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Discussion Starter #1
At least that is what we think they are. I haven't found a name on them yet. Got 2 front discs and a rear on a set of Comstar wheels. Obviously they are not made of stainless

20150719_141953.jpg
 

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whats going on with the holes on the disc on the bottom? it looks like they were drilled partially over the edge of the disc or that the disc was worn down on the outside to expose the holes... is there a reason behind this?
 

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whats going on with the holes on the disc on the bottom? it looks like they were drilled partially over the edge of the disc or that the disc was worn down on the outside to expose the holes... is there a reason behind this?
At a guess I would say someone has machined down the outside of the disc after it was drilled to suit whatever fork / caliper combo.
 

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whats going on with the holes on the disc on the bottom? it looks like they were drilled partially over the edge of the disc or that the disc was worn down on the outside to expose the holes... is there a reason behind this?
They often do it to reduce weight or maybe even to increase the surface area for air cooling. It even might assist dirt being flung off on dirt bike discs. Some brands of current aftermarket discs are like that. The pads don't run right out there, so it's not a braking function concern.

Danger, is my business."
 

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At a guess I would say someone has machined down the outside of the disc after it was drilled to suit whatever fork / caliper combo.
that makes sense... however what impact, in conjunction with the drilled holes, would this have on the structural stability of the disc? it seems you're greatly multiplying the chances for cracks and fractures to occur.
 

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that makes sense... however what impact, in conjunction with the drilled holes, would this have on the structural stability of the disc? it seems you're greatly multiplying the chances for cracks and fractures to occur.
If slots and holes were a serious stress riser in discs, the factories wouldn't do it. They are not an issue.

Danger, is my business."
 

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Discussion Starter #8
These may even have have the hole cast in, like real race cars. I haven't done much research on them yet. A friend had a similar set market PM
 

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that makes sense... however what impact, in conjunction with the drilled holes, would this have on the structural stability of the disc? it seems you're greatly multiplying the chances for cracks and fractures to occur.
If you're talking about the outer semi-circled "holes" which are there as a result of the disc being machined down, then they shouldn't pose a risk of cracking the disc.

In fact, you can pretty much cut any shape hole into a disc as long as the corners are radius-ed (IE: no sharp corners / edges).

 

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If slots and holes were a serious stress riser in discs, the factories wouldn't do it. They are not an issue.

Danger, is my business."
I have seen failures on racebikes with home drilled discs, but then again I have actually built and maintained and raced race bikes.
Here is what 15 seconds on the Google showed:





Looks like the holes might be stress risers after all.
I also know why brake discs are drilled, not just some speculation on the possible reasons.

Ken
 

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But Ken - you know Google is full of lies.

Like those pics of SV cranks that were broken - that's never happened......
 

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"Serious stress risers". Obviously the factories consider discs with slots or holes to be acceptable for the duty cycles of most road bikes braking systems. Therefore they must consider them minor stress risers. Clever old factories.

I've never had any trouble with all discs I've drilled for customers, no returns and zero complaints. Lucky old me, as usual.

I've only ever had minor problems with maintaining road racing disc brakes. They usually work far better than the competition. The lap times proved it.

Danger, is my business."
 

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Facade? You jest.

It's amusing to see you project your perceived inadequacies onto others. Carl Jung would be proud.

You spend plenty of time online, maybe you should go finish the GS450 or FJ1200?

Danger, is my business."
 

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I spend a lot of time on-line?

Excluding your ban time-out you've been here just under 12 months and nearly have 5K posts.

You've spewed so much crap for so long it feels like you've been here longer than Adam.

If you tried to write a screenplay for this no one would buy it.
 

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I have seen cracks in disks with holes and cracks in disks without holes.
Don't think the holes are the issue.
When people post those pictures often there was other extremes that had a larger effect.

And Hillsy, this is one of those times you sound more bent then having a good time.
If you feel WW really is a troll then stop feeding him.
I know you think you are fighting the good fight and fear some newbie might take WW's posts as gospel.
But honestly if someone takes anyone's word as gospel from the web they deserve what ever ill fait befalls them.
 
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