Subaru Outback Forums banner
1 - 20 of 21 Posts

·
Registered
Joined
·
33 Posts
Discussion Starter · #1 ·
I recently bought an OB 6MT, and I love it.
However, I was somewhat worried to learn from this forum that it is a little bit trickier to drive in snow than I was expecting.

I have a couple of steep descents on which I need to be able to drive. Usually, with my 2WD with chains, I put 2nd gear, and I go down slowly, using engine braking in place of the ABS I don't have (since brakes don't lock weels when there is an engine attached).

With the OB, I learned that when you use engine brake in a steep, snowy descent, and you let off the gas pedal, the deceleration together with the 50% front-rear split often causes the rear wheels to slip, and the rear end of the car to start to try to come around. This makes some sense: the rear wheels are only lightly weighed, and the 50% split in engine braking power makes them prone to slipping. I was hoping the effect was more limited, since I was hoping that the AWD system would still keep the rear wheels turning at the same speed as the front ones, thus preventing slippage.

But my question is then, how do you slow down while going downhill? The remedy for rear-end sliding seems to be to increase gas, but that accelerates the car -- how do you slow down in those situations? You push on the clutch and brakes and hope that ABS (or, is it called VDC/TCS in Subaru's terms?) do its thing?
 

·
Registered
Joined
·
22,806 Posts
Yes my 2001 Legacy GT did the same thing. Only way I could work around that behavior was to be very very light on the throttle when letting off ie backing down on the throttle slowly thus avoiding the shock to the rear wheels when the engine suddenly goes to idle and loads up the rear wheels to the point they break loose and skid.

Pressing the clutch in simply continues the skid but gives you a glimmer of hope if you need to really stop!

For a controlled down hill run with no stopping needed I would stick to 2nd and simply feather the throttle let up till the back end started to skid then give it a very light touch of throttle to get the rear wheels turning and tracking again. Once you get this trick down you can can use the throttle control to wave off tailgaters by breaking the rear and having it step out then touch the throttle and square up the car again and if they keep tailgating just keep wagging the tail generally by the third wag the tailgater thinks your out of control and backs WAY WAY off LOL ;-)

Your answer is being super super super smooth with very small throttle changes at a time and you can easily make the down hill run. Its the abrupt throttle inputs such as just letting completely off the gas that will break the rear tires loose every time.

Oh and the number one rule ALWAYS have your best tread tires on the rear end! If you have two tires with tread thats worse than the other two make sure the best tread is on the back of the car! This by the way is an AWD thing for all AWD's you want the best tread tires on the back end.
 

·
Registered
OBW H6 VDC, Tribeca, XT6
Joined
·
12,385 Posts
better tires, if it's that bad you should have them. studded if it's really bads. downhill is just plain tough and if it's iced up or something you're really hosed.
 

·
Registered
Joined
·
33 Posts
Discussion Starter · #4 ·
better tires, if it's that bad you should have them. studded if it's really bads. downhill is just plain tough and if it's iced up or something you're really hosed.
My problem is that even in winter, 99% of my driving is not in the snow, so I am hesitant to replace my stock Contis (which are apparently great in the rain) with snow tires. If I were lucky to live on the mountains, I would get snow tires... but all I need is to learn how to cope, with the Contis, with those nasty downhills (one on HW80 approaching Truckee driving down Donner Pass, the other in Truckee itself).
 

·
Registered
Joined
·
22,806 Posts
My problem is that even in winter, 99% of my driving is not in the snow, so I am hesitant to replace my stock Contis (which are apparently great in the rain) with snow tires. If I were lucky to live on the mountains, I would get snow tires... but all I need is to learn how to cope, with the Contis, with those nasty downhills (one on HW80 approaching Truckee driving down Donner Pass, the other in Truckee itself).
LOL hey thats the same spot I let it all hang out to get the stupid tailgater SUV's off my tail. Just take it easy on letting off the throttle fast and keep more room infront of you so you can ease off the throttle in smaller increments. The first time you experience it - its pretty spooky but after 10yrs of making that trip on that piece of road way you get so you can wag the tail on command to shake the tailgaters off your back side. Just keep in mind that all you need is very slight throttle and the back of the car will step back in line - then you can press the clutch in and give it brakes letting ABS do its thing. You don't want the back end hanging TEN and be hitting the brakes all at the same time you'll end up sideways or worse pointed the wrong direction.

With throttle the car will square up every single time which is why having a little extra room between you and the car infront of you is pretty important. All it takes is a very slight touch on the throttle and the car will square up just fine.

I ran the standard stock tires all those years no problems never got stuck just had to really watch the throttle inputs on that section of the road.
 

·
Registered
Joined
·
22,806 Posts
By the way the MT will do the same thing on dry pavement if your really hauling the mail so knowing that just a slight throttle input will square the car up on dry pavement as well as snow will keep you out of trouble assuming you have room vs needing to stop Pronto.
 

·
Registered
2013 Legacy Lim CVT Car: 2011 OB Prem 6MT Car: 2006 Miata GT 6MT mc: 2003 Honda GL1800A * Reunite Gondwanaland *
Joined
·
3,565 Posts
Too slippery for engine braking?

Put it in neutral and use the ABS.

...yes, it's that simple,

Looby
 

·
Registered
Joined
·
33 Posts
Discussion Starter · #8 ·
LOL hey thats the same spot I let it all hang out to get the stupid tailgater SUV's off my tail. Just take it easy on letting off the throttle fast and keep more room infront of you so you can ease off the throttle in smaller increments. The first time you experience it - its pretty spooky but after 10yrs of making that trip on that piece of road way you get so you can wag the tail on command to shake the tailgaters off your back side. Just keep in mind that all you need is very slight throttle and the back of the car will step back in line - then you can press the clutch in and give it brakes letting ABS do its thing. You don't want the back end hanging TEN and be hitting the brakes all at the same time you'll end up sideways or worse pointed the wrong direction.

With throttle the car will square up every single time which is why having a little extra room between you and the car infront of you is pretty important. All it takes is a very slight touch on the throttle and the car will square up just fine.

I ran the standard stock tires all those years no problems never got stuck just had to really watch the throttle inputs on that section of the road.
Yes, that is the one spot where I had an accident a couple of years ago. I was driving with a 2WD Accord, with chains on the front wheels. The rear end started sliding to the right. I counter-steered, and brought the rear end back in line -- but then the rear end, after coming in-line, continue to slide on the left, and I did a 135 (not quite an 180) and hit the guard rail. As I was going very slowly in what was a monumental snowstorm, the damage was minimal (one cracked turn indicator), but the experience gave me a lot of respect for rear-end slides.
After that, in true storms, I took to putting chains front and back on my Accord.
I was hoping that, with a Subaru, I would have a more controllable car, but after reading this group for a while, it seems that a Subaru with all-season tires can be just as temperamental... I'll probably get cables for the Subaru, just in case.
 

·
Registered
OBW H6 VDC, Tribeca, XT6
Joined
·
12,385 Posts
that's a tough situation, downhill is just straight difficult and there is very little margin for error. i've experienced the rears kicking out behind you on steep descents many times in my manual trans too.

are automatics less immune to this?

is there any chance that weight has an effect? there's already little weight in the rear, if you're pointed down hill then there's hardly any weight on the rear.
 

·
Registered
Joined
·
42 Posts
I have a MT Outback and live in the snowy hills of Vermont. The key to using engine breaking is to use just enough to keep your car from "running away" but...don't shift into a lower gear too early. Gradually get to the right gear and you will have no problem. If you are sloppy in your shifts or shift into too low a gear, any car will give you problems.
 

·
Registered
Joined
·
22,806 Posts
So far our cvt seems to be more stable and smarter about loading up the rear wheels with engine breaking and seems far better regarding this compared to the mt i drove for many years. Being super smooth and keeping abrubt throttle changes tempered made all the difference in the world with the mt subaru on that stretch of 80. Never had any issues even in the really bad storms but i had to pay close attention to the throttle inputs to keep the rear end happy and behind me

You can litteraly control how far out the rear will swing by how far and sudden you back off on the throttle and by feeding a touch more throttle back to the car you can bring the rear end back in line. Ive driven an accord on that stretch and your control is nearly zero the subaru is fully controllable as long as you know how to react ie feed a little more throttle to square up then either back off on the throttle very very slow in small increments or press the clutch in and use the abs

Very iportant to understand that you cant just lift your foot off the accelerator suddenly with out causing loss of traction. If you need to lift your foot off all the way you need to press the clutch in also to avoid causing traction loss
 

·
Registered
2011 Outback 3.6 Premium
Joined
·
721 Posts
Shifting to a lower gear on a slippery steep descent can be worse with an AT car as abrupt lockup can cause a skid. With a MT car, one can slowly let out the clutch.

What one really should do, though, is to shift to a lower gear before it's necessary or use the brakes to slow the car down so that when the shift is made the car is going relatively slow for that particular gear.
 

·
Registered
Joined
·
33 Posts
Discussion Starter · #14 ·
This is comforting: I've been driving MT all my life, and I know how to be super-smooth in throttle and power transitions.
A few more questions:

- If I am in (say) 3rd gear and no throttle, using engine brake, and I start to add also some ABS brake (i.e., start gently pressing on the brake pedal), does this work well? Is ABS able to work well when the car is in gear?

- I read somewhere that putting the car in neutral disables ABS. Is this true?

- What's the purpose of disabling traction control in the snow? In fact, does traction control (VDC or TCS, I am very confused about the difference) do in an MT car?
 

·
Registered
Joined
·
22,806 Posts
Abs keeps the brake from locking up the wheel causing a slide. Mt and engine braking can cause the tires to skid ie turn slower than your speed only fix is to speed up the wheel with throttle or press the clutch in allowing the wheels to turn with your speed. Abs works all the time regardless of being in gear or not.
 

·
Registered
Joined
·
22,806 Posts
Disabling traction control is for slow speed stuff. Example would be car parked in a snowed in pariking lot where spining your tires and needing power to plow through snow is needed. Traction control on 80 is good it limits throttle input and does a few other things to prevent skids at speed.
 

·
Registered
Joined
·
22,806 Posts
3rd gear and braking will work. But if 3rd gear is maxing out your available traction applying the brake could skid the tire and abs cannot release the clutch to stop the skid. If your coasting in3rd and need to slow your speed and traction is very limited pressing the clutch in first then using the brake to shed some speed is probably the best approach this way abs can do its full job. Then with your speed down you can ease back into 3rd slowly to avoid skidding the rear tires with a sudden clutch release.
 

·
Registered
Joined
·
22,806 Posts
The whole issue is that the rear tires on that down hill run have less traction than the front tires. Abs will keep the rear tires turning thus keeping the car strait. But with the car in gear the transmission will only turn the rear wheels so fast ie too slow and cause the rear tires to slide thats when the back of the car fish tails or tries to pass the front of the car. Getting those rear tires turning fast enough to get traction again happens three ways. You simply speed up very very slight throttle or you press the clutch in allowing the wheels to free spin with ground or with the brakes on abs says hey let the rear wheels spin
and puts pressure on the front wheels with more traction. Etc

But you want the car square before you use the brakes! So you get a slide going but have room and traffic is moving give the car a little throttle and it will square up. You start to slide and traffic is slowing and you have very lityle room press the clutch in asap! Then get on the brakes. The car will start to square up as soon as you press the clutch in but will do this much slower than it does with slight throttle which kicks the car square instantly in every case i had this then press the clutch and hit the brakes.
 

·
Registered
2013 Legacy Lim CVT Car: 2011 OB Prem 6MT Car: 2006 Miata GT 6MT mc: 2003 Honda GL1800A * Reunite Gondwanaland *
Joined
·
3,565 Posts
Going out of gear and using the abs is an option if its really bad but not
ideal for that stretch of road given the long down hill run.
OK, when it breaks loose, de-clutch to re-gain directional control,
then shift to a higher gear (where the engine braking force at the
contact patch no longer exceeds available traction, on ANY wheel),
then ease the clutch out and let engine braking and ABS share the
deceleration load. If/when it breaks loose again, repeat from "OK."

...oops, nevermind! I forgot that you're AT-incapacitated. :roadtrip:

Looby
 

·
Registered
2013 Legacy Lim CVT Car: 2011 OB Prem 6MT Car: 2006 Miata GT 6MT mc: 2003 Honda GL1800A * Reunite Gondwanaland *
Joined
·
3,565 Posts
- If I am in (say) 3rd gear and no throttle, using engine brake, and
I start to add also some ABS brake (i.e., start gently pressing on the
brake pedal), does this work well?
Yes it works fine -- IFF every wheel has enough traction to avoid
skidding due to engine braking alone. Slowing the wheels further
with ABS won't cause a lockup -- but neither will it prevent lockup
if traction deteriorates to the point where the engine braking alone
would cause any wheel to lose traction.

BTW, with ABS it's not necessary to be "gentle" on the brake pedal;
stand on it as hard as you like and let the computer earn its pay.

I read somewhere that putting the car in neutral disables ABS. Is this true?
That's not true for any ABS that I've ever owned -- but I guess it's
possible for some (brain dead) designs.

- What's the purpose of disabling traction control in the snow?
Many TC systems prevent wheel spin by reducing engine power and/or
applying some braking force to the slipping wheel. If you're trying to
climb a slippery grade in deep snow/slush, you may well need a little
wheel spin to keep going (especially in FWD cars).

If the engine "bogs down" under these conditions, turn off the TC.

...Disclaimer: haven't had my first AWD car out in the snow, yet.

Looby
 
1 - 20 of 21 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top