R26 Front discs

Discussion in 'Suspension, Brakes, Wheels & Tyres section' started by Steve Rawlinson, Jan 17, 2020.

  1. My OEM disks cracked around the holes after two track days and since then I've been using Brembo HC. I'm very happy with the braking performance but less happy about their tendency to warp.

    (Now when I say warp I do not mean literally warping the disc. I mean juddering under hard breaking for what might be a variety of reasons. Swapping the discs cures it. I am extremely careful with the bedding in procedure and cooling down lap. Even If I come off for a red flag I keep the car moving slowly for a few minutes.)

    I don't want to go back to OEM drilled but there's an OEM plain that appears to be for ph1 225 non-cup models. Any reason they won't work?

    Any other options?
     
  2. non at all, reason drilled fail is temp around holes is different to rest of disk and iron just cracks to accommodate
    plus plain offers more surface area for pad to grab onto but also retains heat longer
     
  3. ianplymouth

    ianplymouth RSM Club Member

    Upgrade to a 250 setup Steve, you won't look back and pads are cheaper as well.
     
  4. I’ve replaced mine all round for solid rather than the drilled, been running them over a year with no issues
     
    Steve Rawlinson likes this.
  5. ianplymouth

    ianplymouth RSM Club Member

    I ran plain 250 disc's and calipers on my 225 they were stunning
     
  6. Yeah but you have to get discs drilled every time!
     
  7. ianplymouth

    ianplymouth RSM Club Member

    Mine lasted ages, well worth the mod ask Chris P
     
  8. I had same issue and everyone suggested the 250 brake conversion but that seemed an expensive fix so I removed front fogs and put venting to the brakes. Also use EBC blue pads which are some of the cheapest cos everyone hates EBC.
    Zero issues since. Job done ;-)
     
  9. completely agree, its cooling that lets these megs down and folks just keep upgrading to stronger disc/pad/fluid when in fact with bit cooling standard brake system not half bad
     
    eddie ninja likes this.
  10. What pads are you running? It could be no fault of the disc as the ‘warped’ feeling is most likely to be due to uneven deposits of pad material. Excessive heat still in the disc when the brakes are applied whilst stationary can lead to this and will be worse if using a pad material that isn’t designed for the high temps seen during track use.

    An issue may I had with an old car (and to be fair I don’t think it’s the same as yours) was excessive hub face runout causing the disc to sit unevenly. At first, the brakes were fine, but after about 2000 road miles, a judder would start to creep in that only got worse. Like you, new discs would temporarily cure it. It might be worth running a dial gauge round the hub face, and mounted disc to make sure the tolerances are as they should be.


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  11. I'm using DS1.11s. Per my first post I'm extremely careful with cooling the discs before stopping the car.

    The hub face is an interesting one. I will definitely get that checked. Why do new discs cure that temporarily?
     
  12. i think its deposit build up on the disks.It was always worse on plain brembos than drilled.
    I have probally the best brake cooling of any R26,but they still have to be managed when raping the brakes to stop judder.
     
  13. pad deposit build up..
     
  14. The new discs still had excessive (outside of manufacturer’s tolerance) runout when fitted, but it wasn’t detectable under braking. As time went on, the pads were depositing material on the ‘high’ spots on the disc, and gradually the judder would start to become noticeable through the steering wheel / brake pedal.

    Unfortunately because I sold the car not long after (and bought the Megane!) I couldn’t tell you what kind of values I was seeing vs what they should be on a car with no issues, but I’m sure someone will have something to work from posted on the net.


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