Brake lever feel

the_gooch · 09-11-2012, 12:03 PM

Did my first track day on the S1 the other day. Throughout the day I noticed a different feel in the lever during different times in the session.

Sometimes the first 1mm or 2mm of travel and the brakes would really bite. Other times it seems they were more progressive and required a little more travel of the lever to bite.

This did not coincide with the bite being there at the beginning of the session and fading off at the end. It could be softer at some points and firmer others. Sometimes corner to corner.

Bike only has 1200 miles on it so it shouldn't be pads or fluid.

Maybe the lines need to be bled??? Anyone else experience the same?

How is the bleed process with the ABS module anyway?

**1000RR** · 09-11-2012, 12:55 PM

Bleeding the brakes is the same process as a non-ABS bike...

As for the brake fade and inconsistency you experienced, my guess is it is just the pads. For better consistency and less brake fade, go with a trackday or race pad for when you're at the track. You could certainly bleed/flush/change your fluid which you should after the first year anyway, but my guess is you'll have better results with a different pad choice.

kismetcapitan · 09-11-2012, 01:14 PM

under heavy use, like on a track, brake feel changes. even with racing brake fluid, it changes. that's why there are remote brake lever adjusters on race bikes.

tie your brake lever down every night; it helps squeeze out bubbles that even the most meticulous bleed misses, and minimizes this effect.

but it's something you'll always deal with, no matter how good the brake system is. if the MotoGP guys with their megabuck brake systems are having to adjust their levers due to more "mush" in a 45min race, you'll inevitable have to as well.

**1000RR** · 09-11-2012, 02:34 PM

True on the brake adjuster... that said a good set of pads designed for the track will make a WORLD of difference. That said, just be aware that these same pads likely won't work near as well on the street as they do need some heat to work their best.

AK1 · 09-11-2012, 04:57 PM

I had the same scenario during my first track day. I bled the brakes with Motul RBF600 and changed to SBS Dual Carbon 870DC track pads. It still happened on the next track day, but not as bad since I didn't have to brake as hard. The real problem is the brake lever, need to upgrade to Brembo or Accossato brake lever.

the_gooch · 09-12-2012, 08:45 AM

Quote:

Originally Posted by AK1

I had the same scenario during my first track day. I bled the brakes with Motul RBF600 and changed to SBS Dual Carbon 870DC track pads. It still happened on the next track day, but not as bad since I didn't have to brake as hard. The real problem is the brake lever, need to upgrade to Brembo or Accossato brake lever.

You mean master cylinder, correct?

AK1 · 09-12-2012, 04:04 PM

Quote:

Originally Posted by the_gooch

You mean master cylinder, correct?

Yeah

I couldn't figure it out the other day...

Borrowedbike · 09-12-2012, 11:55 PM

Quote:

Originally Posted by kismetcapitan

tie your brake lever down every night; it helps squeeze out bubbles that even the most meticulous bleed misses, and minimizes this effect.

+1

If you are not doing this try it. Huge difference on the S1k. Not sure why it's so pronounced on this bike.

DrD · 09-13-2012, 01:18 AM

I also notice how my front brake level will drop into the bar further. It seem to coincide with brake and system temperatures.
It's normal when the brake pads and calipers heat up, the fluid will expand. I think it might also have something to do with the fact they're linked front to rear also. The ABS control module is always monitoring and adjusting pressure for the linked brakes. Mine has a tendency to change back to normal after the bike sits and everything cools off. It's never been a problem, but my 08CBR1K never was effected like this one is. They're not linked or ABS equipped on the CBR.

Just my observation

I might bleed the system at the next service and see if it changes.

M-Coupe99 · 12-10-2012, 03:15 PM

I'm always interested in hearing about the change in brake lever feel on the ABS models when ridden at the track. Read about some levels of observed brake fade or lever movement in various magazine track riding comparisons as well.

My bike is a base model (no ABS or DTC) and I've never experienced a noticeable difference in the brake lever feel while riding at the track. For reference, I'm using the stock (Brembo) pads and stock (BMW dealership provided) brake fluid, riding in the advanced/expert level (bottom 1/3 pace), last set of brake pads lasted about 8 track days, my weight in full gear is ~155 lbs.