Rear gearing and snow

[supton]

Dumb question: Back in the era of BOF RWD V8 automatic sedans, was it beneficial, in snow, for deeper (think towing) gearing; or taller rear end ratio (think highway/mpg gearing)? I'm thinking of tall gearing in snow, lowering torque, was better. Engine rpm's stayed lower, so goosing the throttle was less likely to spin a tire.

I know limited slip helps, traction control helps, FWD helps, AWD helps, etc. Just looking at gear ratio with a torque convertor. [Feathering a clutch is a bit different.]

 

[HerrStig]

I used to start my Volvo's with LS in second gear. A spinning wheel generates no side location forces which is why the old clutch type limited slips would kick the tail out in a curve if excessive torque overcame traction. They were OK with ONE wheel having good traction, but not with BOTH on slippery stuff. Then they got tricky.

 

[supton]

I recall reading that some of the automatics would start in 2nd gear, if you selected 2nd; but I think some of them would just start in 1st and go no higher than 2nd. Depended upon what the OEM programmed the transmission to do.

In light of current discusions about cheapest vehicles etc, I'm wondering if I should explore RWD sedans for a bit. Bought cheap enough I should be able to afford a mechanic to go through all systems, make 'em good; and then swap in limited slip and rear gears of choice. But my VW just isn't a snow machine (snow tires only go so far), and it's been years since I've had RWD. I don't think I can justify something worse in snow, but it can be just slightly better and be ok.

 

[HerrStig]

Keep the gas tank full and don't get carried away with tire width. Wide tires look nice but are hard to push through snow. The idea is to have the drive wheels dig through a couple of inches of snow and contact the road surface. Wide tires tend to float. I had to BACK a SAAB up a hill near my home more than once. Weight in the wrong end for hill climbing with FWD.

 

[mpvue]

just put it in drive, use skinny tires, go light on the throttle, don't goose it in the turns and you'll be ok.

 

[WishIhadatruck]

My wagon is BOF RWD. I use Bridgestone Blizzaks, it does have a limited slip rear end. Even though it has the tow package and different gears (2.93 vs 2.54) it is still pretty much geared for highway cruising getting good mileage. It keeps the rpm's pretty low. I can put the gear shift lever on 2 and it will start in 2nd, but I never do. It might be handy if I had 3.73 or 4.10 gears.

 

[supton]

I'm guessing if I did a rear swap, it would be technically worse in snow. That can be mitigated by adding a limited slip (I've read the GM G80 "locker" doesn't work above 25mph or somesuch, have not confirmed that), possibly using 2nd gear (assuming it locks into 2nd gear) and of course, proper winter tires.

I usually run narrow snow tires; but one year I tried Nokian WR's in the stock size (195's) and thought them horrible. Well, maybe not horrible but definately not very good. Hakka 2's in 185's were really good. Nordman 2's have been good, but useless for climbing up an icey drive once.

 

[JHZR2]

Though a ton of other criteria exist, including weight and all, the two worst cars we have had in the snow were our integra and our 318i. The 318i has a 4.10 LSD, and the integra had a 4.266 open final.

Other cars, RWD and FWD with less aggressive gearing have always done better in the snow, it seems to me.

But this is not an emperical study...

 

[HerrStig]

Older BMWs without traction control or AWD are cursed in the snow. We could never figure ot why. Must be the camber on the IRS.

 

[PeteTheFarmer]

My friend had a Grand Prix with a a button on the dash which started the transmission in second gear on a slippery surface, so I'm thinking the taller ratio would help in snow.

 

[The_Jeff]

I would give the nod to shorter gearing, though it doesn't matter much. I like going up hills in lower gears with significant engine revs compared to dry roads driving. The engine's flywheel inertia is magnified by lower gearing so if a tire breaks loose for a foot of travel the flywheel soaks it up better. There are some hills I have to take with a running start and am on this threshold of traction most of the way up.

This applies to "already driving" handling. I would expect it to be more touchy getting going with the power multiplied.

 

[AVB]

Isuzu's SUVs usually have a winter mode button, it makes it start off in 3rd gear.

My 1996 Trooper had 4.56:1 gears.

 

[Garak]

Originally Posted By: JHZR2
Other cars, RWD and FWD with less aggressive gearing have always done better in the snow, it seems to me.

But this is not an emperical study...


Well, here's another data point for you.

My old 1983 LTD with the 2.3 was absolutely gutless. I have no idea what its gear ratio was, but due to its absolute lack of power and its decent balance, I never got the thing stuck no matter what I threw it into. While that car had its share of faults, an ability to carefully modulate the throttle in poor traction conditions was not one of them.

 

[supton]

There you go: on a V8, pull some plug wires and make it into a V6, and voila! instant snow machine!

 

[crw]

The lower highway gears would be slightly better. But there are so many factors involved. Wheelbase would be a big one, for example. Longer vehicles are going to resist fishtailing more than short vehicles.

I've turned many a FOX bodied Mustang into a gyroscope, lol.

Good tires are probably the best antidote. But I'm planning to park the BMWs and drive my old F-150 this winter.

 

[ARCOgraphite]

What truck would you change the gearing on? You cant change the final drive without major effort and expense.
Low torque, tall gears are better in snow. On a MT try to start in 2nd with slippage. I gave up on my subcompacts and bought narrow Firestone Winterforce snows mounted on 14" (-1) steelies. They go great for cheap - the most aggressive open treadblocks in passenger car tires and good dirt filled rubber compound. Read here, also, that General Altimax have their loyal followers for a few bucks more a tire..

 

[supton]

Ok, back to the begining: I keep toying with a spare vehicle, to augment my fleet. I have the Camry, which makes a good family vehicle. My TDi makes a good commuter. They both do ok in the snow: nothing exceptional. The TDi gets dedicate snows for winter; and every couple years I get it stuck. Eventually I can dig it out (ruts and/or high ended). So, as much as I want a 4WD/AWD vehicle, I don't actually *need* one. Would like, could justify; but...

However, I picked up a camper this summer, a small popup, which my TDI pulls ok. But the car is kinda small for the family; and it's about useless for backing my camper up in the yard (uphill, in reverse, no good with manual transmission). So, perhaps one of those body-on-frame sedans, with a V8 and automatic, will do the trick. There is this following for the Crown Vic's, which technically have a too-low tow rating for my tastes, and of course the older-still Caprices (which could get me out of OBDII inspections, if I go old enough).

On these types of vehicles, the factory towing package could be tacked in, since the frame and brakes generally didn't change (much). Springs, swaybar, transmission cooler are more or less bolt in, leaving just the rear gearing (which could go limited slip at the same time). None of it should be too expensive to do.

However, I just want to quantify a bit how much damage it does to snow driving ability, once one gets in there and mucks with the gears.

 

[Kuato]

Originally Posted By: supton
Dumb question: Back in the era of BOF RWD V8 automatic sedans, was it beneficial, in snow, for deeper (think towing) gearing; or taller rear end ratio (think highway/mpg gearing)? .... Just looking at gear ratio with a torque convertor. ...



Torque converter first. A low stall converter would start to put power to the transmission at lower rpm, therefore less power in the system and easier to modulate.

A high stall torque converter would start to put power to the trans at a higher rpm, so by default you are getting more power, and a high performance TC would have you spinning the tires.

Generally in the really old stuff (older than you're looking at, I'm editing after reading your most recent) you'd have a high stall TC in a high powered engine that wouldn't idle with a lower stall TC, and which would put out gobs of power from the start. My brother's 440 with a TC stall of somewhere in the mid-2000s would sit and spin in the parking lot, while my stock (1500 or so) would putt right out.

Gears are a little less important, especially if the driver knows what they're doing. You can still spin 'em with a low (highway) gearset, or have no issues with a higher gearset....it's directly affected by the gas pedal.

Then there's the car itself. I had some that were tanks in the snow, others that absolutely would not climb a hill. Of course momentum is your friend in an old RWD in the snow. Especially with an open differential.


BTW what's "BOF"?

 

[AuthorEditor]

When starting up from a slippery surface I frequently put my '95 Grand Marquis in 2nd gear and it makes a significant difference in preventing wheel spin. I've even done it a few times on slippery mud surfaces. I thought that was pretty common knowledge from the old RWD car days.

OT, but someone mentioned RWD cars in winter, and I find the Crown Vic/Grand Marquis platform is actually very good in the winter, except for starting up from deep snow or ice, or heading up steep hills. Once up to speed, like on a slippery highway, the cars are extremely well balanced and predictable if you do encounter very slick areas. I do carry around more than 100 lbs in the trunk in the winter, and keep the gas tank full if expecting bad weather.

 

[Kuato]

Originally Posted By: AuthorEditor
When starting up from a slippery surface I frequently put my '95 Grand Marquis in 2nd gear and it makes a significant difference in preventing wheel spin. I've even done it a few times on slippery mud surfaces. I thought that was pretty common knowledge from the old RWD car days.

OT, but someone mentioned RWD cars in winter, and I find the Crown Vic/Grand Marquis platform is actually very good in the winter, except for starting up from deep snow or ice, or heading up steep hills. Once up to speed, like on a slippery highway, the cars are extremely well balanced and predictable if you do encounter very slick areas. I do carry around more than 100 lbs in the trunk in the winter, and keep the gas tank full if expecting bad weather.


Very true; I've had a couple GM/Crown Vic; also carried some sand and a small shovel in the trunk.

To OP: If you change the gearing for towing (a good idea) and leave the TC stock, you should be fine. What AuthorEditor said about starting in a higher gear does help in many situations.