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The mkiv Supra Owners Club

Brake Guru needed, which way round do the disks go??


Mike B

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I fitted these disks according to Rotora's instructions, (the L and R fitment - ie direction of fins and slats) but to be honest I am now convinced that they are completely clueless... just repackaged and remarketed exsiting components from a marketing company...

 

Spoke to a good friend who preps rally cars (to an international level) - he said I have them on the wrong way round, which explains why I have cooling issues.

 

can you have a look at the pics and tell me if you think he's right and Rotora is wrong.. or vice versa...

side.jpg

top.jpg

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If my perspective on the pictures is correct, they are the wrong way round..

 

The grooves should push gasses and material towards the outside of the disc when the wheels are rotating. It looks at the mo that they are pushing towards the centre of the hub.

 

Also the fins need to pull the air into the disc rather than blow past.

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Also the fins need to pull the air into the disc rather than blow past.

 

This is the main issue perhaps... I wouldn't put it past rotora to put the fins and grooves the wrong way round!!!

 

Jamie; you have any idea wether the internal fins pull air into the disk or push it out from the centre?

 

Hopefully CW will be along soon...?

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The grooves on the outside don't matter....it's the fins inside that do.

 

The grooves just allow brake pad gas to escape.

 

IMO, The fins should be gulping air in the direction the car is going in. But as proved later in this thread it's the exit of the air that's more important than the entry, which also stands to reason...

Edited by Alex (see edit history)
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I fitted these disks according to Rotora's instructions, (the L and R fitment - ie direction of fins and slats) but to be honest I am now convinced that they are completely clueless... just repackaged and remarketed exsiting components from a marketing company...

 

Spoke to a good friend who preps rally cars (to an international level) - he said I have them on the wrong way round, which explains why I have cooling issues.

 

can you have a look at the pics and tell me if you think he's right and Rotora is wrong.. or vice versa...

 

2bh ive just fitted some vented ktec racing discs on my Clio i hope yours are right as mine are going the same way.......

 

Whats those washers about tho? on the lugs

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IMO, The fins should be gulping air in the direction the car is going in.

 

so the fins are pulling air in on the forward travelling section of disc?

 

Whats those washers about tho? on the lugs

 

They are just there bolting the disk on tight when the wheel was off.. I was chacking for warp and testing the alighnment of the caliper.

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Front driver on the monaro. yours look right to me.

Jamie, if that's the drivers side of your car then it's pointing in the same direction as we're saying it should.

 

And from the pictures in the first post, they're the opposite way round which is wrong.

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Guest Garfy
The grooves on the outside don't matter....it's the fins inside that do.

 

The grooves just allow brake pad gas to escape.

 

IMO, The fins should be gulping air in the direction the car is going in.

 

thats my understanding to

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The right hand picture should be the LR disc

 

Thanks Chris, just to interpret this correctly;

 

The right hand picture in the first post, (both pics show the same hub incidentally) should be the Left Rear disk...

 

In which case the hub I am showing you is the LF (Left Front), so they are actually on the right way round, and the motion of the wheel should have the disk vanes blow air from the centre of the disk to the outside of the disk...?... I assume...

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So is the disc on the wrong way:blink:(

 

According to the outside slots it looks like jamie and I have it right as regards the outside marks, but it's the inside vanes on these big disks I think make more difference to the fade and heat dissapation..

 

see what chris says when he comes back...

 

your vanes may the other way round to mine...

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the wheel should have the disk vanes blow air from the centre of the disk to the outside of the disk...?... I assume...

 

I believe you're correct.

 

The motion of the disc ensures that the air within the vanes is 'pumped' outwards, creating air flow from the center of the disc outwards.

If the vanes are the other way round, they'll be trying to draw air inwards and working aginst centrifugal force rather than with it.

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I believe you're correct.

 

The motion of the disc ensures that the air within the vanes is 'pumped' outwards, creating air flow from the center of the disc outwards.

If the vanes are the other way round, they'll be trying to draw air inwards and working aginst centrifugal force rather than with it.

 

exactly what the boffin part of my brain was telling me...

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As already metioned by Alex, its the internal cooling fins that matter.

 

Dont discs normally come marked up for which side they are intended?

 

Yes, but I have a motorsport officionardo telling me different!!

 

I had an argument with a right cocky git at the ring carpark as he said henks ap`s were on the wrong way, i asked him to explain why and he couldn`t, also i noticed that stever`s are on the opposite way to henk`s so gawd knows.

 

Finding excuses to start ww III in a german carpark Si? lol... watching too much top gear :)

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