brake discs - how "loose" should they be? - SV650.org

Geordie Mick · 25-04-15, 09:10 PM

Not been on here for a while for various reasons, but hoping organs collective wisdom can help me out!

Had to replace the front discs on my SV which runs a GSXR front end as one (maybe both) was warped. Can't afford to keep chucking new discs at it, so bought a used set of GSXR ones.

One is very loose and rattly. If I hold the carrier (bit you bolt to the wheel), the disc itself moves at least 1mm (probably more) in all directions around the buttons/pins (whatever they're called).

Seems a lot to me, but wondered if anyone has experience of similar?

Mick..

Bibio · 25-04-15, 10:03 PM

they should flex but not rattle. the button should have crinkle washers under the washer at the back.

top tip: https://www.youtube.com/watch?v=1qoPqN2GBdw

26-04-15, 12:02 PM

One of my racing buddies had discs on his TZ250 that had no wave washers in the buttons at all, which was annoying if you rode to the track with him in his van as the rotors rattled all the time. They did their job in stopping the bike though.
What you shouldn't have is too much clearance between the pins and buttons that would allow the rotors to move radially.

Bibio · 26-04-15, 02:00 PM

thats due to them being fully floating.

garynortheast · 26-04-15, 02:22 PM

That's a handy little video there Lance. Never really thought about doing that before.

Geordie Mick · 26-04-15, 06:54 PM

Well, I've definitely got movement in all sorts of directions. The buttons rotate real easily. I only noticed it when I was refitting the wheel - pushing the calipers over the discs was what made me notice it.

I'll pop out and have a close look for evidence of the washers. Usual story - hoping they're ok as can't be faffed trying to sort a refund etc!

Mick..

27-04-15, 12:17 PM

Quote:

Originally Posted by Bibio

thats due to them being fully floating.

Indeed. Nothing wrong with fully floating except they are noisy and the rattling around wears out the pins quicker I expect.

Bibio · 27-04-15, 12:33 PM

only problem over here is that most MOT inspectors dont like them and will fail them.

i recently got some serviceable buttons that i can chop and change between the two if i wanted.

Geordie Mick · 28-04-15, 07:12 PM

Well, I've took them off and intend to take them to my local, tame mechanic for a second opinion. My money says he laughs out loud and tosses them in a skip, but we'll see...

Mick..

PhilSV · 28-04-15, 07:33 PM

Mick, snap !! Gixer front end on the track bike, and discs are as yours, pad wears even and she stops well so its staying like that !! Cadwell Friday Yehaaaar !

25-04-15, 09:10 PM	#1
Geordie Mick Member Join Date: Jun 2011 Location: Dalkeith Posts: 290	brake discs - how "loose" should they be? Not been on here for a while for various reasons, but hoping organs collective wisdom can help me out! Had to replace the front discs on my SV which runs a GSXR front end as one (maybe both) was warped. Can't afford to keep chucking new discs at it, so bought a used set of GSXR ones. One is very loose and rattly. If I hold the carrier (bit you bolt to the wheel), the disc itself moves at least 1mm (probably more) in all directions around the buttons/pins (whatever they're called). Seems a lot to me, but wondered if anyone has experience of similar? Mick.. __________________ 2003 ZX6R b1h track bike project 1994/97 Ducati 750SS Project Previously: SV650 SK3 cafe racer, SV650 SK6 (track bike), VTR1000F, VFR800 VTEC (x2), SPRINT 1050, VTR1000F (track bike), XT660X, ZX6-R, CB500, VFR750 FL, City Fly 125, GS450, GS500E, NS125R, DT50MX.

25-04-15, 10:03 PM	#2
Bibio Member Mega Poster Join Date: Jul 2008 Location: here as devil's advocate Posts: 11,540	Re: brake discs - how "loose" should they be? they should flex but not rattle. the button should have crinkle washers under the washer at the back. top tip: https://www.youtube.com/watch?v=1qoPqN2GBdw

26-04-15, 12:02 PM	#3
wideguy Guest Posts: n/a	Re: brake discs - how "loose" should they be? One of my racing buddies had discs on his TZ250 that had no wave washers in the buttons at all, which was annoying if you rode to the track with him in his van as the rotors rattled all the time. They did their job in stopping the bike though. What you shouldn't have is too much clearance between the pins and buttons that would allow the rotors to move radially.

26-04-15, 02:00 PM	#4
Bibio Member Mega Poster Join Date: Jul 2008 Location: here as devil's advocate Posts: 11,540	Re: brake discs - how "loose" should they be? thats due to them being fully floating.

26-04-15, 02:22 PM	#5
garynortheast Member Mega Poster Join Date: Mar 2010 Location: Mid Wales Posts: 2,488	Re: brake discs - how "loose" should they be? That's a handy little video there Lance. Never really thought about doing that before.

26-04-15, 06:54 PM	#6
Geordie Mick Member Join Date: Jun 2011 Location: Dalkeith Posts: 290	Re: brake discs - how "loose" should they be? Well, I've definitely got movement in all sorts of directions. The buttons rotate real easily. I only noticed it when I was refitting the wheel - pushing the calipers over the discs was what made me notice it. I'll pop out and have a close look for evidence of the washers. Usual story - hoping they're ok as can't be faffed trying to sort a refund etc! Mick.. __________________ 2003 ZX6R b1h track bike project 1994/97 Ducati 750SS Project Previously: SV650 SK3 cafe racer, SV650 SK6 (track bike), VTR1000F, VFR800 VTEC (x2), SPRINT 1050, VTR1000F (track bike), XT660X, ZX6-R, CB500, VFR750 FL, City Fly 125, GS450, GS500E, NS125R, DT50MX.

27-04-15, 12:33 PM	#8
Bibio Member Mega Poster Join Date: Jul 2008 Location: here as devil's advocate Posts: 11,540	Re: brake discs - how "loose" should they be? only problem over here is that most MOT inspectors dont like them and will fail them. i recently got some serviceable buttons that i can chop and change between the two if i wanted.

28-04-15, 07:12 PM	#9
Geordie Mick Member Join Date: Jun 2011 Location: Dalkeith Posts: 290	Re: brake discs - how "loose" should they be? Well, I've took them off and intend to take them to my local, tame mechanic for a second opinion. My money says he laughs out loud and tosses them in a skip, but we'll see... Mick.. __________________ 2003 ZX6R b1h track bike project 1994/97 Ducati 750SS Project Previously: SV650 SK3 cafe racer, SV650 SK6 (track bike), VTR1000F, VFR800 VTEC (x2), SPRINT 1050, VTR1000F (track bike), XT660X, ZX6-R, CB500, VFR750 FL, City Fly 125, GS450, GS500E, NS125R, DT50MX.

28-04-15, 07:33 PM	#10
PhilSV Member Join Date: Apr 2012 Location: Lincolnshire Posts: 366	Re: brake discs - how "loose" should they be? Mick, snap !! Gixer front end on the track bike, and discs are as yours, pad wears even and she stops well so its staying like that !! Cadwell Friday Yehaaaar !

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