Brake disc specs?

[drewski]

Hi Dave,

I did not use longer bolts... I checked and IIRC, they threaded in 13 - 14 turns, which came out to 1.4 - 1.5 times the diameter.

A couple things that I'm a bit concerned with...

- After bedding in the pads per Carbotech (multiple hard stops, and multiple moderate stops), I noticed a lip on the outer front rotors. I did not expect that. It is not huge, but it is noticeable. There is definitely more bite with these, but I'd hate to eat through the rotors that quick.

- The rear pads had some sort of pin cast into the back plates of the pads. There was one on each pad and it was not centered. If I installed like that, the pads would be slightly angled. I decided to file each of them down so that they would be flush with the piston. I also reused the thin plates that were glued to the rear pads... not sure if I needed to or should have.

Lmk what you think.

Thanks.

which Carbotech pads are you using? AX6?

the 1521 compound will be more rotor friendly, but less aggressive stopping power.

 

[hcsharp]

- After bedding in the pads per Carbotech (multiple hard stops, and multiple moderate stops), I noticed a lip on the outer front rotors.

Are you sure you got a lip on the rotor? I've been driving with Dave's rotors for several years. It's my daily driver most of the year. I have no lip whatsoever on any of my 4 rotors. I'm using AX6 pads.

When my rotors first arrived they had what I call a "shipping coating" of black gritty material. This wore off the first time I hit the brakes hard. I think it's there to help bed the pads. Maybe Dave can speak more to the purpose of the black material. Perhaps that is what your lip is composed of? If so, don't worry, it won't be there long and your underlying rotors will show far less wear than the OEM rotors.

 

[hanknum]

I go with 2 diameters for the bolt engagement, I have 75mm bolts I had made for a big rotor kit I made for Lotus Elise/Exige cars if you want longer bolts for peace of mind.

Don't worry about a little overhang on the pad going past the outside diameter of the rotor, it's pretty normal for these cars.

The rear calipers are a single piston with a sliding bracket, it's common for manufactures to create a wedge shape on the backing pad to counteract the tendency for the pads to wear in a wedge shape. This allows the pad to wear down to the back plate with consistent pad material.

Probably not a bad idea to go 2 diameters... let me solve the chatter first, then I'll address the bolt length.

The pads actually sit fully on the rotor, so I will have a slight lip on the outer edge of the rotor, not the other way around.

Too late on the on the pin, they have been filed down. What do you think about including the thin plate/shim on the rear pads? I know it is kind of lame, but it does say Brembo on it .

 

[hanknum]

which Carbotech pads are you using? AX6?

the 1521 compound will be more rotor friendly, but less aggressive stopping power.

I got the AX6... and figured they would wear the rotors more quickly, but wanted the best braking possible.

Are you sure you got a lip on the rotor? I've been driving with Dave's rotors for several years. It's my daily driver most of the year. I have no lip whatsoever on any of my 4 rotors. I'm using AX6 pads.

When my rotors first arrived they had what I call a "shipping coating" of black gritty material. This wore off the first time I hit the brakes hard. I think it's there to help bed the pads. Maybe Dave can speak more to the purpose of the black material. Perhaps that is what your lip is composed of? If so, don't worry, it won't be there long and your underlying rotors will show far less wear than the OEM rotors.

Might be a bit of an illusion. It does feel like a minute lip on the outer edge, but I don't feel anything discernable on the inner part of the rotor... I can see where the contact area is on the rotor. And, I'm using OEM rotors, not TiDave's.

 

[X.l.r.8]

Mine have an outside lip (EBC's and stock rotors) making the rear caliper removal a bit harder than just rotating it backwards. I also have 150k KM on them though.

 

[Gabner]

I just replaced the seals for the sliding pins on rear Brembo calipers with replacements I got from Lotus Parts. Work like a charm. Also, installed EBC Yellow pads - Front and Rear which are spec'd for both Lotus Elise and Tesla Roadster. I used the yellows because they have excellent stopping power when cold. My brakes are almost always cold.

Did you consider the carbotech 1521 brake pads?

In Seattle I can expect mostly cold and wet.

 

[da2ny]

Did you consider the carbotech 1521 brake pads?

In Seattle I can expect mostly cold and wet.

Unfortunately in socal we don't deal with wet. I've used the EBC Yellows for years on on my 76 Jag as well. Very happy with them. Never tried the carbotech.

 

[X.l.r.8]

The g-loc gs1’s are the same as 1521. I got mine from here.

The problem with the damp climate is the disc will rust daily. The stock pads are not good with the disc’s. So any change will be better, new pads will work better with the disc’s, but the instant rusting will only come with new disc’s. Pads are a good easy consumable to start with, it makes a huge difference, but if keeping stock discs I would go yellow’s, they work great in all conditions.
“For G-loc the GP109L and the GP491 L is the correct pad for your car.”

 

[Gabner]

I'm changing all the brake pads but I was only going to replace the rear rotor set that was damaged. (I had a pad fall out and it's grooved pretty good.)

Maybe I should change the front rotors as well? They are undamaged.
Would you expect any better performance or less rust with the EBC USR1070 rotors vs stock?

Thanks for the feedback!

 

[hcsharp]

Did you consider the carbotech 1521 brake pads?

In Seattle I can expect mostly cold and wet.

I'm using Carbotech AX6. They're performance is impressive, way better than OEM pads. Strong, aggressive grip, minimal dust, no squeal. If I was doing it again I would probably try the 1521 compound because it's likely to work better in cold weather. What I've heard from people who've used both AX6 and 1521 is that the 1521 is slightly better in cold climates while remaining quite strong when hot. They may not hold up as well as the AX6 in extreme heat like you would get if you track the car.

If you're in Seattle I would highly recommend Titanium Dave's rotors. I'm pretty sure that's what Carl Medlock is selling. Those rotors are especially good for EVs because they are coated with a material that substantially reduces rust.

 

[Gabner]

I've looked at those beautiful rotors more then once on Carl's site. They are impressive and the no rust thing would be really nice. Ultimately i need a more budget friendly option right now.

I would really like Carl do the suspension upgrade so I need to save my pennies.

How do you like your titanium Dave rotors?