Uneven Wear

Here are a couple of pics of uneven wear on my race bike front brake pads just to show how bad it gets under load. 2 x sets in six months
Ludwig has supplied info on how to get around this problem which is covered in older threads
New set on the right as a comparison Vesrah VD 904 NRQ
Regards Mike

You think that this wear is a problem :?: - its nothing compared to the 70s Hondas with their man adjustable calipers they were horrendous :!:
Lockheed/Girlng thought they had cured the pad wear taper with their 4 pot calipers, but not quite :!:

Even though the action of the caliper pistons is linear, there's nothing keeping the leading edge of the pads from being sucked onto the rotor as it turns with the result being uneven wear. It likely adds to braking power up to the point where the pad can no longer rotate axially, like the leading shoe on a drum brake. I have seen uneven wear on 4- and 6-piston caliper brake pads at their leading edges.

I have noticed this on my road bike as well, many, many years of use though, and certainly not under brutal racing conditions. Don't cringe now, but I just swap them in the caliper.

I had a wedged wear pattern with a Lockheed racing caliper and a single Norvil floating rotor on a relatively heavy Norton Commando road racer. The higher wear was on the outside radius rather than the leading edge. I never could determine what was the cause and reasoned either the caliber was bowing under pressure (I had an aggressive hydraulic ratio) or speed and swept area difference between the inner and outer radius.

This wear manifested itself quickly. It was problematic in that it resulted in lost motion at the brake lever.

The bike was a relatively heavy Commando and I was heavy; what I did not have in speed I made up for in braking hard. I suspect the brake system was at its' limits.

When i put in the new set, I get about 2 or 3 race meets out of them and then start to get brake fade and loss of lever pressure at the start of its travel, needs a few pumps to get it to come right , not the greatest feeling at race pace!
Dances, sent you a reply to your PM
Regards Mike
PS Vesrah pads getting harder to find these days, not listed on their website that I can find

Hi Mike. it is a common problem in the auto field. You cant predict how pads will wear in most vehicles although, because of the design, the Norton pads are predictable. What you are experiencing is normal. Most auto makers have pads made that suit the disk . The ends are cut radially and the pads are roughly kidney shaped. The outer diameter of the discs is bigger so naturally it will wear away the out section of pad quicker unless it is correspondingly bigger. The Norton pads are round,. This means the outer and the inner portion of the pads will wear quicker, causing a slight convex effect. This is what causes your brake fade or sponginess because the pads want to bend.
From your description,. i would recommend you change your pads every 1-2 race meetings. Most professional racers will use better brakes or change the pads every meeting i would think.
Dereck

ps have you fitted that Iwis rear chain yet

Hi Dereck, will try with the modified pistons to see how it goes.
No need to fit the IWIS chain as the REGINA one I am using gets a hot dip in a Putoline grease pot after every race meet and is lasting well.
Regards Mike

Mike, are you limited to the Norton caliper by the rules?

Biscuit said:

I have noticed this on my road bike as well, many, many years of use though, and certainly not under brutal racing conditions. Don't cringe now, but I just swap them in the caliper.

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Doesn’t work in my experience as the brake then “stick on” when it comes close to the disc, that is until you wear the pads round the other way :shock:

Danno said:

Even though the action of the caliper pistons is linear, there's nothing keeping the leading edge of the pads from being sucked onto the rotor as it turns with the result being uneven wear. It likely adds to braking power up to the point where the pad can no longer rotate axially, like the leading shoe on a drum brake. I have seen uneven wear on 4- and 6-piston caliper brake pads at their leading edges.

Click to expand...

No surprises there

Hi Nigel,I could put on one or two discs from Grimeca or even Norvil after market set up, just have to be 2 x pistons max, ie one either side to stay in class.
Also non floating caliper or disc.
Im trying to stick to the original if possible and when the pads are new it works great.
Rear brake is still a drum and the brake pedal is only somewhere to rest my foot as pretty ineffective although good in the pits!!!
Regards Mike

Brooking 850 said:

Hi Nigel,I could put on one or two discs from Grimeca or even Norvil after market set up, just have to be 2 x pistons max, ie one either side to stay in class.
Also non floating caliper or disc.
Im trying to stick to the original if possible and when the pads are new it works great.
Rear brake is still a drum and the brake pedal is only somewhere to rest my foot as pretty ineffective although good in the pits!!!
Regards Mike

Click to expand...

Fairy Nuff Mike,

'To each his own' of course... but it seems to me you are expending a lot of mental and physical energy on that Norton caliper...!

I'd have it on ebay, and a nice new AP Lockheed caliper on the bike (with EBC pads) in the blink of an eye!

Hi Nigel true enough, if I do go to the twin front disc's and calipers, might as well go to a rear disc as well.

Regards Mike