cars are rubbish

[PBancroft]

Next door were doing the wheel spinny thing to try to get off the drive earlier. Didn't make it. I went out and offered cardboard under the wheels, but was turned down. He tried again for another ten minutes and then started chipping ice off the tarmac with a spade.

I think he's still there.

 

[KentMikey]

Recumbent users are poseurs but I look so good and people look at me.

 

[BentMikey]

Surely starting off in 2nd would require more torque than 1st as you are using a stiffer gear (speaking of cars that is)? I would start off in 1st but using very little if any acceleration, that way I start the car rolling with the maximum bite into the slippy surface but with the minimum force.

If you try to pull off in 2nd you may find you need more acceleration and therefore more torque and more likelihood of wheel spin.

Its the same when you are cycling; if you start off half way up the cassette you will spin the rear wheel in snow or wet road so you always start off in 1st; less torque.

Of course if you accelarate in 1st like a looney then wheel spins you shall have.

Descending in low gear makes sense and if you want to warn the driver behind you can touch the brake without engaging brake pads and you will engage the rear lights without braking at all.

But what do I know? I'm just an advanced driver B)

GrasB is right. I think you're confused between the engine side of the gearbox and the wheel side. Low gear means low tyre rpm and high torque. A higher gear like 2nd or 3rd drops the torque, i.e. reduces the peak forces between the tyre and the road. Look at it another way - it's easy to wheelspin in 1st gear - and not in 2nd or 3rd.

 

[Zippy]

I take your point BentMikey but a lot of cars cannot pull off in 2nd wthout stalling, hence I would pull off in 1st with either no or very little acceleration.

When the cycling the torque is highest when pulling off in 1st which if you pulled off too hard would likewide cause a wheel spin.

However, if pulling off in your highest gear you may find yourself rising out of the saddle (which increases torque by extending leverage) as the comparatively lower torque is insufficient to get the rear wheel moving. Am I right?

 

[BentMikey]

Exactly - the higher gear reduces force at the driving wheel, especially peak forces. That's exactly what you want when traction is low. Thus GrasB is correct - use a higher gear in low traction conditions, and don't put down too much power either.

 

[gaz]

a lot of cars cannot pull off in 2nd wthout stalling

total rubbish! i bet most cars can pull away in 3rd without to much trouble. 4th and 5th is fishy as you wear out the clutch more that it's worth. It's all in the drivers ability to control the clutch.

 

[Zippy]

total rubbish!

Ouch - I'm hurt enough to try pulling off in 2nd to see now; maybe even try third - but if it's all in the driver's ability to control the clutch I suggest that it should be just as efficient to pull off in 1st which is easier on the engine overall.

 

[BentMikey]

No, 1st will still not be better. If the driver makes a small mistake in clutch/accelerator co-ordination, then there will be a much sharper rise in peak forces on the tyre/road in 1st gear, and much higher overall peak forces. In 2nd or 3rd the effect of that same mistake will be much smaller, and will reduce the chances of wheelspin.

 

[Zippy]

If the driver makes a small mistake in clutch/accelerator co-ordination, then there will be a much sharper rise in peak forces on the tyre/road in 1st gear,

I agree - so 2nd gear would allow greater margin for error.

Now, so why would it be better to pull off always in 1st gear when cycling to prevent the same thing? Presumably because the quadricep/brain/nerve pathway is better able to deliver exactly the right amount of force to enable drive without wheel spin. If we just stamped down on the pedal in first we would spin just the same but the human body (experienced cyclist?) is usually more sensitive to these forces so a spinout is less likely.

However to pull off in second on a cycle would require more sudden Power than steady Force (M x A) which gives rise to less sensitivity and loss of optimum balance which would make a wheel spinout more likely.

I think that's what I mean

 

[Norm]

On a bike in a low gear, half a pedal stroke moves you forward a few inches. If you break traction in that time, either put the other foot down or be more careful when you get the other foot on the pedal.

In a car, the engine just keeps on going.

 

[GrasB]

Basically you're trading off likelihood of stalling the engine & spinning the wheels. Go to tall or too short on the gearing & you have to be very skilled with the clutch to prevent one or the other. On snow/ice it's very easy to spin the wheels so you need to use a higher gear.

What I used to do with my turboed hill climber on slippery starts was to get the revs up to about 2500 rpm in 2nd or 3rd & get it so the front wheels where just about to spin against the handbrake (fly off type) then release the h/brake, wait until the clutch stopped slipping then floor the throttle as quickly & smoothly as possible. The car would surge off the line with near perfect traction while on a wave of torque thanks to the turbo being on full-boost. I'd not recommend doing something that aggressive on snow/ice & revving the engine that high & holding it on the clutch kills the clutch in no time, the basic principle can be applied to driving on snow ice. Little or no throttle 2nd, 3rd & possibly 4th hold the car on the h/brake & let the clutch a bit a little bit then release the h/brake, no more throttle input should be required & the car should just gently pull away.

 

[gaz]

Ouch - I'm hurt enough to try pulling off in 2nd to see now; maybe even try third - but if it's all in the driver's ability to control the clutch I suggest that it should be just as efficient to pull off in 1st which is easier on the engine overall.

it damages the clutch not the engine.

 

[fossyant]

Stop fluffin arguing over gears in a sodding car.....get a bike

You pull away lightly....keep a steady momentum... 2nd gear recommended, although any gear if you know wht you are doing....most folk don't though .........zzzzzzzzzzzzz zzzzzzzzzzzzzz zzzzzzzz as they spin away.....

sheesh......

 

[gaz]

Stop fluffin arguing over gears in a sodding car.....get a bike

You pull away lightly....keep a steady momentum... 2nd gear recommended, although any gear if you know wht you are doing....most folk don't though .........zzzzzzzzzzzzz zzzzzzzzzzzzzz zzzzzzzz as they spin away.....

sheesh......

It's all right for you, you've got those studied tyres

 

[Zippy]

it damages the clutch not the engine.

...well it does damage the clutch but if you put a load on the engine by pulling off in too high a gear all the time it is bound to have a knock on effect; that's why there's a first gear.
... not trolling; jus' saying ... anyway I don't drive in snow, I walk and I'm gonna put my studdies on me bike this weekend and cycle to work off road next week so I don't know why I'm even bothering with this debate any more. sheesh, I'm ofta bed nite nite x