Hill descent

Buckcreek · Feb 10, 2005

I have had The same thing happen on my little BX, When ive forgot to put it in 4 wheel drive. I have a very steep bank i have to mow, i usually go straight down it to my dads yard then take a round trip back up my drive way, and go down again, It is so steep that when the grass even has dew on it i will spin if i try to back up even with diff lock . I try to beat my dad tho this part of the property but one day i was gone and he decided to mow i seen where he had made a few passes and quit when i pulled in the drive way i got a sick feeling that somthing was wrong so i went straight to his house to check on him , and thats when i seen the two bare lines down the hill , i was doing somthing the evening before and forgot to put it back in 4wheel drive. he made the first trip down the hill and slid very fast down the hill, what scared me the most is he wont wear the seat belt, and at the bottom of the hill is a rolling ditch and when he hit it he almost went over the steering wheel , it shook him up a little and he had some bruises but he wasnt hurt seriuosly. from now on i always check to see if im in 4wheeldrive but i still cant get him to wear the seatbelt. He is getting stubborn in his old age.

rbarker · Feb 10, 2005

( Apparently they cut the tree down, the tractor came down with it, and he drove it away - something about old Fiat tractors.
)

Holy Crap! /forums/images/graemlins/shocked.gif /forums/images/graemlins/shocked.gif I would have like to have seen this! /forums/images/graemlins/grin.gif

rbarker · Feb 10, 2005

( You could have disengaged the clutch and pumped the brakes very gently to slow your descent. )

I'm not sure I agree with this. The tractor was experiencing some engine braking even though it was less effective. By disengaging the clutch the braking effect of the rolling wheels would have been lost and the tractor would have sped up more. Pumping the brakes would be much more likely to cause wheel lock and loss of control. Re-engaging the clutch after the tractor sped up would probably have caused a worsened skidding condition as well.

Maybe a throttle up would have helped match the wheel speed to the tractor's ground speed thus regaining more control over the tractor. I don't think a gear change during the wild ride would have been advisable for the same reasons.

Well, that's just my opinion anyway... /forums/images/graemlins/crazy.gif

Jim_Fisher · Feb 10, 2005

Bob,

( The tractor was experiencing some engine braking even though it was less effective. )

I can't think that the tractor was running away (as in overspeeding the engine) without losing traction since Catch95 stated that he has never experienced a problem with this hill when the surface was dry.

I suspect that the engine braking was a big part of the problem. Once traction is broken, there is no way to reduce the engine's braking effect without disengaging the clutch or increasing the engine speed to match the tractor speed. Engine braking amounts to the same thing as steady pressure on a brake pedal in slippery conditions. If you apply too much brake you will slide and you will very likely continue to slide until you let off the brake.

( Pumping the brakes would be much more likely to cause wheel lock and loss of control. )

Pumping the brakes has been the accepted practice for slowing a vehicle on a slippery surface for many years. It actually reduces the likelyhood of wheel lock. The advent of anti-lock brakes has made the practice obsolete in those vehicles so equipped.

( Re-engaging the clutch after the tractor sped up would probably have caused a worsened skidding condition as well. )

I could not agree with you more. Re-engaging the clutch would be a huge mistake.

( Maybe a throttle up would have helped match the wheel speed to the tractor's ground speed thus regaining more control over the tractor. )

That would have been my first instinct, assuming that the throttle wasn't already open. Not sure how the tractor is geared but I suspect that 2nd/low range might not have enough speed to catch up.

( I don't think a gear change during the wild ride would have been advisable for the same reasons. )

I aggree. Unless you have a synchronized transmission and a way to control engine speed with your foot shifting gears is not an option.

I went through a similar experience in a tractor trailer about twenty-five years ago. I was following a salt spreader after some freezing rain had fallen. After topping a hill, the salt spreader apparently ran out of material. I was about a half mile behind him and could see that he was still ahead of me but I couldn't see what was coming out of the back of his truck. Suddenly, the inside of the cab was very quiet. I looked at the tach and noted that the engine was idling. At the speed that I was traveling and the gear that I was in, it should have read about 1800 rpm. I applied the throttle very gently and put a very slight pressure on the trailer brakes. The driver of the truck behind me later told me that he could see my rig start to bend in the middle and then straighten out. Definitely a high pucker factor incident. /forums/images/graemlins/grin.gif

farmermatt · Feb 10, 2005

NEVER DISENGAGE THE CLUTCH WHEN GOING DOWN A STEEP HILL!! the centrigugal force of the mower wouldve been pushing you down the hill through the pto. if the wheels were spinning faster than you were moving then you shouldve disengauged pto, throttled all the way down to idle and applied a little brake pressure. diff lock wouldnt have mattered unless one wheel was spinning more than the other, but it doesnt sound like that was the case. if you did have diff lock engauged, on most tractors once you press the brakes it automatically disengages the diff lock.

matt

JerryG · Feb 10, 2005

Fellows,
If you had slid down as many hills in a truck (not a pick-up) or a tractor as I have you would know that you have two options. #1 is to out run the slide, That is to keep up gearing. Then pray that there is enough shut down area at the bottom. #2 Is to disengage the clutch and let the tires start to roll and then start applying the brakes again. If the tires are not rolling you can not stop it with the brakes nor can you control the slide.

GaryE · Feb 10, 2005

Matt,

I have to agree with Jim and Jerry, tires that are loosing traction are useless. I have spent countless hours on high speed road courses and I can tell you the last thing you ever want to do is lock up a tire.

The best thing you can do is let the vehicle regain a neutral balance then apply braking without loosing the ability to steer. I would much rather steer out of a problem than to skid and hope I will survive!

Gary

PineRidge · Feb 10, 2005

We have a pond on our property and last winter I descended the backside of the dam on the TC-40D. It was rather a wild ride from the top to the bottom, kind of a long controlled skid just like the backside of my pants looked after I jumped off the rig at the bottom. /forums/images/graemlins/blush.gif

The dam is now off limits once the snow falls until after early spring. Skids like that are no fun at all.

rbarker · Feb 12, 2005

( I suspect that the engine braking was a big part of the problem. Once traction is broken, there is no way to reduce the engine's braking effect without disengaging the clutch or increasing the engine speed to match the tractor speed.)

Yes, I can see your point. I was thinking the whole "rolling tire vs. locked wheel" issue in which the rolling tire is a better scenario. In this case you could be right, it might not have made any difference. Others seem to agree with you on that as well! /forums/images/graemlins/blush.gif

( Pumping the brakes has been the accepted practice for slowing a vehicle on a slippery surface for many years. It actually reduces the likelyhood of wheel lock. The advent of anti-lock brakes has made the practice obsolete in those vehicles so equipped. )

Of course you are right! I've done it many times prior to having antilock brakes. I guess I was thinking that in this case while traveling down a slippery slope at acccelerating speed it would be pretty easy to lock up a wheel or two with a pump on the brakes. If done carefully it could certainly help.

( The driver of the truck behind me later told me that he could see my rig start to bend in the middle and then straighten out. Definitely a high pucker factor incident. /forums/images/graemlins/grin.gif )

Oh yeah! That'll keep you regular for the day! /forums/images/graemlins/wink.gif

Catch95 · Feb 22, 2005

Thnaks for all the posts on this.

I had to go up and down the same hill the other day and approached the hill with some caution. I had the same implement on the 3PL but not with the PTO engaged - I'm sure it was engaged when I had the problem. I went down the hill even after some rain with no difficulty at all.

So I am fairly sure the problem I had the other week was caused by action of the implement driving me down the hill - as was suggested in a post.

Thanks again for all the advice.

Mark