Bad hub/disk matching?

Daniel · Post by **Daniel** » Thu Jul 03, 2008 4:41 pm

Hi,

Last day when I did a first front/rear wheel permutation after having placed new disks 15000km ago I noticed that the disks (both sides) can move around the detend screw. Look at pic. Is that normal?

Thanks,

Daniel

MMamdouh · Post by **MMamdouh** » Thu Jul 03, 2008 4:49 pm

i might have not understood the problem well so i will tell you what i do understand

you are complaining that the rotor can rotate a tiny bit around the hub due to a very little gap between the hub and the center hole in the rotor... right?

if this is the case then you only need to really tighten the fastening screw that holds the rotor to the hub to reduce the play... and that is not a problem to worry about because what really holds the rotor to the hub is the wheel bolts so if you got your wheels bolted up tight then you got no free play whatsoever... the screw only keeps the rotor from falling out when you remove the wheels

MMamdouh

Daniel · Post by **Daniel** » Thu Jul 03, 2008 5:33 pm

My bad explanation, sorry. And the red arrow should have to be straight.
In fact the small screw is actually a centre of rotation. Since there is a gap all around the hub and I can move the disk by hand "front and rear" as viewed from driver place. It doesn't turn, it's "balancing" .

Pir0 · Post by **Pir0** » Thu Jul 03, 2008 6:03 pm

So if you hold the disk at the sides, and move your hands horizontally, it pivots about the retaining screw? I know there's always a small bit of play, or else the disk would be really hard to put on getting it perfectly centre etc, but, if it seems like a lot there may be a problem. But as far as i know there usually is a smalllll bitta play.

Daniel · Post by **Daniel** » Thu Jul 03, 2008 6:28 pm

Pir0 wrote:So if you hold the disk at the sides, and move your hands horizontally, it pivots about the retaining screw? I know there's always a small bit of play, or else the disk would be really hard to put on getting it perfectly centre etc, but, if it seems like a lot there may be a problem. But as far as i know there usually is a smalllll bitta play.

That's it! The total play is about 0.6mm. I guessed that this was too much but if this looks correct for you than I don't go further. I don't have the old disks anymore to compare centre hole dia but I remember the old one were quite sticky to remove at 88000km. Maybe they were just rusted.
Maybe tomorrow I'll remove one disk to be sure of diameter fitting.
Keeping you informed how things go.

Daniel

Pir0 · Post by **Pir0** » Thu Jul 03, 2008 7:28 pm

use a caliper and measure in the innside diamter of the disk wher eyou think it's too large, and check up some specs for what it should be, im not 100% on what it should be.

Easy to do anyway, will take ya 15 mins max.

Daniel · Post by **Daniel** » Fri Jul 04, 2008 12:19 pm

Well measurements are done. I'm screwed

.

Rotor hole is well 60mm dia and hub is 59mm dia. I haven't be aware of this bad fit when I mounted rotors 15000km ago. I had tightened the detent screw and the rotor didn't move, of course! I had well checked for lateral runout but not for out of round.

Here a short video.
http://video.google.fr/videoplay?docid= ... 4175&hl=fr .

And hub diameter.

Temporarly I've centered the rotor with 4x 0.4mm shims before torking detent screw. Carefully fitting the wheel but I think I'll need new "officials" rotors

.

Does anyone know the correct reference in Brembo?
BTW for information it's for my (EU) Nubira Y2000 1.6DOHC. All rotors I've found are of 60mm dia

.

Daniel

MMamdouh · Post by **MMamdouh** » Sun Jul 06, 2008 11:06 am

the correct value is 60mm and it is the same value on all daewoos

i don't see the problem here man... as i said the rotor will get held in its position when you put on the wheel and fasten its bolts... the rotor won't move at all

i have posted the online brembo catalog link long time ago in the brakes section so you will find it with a quick search but i am telling you i have done this check before and it is 60mm indeed

if you are worried about centering the rotor then you can take a can of coke and cut it to make a strip of fine metal and use it to fill in the gap that is causing the play... i can't think of anything that is thinner than a can of coke so i f you have a better source then use it

and up till now i am not sure why does the rotor move with the screw tightened... this is strange

MMamdouh

daewoomofo · Post by **daewoomofo** » Sun Jul 06, 2008 1:30 pm

you need that little bit of play in there. when you stop your rotors get hot, when metal heats up it expands. do you have any wheel shake? honestly i wouldnt be worried about it at all. id trust it for myself. as said all of the disks out there are 60 mm, chances are thats what you want. that 1mm translates to .5mm each side, thats not really that much play.

Daniel · Post by **Daniel** » Sun Jul 06, 2008 2:30 pm

You're right, all disks I've looked for my Nubira have a 60mm centre hole. Next time I need to change wheels again I'll use those shims.
I was just perplex why Brembo (and others) make a precision center hole of 60mm -0.000/+0.084 to fit on a 59mm diameter hub.
About wheel shake there is a little but I can't say for sure cos my wheels are maybe a little out of balance.

Thanks for your help.

Daniel

Daniel · Post by **Daniel** » Wed Jan 14, 2009 7:36 pm

I finally find a reference for disks with a centering hole diameter of 59mm. Those are Bosch one's. It seems that there are two kinds of hub's diameter: 59mm and 60mm.

Sorry, french site: "diamètre moyeu de roue" stands for "centering hole diameter".
Here is the site where I find it

So next time I change disks I know what to order

.

Daniel

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Bad hub/disk matching?

Bad hub/disk matching?

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