winter driving

Watch this and learn:

http://www.youtube.com/watch?v=PUQkUsg7bJU&feature=related






http://ca.video.search.yahoo.com/vi...t=Explaing+chaining+up&sigr=11vmn0lm9&newfp=1

 

You and hotrodder Condo are definitely right.

We use gentle throttle and the highest gear possible for a given road speed if you don't want to lose traction. If we drop gears to use high RPM, the transmission and rear end gearing multiplies torque. That multiplication more than offsets the 20 or so % torque difference from say 1200 RPM to redline.

 

just remember the colder the better when the road is snow packed or icy!! 32 degrees is the most dangerous.. loose snow means traction,going over a mountain pass look for loose snow if its not sanded, watch your tires if they are coming up white the snow is sticky and there is more traction, if there black and shiny means less traction... in very cold temps if your planning to stop a mile up the road and the roads are dry, slow down gradually use you brakes little or none, using your brakes in very cold temps even if the roads are dry the heat from your brakes and the cold weather will create condensation and your brakes can freeze when you park for your nap...

 

Also if you are driving through lots of fresh snow do the opposite and drag your brakes some 5 miles or so before you stop to get all the packed in snow out of the brake drums. Then once stopped depending on the temperature move your truck a few feet every 5-10 min 2-3 times to makes sure that your trailer brakes don't freeze up and never apply them when parking for the night. If you don't get the snow out of the drums there is enough warmth from the axle to melt the snow and your brakes will be jammed up even without applying them. Learned this the hard way with a super b almost all locked up the next morning.

Tighter brakes are better than looser ones in snowy conditions as there is less of a space for snow to get into the brake assembly. which means better braking when you haven't used them for a while driving down the road and less of a chance of freeze up when parking.

If your tractor brakes are stuck on the next morning throw your trucks axle locks in and gently try and get the truck moving in low gear. Most times the truck will break free. If not then it is best to beat the brakes with a hammer because that is better then dropping a driveline.

 

Low torque is what keeps tires from breaking loose. In diesel engines high torque is produced at low RPM, low torque only happens at higher RPM's when its replaces with gutless, zippy Horsepower.

I mean no offense to you condo, but you are wrong in a few aspects. First you are wrong about everything I underlined. You are right about running in low rpm range on slick roads, except for climbing hills. When climbing slick roads you use high rpm. Other than that you are better using low RPM but not for the reason you listed. Using low RPM gives you the ability to quickly without hesitation softly push on the gas and outrun your trailer at any moment. That is also why when going down slick roads you also run at low rpm, that is the time you are most likely to get into a race with the back of your trailer. You need to be able to outrun it and keep it behind you, then gently slow down once you have gained control. You need that power on tap on slick roads, except for climbing in which case you do not want or need that power.

Gasoline and diesel engines are quite different. Diesels run at low RPM extremely high compression and produce mountains of torque at low rpm, the torque dwindles and the HP doesn't really hold its own in the high RPM of a diesel engine. Gas engines produce very little torque in general (lower RPM range as well) and rely almost solely on HP not Torque to move. Horse Power in both gas and diesel engines peaks in the higher RPM range, the low RPM range produces very little HP and most of the engines torque. Unless your partially aspirating your Cat, Detroit whatever with propane there is really very little similarities between gas and diesel engines and there performance.

Reminder to self: look up HP and torque so I can prove that they are indeed the same thing.

 

Here are 2 links to web sights that I find useful in my travels first one is www.fhaw.dot.gov/webstate.htm it will link you to all state transportation web sights giving you traffic information along with road construction and a lot more Second is www.nws.noaa.gov/ you can access up to the minuet weather data any ware in the country useful for planning you trip.

 

Once in Idaho It snowed so bad that we got snowed in at the shipper for 36 hours. two feet of snow fall, then the shipper started assigning doors to the guys who had been sitting. Guess What? At first it was ok but then after the truckers bumped the dock a few times they had packed the snow and the dock area became too slippery. Chain-up time!

My suggestion is stay out of truckstops during heavy snowfalls. Too many times I have seen TS become frozen pads of ice and the worst is when the Snow melts and refreezes at night, then there will be absolutely no traction on that kind of ICE. Just park near the TS for the night and save yourself from an preventable accident.

 

Got a question about Winter driving because driving in this snow is scaring the crap out of me. So, far I've been late on every load where it has snowed because I'm so overly cautious which I'd rather be overly cautious than not, but that's me and my personality and how I was raised. If my GVW is 77,000LB's and I'm on a 5-6% grade downhill and there's snow on the road what is the safest way to go down? I've had my Class A CDL since 8/5/10, so that should speak for itself on why I'm asking this question. I'm from Kentucky and even though we get snow, it's never a whole lot and even when it did snow, I never ever drove in it unless I had to. I'm 34, so I do have some driving experience in snow, but this whole commercial truck driving business is scaring the crap out of me. So far, I've been caught in two pretty bad snow storms up around the Cleveland, OH area from that #### stupid lake effect snow. God, I almost want to move some place where I never have to see the white stuff ever again....I HATE WINTER, PERIOD

Ok, so just trying to use common sense, I feel comfortable driving between 50 and 58 mph on snow covered roads or during the snow storm. Any faster I start envisioning me loosing control and jack-knifing. Luckily, I've not been caught on any 5-6% grades during a snow storm, but if I ever am like say over on I-68 in WV or on the PA turnpike(I-70/76) traveling to the east coast and have a heavy load how is the best way to approach going down hill? We have Volvo straight 10 speeds.

1. I would think to go to 9th and keep light pressure on the brakes to keep the momentum under control.

2. Or, should I just go slower and maybe put it in 8th again keeping light, constant pressure on the brake and just creep down the curvy, hilly road?

The Co. I work for SHOULD have stuck all of us new drivers with an experienced Winter driver this season. I think it's ######## that I get no Winter driving training because since I, THE DRIVER, am held ########## responsible for my accidents then I should be trained on how to drive in crappy, Winter weather. On the other hand, the company I work for is small and would rather put money into making their parking lot and office building look better than to give top notch training to it's drivers and have top notch equipment. Our equipment isn't the worst, but it could definitely be better, newer stuff.

EDIT:

Also, is it better to "lug" when shifting and driving when on snow? I know it's horrible for the gas mileage, but I'd think it'd be better for traction to somewhat lug while driving on snow covered roads.

 

Less torque is definitely what keeps tires from breaking loose and it is true that torques falls off as RPMs go up, but your suggestion doesn't make sense when we consider that both the transmission and rear end multiply torque. I've never heard an experienced driver say that high RPMs are the way to safely handle bad roads and I'd appreciate a link to anything suggesting such a thing.

Lets take an average big truck, give it a 475 horse CAT motor, a ten speed overdrive tranny and a 3.55 rear end ratio. That motor makes max torque of about 1650 ft/lbs at around 1300 RPMs but the torque falls off about 12% to about 1450 ft/lbs at 1800 RPMs.

Now take a look at the tranny. Look in the manual for your truck under transmission ratios and steps. Lets say that the driver decides that 39 MPH is a good safe speed for road conditions. That equals 1800 RPM in 8th gear using your theory. Well, 1450 ft/lbs x the 8th gear ratio (1.37 is typical) x the rear end ratio of 3.55 means that driver is applying 7,051 ft/lbs of torque to those drive axles.

Condo and Yukon decide to cool it at 39 MPH in 9th gear. Hmmm, that's a whopping 1650 ft/lbs x 1 (9th gear is typically direct) x that same rear end ratio of 3.55. How much torque are they applying to their drives? I figure 5,857 ft/lbs or 1,193,5 ft/lbs less than the guy using your method.

Really, you already know this because you drop a gear to maintain speed when you run up grades, don't you? Yes, you're downshifting into a part of the power band where the motor does make less torque, but your transmission and rear end ratio more than make up the difference by torque multiplication. You can read spec sheets for all sorts of truck motors/trannies and rear end ratios and experiment with different numbers but the fact remains that the loss at high RPM is offset by those ratios.

As for outrunning your trailer uphill (???) on bad roads just ease off the brakes and it will get back in line. You don't need tire spinning brute force to handle bad roads or outrun trailers. The only time I might use higher RPMs is when I'm using the motor to slow or maintain my descent on downgrades.

If we're traveling so fast that centrifugal force is causing the trailer to step out, we have a much more severe problem than just our choice of gears.