Topic: Small crack in front brake disc - critical?

[Glaede]

Hi guys

I noticed a small crack in the front brake disc yesterday when mounting the disc. Is this crack critical? :/ I would like to replace it, but its kinda expensive, so if its not critical, I'll just continue using it..

I've attached a picture of the crack:

[Eydugstr]

I'd go ahead and replace it.  Used rotors aren't that expensive.  Good eye at spotting it before it became a problem!

[Glaede]

Okay, well here in Denmark, used parts is not so easy to come by ;-) So I would probably have to import it from Germany or UK. What is the std. thickness by the way in mm?

[bollingball]

Okay, well here in Denmark, used parts is not so easy to come by ;-) So I would probably have to import it from Germany or UK. What is the std. thickness by the way in mm?

It should be stamped on the rotor.
Ken

[Fritz]

Hi!

Although this crack might not seem to be really serious, I would not take any chances when it comes to brakes.

The disc is stainless steel, so I would not expect a lot of wear. In my 500/550 workshop manual I could not find any numbers for minimum thickness.
Wobble seems to be more of a concern. But you could always have the disc machined back to get an even surface. There's a lot of 'meat' on it.

On ebay.de used discs ("Bremsscheibe") range from 60€ up to 100€ (drilled). On ebay.co.uk they range from £30 to £50. I think that's not too much for your safety

Cheers
Carsten

[Glaede]

Hi!

Although this crack might not seem to be really serious, I would not take any chances when it comes to brakes.

The disc is stainless steel, so I would not expect a lot of wear. In my 500/550 workshop manual I could not find any numbers for minimum thickness.
Wobble seems to be more of a concern. But you could always have the disc machined back to get an even surface. There's a lot of 'meat' on it.

On ebay.de used discs ("Bremsscheibe") range from 60€ up to 100€ (drilled). On ebay.co.uk they range from £30 to £50. I think that's not too much for your safety

Cheers
Carsten

I agree which is why I made this topic to convince my self ;-)

I'll order a used disc from ebay! Thanks guys..

Btw, the minimum thickness is 6 mm, but I was wondering what the standard thickness is of a brand new disc.

[LesterPiglet]

I have seen discs that have been skimmed as thin as 4mm, it seems a common weight saving effort.

[754]

Is.it a crack or raised line.. May be from a crack in the mould or die.. If it is sticking UP.

[flybox1]

Hi!

Although this crack might not seem to be really serious, I would not take any chances when it comes to brakes.

The disc is stainless steel, so I would not expect a lot of wear. In my 500/550 workshop manual I could not find any numbers for minimum thickness.
Wobble seems to be more of a concern. But you could always have the disc machined back to get an even surface. There's a lot of 'meat' on it.

On ebay.de used discs ("Bremsscheibe") range from 60€ up to 100€ (drilled). On ebay.co.uk they range from £30 to £50. I think that's not too much for your safety

Cheers
Carsten

I agree which is why I made this topic to convince my self ;-)

I'll order a used disc from ebay! Thanks guys..

Btw, the minimum thickness is 6 mm, but I was wondering what the standard thickness is of a brand new disc.

New thickness is 7mm.  Stamped minimum thickness is 6mm.
I love my drilled 4mm rotors from Godfferys Garage

http://www.vinmoto.org/gallery/v/VinMoto-Garage/album03/Godfferys-Garage-123/album185/Brake+Rotors+_+Thinned+and+Drilled/

[Powderman]

It is definitely a crack but not in the rotor, it is in the aluminum carrier. I would replace it as the cracked aluminum will probably deteriorate faster than the steel rotor will

[lucky]

FIRST clean it to bare metal before making any decisions.

You cannot do a good visual inspection until it is clean shiny metal.

NO paint.

[Glaede]

Yeah.. I've found a used one in Germany, so hopefully it will be here by the end of the week :-)

Got the bike on wheels yesterday btw - bought the bike in february and have been restoring it for the last three months (my first bike):


After inspection (hopefully friday when I have a day off) I'll continue cafe racing it. I have some clip ons - just need a new seat and taillight really.

It looked like this when i bought it - pretty ugly, but running:

[Powderman]

Do you plan on rear sets. Standard pegs with clip-ons will put you in an awkward/uncomfortable position.

[Glaede]

Do you plan on rear sets. Standard pegs with clip-ons will put you in an awkward/uncomfortable position.

I haven't really decided yet. I think the ones that you bolt on to the passenger foot peg makes an even worse riding position, and I don't want to modify the frame since it's illegal and it's freshly powder coated. But I'll decide when I've ridden it I guess :-)

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[lucky]

Can you please get back on subject, and tell us if the disc was cracked or not?

[Glaede]

Can you please get back on subject, and tell us if the disc was cracked or not?

? It is cracked - never said it wasn't. Look at the picture. I was asking if it was critical.

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[Fritz]

Yeah.. I've found a used one in Germany, so hopefully it will be here by the end of the week :-)

Got the bike on wheels yesterday btw - bought the bike in february and have been restoring it for the last three months (my first bike):

Not my choice of color but the 550 is a real beauty. Isn't she?

[Glaede]

Yeah.. I've found a used one in Germany, so hopefully it will be here by the end of the week :-)

Got the bike on wheels yesterday btw - bought the bike in february and have been restoring it for the last three months (my first bike):

Not my choice of color but the 550 is a real beauty. Isn't she?

Yeah it's a nice bike. The color is only temporary. I bought the tank black and don't have the money at the moment for a professional paint job. I think it's prettier than before though :-) I'll probably ride it like this for the summer..
 
But enough off topic for now - don't want to ruin luckys day ;-)

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[Fritz]

But enough off topic for now - don't want to ruin luckys day ;-)

Ah, Lucky's just missing a bit of humour

Too bad I'm living next to the former Danish border. Århus (or is it Aarhus?) is just too far to join the first ride on your bike

But maybe, if you happen to be around the Flensborg/Sønderborg area some day, I'd be glad to ride with two 550s along the Flensborg Fjord...

Cheers
Carsten

[Glaede]

But enough off topic for now - don't want to ruin luckys day ;-)

Ah, Lucky's just missing a bit of humour

Too bad I'm living next to the former Danish border. Århus (or is it Aarhus?) is just too far to join the first ride on your bike

But maybe, if you happen to be around the Flensborg/Sønderborg area some day, I'd be glad to ride with two 550s along the Flensborg Fjord...

Cheers
Carsten

Cool, where do you live? Well I am in Flensborg sometimes when I need cheap beer ;-)

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[Fritz]

Cool, where do you live? Well I am in Flensborg sometimes when I need cheap beer ;-)

Well cheap beer and riding motorcycles does not go along very well, no matter the condition of your brakes, I guess

I'm living in Hamburg. It's just a 90minute's ride to up to the Danish border...

Cheers
Carsten