The wait is over, she is here and I love her!

[Gloucesternige]

P.S. Is there anyway of measuring a disc run-out of a car? I ask because they are a very tight fit on the hub so maybe they are perfect but because the hub is marginally too large means even when torqued up the disc is not absolutely flat/perfect to the hub causing this run out as this run out is just as bad at hub so maybe the fitment is just too tight????

If I can get them measured off the car and if they are spot on I guess I could sand paper inside the bell and sand paper the hell out of the outside of the hub to create some more clearance so hopefully the fitment is not so tight, of course this is assuming this is the issue......

Best bet is first try to measure the run out of the car.

The bell should fit flush on the face of the hub Gibbo. If there's any interference with the od of the hub and id of the bell the kit is not fit for purpose and needs to be machined in the back face to give clearance.

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[hinch]

your 10.05 indents which according to the scale is 0.1005mm out to me.

have you got a spare bearing or something you can rest the disk on horizontally ie: off the car and spin just the disk on its own so you take away any affectors coming from the bell. and just measure the disk as at the moment you're measuring the impact of the whole assembly. If you have a perfectly straight edge you could achieve the same across the face of the disc and rotate the edge.

 

[Optimum Performance]

Is it not showing that it's 1.2mm out on the gauge, as if I read the gauge correctly it measures from 0-10mm, so each main number is a millimetre

One full sweep should be 1mm. so he is measuring .100mm.

 

[Eclipsar]

Just watched this video that says this reading is 10,000 of a inch out :shrug:

 

[Gibbo205]

The bell should fit flush on the face of the hub Gibbo. If there's any interference with the od of the hub and id of the bell the kit is not fit for purpose and needs to be machined in the back face to give clearance.

The stock disc fit with zero interference, so they hang loose, these uprated disc are a tight interference fit, need few wacks with a rubber hammer to go on and then torquing up. Then to remove they take a lot of wiggling or need wacking from behind with rubber hammer because of the tight fitment.

My guess is the hat is maybe a mm too tight, guess I could sand paper the inside of the hat and the hub, but then risk voiding the warranty and they still might not fit or actually be too much out anyway.

 

[Gloucesternige]

Guys, I use dti's every day which what the clock Gibbo has shown is.
They are available in Metric or Imperial scales.

Gibbo has a metric clock with 10 micron intervals, so 10 microns times 10 equals 0.1 mm, which is around .004" or 4 thousandths. I would consider 3 thousandths too much, let alone 6 thousands which is what the manufacturers are suggesting.

However, there are two different issues with disc brakes which give two completely different symptoms. If the disc is warped, with no radial variation in disc thickness you will get shuddering through the steering wheel. Then you can have hard/soft spots in the disc which will cause variation in disc thickness and a pumping sensation on the pedal when braking.

 

[Optimum Performance]

That's all fine and good but I believe Ford's spec is more like .04mm runout. or .0015". The hub face needs to be clean and the rotor hub face needs to sit on the hub flat. Rotor needs to be torqued (all studs) to spec.

 

[Nookie]

Run out reads to me as 0.1mm (10 x 0.01mm) so I think you've got a hat-to-hub issue. Think it's a bit strange that it's such a tight fit... as where's the allowance for heat expansion conducted through from the disc?

 

[Gibbo205]

Guys, I use dti's every day which what the clock Gibbo has shown is.
They are available in Metric or Imperial scales.

Gibbo has a metric clock with 10 micron intervals, so 10 microns times 10 equals 0.1 mm, which is around .004" or 4 thousandths. I would consider 3 thousandths too much, let alone 6 thousands which is what the manufacturers are suggesting.

However, there are two different issues with disc brakes which give two completely different symptoms. If the disc is warped, with no radial variation in disc thickness you will get shuddering through the steering wheel. Then you can have hard/soft spots in the disc which will cause variation in disc thickness and a pumping sensation on the pedal when braking.

These are rears.
Based on my gauge reading 10, what is that in thousands/mm based on the gauge I used mate?

The symptons I had was judder/vibration from rear and slight pedal modulation, no steering wheel wobble but as rear disc would not expect it.

 

[Optimum Performance]

The stock disc fit with zero interference, so they hang loose, these uprated disc are a tight interference fit, need few wacks with a rubber hammer to go on and then torquing up. Then to remove they take a lot of wiggling or need wacking from behind with rubber hammer because of the tight fitment.

My guess is the hat is maybe a mm too tight, guess I could sand paper the inside of the hat and the hub, but then risk voiding the warranty and they still might not fit or actually be too much out anyway.

It should be about 70.5mm, sounds like they are on the tight side. This will cause all your problems. Nothing should be fitted that tight, hub, rotor, spacers, or wheels. There has to be room for thermal growth.

 

[Gibbo205]

That's all fine and good but I believe Ford's spec is more like .04mm runout. or .0015". The hub face needs to be clean and the rotor hub face needs to sit on the hub flat. Rotor needs to be torqued (all studs) to spec.

Should it be tight though? My hub is spotless zero corrosion as I proper cleaned them up before install.

But disc fit on tight, to do the test I fitted a 5mm solid spacer, then torqued all 5 bolts up and then did the run out test.

Once finished I removed disc and rotated, and removing the disc was not easy, so tight on there.

Whereas a stock disc just falls loose when undoing the bolts just like a wheel does.

So do you think the issue is the hats are too tight on the hub?

 

[Gibbo205]

It should be about 70.5mm, sounds like they are on the tight side. This will cause all your problems. Nothing should be fitted that tight, hub, rotor, spacers, or wheels. There has to be room for thermal growth.

The tightness is not at the centre 70.5mm that is fine I think, it is more on the outer diameter of the hub.

I guess I will have another play but kind of miffed about all this fiddling, the fuckers should just fit up nice and easy, I should not be having to mess about like this.....

 

[hinch]

sounds like the bell needs abit more milling on the inside to make sure it doesn't catch the outer top corners of the hub either that or take an angle grinder to the hub and shave 0.5mm off all the way around

 

[Optimum Performance]

The tightness is not at the centre 70.5mm that is fine I think, it is more on the outer diameter of the hub.

I guess I will have another play but kind of miffed about all this fiddling, the fuckers should just fit up nice and easy, I should not be having to mess about like this.....

Oooohhhhh! That is not good, the bell should not contact anything but the face of the hub, if they are trying to fit this under the caliper bracket by fitting the hat to the OD of the hub that is an issue. Girodisc and I have discussed doing a caliper bracket and larger disc (move the caliper out) so the hardware can clear the hub and the caliper bracket.

They need to enlarge the id of the hat so it is not in contact with the hub. I.e. These rotors you have do not fit.

 

[Gibbo205]

Oooohhhhh! That is not good, the bell should not contact anything but the face of the hub, if they are trying to fit this under the caliper bracket by fitting the hat to the OD of the hub that is an issue. Girodisc and I have discussed doing a caliper bracket and larger disc (move the caliper out) so the hardware can clear the hub and the caliper bracket.

They need to enlarge the id of the hat so it is not in contact with the hub. I.e. These rotors you have do not fit.

So a cure would be to machine the outer edge of the hub and also machine the inside of the hat, so they fit freely with no issue?

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