Topic: Brake Fade

[bwaller]

It may be time to take another step in braking performance. At Barber, T5 is a heavy braking zone and I was told the binders were OK there but into the next zone he experienced enough fade that it eventually affected his entry speed because of lack of brake force. I told him to use the rear there too, but it was tongue in cheek as the rear drum is for show & nearly useless!

I had been using BelRay fluid, changing every year from a sealed container. This year I switched to BelRay racing fluid with a higher boiling point. Maybe sucked in by the name! I'm uncertain if it's a fluid issue, or mechanical but it'll be one focus before next season. As time went on I relied less on brakes and never had a fade issue. He's coming from a lightweight FZR with FZR1000 brakes and never felt my Brembo FO5's on lightened stock 275mm rotors were worth a damn.

I am (was) old school believing twin rotors up front won't try to "twist" 35mm forks but I do use a really good fork brace so now am wondering about slikwilli's set up with a single, larger diameter cast rotor and bigger caliper. I have plans to switch up the rear to possibly a TZ hub/disc setup. I need to replace all my alloy rear sprockets anyway. Lighter wheels/better brakes is the new goal. Several benefits involved.

What say you roadrace guys?

[slikwilli420]

How about a couple cast iron rotors, either RPE thinned down or some Brembo units with the F08 (instead of F05) calipers? You will get a bigger piston in the new calipers and more performance from the cast iron. Might need to get a new master to match the larger pistons. I went with Motul RBF660 fluid as the guy from Bevel Heaven recommended that over anything else. Any way to add a scoop to force air into the calipers? I will also be adding titanium spacers between piston and pad to eleviate heat transfer to the fluid from braking. That's and autocross trick I heard about.

[turboguzzi]

Brent, what pads do you use theses days? i'm totally sold on brembo SC compund....

They dont make pads for the older calipers with it, so i buy GSXR SC pads and cut them to fit the 05 or 08 calipers. not that hard.

[bwaller]

TG, I still use the Ferodo 207P (organic) I always felt they were adequate, plus lacked that initial bite for ease of trail braking. I didn't like the race pads for that reason.

Tyler complained after that hard braking area he couldn't get enough lever next time he needed them (10 seconds later maybe), no matter how much he pumped it. The rest of a lap-no problem, I suspect they cooled enough. Fluid issue???

When he came in they were damn hot indeed.

[Captain]

 Deleted

[bwaller]

??

[turboguzzi]

well, discs act also as heat sinks, if two braking zones come in close succession, light and thin discs dont have the time to cool and / or the capacity to store the heat.

Nevertheless, pads that are more heat resistant could help, i really suggest that you give my idea a try

[livefast_dieold]

TG, I still use the Ferodo 207P (organic) I always felt they were adequate, plus lacked that initial bite for ease of trail braking. I didn't like the race pads for that reason.

Tyler complained after that hard braking area he couldn't get enough lever next time he needed them (10 seconds later maybe), no matter how much he pumped it. The rest of a lap-no problem, I suspect they cooled enough. Fluid issue???

When he came in they were damn hot indeed.

Sound like fluid issue. I had fading with organic compound, but the lever was working as usual

[scottly]

am wondering about slikwilli's set up with a single, larger diameter cast rotor and bigger caliper.

I've been thinking along the same lines, using a Ducati 320mm rotor with a 30mm twin-piston Honda caliper. I've acquired most of the parts, thanks to Tweakin and 754, and have been working on adapters so I can test with both 297mm rotors and 320mm rotors.
I started by measuring how much G-force my current dual Yamaha 297mm with K7 42.8mm calipers could make: -.75 G's was as much as I felt comfortable doing, although higher numbers may have been possible. (Better make sure the bike is straight up and there isn't a grain of sand on the road. )
Next, I removed one caliper, and the best I could do was -.68 G.
I've since fitted a 295mm iron rotor with a K7 caliper, but have yet to test it with the accelerometer..   

[scottly]

Tyler complained after that hard braking area he couldn't get enough lever next time he needed them (10 seconds later maybe), no matter how much he pumped it. The rest of a lap-no problem, I suspect they cooled enough. Fluid issue???

Not getting enough lever makes me think you may have some air in the calipers, especially since it became a problem after changing fluid.. BTW, what size pistons do the F05 calipers have? What size MC are you using?
I did a test with an iron rotor and a K7 caliper/MC, and got a reading of -.71 G. These measurements are relative, not absolute, and were obtained using a G-tech device.