Loose front Disc


17 replies to this topic
  • gawarrior

Posted February 23, 2005 - 07:34 AM

#1

Yesterday I was cleaning my bike and noticed that my front disc has some play in it. I looked and it is straight and it is very tight where it is bolted on the wheel. It has a very small amount of play where the actual disc is attached to the part that bolts on. There are little round circular pieces that you cannot adjust or tighten where the play is. I hope ya'll can understand where I am talking about. Anway, it doesn't seem to affect the riding I just don't think it should have any play in it at all. BTW, the play is from front to back and it is maybe .5 cm or so. Is this normal or should I do something about it? Or can anything be done about it?

thx

  • 5valve

Posted February 23, 2005 - 07:42 AM

#2

well you must be equipped with WR 450, wich received a brake blessing, called floating disc
this is normal behaveour for such disc and is ment to eliminate any vibration occuring for diffrent reasons

  • gawarrior

Posted February 23, 2005 - 07:45 AM

#3

well you must be equipped with WR 450, wich received a brake blessing, called floating disc
this is normal behaveour for such disc and is ment to eliminate any vibration occuring for diffrent reasons



Actually it is the WR426, but hey I guess it is the same thing. I guess I learn something new everyday :) Well, isn't that ccol :)

  • Jackazz

Posted February 23, 2005 - 08:42 AM

#4

BTW, the play is from front to back and it is maybe .5 cm or so. Is this normal or should I do something about it?


You mean .5mm, not .5cm, right?

  • gawarrior

Posted February 23, 2005 - 08:43 AM

#5

Umm, isn't .5 cm the same as 5mm? :)

  • Jackazz

Posted February 23, 2005 - 09:04 AM

#6

No, I mean 1/2 a mm, not 1/2 a cm... 5 mm seems like a rather large amount of play for a floating disk, especially if it's in the rotational axis, & not side to side. When I got the Berringer setup for my KTM supermoto, it was the loosest floating disk I had ever seen, & it didn't wiggle that much. :)

  • 5valve

Posted February 23, 2005 - 09:19 AM

#7

i think (but not know) it should have somewhat 2-3 mm of play
its hard to measure with eye

  • Jackazz

Posted February 23, 2005 - 09:29 AM

#8

That sounds about right for side-to-side, but I'd think about 1mm front & rear (rotationally) would be about as much as you'd want... :)

  • grayracer513

Posted February 23, 2005 - 09:31 AM

#9

The actual purpose of floating the rotor is to allow it to absorb heat without turning into something that looks like it came from a Pringles can. Floating it frees it from being rigidly bound by the bolts fastening it to the hub. Check how tight it is after you've ridden a while. But wear gloves!

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  • gawarrior

Posted February 23, 2005 - 09:49 AM

#10

It may not be 5mm, it may be less than that. I will check when I get home. It just seemed like a lot. I guess it doesn't really matter because there is no way to adjust it or tighten it anyway. And it really doesn't move from side to side at all, just front to back.

  • Jackazz

Posted February 23, 2005 - 10:00 AM

#11

I'll have a look at mine when I get home tonight too, just to see, but in my experience (which is fairly limited in the Dirt Bike area, I used to be a "street guy") most of the play was supposed to br from side to side.

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  • gawarrior

Posted February 23, 2005 - 10:05 AM

#12

Well heck, I don't know. I will look again tonight at both my bikes. I looked last night at my R1 and it didn't move at all in any direction. But I will look again at the WR tonight to see how much and if it is side to side at all.

  • Gadsen

Posted February 23, 2005 - 12:55 PM

#13

Normal, this is a floating disc. The 426 came stock with these as did the 450. Not sure on the 400's

  • Jackazz

Posted February 23, 2005 - 01:09 PM

#14

Normal, this is a floating disc. The 426 came stock with these as did the 450. Not sure on the 400's


This I understand, I'm just curious as to how much it moves. It seems to me that if the disc moves 5mm (1/2 cm) front to back (not side to side) it might be a bit worn & need replaced, as that seems like a ton of movement for the rotational direction of a floating disc.

  • gawarrior

Posted February 23, 2005 - 01:17 PM

#15

This I understand, I'm just curious as to how much it moves. It seems to me that if the disc moves 5mm (1/2 cm) front to back (not side to side) it might be a bit worn & need replaced, as that seems like a ton of movement for the rotational direction of a floating disc.



Yeah, I am curious of that too. My bike only has about 800 miles on it but if it is too much movement and is worn I will be looking to change it soon.

  • gawarrior

Posted February 23, 2005 - 03:55 PM

#16

Ok,looks like I am in good shape. I looked just now and it only has a couple mm's of play in it. Shew, glad I got that taken care of. lol.

  • SM-WR450F

Posted February 24, 2005 - 08:20 PM

#17

The actual purpose of floating the rotor is to allow it to absorb heat without turning into something that looks like it came from a Pringles can. Floating it frees it from being rigidly bound by the bolts fastening it to the hub. Check how tight it is after you've ridden a while. But wear gloves!


Isn't the point of a floating rotor so that the braking surface can be of one material that is better for braking while the material that attaches it to the hub can be a stronger material that may not be as good for brake friction?

I'm not saying that grayracer is wrong, but I just understood it differently.

  • 99wr400

Posted February 24, 2005 - 08:29 PM

#18

My WR400 came with a solid front brake rotor, it's a 1999.




 
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