Sorry if you misunderstood my intent. Yes, decelerating to the apex is always faster if done properly. I was primarily trying to say that driving a more circular entry to the apex at the limit (working on entry car control skill) is going to be faster and better for learning than "trail braking" at 90 percent (well under the limit with a slower apex speed, but your driver inputs and line "looks" correct.)

I think I should avoid any "erring on the side of" talk as it gets misconstrued too easily as a recommendation.

 

I can't believe how many posts and articles I've read and see about trail braking...so many of them written to confuse the driver vs nice and simple info.

As a newer driver, if you focus so much on trail braking you will 100% guaranteed over slow the corner.

Focus on entry speed, if you can't make the turn with hard braking, you went too deep before braking
Back up the zone until hard braking allows you to lift off brake and still make the turn
Get off the brakes and focus on mid corner speed...let the tire do it's job and turn the car...it will handle way more velocity than you think without spinning the car.
Then work on getting back to throttle as soon as you can without crashing the car.

The trailbrake will happen all on it's own when you go deep enough to require you to hold the pedal long enough to turn and still make the corner.

Sooooo more time spent working on mid corner speed will yield better results than obsessing on trail braking and thereby over slowing the corner.

 

The best discussion of this is in Carl Lopez's book, "Going Faster."

Few drivers brake consistently enough to gauge the proper brake zone, let alone move it in as needed.

 

I remember talking with a pro at WG who was coaching there. When I asked him the biggest difference between good pros and good amateurs, he said it was in braking, starting with choosing the brake point initiation and continuing into modulation of brake pressure through corner entry.

 

For me, the best discussion is in Adam's books!

 

The good thing about modern cars mostly all having ABS is it resolves a lot of the braking pressure issues...just stand on them! Helps with heel/toe as well on manuals as it can trick the brakes if you aren't consistently full pressure...just brake later and stand on the ABS

 

I generally regard ABS activation as a mistake. A few pulses for the rear in a bumpy braking zone is fine - regularly getting into the ABS is not as it upsets the car too much.

Trailbraking and abs go together like orange juice and toothpaste.

-Mike

 

Agreed. Far better to properly modulate brake pressure and stay out of ABS. Moreover, when I initially was using too much ABS with my GT3, I found that the ABS was generating a lot of extra heat and boiling the SRF.

 

Change braking to slowing and I think it's completely accurate. Braking is the majority of it, but the final nuance is in steering inputs (in my experience).

 

Change braking to slowing and I think it's completely accurate. Braking is the majority of it, but the final nuance is in steering inputs (in my experience).

 

Depends on the car...the BMW i'm racing now the ABS is a nightmare but other cars I have found it to be totally fine and very helpful especially with the heel/toe pressure

 

Manifold, that pro whoever it was nailed it.

I'm not a fan of street car ABS on track. But a full race system such as in the 996 Cup or from Teves or Bosch which is often added to 997 and 991 cups can be a real competitive advantage when used properly

 

It really depends on how old a system you're talking. You won't beat a modern ABS controller in stopping distances. A lot of what you see in race applications was developed from the street car application. ABS is 100% a competitive advantage....if is was tuned reasonably well. It will also provide a huge advantage in trail braking. It has independent wheel pressure control and what are we trying to actually achieve with trail braking? Yaw moment modification. The system can work each wheel to provide the driver desired yaw moment. The driver doesn't have enough control resolution to do that. At most, the driver has a brake bias adjuster and can move pressure on or off the rear axle, which provides an ability to affect the yaw moment of the vehicle during braking. The caveat to that is how much brake pressure the driver is requesting. You can't stand on the pedal, steer, and expect to make the apex. At some point the ABS system needs the driver to give it some tire capacity back to get the desired yaw output.

From an academic perspective I find looking at the yaw moment the more intuitive way to approach trail braking. Look at your 4 contact patches, relate the amount braking requested, the weight transfer, and consider how the slip angle will change and which during trail braking leads the driver trying to increase the rear slip angles in relation to the fronts.

 

Here is an idea for how to simplify the idea of trail braking in your head. Imagine taking a corner in a powered unicycle with brakes. We'll say it's electronically stabilized so you don't have to worry about falling over. This way you don't have to deal with all the car control stuff like balance, rotation, slip angle, etc... Just basic line optimization with one tire.

Would you still trail brake and would the line be the same as a car of equivalent performance?

 

Perhaps in a straight line ABS systems have improved compared to what I'm used to - a 20 year old BMW M3 with stock ABS.

However, in trail braking, I'm not worried about lockup. The concern is transferring too much weight off the rear wheels as I would like them to have enough lateral grip to avoid trying to swap ends with the front. Braking effort here is no where near enough to cause the ABS to trip.

I may be out in the weeds, but to me, and ABS system that is taking into account lateral grip and rotation isn't ABS that's traction control or PSM. In my car, all the ABS system does is prevent wheel lockup.

-Mike