Play in front brake rotor?

[bad mechanic]

I know the front rotor floats and it's normal to have side to side play in it. However, I've noticed mine has front to back play. In other words, if I hold my front brake I can rock the bike back and forth slightly and can brake disc moving back and forth on its carrier. Right now there's probably about 2mm of total movement.

How much play, if any, is normal?

This is for a DRZ-SM.

Edited May 14, 2013 by bad mechanic

[bmwpowere36m3]

I know the front rotor floats and it's normal to have side to side play in it. However, I've noticed mine has front to back play. In other words, if I hold my front brake I can rock the bike back and forth slightly and can brake disc moving back and forth on its carrier. Right now there's probably about 2mm of total movement.

How much play, if any, is normal?

By "rotor" I think you mean caliper, because as far as I know the OE rotor is solid (neither a semi or fully-floating design). The caliper is free to slide laterally (perpendicular to the rotor face) because of its single-sided piston design (floating caliper).

However if you have an aftermarket rotor, then it could be a floating rotor. 2 mm sounds like a lot of movement, I’m surprised the buttons holding the brake rotor to the carrier don’t fall out.

[Jeekinz]

Mash down on the rivets, should tighten back up.

[bad mechanic]

By "rotor" I think you mean caliper, because as far as I know the OE rotor is solid (neither a semi or fully-floating design). The caliper is free to slide laterally (perpendicular to the rotor face) because of its single-sided piston design (floating caliper).

However if you have an aftermarket rotor, then it could be a floating rotor. 2 mm sounds like a lot of movement, I’m surprised the buttons holding the brake rotor to the carrier don’t fall out.

I mean the rotor. The OE rotor on the SM is floating.

[GuyGraham]

2mm ain't nothing to worry about

The old GSXR -WT's were reknowned for it, and they would wear so bad the rotor would eventually roll up onto carrier

Its the soft Aluminium carrier that wears away causing the disc buttons to be loose

Just keep an eye on it and sort it out when it gets bad

[bad mechanic]

2mm ain't nothing to worry about

The old GSXR -WT's were reknowned for it, and they would wear so bad the rotor would eventually roll up onto carrier

Its the soft Aluminium carrier that wears away causing the disc buttons to be loose

Just keep an eye on it and sort it out when it gets bad

So...what's bad?

[bmwpowere36m3]

So...what's bad?

I'm guessing when the rotor falls off ?

[Mad Dogg W]

My full floater has had about 2mm play in it for over 6 months now that I am aware of (could be longer but I noticed 6 months ago), I have been meaning to replace it but haven't done so yet. I can actually move mine by hand without using the front brake. In six months it hasn't gotten any worse. That said I am not heavy on the front brakes very often as I ride pretty much 100% road. Keep an eye on it and replace it as soon as you can afford to....

[GuyGraham]

So...what's bad?

You'll know, coz the disc will be slopping about all over the place and making a right old racket

seriously though, there's no magic figure of when its 'bad'

keep an eye on it, the disc is in no danger of coming off' - I'd say when its gets to about 5-6mm of play then find a replacement

'mashing on the rivets' like suggested above will do nothing as the excess clearance is radial

[Jason Brenner]

My bike has about 200 miles on it. Grabbing the front brake and rocking back and forth yields a slight movement. It seems like it’s coming from the rotor and not the steerer bearings. I’m pretty sure I can see the rotor moving about the hub. The head bearings have a slight amount of movement, but seems like a tiny(normal) amount that’s only visible when looking at the top seal. I was thinking of inspecting further this weekend, but I might let the dealership handle it since it’ll be under warranty. 
 

How much front to back play is normal on a new floating rotor?

[bumtarder]

I don't have any perceptible play on mine.

The DRZ is notorious for having very little grease in the steering head bearings and very little pre-load. You may want to have a look.

 

[Jason Brenner]

3 hours ago, bumtarder said:

I don't have any perceptible play on mine.

The DRZ is notorious for having very little grease in the steering head bearings and very little pre-load. You may want to have a look.

 

Is there a specific protocol for the DRZ, such as a certain amount of rotation past zero play?

[Jason Brenner]

I called one of the dealers nearby. They said 32 1/2 pounds on the bottom nut, then turn the steering left to right to help seat the bearings, then back it off a quarter to a half a turn and on the top nut torque to 65 pounds. 
 

Sound about right?

[bumtarder]

 I do it like that but then when I back the stem nut off,I snug it up hand tight with a leather glove on as snug as I can and call it good. Then go back and forth several times to make sure that the steering is free but no excess drag, not floppy loose like it is when delivered. I use Bel-Ray marine grease. Yes top clamp nut torque is 65lb-ft.

 

 

[AZ_atypical]

On 4/16/2021 at 8:06 AM, Jason Brenner said:

My bike has about 200 miles on it. Grabbing the front brake and rocking back and forth yields a slight movement. It seems like it’s coming from the rotor and not the steerer bearings. I’m pretty sure I can see the rotor moving about the hub. The head bearings have a slight amount of movement, but seems like a tiny(normal) amount that’s only visible when looking at the top seal. I was thinking of inspecting further this weekend, but I might let the dealership handle it since it’ll be under warranty. 
 

How much front to back play is normal on a new floating rotor?

They'll probably consider the rotor a wear item and not warranty it. I had the same thing on my SM. I'm sure that's your issue from the sound if it. I rode it until the slop got excessive and then upgraded the front brake system to a 4 piston moto master caliper and 320mm rotor that solves that fore and aft weakness in the stock rotor. I couldn't find a replacement for the stock rotor that was worth a damn, so upgrading was the way to go for me.

There's probably a retired japanese dude at home watching TV right now that knows what the play limit in the rotor can be, but good luck finding him lol. 

Edited April 18, 2021 by AZ_atypical

[Jason Brenner]

Here’s a short video showing the rotor shifting on the rivets. Compared it to the 15 year old galfer floating rotor on my other SM which has zero play. Kinda sketchy feeling for a component of the most important system on the bike...

https://rumble.com/vfrubr-drz400sm-with-less-than-200-milesfront-rotor-play.html

Edited April 18, 2021 by Jason Brenner

[Jason Brenner]

https://rumble.com/embed/vd5o5n/?pub=axwcn

[bumtarder]

My 16yr old SM original front w/ nearly 50,000 mi doesn't do that, I think that rotor is defective imo.

 

[Jason Brenner]

On 4/16/2021 at 2:02 PM, bumtarder said:

 I do it like that but then when I back the stem nut off,I snug it up hand tight with a leather glove on as snug as I can and call it good. Then go back and forth several times to make sure that the steering is free but no excess drag, not floppy loose like it is when delivered. I use Bel-Ray marine grease. Yes top clamp nut torque is 65lb-ft.

 

 

Where did you pick up the socket for the stem nut?

[Jason Brenner]

Okay, I’m ordering a new rotor. Suzuki’s site says 300mm, but several aftermarket companies list the SM front as 310mm or some other number.

Any recommendations on a rotor for the SM? I’ve always had luck with Galfer, but I’m open to opinions.