Early Tonti Front Disc Brakes

[Groover]

Seems they come apart vs the later Brembo one piece ones. Are the earlier ones better, as in more flexible. Can you replace the actual disc part keeping the "basket"? Which would you pick if you were doing sort of an older G5 build with parts from the late 70's early 80's keeping somewhat OEM parts/look. I think the two parts ones mostly came on the Converts? Not sure, let me know what the pros and cons are, and which wheel types they fit - (spoke, mag)


Thanks for the help.

[Antietam Classic Cycle]

I like the two piece discs - they're a bit lighter and look cool.  Yes, the disc part can be replaced and the "basket" retained. They fit either type of wheel.

[Groover]

Thank you Charlie, the answer I was hoping for. Thanks again.

[n3303j]

I installed the stainless disk rotors on my T3 after I wore out the original cast iron (one piece) rotors. Couldnt find quality aftermarket cast iron rotors. I feel that the OEM cast iron rotors provided smoother application progression and greater stopping power for a given lever pressure (HH Pads) than the stainless rotors.

[PeteS]

Years ago I notice the brakes were pulsing on my 850 LeMans. Checking with a dial indicator showed they weren’t warped, rather the thickness varied. I had the disks and backing plate blanchard ground and they have been perfect since.
I believe cast iron is more stable and stops better than stainless.

Pete

[73 sport]

      Sintered brake shoes and pads are extremely efficient stoppers. They are also extremely efficient destroyers of drums and discs. We used them on our race cars and tow cars in the late '60s, we replaced drums about every 18 months.

[n3303j]

Years ago I notice the brakes were pulsing on my 850 LeMans. Checking with a dial indicator showed they weren’t warped, rather the thickness varied. I had the disks and backing plate blanchard ground and they have been perfect since.
I believe cast iron is more stable and stops better than stainless.

Pete

"Good cast iron" is better. I got some aftermarket cast iron rotors that were poorly made and alloyed. They had hard spots in the surface. As a result the turned surfaces were of inconsistent thickness and texture.

[John A]

In the rain the difference between cast and stainless is more noticeable, at least on Guzzi brakes. The cast iron seems to start working sooner than the stainless. ‘ Snot enough to make much difference to me except it might be easier to overbrake initially in the wet with the cast. Edit: I think the cast are more consistent in the rain.

[PeteS]

From experience turning requires taking deeper cuts than grinding on hard metals. You need an ultra sharp tool to remove say .003” or it just skips. With grinding you can take as little as .001” per pass.
As for sintered pads, they work but they turned the disks on my EV into a pretzel in 30k miles plus I don’t think they are recommended on cast iron.

Pete

[n3303j]

From experience turning requires taking deeper cuts than grinding on hard metals. You need an ultra sharp tool to remove say .003” or it just skips. With grinding you can take as little as .001” per pass.
As for sintered pads, they work but they turned the disks on my EV into a pretzel in 30k miles plus I don’t think they are recommended on cast iron.

Pete

Machining the rotor wasn't the issue. Many are lathe turned from the factory. But if you have a casting made from old Chevy blocks,, bath tubs, tire chains and fire hydrants and care isn't taken in getting a complete mix there is a real chance that there will be hard inclusions in the finished product. When a lathe cutting tool hits the hard spot it deflects and often chatters. This leaves high and rough spots that will cause brake pulsing.
If the disks are ground the harder inclusions will grind flush with the surface. The disks will work great when new. But they will wear unevenly in use because of harder sections in the disk. They will pulse more and more as they age.

[Grounded45]

From experience turning requires taking deeper cuts than grinding on hard metals. You need an ultra sharp tool to remove say .003” or it just skips. With grinding you can take as little as .001” per pass.
As for sintered pads, they work but they turned the disks on my EV into a pretzel in 30k miles plus I don’t think they are recommended on cast iron.

Pete

Hi Pete! Sintered pads are definitely NOT recommended for cast iron rotors.