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2015 DENVER/FRONT RANGE ROADMEET - MAY 30, 2015

Started by corco, December 20, 2014, 10:40:02 PM

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Duke87

I think I was also being overcautious knowing that my ability to engine brake was stunted because of the transmission's design. If I had a looser low gear that I could stay in the whole way down without it making me crawl, or individual gear selection ability, I definitely would have been more aggressive (and likely would have found the drive a lot more fun).

With regards to silly flatland drivers, I recall on a family trip to Colorado in 2006 we drove Trail Ridge Road in a rented minivan that had a couple of low gear options - which my father knew enough to make use of. But, every time he switched into a low gear or between the two low gears, he insisted on first using the brakes to come to a complete stop in the middle of the road, because "you should never shift an automatic transmission while you're moving".
If you always take the same road, you will never see anything new.


corco

#101
I don't know...maybe it's because I've been driving on mountain passes since about three weeks after I started driving (that was part of my driver's ed!), but I think you guys overthink it.

I've driven up and down mountains hundreds of times and never come close to burning out brakes, and I don't feel like I really do anything weird. In an automatic, I'll flip overdrive off sometimes or use cruise control to force engine braking (okay, I guess that is weird - but nice tip in an automatic: at least in modern cars without manual gear selection, set your cruise control to slightly less than the speed you want to go and the cruise will force the car to downshift), but otherwise I feel like I just drive normally and I've never had a problem. I don't remember the last time I switched to 2 or L in an automatic in non-icy conditions (in icy conditions, none of this post applies- I would never ever do things like brake mid-curve on ice).

I'm also comfortable going significantly faster around corners than most flatlanders, I guess, even in an SUV (I have a car now in addition to my Jeep Liberty, but the majority of my mountain driving has been in top heavy vehicles), so perhaps that's part of it - I guess I've developed the instincts to judge the geometry in advance to know the top speed I can safely handle it (I find the yellow squares to be terribly underposted most of the time-  Montana doesn't even post the yellow squares a lot of the time), I don't slow down more than absolutely necessary, saving brake wear. I usually find myself using brakes most when I get behind another car, and have successfully caught up with sports cars in my Jeep Liberty on mountain roads on many occasions before.



J N Winkler

#102
Quote from: corco on June 12, 2015, 07:38:27 PMI've driven up and down mountains hundreds of times and never come close to burning out brakes, and I don't feel like I really do anything weird. In an automatic, I'll flip overdrive off sometimes or use cruise control to force engine braking (okay, I guess that is weird - but nice tip in an automatic: at least in modern cars without manual gear selection, set your cruise control to slightly less than the speed you want to go and the cruise will force the car to downshift), but otherwise I feel like I just drive normally and I've never had a problem.

This form of hill descent logic is a comparatively recent development in automatic transmissions.  Toyota NCF books suggest their cars have had it since the early noughties, but I don't think I have it in my 1994 Saturn and I am quite sure my 1986 Nissan Maxima did not.

I have personally never experienced brake fade in spite of occasional unconservative choices of gear on downgrades, but I have a close friend who attempted the US 14A descent west of Burgess Junction in D and burned out the brakes in the Dodge minivan he was driving.

Quote from: corco on June 12, 2015, 07:38:27 PMI don't remember the last time I switched to 2 or L in an automatic in non-icy conditions (in icy conditions, none of this post applies- I would never ever do things like brake mid-curve on ice).

My Saturn has a four-speed automatic, and I clearly remember using 2 (the bottom gear range in this model) going over Ebbetts Pass (maximum grade 15%) as well as the Pikes Peak Toll Road.  On the latter facility, coasting downhill in 2 resulted in my exceeding the speed limit by 20 MPH (speed limit 15, top speed 35).

In the Maxima (gear range choices D with overdrive, D without overdrive, 2, and 1), I used 1 going down Marin Avenue in Berkeley, California, which is still my gold standard for difficult downhill driving.  Even in 1 the car barely stayed under 30 MPH going downhill.

Quote from: corco on June 12, 2015, 07:38:27 PMI'm also comfortable going significantly faster around corners than most flatlanders, I guess, even in an SUV (I have a car now in addition to my Jeep Liberty, but the majority of my mountain driving has been in top heavy vehicles), so perhaps that's part of it - I guess I've developed the instincts to judge the geometry in advance to know the top speed I can safely handle it (I find the yellow squares to be terribly underposted most of the time-  Montana doesn't even post the yellow squares a lot of the time), I don't slow down more than absolutely necessary, saving brake wear. I usually find myself using brakes most when I get behind another car, and have successfully caught up with sports cars in my Jeep Liberty on mountain roads on many occasions before.

Finding the apex of a curve is a useful skill.  That said, I lost whatever appetite I had for pushing the envelope on curves 20 years ago on a county road when I tried to take a left-hand curve at 55 MPH.  The right rear tire blew out and the wheel rim anchored in the pavement, so instead of understeering as designed, the car oversteered and shot forward into the inside of the curve, jumped the ditch, narrowly missed two trees, tore through a barbed wire fence, and finally rolled to a stop in front of a confused cow.  The whole thing took probably less than three seconds to happen, and everything from the initial drift off the line to the stop in front of the cow happened so fast I couldn't track it with my eyes.  It was like watching a film while someone was violently kicking and shaking the screen.

The curve had a warning sign but no posted advisory speed.  I reported the incident to the county public works department and a 30 MPH advisory speed plate was erected about six months later.

It can be argued that our standards for fixing curve advisory speeds are overly conservative.  They are certainly comfort-oriented.  However, having actually had the experience of running off a curve on a paved road through excessive speed, I have resolved never to accuse anyone of exercising too much caution on curves.

Geometry is not the only consideration.  Some cars do not have curve-holding behavior that is totally predictable at the edge of the envelope.  Sometimes a curve on a paved road that is normally capable of sustaining quite high speeds is compromised by spilled oil or the sand and fine gravel that is laid down for traction during winter storms.

While it is all well and good to save pad and clutch material by not gearing down or braking hard for curves, those are not the only wear parts that come into play.  Some time after my accident I had to buy four new tires and although I was able to get better than 100,000 miles out of all four, I was later forced to replace two of them for excessive shoulder wear.  Toe-in was correct, and the tires had consistently been inflated about 4 PSI above label pressures, so the likeliest cause of the shoulder wear was taking curves at speed.
"It is necessary to spend a hundred lire now to save a thousand lire later."--Piero Puricelli, explaining the need for a first-class road system to Benito Mussolini

corco

QuoteWhile it is all well and good to save pad or clutch material by not gearing down or braking hard for curves, those are not the only wear parts that come into play.  Some time after my accident I had to buy four new tires and although I was able to get better than 100,000 miles out of all four, I was later forced to replace two of them for excessive shoulder wear.  Toe-in was correct, and the tires had consistently been inflated about 4 PSI above label pressures, so the likeliest cause of the shoulder wear was taking curves at speed.

To be fair, I have noticed that I have burned through tires faster than the average bear, and since a substantial portion of my long distance driving involves curve-heavy routes (I fairly routinely drive from Helena, MT to McCall, ID via Lolo Pass), that seems like a plausible explanation.

Duke87

Quote from: corco on June 12, 2015, 07:38:27 PM
In an automatic, I'll flip overdrive off sometimes or use cruise control to force engine braking (okay, I guess that is weird - but nice tip in an automatic: at least in modern cars without manual gear selection, set your cruise control to slightly less than the speed you want to go and the cruise will force the car to downshift)

This has to be car dependent. My automatic CVT will downshift any time I'm speeding up and neither pedal is depressed. Occasionally this is annoying since if I want to roll down a hill and use the momenum to get up the next one... well, I can't. Car will engine brake on its own, even if it's not in cruise control. Meanwhile, in cruise control or not, it will only downshift itself up to 3000 RPM or so unless I put it in low gear. I've had to interrupt my cruise control to use the brakes on long downgrades because I was speeding up significantly past my cruuse setpoint.

Meanwhile my old Focus had no cruise control, and the six speed automatic would not downshift to engine brake at all unless I put it in low gear - so I could roll down hills all I wanted, but had to be more careful on steep ones. When I drove the downgrade on MA 57 approaching MA 8 in the Focus, there was much fierce braking and I almost didn't manage to stop at the stop sign at the bottom. When I did it in my Sentra it was no sweat since the car engine braked itself the whole way down.
If you always take the same road, you will never see anything new.

Zmapper

Quote from: J N Winkler on June 11, 2015, 03:05:19 AM
Many (but not all) native Coloradans like to complain about flatland tourist drivers, but in so doing the kvetchers forget that Colorado residents are more likely to be familiar with the major mountain passes and to have more opportunities to practice mountain driving.  Moreover, much of the stereotypical flatland behavior is actually exhibited by cars with Colorado plates, and inevitably some of it flows from technical limitations rather than driver naïvete.
I have that feeling that this is vaguely directed at my radiator overheating on Loveland Pass... :paranoid:

Downshifting: I've found that I'm more unpredictable in downshifting in my current car than the one I had last year; the difference is that my current car has an automatic column shifter, while my previous car was a floor-shift automatic with an autostick mode. In my previous car, I almost universally used the autostick mode; I used to make it down canyons without needing to use the acceleration pedal and only slight break usage in corners by manipulating the gears in autostick mode. In my current car, not only is the column shifter less ergonomic to use but third gear is a kludge, I have to press a button to disable overdrive/4th which holds the car in 3rd. Frequently, I don't notice the overdrive light/button and shift from 2nd to 4th when I still need to hold the engine back slightly in 3rd.

Curves: CDOT is notorious for underestimating the safe speed in curves that my otherwise conservative driving education instructor outright told the class to expect to be able to go about 5-10 over the posted advisory speed in passenger cars on dry pavement with no precipitation.

J N Winkler

Quote from: Zmapper on June 14, 2015, 05:43:28 AMI have that feeling that this is vaguely directed at my radiator overheating on Loveland Pass... :paranoid:

Actually, the parenthetical "not all" was designed to exclude present company.  I didn't know before your last post that your car had had problems with temperature control on the climb up to the pass summit.

Quote from: Zmapper on June 14, 2015, 05:43:28 AMDownshifting: I've found that I'm more unpredictable in downshifting in my current car than the one I had last year; the difference is that my current car has an automatic column shifter, while my previous car was a floor-shift automatic with an autostick mode. In my previous car, I almost universally used the autostick mode; I used to make it down canyons without needing to use the acceleration pedal and only slight break usage in corners by manipulating the gears in autostick mode. In my current car, not only is the column shifter less ergonomic to use but third gear is a kludge, I have to press a button to disable overdrive/4th which holds the car in 3rd. Frequently, I don't notice the overdrive light/button and shift from 2nd to 4th when I still need to hold the engine back slightly in 3rd.

Ergonomics does matter.  The first mountain driving any member of my immediate family did was in the 1986 Nissan Maxima which used to be the family car but later became my roadtrip car:  the setup was similar to the Ford Taurus station wagon you were driving, except that the shifter was floor-mounted and the overdrive cancel button was on the console bin.  This made progressive gear reduction a little cumbersome to do, though I believe once I was in 2 or 1 I could bump back up to a higher gear range without depressing the selector button.

I borrowed a 2009 Honda Fit for a Colorado trip when my own car was in the shop receiving long overdue repairs.  (I used an insurance settlement from a bad hailstorm in May 2012 to have nonfunctional A/C repaired, a leaky radiator replaced, and brake pads and rotors replaced so that I could drive the car anywhere without worrying about audible brake wear indicators I cannot hear.  We couldn't see any value in having hail damage repaired in an ungaraged car then almost 20 years old, and while improved cosmetics would have been nice, we saw the car at that point as a way of avoiding spending money on a newer vehicle.)  The Fit had paddle shifters and I usually drive with both hands on the steering wheel, which made it much easier to obtain correctly timed downshifts than with any other car I have driven.  However, I didn't have the option of selecting a lower gear with the paddle shifters and then riding in it with foot on the gas unless I moved the floor shifter to S (selective-shift mode).  Selective shift in D is a temporary mode the car enters when downshifted with the paddle shifters and exits when the throttle position sensor tells the PCM the throttle is no longer fully closed.  Aside from this, the system is pretty foolproof since the PCM will reject input from the paddle shifters that would otherwise put the engine out of the correct rev range for the intended gear.

My Saturn falls between the Maxima and the Fit in convenience.  It has no overdrive cancel button, so the floor shifter is all I need to touch, and it can be bumped back up to a higher gear range without a button press.  The most irritating limitation is no 1 gear range, but I have been able to live without it so far.

I haven't tried a CVT, either in mountains or on the level, but I suspect a lot of the difficulty in mountains is an indirect consequence of too-easy revving being used to fake absent low-end torque.

Quote from: Zmapper on June 14, 2015, 05:43:28 AMCurves: CDOT is notorious for underestimating the safe speed in curves that my otherwise conservative driving education instructor outright told the class to expect to be able to go about 5-10 over the posted advisory speed in passenger cars on dry pavement with no precipitation.

Yeah, I've long suspected CDOT is conservative like that.  But I'll leave the envelope-pushing to others!
"It is necessary to spend a hundred lire now to save a thousand lire later."--Piero Puricelli, explaining the need for a first-class road system to Benito Mussolini

SSOWorld

I've driven my car through various climates and altitudes over the five years it's been in my possession.  I engine brake quite regularly in mountainous terrain and the car having an easy shifter to use without having to labor though a column or floor that you have to press a button to move the stick.  I regularly avoid using brakes to descend to keep them from overheating and wearing - though it didn't always succeed ;) .
Scott O.

Not all who wander are lost...
Ah, the open skies, wind at my back, warm sun on my... wait, where the hell am I?!
As a matter of fact, I do own the road.
Raise your what?

Wisconsin - out-multiplexing your state since 1918.

skaguy

I had a 2008 Nissan Altima 3.5 with a CVT and the lack of engine braking capabilities is one of the main reasons I got rid of it.  I had two close calls in the snow with it last year in NOVA and I should've had more capabilities to slow down than I did.  It actually terrified me to drive that car in the snow.  I bought a 2012 Mercedes C300 4Matic that's an automatic and it's night and day between it and the Altima.  Driving it on the snow this year, I could actually downshift enough (without red lining or going above 3,000 RPMs on the tach) to use no brakes at all and come to a complete stop.

Last weekend I went down a 12% grade gravel road off of Corridor H in my girlfriend's 2010 Ford Explorer with an automatic with no issue.  I downshifted in to 1st and coasted most of the way at 10-20 MPH, applying brakes sparingly when needed.  I don't think the tach went above 2,250 RPMs.  I use to have a 1998 Ford Taurus with an automatic and I went all over the Plains for up to 50 miles at a time on dirt roads at some points and drove in all kinds of winter weather as well with it with no issue.

In terms of taking curves, the best method is to brake going in to the turn and then accelerate when reaching the apex.  There are some instances where I've let off on the accelerator just enough to slow down and then accelerated after the apex, but every turn is different and this is the outlier rather than the norm.  It's a "feel" thing and braking or accelerating too soon or too fast is bad.  I should also note that I don't employ these tactics for daredevil-like speeds.



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