Does anyone know the facts as to why race drivers downshift twice before entering a corner on the track? I heel-n-toe myself but only do it once before a corner. I've always wondered why they downshift - say from 4th to 3rd, then again from 3rd down to 2nd before entering a corner. There must be a reason of doing twice the amount of work?

Is it because of the speed that the car is travelling, would be easier to shift to the next lower gear before downshifting to the optimal gear (next gear down again), for the corner? Easier on the tranny and keep the car more balanced perhaps?

Any race drivers out there and know the facts?

 

Its a preference.

Its easier for me to go 4-3-2 or 5-4-3, rather than 4-2 or 5-3 - less chance of zinging the motor to 11K.

 

I agree... go down through all the gears you need to shift through to get to the one you want to exit the corner. Less chance of busting stuff by a missed shift.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by .RJ &raquo;</TD></TR><TR><TD CLASS="quote">Its a preference.

Its easier for me to go 4-3-2 or 5-4-3, rather than 4-2 or 5-3 - less chance of zinging the motor to 11K.</TD></TR></TABLE>
yea i don't like skipping gears, i like going though all the gears...it's preference

 

I don't skip gears either. Especially on the 5-3 downshift where going into 1st @ 90MPH is very possible.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by .RJ &raquo;</TD></TR><TR><TD CLASS="quote">Its a preference.

</TD></TR></TABLE>

Most likely it's a sequential tranny....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by El Pollo Diablo &raquo;</TD></TR><TR><TD CLASS="quote">Most likely it's a sequential tranny....</TD></TR></TABLE>

Dont see alot of those

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by .RJ &raquo;</TD></TR><TR><TD CLASS="quote">

Dont see a lot of those </TD></TR></TABLE>

J00 do on TV...which is where [i'm assuming] that guy was watching them...

-out on a limb

 

I've always skipped gears when I dirve on the street autocross or track... but that is what I am comfortable doing in my car so I probably would not recomend that to anyone else...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by .RJ &raquo;</TD></TR><TR><TD CLASS="quote">Its a preference.

Its easier for me to go 4-3-2 or 5-4-3, rather than 4-2 or 5-3 - less chance of zinging the motor to 11K.</TD></TR></TABLE>

ditto on that with me. Just easier for me that way

 

it's a rythem thing sortof. i know how much throttle i need to apply to downshift 1 gear at a time, not 2. there's no mechanical reason behind it, just a consistancy/rhythem thing.

 

I take a somewhat unorthodox style of downshifting that helps me keep my rhythm and also saves my clutch by at least one downshift. If I am going into a turn that requires a 4--&gt;2 downshift I will stay in 4th until I am about to turn-in, then heel-toe into 3rd (but DONT release the clutch yet), then hell-toe into 2nd and then release the clutch. The key to this is to do it at late as possible in order to save the syncros and clutch, but have the car in 2nd and settled before turn-in.

 

For me rythmn and avoids making a bad judgment call (engine braking) letting out the clutch too early on the gear you went directly to (say 5th to 2nd).
Barry H.

 

Originally, racers HAD to go through the gears. They had to go from 5-4-3 or 4-3-2 because Synchros haven't always been as advanced as they are today (today being last 25-30 years). I remember my dad (63) telling me about his old Alfa Romeo's and Lotus's and how he HAD to rev match because the synchros (if the car had synchros) only lasted about 20k miles.

Nowadays they synchros are very well designed and there is no need to go from 4-3-2 but most people still do as good habit to keep them from accidently mis-shifting and blowing a motor.

In my crx it's easy and simple to go from 5-3 but my engagements are MUCH smoother if I go from 5-4-3... besides.. If I'm following a pack of cars closely as we are entering a turn from a high speed straight I may need to manuever in 4th gear (on the fly) to avoid someone or something whereas if I waited a bit longer so I could go from 5-3 I may not have the power in 5th or the rev's in 3rd.

It depends on your driving style. If I'm alone on the track and I'm braking VERY late then I will skip a gear.

 

I think that this is actually pretty interesting. If you can manage to skip a gear wouldn't that give you the ability to be even more judicious with the brakes just by being able to concentrate on them more (spending less time/thinking/effort with clutch and the throttle)? In Secrets of SOLO Racing the author talks about trying to keep downshifting limited to the end of the braking zone. I don't remember the exact reasons, and I don't seem to have my copy handy, but by cutting the amount of time necessary to spend downshifting you effectively push the time at which the action occurs even deeper into the braking zone.

This all probably sounds a bit convoluted, I can't seem to put down exactly what I'm thinking. Anyways - thoughts?

 

All I know is that I've heard about as many different philosophies on this as I've had instructors. And I can do all of them equally poorly. I tend to downshift early and go through each gear since I shift slowly and I need all the practice I can get. Or if I'm particularly sick of sucking, I'll skip a gear so I can suck a little less.

 

I go sequentially down. Being in the successive gears helps give me an audible reference point for entry speed into a corner, whether or not I'm going too fast, whatever. It's not all I use but it's one more data point that helps me be more precise lap to lap.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ASteele2 &raquo;</TD></TR><TR><TD CLASS="quote">I think that this is actually pretty interesting. If you can manage to skip a gear wouldn't that give you the ability to be even more judicious with the brakes just by being able to concentrate on them more (spending less time/thinking/effort with clutch and the throttle)? In Secrets of SOLO Racing the author talks about trying to keep downshifting limited to the end of the braking zone. I don't remember the exact reasons, and I don't seem to have my copy handy, but by cutting the amount of time necessary to spend downshifting you effectively push the time at which the action occurs even deeper into the braking zone.

This all probably sounds a bit convoluted, I can't seem to put down exactly what I'm thinking. Anyways - thoughts?</TD></TR></TABLE>

If you wait to shift until you're pretty deep into the corner, the motor is working with the brakes to help slow you down. At least, that's how it's been explained to me, and it makes sense to me.

 

I found the book, and the paragraph where the author adresses the subject. It basically summarizes what's been said - preference, engine wear, etc. The only argument he makes that I can see as being aimed at lowering lap times and decreasing the liklihood of a spin is for RWD cars: "when you engine brake in a RWD car it puts drag on the rear wheels, which can upset the weight distribution. If you're trailbraking this could have some pretty funky effects, leading to an abrupt spin (or, in a straight line, causing the rear to wander possibly)" (paraphrased).

Andrew - who's not making an argument, just adding to the discussion

 

For me it depends on the corner. Some corners I'll row through the gears and others I'll skip. It's completely unconcious for me. I'm not choosing which corners I skip on, it just happens.

I don't necessarily believe in the "concentrate on braking" then do all your downshifting at the end. Once you get enough seat time, downshifting becomes subconscious and you are not spending any concentration on it.

In sedan racing the braking zones are long enough that there is more than enough time to downshift through every gear (including double clutching).

Gary
Sheehan Motor Racing
http://www.teamSMR.com

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ASteele2 &raquo;</TD></TR><TR><TD CLASS="quote">I found the book, and the paragraph where the author adresses the subject. It basically summarizes what's been said - preference, engine wear, etc. The only argument he makes that I can see as being aimed at lowering lap times and decreasing the liklihood of a spin is for RWD cars: "when you engine brake in a RWD car it puts drag on the rear wheels, which can upset the weight distribution. If you're trailbraking this could have some pretty funky effects, leading to an abrupt spin (or, in a straight line, causing the rear to wander possibly)" (paraphrased).

Andrew - who's not making an argument, just adding to the discussion</TD></TR></TABLE>

that's true if you don't properly rev-match the rear wheels will lock temporarily or the car will lunge depending on if you over or under rev. it doesn't affect the car too much in straight line breaking (if you're shifting, braking, and turning at the same time, i think you're crazy). but i can definitely see how if you were way off with your shift it could get interesting.

travis
-who's never driven a fwd car on track

 

Hmm. Good point. I wonder if it would be significantly more so that it would cause such a rear-biased braking though. Alternatively, if it did, then on a FWD it would cause MORE of a front-biased braking, and would possibly encourage tire lockup more, according to how the book describes it. Although, in that situation, you could just use less brake pedal pressure. But then the rears wouldn't grab as hard...ARgh, this is hurting my brain, so many variables to consider...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sscguy &raquo;</TD></TR><TR><TD CLASS="quote">
If you wait to shift until you're pretty deep into the corner, the motor is working with the brakes to help slow you down. At least, that's how it's been explained to me, and it makes sense to me.</TD></TR></TABLE>

When trying to get the car from 120 MPH to 40, I wouldnt count on the engine helping out too much. In this regard, engine braking is a m00t point and shouldn't be taken into consideration, IMO.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sscguy &raquo;</TD></TR><TR><TD CLASS="quote">Hmm. Good point. I wonder if it would be significantly more so that it would cause such a rear-biased braking though. Alternatively, if it did, then on a FWD it would cause MORE of a front-biased braking, and would possibly encourage tire lockup more, according to how the book describes it. Although, in that situation, you could just use less brake pedal pressure. But then the rears wouldn't grab as hard...ARgh, this is hurting my brain, so many variables to consider...</TD></TR></TABLE>

engine braking doesn't affect brake bias.

here's what happens. when you downshift into a gear, given the rpm's you rev-matched at and your gear selection, the wheels should be rotating at a given speed. if you underrev the motor the wheels actually try and turn slower than they actually are, this is when they skid. it takes just a fraction of a second for the theoretical speed and actual speed to even out assuming you aren't too far off, and everything is back to normal. i'm not sure if the tires actually lock up, or if they just sound like they do because the surface beneath the tire is moving faster than the tire is.

anybody?

 

They slip but a lockup would have to be a pretty extreme missed shift/revmatch, although like you said the wheels match with the speed of the car very quickly unless you broke something when you messed up the rev match.

tnord: Your sig sounds like something Jude would say. I was on track at Gateway with Steve Burkett and Nadeem Bari's cars on Saturday. I made it a point to pass them as fast as possible so I wouldn't have to listen.