In 1985 pretty well autos were three speed and controlled only by hydraulics.
Very different now.
- Vote on answer
- posted
3 years ago
electric cars and frosty roads
Loading thread data ...
- Vote on answer
- posted
3 years ago
Many autos prevent the car running backwards on a hill.
- Vote on answer
- posted
3 years ago
You need to get a better one, then. The ZF 5HP in my 90s BMW did. As have all since.
- Vote on answer
- posted
3 years ago
No mystery with mine, if you're stopped the hold assist *is* on and the "handbrake light" is green to say that it is using the ABS brake servo to apply all 4 pads, if for any reason (the ABS overheats, the car stalls etc) then it applies the electric parking brake to the rear wheels and the LED turns red like a normal handbrake light. In either case touch the accelerator and it's released and sets off.
There's a button to disable this, but I never use it.
- Vote on answer
- posted
3 years ago
I actually bothered to read the manual. It just disengages on throttle position sensor when in 'Drive' or 'Reverse'. So no control at all.
Garage warned me that they often stick on ruining the disks...
- Vote on answer
- posted
3 years ago
haven't
Wish my mine had that. I think the trigger for hill start assist is tied in with fully releasing the clutch in neutral and the car being slightly down at the back, FSVO "slightly".
- Vote on answer
- posted
3 years ago
wrong and wrong
I hit black ice at speed - no brakes - first sign was steering wasn't steering.
I didn't dare hit the brakes, ABS or not. I had just enough steering to aim the car towards a patch of sunlit road. Once there I turned the car straight and let it slow down on the NEXT bit of ice until I was doing a lot less than 100mph...
My mum had a Mk1 Ford escort 1100. The only car that would lose its front first, and then its rear, on a wet or icy road.
One time going down an icy hill in a manual XJS, I was not on the throttle, but the engine braking was enough to star the rear swinging...I uses a bit of throttle to get it straight and prayed for enough steering for the bend at the bottom. Well there was a lot of gravel on the edge of the rad, and the front gripped that,
Any set of wheels can break first but you HAVE got a certain amount of control even so, the key is to react fast and react lightly before te swing is beyond recovery
- Vote on answer
- posted
3 years ago
You need lots of sipes for snow.
Yep and if you're not bothered about wear a very soft compound. You ought to see the amount of rubber marbles that collect on the outside of bends on motor racing circuits.
Sipes don't clear water, the wider grooves and channels separating the blocks do.
Blocky/chunky tread patterns are more for mud than snow. Packed snow is a pretty firm surface, better to have lots of sipes in the block faces to grip the snow. I think what happens is the sipes open along the leading edge of the contact patch, snow gets forced into them, the sipes then get forced closed in the contact patch, the increased pressure on the snow turns it to ice "attached" to the packed snow surface providing the grip.
Too true, deep fresh snow or slush is more akin to mud than packed snow.
- Vote on answer
- posted
3 years ago
No clear definition as to when a sipe gets to be a groove. All of them help
Packed snow you need studs or spikes
- Vote on answer
- posted
3 years ago
My VW Transporter Hill Start Assist only comes into play when the vehicle is past a certain angle incline/decline. It won't activate on the fairly shallow motorway "off ramp" with traffic lights but then it doesn't need to as the transition from brake to accelerator wouldn't warrant the use of the handbrake either. Might be linked to the "anti-tow" alarm sensor which I believe is known to cause problems with channel ferry crossings setting off the alarm if not deactivated.
- Vote on answer
- posted
3 years ago
There are good hill hold systems and bad ones, sometimes on the same model.
A friend had an old manual Audi A6 on which the hill hold/auto hand brake worked perfectly.
When the car got long in the tooth he bought a new A6. The handbrake released the moment you started to lift pressure off the clutch pedal but well before the clutch bite point causing it to roll backwards on hills.
After much arguing with the dealers he got an AA engineers report and successfully rejected the car.
But garages are well known for talking bollocks.
Tim
- Vote on answer
- posted
3 years ago
So very true. I often wonder if they have a book of lies to quote. Rather like BoJo. ;-)
Not that long ago, got a local garage to fit a new handbrake cable to the old Rover. To fit it myself meant getting the whole car raised in the street - a real PITA. Far easier on a ramp.
I'd replaced both brake cylinders (one was leaking) and new shoes. Drums were unworn. Everything stripped and cleaned. Made sure the auto adjusters were working and the internal handbrake levers working correctly - they have pivots that can seize.
They gave me some guff about having to remove the drums and slacken the adjusters to get the cable to fit. When I looked later, no surprise. They'd adjusted up one side of the cable to maximum - not understanding how it functions. Luckily the adjustment at the actual lever itself was OK, so merely slackening off the adjustment at the drum and setting it correctly after making sure the shoes had self adjusted properly got it correct. Incidentally, my last BMW had a cover beside the handbrake which you removed to adjust it. Without having to get underneath the car. Nice touch.
Lot to be said for autos on hill starts. All you need is a one way clutch (sprag) which is only operational in drive. Prevents the car running backwards easily.
- Vote on answer
- posted
3 years ago
well this is a son of a friend who spent a long time in car insurance and now is workshop manager.
- Vote on answer
- posted
3 years ago
Idiots are frequently promoted out of harms way
- Vote on answer
- posted
3 years ago
It's selectable on ours. Either regen when you take your foot off or freewheel.
- Vote on answer
- posted
3 years ago
Ours has just the one gear so there's nothing to change down to. In regen mode it simply switches the motor into a 'dynamo' and gently brakes the car.
- Vote on answer
- posted
3 years ago
+1
On ours, it is.
- Vote on answer
- posted
3 years ago
And presumably *either* way it uses regen in some proportion compared to friction when you press the footbrake - by turning off regen for freewheel it presumably doesn't turn it off also for explicit braking.
- Vote on answer
- posted
3 years ago
Given that stops the car in a shorter distance than 'coasting', doesn't it actually waste power? No form of power generation is 100% efficient.
- Vote on answer
- posted
3 years ago
Makes sense to use re-gen instead of gentle braking.