Impact of KERS on tyre wear

[Verdigris]

Because the MG5 is a creeper you can't really avoid using the brakes, so that should be sufficient to stop any binding. If you drive more or less daily then you shouldn't really have to worry. It's old codgers, like me, who sometimes don't drive for a week or two, that may need to make a conscious effort to exercise the brakes a bit.

 

[dragon2611]

I thought it used regen breaking at first with the brake pedal even on kers1?

Doesn’t the kerbs setting just control how aggressive it is without touching the brake pedal

 

[kevin ellard]

I think you are thinking of the driving MODE, not the KERS.

No, I'm thinking of the KERS setting. I think that it controls how much the throttle controls the KERS rather than using the brakes . I think the car still uses KERS when you apply the brakes regardless of the KERS setting. The KERS switch could more properly be named "one pedal driving feel preference" but that isn't very catchy.

 

[kevin ellard]

Try this, get up to 70 mph with kers 2, take your foot off the accelerator and note the regen figure in the power meter, now switch to kers 3 and see the increase. It changes the maximum amount of regen available.

That is a result of the kers 3 setting doing the equivalent of pressing the brake pedal when you take your foot off the accelerator. You could put it in kers 1 and gently apply the brakes to get the same amount of power recovered in the power meter.

 

[johnb80]

That is a result of the kers 3 setting doing the equivalent of pressing the brake pedal when you take your foot off the accelerator. You could put it in kers 1 and gently apply the brakes to get the same amount of power recovered in the power meter.

But you also apply the friction brakes at the same time thereby wasting energy.

 

[Verdigris]

A good test of what the difference between K1 and K3 is to find a long steep hill (1:4 is about right), preferably with a few bends near the bottom. Approach the brow of the hill in K3 at 30mph, then take your foot off the accelerator and without touching the brake observe what speed the car maintains. Repeat the exercise in K1 and again note the speed.

It is important to do it in that order as it will give you just enough time to watch your whole life flash before your eyes...

 

[johnb80]

A good test of what the difference between K1 and K3 is to find a long steep hill (1:4 is about right), preferably with a few bends near the bottom. Approach the brow of the hill in K3 at 30mph, then take your foot off the accelerator and without touching the brake observe what speed the car maintains. Repeat the exercise in K1 and again note the speed.

It is important to do it in that order as it will give you just enough time to watch your whole life flash before your eyes...

You make oy larf you do

 

[kevin ellard]

But you also apply the friction brakes at the same time thereby wasting energy.

Does anyone actually know if that is true? Does gentle application of the brake pedal do friction and KERS at the same time? If it does then I'm surprised that people have so much trouble with pitted and rusted brake disks.

 

[johnb80]

Does anyone actually know if that is true? Does gentle application of the brake pedal do friction and KERS at the same time? If it does then I'm surprised that people have so much trouble with pitted and rusted brake disks.

It doesn't need much movement of the pedal for hydraulic pressure to increase. Are there many people that have trouble with rusting disks? more than ICE vehicles?

 

[Verdigris]

I rarely use the brake pedal, I use anticipation and KERS. I mostly use the brake to select drive/reverse and to stop the creep, where necessary. I expect the discs and pads to last the life of the car. The brake fluid might need changing, is all the brake maintenance I'm expecting.

 

[MickeySw]

Does anyone actually know if that is true? Does gentle application of the brake pedal do friction and KERS at the same time? If it does then I'm surprised that people have so much trouble with pitted and rusted brake disks.

On my 1st gen EV pushing the brake pedal will initially only increase regen but once I press further, the disk brakes are also applied.

Not sure how it’s implemented on the MG5 as I rarely need to use the brakes at all…

 

[m4rmite]

Recently I needed to have a rear tyre replaced.
After driving 18 miles from work and within 20 seconds of arriving at the garage, my rear tyre was off.
It was supposed to be a puncture repair but 2 nails changed that.
Anyway, when the wheel was off I thought " I wonder if the brakes get hot?".
I bravely/ stupidly touched the disc.
Nothing. Absolutely ambient temperature.

I know rear brakes are used less but I expected some kind of heat.
The front brakes might be a different kettle of fish though.

 

[johnb80]

Recently I needed to have a rear tyre replaced.
After driving 18 miles from work and within 20 seconds of arriving at the garage, my rear tyre was off.
It was supposed to be a puncture repair but 2 nails changed that.
Anyway, when the wheel was off I thought " I wonder if the brakes get hot?".
I bravely/ stupidly touched the disc.
Nothing. Absolutely ambient temperature.

I know rear brakes are used less but I expected some kind of heat.
The front brakes might be a different kettle of fish though.

If youre using the regen and driving with good anticipation i.e. not using the brake pedal other than to hold it stopped, you wouldn't expect any heat in the disks.

 

[Gomev]

When I use the brakes it's because I want the car to stop quicker than using regen alone, otherwise I wouldn't need to would I

 

[Caramaddy]

Just to add it was the rear brake pin that was seized - the rear brakes get less use than the fronts.

 

[shpub]

I stay in kers 2 as I like that amount of regen. The throttle does affect the regen as I can have a little bit and the current drain/charge stays around the zero level. i.e. practically coasting. A little lift to coast, big lift to regen brake.

Brake pedal pressure also affects the amount of regen as it increases dramatically: brake hard and the regen can reach 200A and the power goes hard into the blue.

There are good reasons for this: regen only affects the front wheels. Too much regen without the corresponding rear brakes can cause the car to go unstable. So the level of regen without applying the brakes is within the safety zone if you like. Apply the brakes and the regen will increase because the additional friction braking stabilises things. Unfortunately brake use does waste energy but the increase in regen reduces that significantly.

There is an interesting point about coasting in neutral. It is illegal. Probably came about from the days in yore when it was complex to get in and out of neutral. The argument was that you are not in control of the car because you can't accelerate or use engine braking.

As I say I just lift a little to coast.

 

[johnb80]

Just to add it was the rear brake pin that was seized - the rear brakes get less use than the fronts.

Interesting statement, how so?

 

[shpub]

Interesting statement, how so?

Quite normal for cars to have a brake pressure reducer feeding the rear brakes to prevent the rear brakes from locking up before the fronts. This reduces the amount of pressure and wear on the pads so they tend to last longer.

Made worse on a Lexus Hybrid as they have rear wheel electric motor and front wheel ice. This allows the regen to effectively replace the rear brakes for most operations so the brakes are not used.

 

[Caramaddy]

Interesting statement, how so?

See above John!

 

[johnb80]

Quite normal for cars to have a brake pressure reducer feeding the rear brakes to prevent the rear brakes from locking up before the fronts. This reduces the amount of pressure and wear on the pads so they tend to last longer.

Made worse on a Lexus Hybrid as they have rear wheel electric motor and front wheel ice. This allows the regen to effectively replace the rear brakes for most operations so the brakes are not used.

The rear brakes aren’t used fewer times which is what I believed your post claimed. Yes of course they don’t do as much work due to weight transfer etc.