75 plate Karoq SE 1.5 tsi

Petrol

8266 mileage

PCP

I was getting some intermittent funky sounds from the car recently and long story short the front drivers brake disc was found to be 30% worn. As we’re about to go on a two week driving-heavy holiday I had it replaced so am now £450 lighter and absolutely fuming about the whole thing!!!! I’ve only had the car since September! Am I being totally unreasonable to think this is effing ridiculous at this point in ownership??

This is my 3rd karoq:

1st one no disc issues;

2nd one both front discs replaced at 3.5yrs.

Some people on here have really decent mileage and are STILL on their original discs so what the heck is going on with my current car? And just the one disc which is so weird to me. I’m still living on the same house, doing the same commute etc as I was with the other cars so I just don’t understand what’s caused this? I cannot afford to be forking out for discs left right and centre! Argh!

“30% worn” is not a valid reason to replace brake discs. It also does not mean braking efficiency has fallen by 30%. Disc thickness has relatively little effect on the braking torque available in an ordinary stop. That is determined mainly by hydraulic pressure, caliper clamping force, pad friction, disc radius and tyre grip. A disc can therefore continue to produce normal braking force while substantially worn.

Manufacturers specify an absolute minimum thickness. For example:

new disc: 25.0 mm

minimum thickness: 23.0 mm

measured thickness: 24.4 mm

Such a disc has lost only 0.6 mm, but it has used 30% of its permitted wear allowance. It still has 70% of its usable wear remaining. Replacing it solely on that basis would be premature.

In such a case I would ask the garage to provide three figures:

the original nominal thickness;

the manufacturer’s minimum thickness;

the actual measured thickness of each disc.

Edited 4 hours ago4 hr by mumpsim
typo

Generally one disc wearing excessively compared to the other side suggests that the pads could be sticking.