Bad Morning

[ladyjaine]

Friend of mine had a very bad morning. She drives an '01 3500 dually, 4X4, no e-brake and I don't know if manual or automatic. It doesn't matter, it's totalled. The frame has a ripple.



No serious injuries, just bumps and bruises. Down hill, standing on the brake and gaining speed. The car she hit had all (ALL) windows explode outwards at once. Road conditions were wet, raining light to moderately all morning, possibly wet leaves on the road. Overcast skies, but good visibility at 11:00 in the morning. The truck was empty, she'd just unloaded all her gear at the event and was going out for coffee.



I can't help but wonder two things, did she have ABS and what gear was she in? She was in no condition to deal with 'you should have... ' comments, so I kept my trap shut. Later, I'll ask her, but by then I expect her memory to be more than a bit blurry.



She'll replace it with another dually. I'm hoping to get her to get an e-brake on the next one and to consider downshifting as a necessary part of driving.



Jean

 

[Whitmore]

Jean

Sorry to hear of your friends mishap, glad she is OK,keep us posted and when she get her new Ram get her to join us here so we can help get her outfitted (bombed) right.



cheers, Kevin

 

[dalton4]

LadyJaine, the bigger question may be if she fell victim to the run-away full throttle situation when some of the electronics go crazy.

 

[nickleinonen]

what tires did she have under it... ? i'm not gonna name brands [don't want to start a flame war] but there are brands popular here that are lousy in wet [and snow and mud] too hard of a tread compound...



good to hear your friend is ok though. .

 

[Dane]

Two thoughts...

The skinny stock tires and slippery conditions don't mix.



The ABS not working at low speeds can cause you to think you are at maximum braking because the rears lock up, but there is still more front brakes to be had. I've had that happen to me.

 

[Pit Bull]

Sorry to hear about this. I'm glad your friend is OK, trucks can be replaced, friends can't. I had a 2000 CTD 3500 4x4 automatic and it would not stop worth a ####. It had the Michelin LTX M/S tires (wear well don't stop well) in the 235/85/16 size and the rear brakes on mine were drumms. The 2000, and I am sure the 2001 have ABS. It is the drumm brakes and tires that were the problem with mine. My new truck with the Goodyears and the disc brakes on all corners seem to make a world of difference.

 

[ladyjaine]

Archery practice was cancelled on account of rain so I haven't seen her since the accident. I'll ask about her tires. She said it was a skid, so I don't think it was the runaway throttle thing. Yesterday she was in no shape for analysis of the failure. She didn't have to drive home, so she was doing pain killers for her nerves and sore left shoulder. Some was homebrew, as in mine. What are friends for, after all?



Jean

 

[csevers]

I think after 99 trucks rated at over 10k had to have 4 channel abs per DOT. I don't much like the abs any way I would rather have abs at 9 miles mph than 90 mph thats just me. Glad to hear she's ok. Did air bag go off?



Craig

 

[Steve Campbell]

Dane...

Could you explain... ...



"The skinny stock tires and slippery conditions don't mix. "??



I always thought the opposite.

 

[ladyjaine]

Phriction Physics

A wider tire is going to give you a bigger footprint, more rubber on the road. That will always provide better traction in slippery conditions. Skinny tires don't 'cut' down to gain traction, they don't stick well because there's a smaller patch of rubber actually on the road.



Try pushing a sliding window open by pressing on the glass with just a fingertip, then push with the palm of your hand. If you push equally hard with your palm as you do with just a fingertip, the window moves faster using your palm than with the fingertip. The same effort gives different results because the traction is different. The only thing changed is the surface area. For the true physicists, try it with wet hands and wet glass. If you have sliding shower doors you've already done this.



It's the same with traction on the road. More area touching = more control with less slipping. If my truck weight is 9000# on a skinny tire and 9000# on a fat tire, the truck is going to have better traction on the fat tire.



Jean

Yes, I used to teach...

 

[Pit Bull]

Jean that is true unless there is a sheet of water under that big foot print. Then tread pattern and tire composition would be more important. With the 235/85/16's that she had on her truck and the dual tires on the rear she should of had all of the foot print she needed on the ground. I think her problem was the rear drumm brakes not doing the job?? Please let us know what you find out.

 

[JyRO]

Wide is not necessarily better...

Jean,

A wider tire is going to give you a bigger footprint, more rubber on the road.

That's true!

That will always provide better traction in slippery conditions.

That is NOT true! Especially the "always" part. Big rubber will provide better traction in dry conditions and in the sand. I'm not sure about the mud though. Probably wide tires in the mud though just to keep a vehicle from sinking so far into the mud. You guys in the know on the mud, let us know.

Skinny tires don't 'cut' down to gain traction, they don't stick well because there's a smaller patch of rubber actually on the road.

Wrong again! This is why skinnier tires do better in the snow and rain. Ever heard of the formula P = M/A. Where Pressure = Mass / Area. The greater the pressure you can put down to the ground, the better the traction IN SLIPPERY CONDITIONS. In this case, skinnier tires have less area, thereby increasing pressure. They push rain and snow out of the way better due to the higher pressure they put to the ground.





Jean, the more surface area you have on your tires, the more snow & or rain you get between the tire and the ground. And that fat tire will have less pressure on it to shove the snow or rain out of the way. That's why fat tires in the snow and rain perform poorly compared to a skinny tire on the same vehicle.

Yes, I used to teach...

I hope it wasn't math!

That was just for grins, I'm sure you understand math, just not this concept of traction in slippery conditions (now you do). BTW, I don't know everything, but I'm pretty sure the above is correct. Somebody let me know if I'm wrong.



- JyRO

 

[jjohn]

JyRO

Well I think your right. Wide tires definitely hydroplane easier. Wide tires have more flotation in the snow and tend to climb up on top and fall in, so to speak. My old 1990 with aggressive tread 235's (mud & snow) alway did better in deep snow than with wider tires in snow and rain. I had a 1995 Yukon 2 door with about 10 inch wide tread on the road... one scary vehicle in the rain at hi way speeds.

 

[SOOT]

JyRO, is completely right. Narrower tires have more contact pressure there for more traction on wet snow covered roads. Dually's are the worst for driving around in the snow, since there are 4 tires in the back spreading the weight, and the back of typical trucks is a lot lighter than the front you have less contact weight there for less traction.

 

[ladyjaine]

Mass is the issue, too

I spoke from automobile experience, not truck. I think it's a 'mass confusion' thing that tripped me up.



I didn't carry out the calculations, but there's a point where mass flips you 'over the hump' so to speak in the footprint calculation. My teensy little 2 seater sports car is on one side and my big truck will be on the other. For my low mass sports car, I want wide tires, soft compound and a pretty significant water managing tread pattern. She's so light, she'll slide on snow at her max allowable weight. Nothing really helps. Mid engine, rear wheel drive, the worst configuration for snow ever built. But so much fun!



Anyway. I'll go with the stock tires when my truck arrives and if I absolutely hate them or they make me nervous, I'll swap them for something different- regardless of wear. I was taught that when safety and price conflict, pick safety.



Jean

 

[JyRO]

What's the 2 seater...

Jean - Whatcha got, an MR2 (Spyder)? Maybe an old Fiero (doubt it, they didn't hold together too well and its been a while since they made 'em, even though I liked 'em a lot). For dry traction, more contact patch is the way to go. IMHO, once you are to the point where the engine doesn't have the power to spin-out the drive wheels from a stop, you've got more than enough contact patch, way more than enough.



The big tires (ones that a car can't spin out) are trading excessive (un-useable) traction for frictional losses (lower fuel mileage and/or lower top speed). Except if you're road racing or into solo II (auto-cross), then you may actually need more rubber than your car can overpower (spin-out) for handling reasons. Those that think they need more rubber than what their car can overpower must be going too fast on public roads. Although fat tires do look good on sporty type cars. And that's a good reason to have'em too. My truck can easily spin the tires, but I feel like my dry traction is way more than adequate, I ain't drag racing it.



I'm having to change to larger (wider & taller, because just taller isn't available) tires for my Celica to correct 3 to 4 mph speedometer error at 60 mph. The current tires are on the TWI's and snow is quickly approaching . Got the tires picked out, just waiting on the close on my mortgage refinance (11/27).



- JyRO

 

[Pit Bull]

Re: What's the 2 seater...

Originally posted by JyRO

Jean - Whatcha got, an MR2 (Spyder)? Maybe an old Fiero (doubt it, they didn't hold together too well and its been a while since they made 'em, even though I liked 'em a lot).

- JyRO

I'm betting an Acura NSX.

 

[JyRO]

eeeew....

An NSX is SWEEEET!



- JyRO

 

[ladyjaine]

My two little'uns

I actually have two little, sporty two seaters. The first is a Toyota MR2. NA 1992 with 143,200 miles. The second is a Nissan 300ZX turbo, 1985 with 70,000 miles. I run high performance all season tires on each of them, no larger or smaller than the originals. The MR2 is going to go away when or before the truck arrives. I have fun in the MR2 sliding around and staying inside my lane when it snows. The Z weighs more and slides less because I stay out of the turbo. Whee, 12 MPH and fishtailing!



I don't push either of them to their handling limit. I am not that good a driver and I'd be way outside my envelope at that point. I'm also not willing to risk the Z in wheel to wheel.



Back to trucks. This is actually exactly the sort of information I was hoping to learn from this board. I'd much rather make an error in words than make an error on the road. I am now really thinking about handling in a 'truck' way, not a 'car' way. It's not the same. What I know could cause accidents.



Based on the discussion I've just read and participated in, I think that poor 3500 was a victim of empty truck and wet road. She had brakes but no exhaust brake and didn't use downshifting. I think Kim stood on the brake as you would in an ABS auto, but didn't do any of the other things she coulda/shoulda. The result is a totalled truck.



What can I do to prevent this happening to me? I think I should not run empty if I can help it, I should downshift and I'm definitely getting that e-brake.



Jean

 

[JyRO]

Good reply...

Pitbull - I guess I win, since the Z is not mid-engine, it doesn't count.

I'd much rather make an error in words than make an error on the road.

Very commendable, I applaud you Jean.

She had brakes but no exhaust brake and didn't use downshifting. I think Kim stood on the brake as you would in an ABS auto, but didn't do any of the other things she coulda/shoulda.

I'm not sure an exhaust brake will help with slippery road conditions. A lotta guys with the exhaust brake say that it works so well that it may lock up the rear tires on slippery roads . If she was in a panic stop, an exhaust brake wouldn't have activated quickly enough anyway. Only thing that would've helped in her case since she stomped the brakes was fully functional ABS.

What can I do to prevent this happening to me? I think I should not run empty if I can help it, I should downshift and I'm definitely getting that e-brake.

If you have ABS, use them as they're intended (empty or not). If they don't work properly you can't help it. The best way to prevent her sort of accident is to be as defensive a driver as possible, but nothing is fool-proof. And if you're in a panic situation, you WILL NOT be trying to downshift, and it wouldn't help you anyway (in a panic situation). The only other things I could think of is if you feel a tire or tires lock up, the only thing you can try is to modulate the brakes. But man, that takes some will power to do in a panic situation - to let off the brake quickly and not re-stomp it to the floor. Just re-apply it as hard as you can before lock-up. I think some accidents are truelly unavoidable. The e-brake is a good idea to extend the life of your service brakes.



- JyRO