aftermarket would be familiar with their products.

[Electric Terry]

I have a 2020 SR/S.  Last year I was 100% convinced my rotors were warped bad.  It would shake with even the smallest brake pressure.  However before I tried to replace them, I took the rotors off to experiment with some carbon wheel covers that went underneath.  To my surprise the vibration went away completely.  Even after taking the carbon covers off, the pulsing is gone.  So somehow the rotors weren't warped after all.  Not sure what it was.  But it is something with mounting or the floating rivets sticking or something else that was fixed by removing the rotors and reinstalling them (without paying attention to orientation or side).  At least it was for me and it's been perfect for over 10,000 miles now.  Glad I didn't replace the rotors themselves as it wasn't the issue.

[Richard230]

Some years ago I asked Rider magazine's shop guy about pulsing rotors and he replied that many times the pulsing was caused by the rotors picking up pad material, which was sticking to the rotors, and that could be causing uneven friction on the disc surface. He recommended removing the rotor and cleaning it thoroughly with brake cleaner and a plastic or nylon kitchen scrubbing pad (or maybe you could use steel wool?), then reinstalling it.  If you decide to try that it might also be a good idea to sand the brake pad material to remove any surface glazing, by placing light sandpaper on a glass sheet and rubbing gently until the surface glaze is removed.

[NervEasy]

Hi Electric Terry,

I am intrigued by your answer and would like to try to remove and reinstall my rotors.

The only question here is how do I support my bike to remove the front wheel. A small scissor lift will not work I guess as the bike may not be supported from the cooling fins on the bottom?

[Crissa]

That's a good question!  There should be a point where the frame goes under the motor controller for the center stand.  Zero tends to use a flat-style workbench stand so there should be a balance point there.

I did look in the manual to see if it was there (gosh knows I've missed it in the manual before) but I don't see it at all, either.  http://media.zeromotorcycles.com/resources/owners-manuals/2020/2020-Zero-Owners-Manual-SRS.pdf

And I don't see any mentions for the F-platform and jack, center, or stand in the unofficial manual.  The last entry is 2018 about the kickstand, so that's a page that pre-exists the third generation.

-Crissa

[NervEasy]

It attaches near the motor and the weight would still tilt the bike forward... I don't think the centerstand points are the way to go?

https://zeromoc.com/product/srfs-center-stand/

[Crissa]

Hmm.

There has to be a spot to lift it!

-Crissa

[Shadow]

Pretty sure all the bikes I've seen worked on (this was years ago... admittedly) at Zero HQ were suspended on a hoist. The small scissor-lift was used in their parking lot for S/DS.

I think if you have the centerstand installed for SRF/SRS it would certainly make lifting the bike half as much work i.e. use any A-frame ladder and some rope to support the front half. I don't know?  @Electric Terry how did you lift your SR/S?

[Say10 15FX 16FXS]

Why even take the wheel off? I would unbolt the rotors and spin them 180 or whatever and bolt them back on and see if it makes a difference. My FXS pulsed pretty bad when new. Rotor was not warped. Changed to EBC HH semi sintered pads and once they broke in, sweet ever since.

[Richard230]

Why even take the wheel off? I would unbolt the rotors and spin them 180 or whatever and bolt them back on and see if it makes a difference. My FXS pulsed pretty bad when new. Rotor was not warped. Changed to EBC HH semi sintered pads and once they broke in, sweet ever since.

It might be tough getting the rotors pass the axle without removing the wheel. Once you loosen the axle and pull it out you will need to support the front end of the bike.  My recollection is that the guys that make rear wheel shop stands typically also make a front fork support stand that either supports the forks by lifting its lower ends or by inserting a rod into the opening under the steering bearing.

[Say10 15FX 16FXS]

No need to take the axle out or support the bike. Remove the rotor bolts, spin rotor to a different position and put the bolts back at the proper torque. Simple!