Trail braking and lean angle

[slylos]

Hi everyone - super beginner question: in the context of trail braking and lean angle: as you start to turn in and you start trailing off the brakes, is it safe then to add more brake pressure if you realize you're too hot into the turn? I ask the question assuming the answer is "yes to a degree" but it allows me to ensure we're on the same page for my next question.

This is my question: if you turn in and realize you're going too fast so you add some more pressure, what option is left if you're still going too fast and now you're leaned pretty far over and know you can't brake too much more or you'll lose the front? Do you just give up your line and let the bike drift out or is there something else to trail braking as a way to continue reducing speed that I am not aware of? Thanks for entertaining super beginner question!

[Hotfoot]

Basically, no, it is not ok to just add more braking if you are "too hot" into a turn and leaned way over, it would be a very dicey and delicate operation with a high likelihood of losing the front, it is VERY easy to blow past the traction limit or run out of ground clearance (hitting hard parts on the bike) doing that. Brakes should be tapering off as lean angle is increased, not the other way around.

Yes, you will have to give up your line; if you are fully leaned into the corner and realize your entry speed was too high, it's too late to salvage your line. You will need to either let the bike run wide (if the entry speed error is small) or if it is way too high you will have to stand the bike up, brake hard, and slow it down as much as possible, then steer it again (at a new reduced speed requiring less lean and hopefully make the turn) or run off (after having slowed down as much as possible first).

If you are getting into turns and not realizing your are too fast until you are already leaned over, it sounds like you might be riding over your head. A review of A Twist of the Wrist II book or movie to discover how to choose a turn point, how to set entry speed, and visual skills (when exactly to look into the corner and WHERE exactly to look) would help a great deal. If you are relying on trail braking to correct too-high entry speed errors, you are approaching things backwards - a better strategy would be to do some no-brakes practice to get your entry speed under control FIRST, then add trail braking (to allow for a later braking zone) once the other skills are in place. Using the brakes while leaned over is a skill that requires a very good foundation of skills - knowing how to choose a line, where to look and when, and a good ability to judge entry speed. Without those foundations, trying to use heavy trail braking to adjust entry speed while already near max lean is a tricky business. 

[faffi]

Follow what Hotfoot says. Adding lean and brake is probably as ill advised as adding lean and throttle.

At 35 degrees of lean, you have about 80% grip left for braking, IIRC, whereas at 45 degrees it is rapidly closing in on zero. This is under ideal conditions; warm asphalt, warm and grippy tires and with a good rider not spending grip by holding on too tight and/or giving the bike confusing/harsh inputs, which also use chunks of your grip account.

 

[Hotfoot]

36 minutes ago, faffi said:

... and with a good rider not spending grip by holding on too tight and/or giving the bike confusing/harsh inputs, which also use chunks of your grip account.

 

Faffi adds an excellent point; a little stiffness in the arms (a common in-too-fast survival reaction) will restrict bar movement, add load to the front, and potentially add some countersteering input that leans the bike over farther which can VERY easily overload a front tire that is already near the traction limit.

Some braking references in Twist II that might help you (the OP) on info about leaned-over braking: Ch 24 Braking sections "Efficient Braking", "In-turn Brakes", "Crash Statistics", and "Brave or Smart".

Also the chapters in Section II on "Rider Input" and Section III on Steering and Lines would be good to review.

 

[slylos]

On 7/6/2020 at 2:51 PM, Hotfoot said:

Basically, no, it is not ok to just add more braking if you are "too hot" into a turn and leaned way over, it would be a very dicey and delicate operation with a high likelihood of losing the front, it is VERY easy to blow past the traction limit or run out of ground clearance (hitting hard parts on the bike) doing that. Brakes should be tapering off as lean angle is increased, not the other way around.

Yes, you will have to give up your line; if you are fully leaned into the corner and realize your entry speed was too high, it's too late to salvage your line. You will need to either let the bike run wide (if the entry speed error is small) or if it is way too high you will have to stand the bike up, brake hard, and slow it down as much as possible, then steer it again (at a new reduced speed requiring less lean and hopefully make the turn) or run off (after having slowed down as much as possible first).

If you are getting into turns and not realizing your are too fast until you are already leaned over, it sounds like you might be riding over your head. A review of A Twist of the Wrist II book or movie to discover how to choose a turn point, how to set entry speed, and visual skills (when exactly to look into the corner and WHERE exactly to look) would help a great deal. If you are relying on trail braking to correct too-high entry speed errors, you are approaching things backwards - a better strategy would be to do some no-brakes practice to get your entry speed under control FIRST, then add trail braking (to allow for a later braking zone) once the other skills are in place. Using the brakes while leaned over is a skill that requires a very good foundation of skills - knowing how to choose a line, where to look and when, and a good ability to judge entry speed. Without those foundations, trying to use heavy trail braking to adjust entry speed while already near max lean is a tricky business. 

Sorry I never got notifications for these replies but this is exactly what I needed so thanks tremendously!!

[slylos]

On 7/6/2020 at 6:35 PM, Hotfoot said:

Faffi adds an excellent point; a little stiffness in the arms (a common in-too-fast survival reaction) will restrict bar movement, add load to the front, and potentially add some countersteering input that leans the bike over farther which can VERY easily overload a front tire that is already near the traction limit.

Some braking references in Twist II that might help you (the OP) on info about leaned-over braking: Ch 24 Braking sections "Efficient Braking", "In-turn Brakes", "Crash Statistics", and "Brave or Smart".

Also the chapters in Section II on "Rider Input" and Section III on Steering and Lines would be good to review.

 

Excellent - I will look these up. Is it safe to say that I can use my knee as a lean angle gauge and if I touch and am still running wide that I've just got too much speed for the corner? 

[Hotfoot]

On 9/7/2020 at 7:22 PM, slylos said:

Excellent - I will look these up. Is it safe to say that I can use my knee as a lean angle gauge and if I touch and am still running wide that I've just got too much speed for the corner? 

You can use your knee as a lean angle gauge. If you are touching it and still running wide it probably does mean you have too much speed, but it doesn't necessarily mean that speed is the ONLY (or even the PRIMARY) problem, for you, in that corner. For example, if you had a bad line or poor body position that could contribute to excess lean angle and thus limit your possible speed through the corner. If you are running wide and you don't know why it is happening, it sounds to me (especially in light of your prior questions in this thread) that you are riding over your head and pushing too hard on corner entries. A better approach would be to slow the entry speed down a bit, get some training and build back up to the speed. 

Getting to school would be the best option but if that is not practical, do you have the "A Twist of the Wrist II" DVD? It is worth watching that to look at lines, throttle control and visuals skills, to find out causes for running wide. (If you don't have the DVD, it is also available for rent on Amazon Video.)

Question for you - if a rider were to turn in early for a corner, and/or steer the bike slowly, what would happen to the rider's line, and what would the rider have to do to correct it?