New Brake Disc Warning

EVguru · Post by **EVguru** » 17 Mar 2007 10:17

Since there has been some discussion about discs and some may go for the remanufactured (by Grimeca) discs that NLM have avalable, I thought I'd post a little warning.

I bought a new disc for my 250 for Stewart, along with the soft NewFren pads they recommend. The discs come with quite a rough ground finish and need to run in to form an almost mirror like running surface. At the time I was using the bike more or less every day and the disc was starting to bed in nicely. However I was riding in the wet (sometimes VERY wet) and noticed that the brake would start squealing, and continue to do so after it was dry.

What seemed to be happening is that the rough disc surface would allow dirt under the pad and this would then score the disc surface. I would have to take the pads out on remove the imbedded material. Now that the disc is bedded in (apart fron the score marks) it doesn't seem to be a problem.

So it seems 'Don't run the brakes in, in the wet!'

After they are fully run in and ONLY then, you can run scintered pads if you feel the need.

Brubru · Post by **Brubru** » 21 Mar 2007 11:41

Thanks for the info Paul,

I understand a bit better what happened when I replaced the three discs some years ago by new ones from NLM. The two front ones soon became mirror-like, as you say, but the rear one got deeply scratched almost as quickly. It appeared that it was due to the sintered pads I had on the back. Strangely enough, the same pads had caused no problem on the old disc. From what I read from you, it might have been because the old one was already run in when I started using sintered pads.

Anyway, this confirms you should take care with new discs, you might as well destroy them if using the wrong material.

Bruno

3narf · Post by **3narf** » 30 Apr 2007 12:20

I think the discs are cast iron, aren't they? The old ones were.

I had the chrome stripped off mine- it's only cosmetic anyway. They get a bit rusty overnight, but who cares if it improves the braking?

EVguru · Post by **EVguru** » 30 Apr 2007 15:02

Look at the holes around the hub.

The edges are sharp, no way were they cast, they're stamped.