GR Yaris Has anyone replaced front discs?

Jip

Jip

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Just wondering if anyone has worn there front discs out? And what are the criteria for them being worn out. I’m looking at about a 2mm lip around the outer edge. No way does this affect the brake's but just trying to gauge when thy will need changing.
8000 miles, and good few Trackdays. Think I’m on pad set 5+.
I’m trying to do my man maths on selling this car and taking on a new GR.
 
Jip said:
Just wondering if anyone has worn there front discs out? And what are the criteria for them being worn out. I’m looking at about a 2mm lip around the outer edge. No way does this affect the brake's but just trying to gauge when thy will need changing.
8000 miles, and good few Trackdays. Think I’m on pad set 5+.
I’m trying to do my man maths on selling this car and taking on a new GR.
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That is some heavy brake use, five sets, I got 40000 miles out of our Cooper S one's and the disc's were still good.
 
There should be some grooves on outer circumference of the disk that indicate the 'worn width'. Best to measure as the lip won't make a hole before it's way too late. wear.webp
 
AP756 said:
Sorry to jump in. The grooves are a result from balancing the disks. Typical in automotive use is 2mm wear in thickness (example: new 24mm, worn out 22mm).

Bye for now Fred
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Could be. Could be both? I'm happily ignorent as I've never worn out a disk amazingly, even after 100k km as I don't track, use soft pads and plan my driving...

There should be a spec somewhere, the OE disks are very thick so I expect there to be quite some wear allowed, more than 2mm??

Edit: that what speaks against Freds statement is that the grooves have a cast surface (already there in the mold) while the remainder of the disk outer edge is machined, if it were balancing I'd expect the grooves in particular to be machined...
 
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At £900 a pair I'm hoping the disks last a fair few miles!

Since the nice weather I've been driving more with the windows down and have noticed a lot more brake pad smell (well I hope that's what it is, not clutch)

I think mine's on its first set on pads at 5,500 but not an awful lot left. I am expecting Toyota to recommend changing when its in for the 6,000 as they likely won't last to 12,000 (though I'll likely decline and do them myself when the light comes on. There is a light, isn't there?

5+ sets in 8,000 miles is a lot, though thinking about it I used a set on a track day in a BX GTi many moons ago so if you've done a few trackdays that makes sense
 
I saw that Roetheli racing found some interresting front discs. Better inside cooling, cheaper than oem ones and 2 kg !!!!! lighter per piece.
I really think about compensate heavier wheels with lighter brake discs as light wheels are very expensive and hard to tüv (thats not really a verb) in germany
 
I have a set of front pads and discs, 3500 miles road use only. If anyone is interested I will send photos and measurements assuming that is possible here?
 
Hi.
i am on my 4 th set of front disc pads with 4800 moles on the clock. I have the same wear on the outer edge of the disc. I have asked Toyota that it’s not right and they have said the you have used the car on the track. I went to Litchfield for some other work on my car and I asked there opinion and they said that the disc do not last to long. The wear is do to track use and hard braking. I will get Litchfield to replace my disc soon.
 
Tralien said:
I saw that Roetheli racing found some interresting front discs. Better inside cooling, cheaper than oem ones and 2 kg !!!!! lighter per piece.
I really think about compensate heavier wheels with lighter brake discs as light wheels are very expensive and hard to tüv (thats not really a verb) in germany
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Lighter disks is certainly a way to go, although they will automatically have less heat capacity (less material) and thus peak higher in temperature, and wear out quicker as they will be thinner. Both can be (partly) compensated if cooling is better due to less material in the middle. And if they are cheaper then the OEM, it's definitely win-win.

Also don't forget tyre weight, even more important as on biggest radius. Usually the better sport tyres coincide with the lighter tyres... Still difference can 2kg between good and 'bad' tyres. Tyrereviews nowadays publishes tyre weights in their reviews, sometimes can also be found on manufacturer websites or on vendor sites such as Camskill or tirerack.
 
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Onehp said:
Lighter disks is certainly a way to go, although they will automatically have less heat capacity (less material) and thus peak higher in temperature, and wear out quicker as they will be thinner. Both can be (partly) compensated if cooling is better due to less material in the middle. And if they are cheaper then the OEM, it's definitely win-win.

Also don't forget tyre weight, even more important as on biggest radius. Usually the better sport tyres coincide with the lighter tyres... Still difference can 2kg between good and 'bad' tyres. Tyrereviews nowadays publishes tyre weights in their reviews, sometimes can also be found on manufacturer websites or on vendor sites such as Camskill or tirerack.
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Tyre wight is a big variable. I had some 18” nankang ns2r from another car and were a lot heavier than the PS4s on the scales. Can’t remember the figure now but 2 or 4 kgs rings a bell.
 
So if heat capacity is the issue use tungsten brake discs (only joking)!
 
The real issue is surely the dynamic performance of the pad material, disc, unsprung weight, etc. Singling out just one variable is unhelpful unless it is the most important variable.
 
Changed my first set of pads at 22K miles. Still on original discs. I've done a season of sprinting and a half track day on mine. The majority is of course road mileage where the brakes don't get used that much in daily driving for work.
 
I only like thin spoke black wheels irl if they show off the big brakes behind them. Cars without nice brakes or busy/covering wheel designs don't look good in black imho. On a positive note, the oem pads don't seem to dust very brown...
 
Onehp said:
I only like thin spoke black wheels irl if they show off the big brakes behind them. Cars without nice brakes or busy/covering wheel designs don't look good in black imho. On a positive note, the oem pads don't seem to dust very brown...
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but they do seem to dust a lot!
 
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