Impact of KERS on tyre wear

[Verdigris]

Doesn't the parking brake act on the rear drums? That should give them enough exercise to prevent seizing, I'd have thought.

 

[Caramaddy]

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.

Thanks John, a long time since I passed my O Level physics!

 

[johnb80]

Thanks John, a long time since I passed my O Level physics!

 

[PVperson]

Hi
I saw a post recently that suggested that KERS resulted in the tyres wearing quickly, especially if you use KERS 3. I usually drive Normal and 3 but after seeing that post I've switched to 2. I do a lot of miles 44k since November 21. Have changed fronts once (Falken-good)and rears will need changing soon. Should I stick with 2? Thanks

I think it's hilarious the Chinese call regen KERS!!!? KERS was a system developed for F1 "Kinetic energy recovery system" which used a vacuum flywheel ("kinetic energy") and revolves at up to 64,500 rpm. Note "Kinetic" which is the energy of something MOVING. Regen is simply converting the "Kinetic" energy of the car (slowing down) into electrical energy (in the battery)
I find level 3 regen on an MG5 about equivalent to a diesel engine breaking, in fact, when the battery is fully charged (and hence no room to store any more energy) the lack of regen I find quite alarming, when I take my foot off the pedal, and the car doesn't slow down as much as it should.
For greatest efficiency, when slowing down on the motorway, it's best that the battery current (third display down from Speedo, on a MG5) doesn't go negative, as there's a large conversion loss, e.g. better not use the energy from the battery in the first place, rather than stuff it back in.
Professionally, I'd say it wouldn't cause more tire wear than engine breaking (in a turbo diesel and you have to brake to slow down anyway, so why not do it nice as progressively with regen, rather than wearing your brake pads and discs?
When I was using a Pug 206SW 1.4Hdi for 8.5 years, I always used as much engine-braking as pos. and I never had to change the brakes until I scrapped it last year! (bought, £480, driven 82,000, sold £2000 (ULEZ) plus £221 for scrap.......

 

[shpub]

I think it's hilarious the Chinese call regen KERS!!!? KERS was a system developed for F1 "Kinetic energy recovery system" which used a vacuum flywheel ("kinetic energy") and revolves at up to 64,500 rpm. Note "Kinetic" which is the energy of something MOVING. Regen is simply converting the "Kinetic" energy of the car (slowing down) into electrical energy (in the battery)

I think that was the Williams systems. They developed it but never fitted it to their F1 cars and used an electrical system like the other F1 teams. The design was sold for other uses though. Other F1 teams used electric motors and batteries. KERS is a pretty good name and it does mean we can claim we have F1 tech in our cars!

I find level 3 regen on an MG5 about equivalent to a diesel engine breaking, in fact, when the battery is fully charged (and hence no room to store any more energy) the lack of regen I find quite alarming, when I take my foot off the pedal, and the car doesn't slow down as much as it should.

I agree. I find level 3 too much.

For greatest efficiency, when slowing down on the motorway, it's best that the battery current (third display down from Speedo, on a MG5) doesn't go negative, as there's a large conversion loss, e.g. better not use the energy from the battery in the first place, rather than stuff it back in.

There is an argument that the occasional bit of charging into the battery rather than constant draining helps to overcome the Peukert effect which limits the battery's ability to deliver all the stored energy. Yes Peukert is associated with lead acid batteries but it is also seen to a lesser degree with LiIon batteries as well. The more the battery is caned, the less of the stored energy you can get is the basic law!
Indeed, it has been said that the most efficient roads are not that are level but have slight hills to go up and down. I was doing some postgrad work on this and there certainly on first inspection seemed to be some validity in it. The batteries get a break and seem to respond better as a result.

When I was using a Pug 206SW 1.4Hdi for 8.5 years, I always used as much engine-braking as pos. and I never had to change the brakes until I scrapped it last year! (bought, £480, driven 82,000, sold £2000 (ULEZ) plus £221 for scrap.......

Never really understood the need for engine braking with modern cars, especially high power sports cars rear wheel cars with lots of torque where engine braking would occasionally lock the rear wheels and a spin like a handbrake turn. It is braking on one set of wheels only for a start so can never be as efficient as using the brakes. The weight transfer is also pretty strange. There is also the small matter of the fact that ABS isn't working as well as there is no brake pressure to modulate. Then there was the cost of the additional clutch wear compared to the cost of brake pads which are cheaper and easier to replace. It is not a good way with a modern car.

Yes I know it was used on old vehicles whose brakes were pretty awful but with modern cars there is absolutely no need. Not possible with EVs as the amount of regen is carefully controlled to prevent this problem.

I digress... yes I agree if you have to brake/slow down then coasting followed by regen and finally the brake is the way to go.

Doesn't the parking brake act on the rear drums? That should give them enough exercise to prevent seizing, I'd have thought.

Its rear discs not drums and the system is a "park brake by wire" in that electronics controls the parking brake application. In normal use this means that the car is virtually stationary when the brake is applied and released.

There is also a motor brake which i think is used when the car is switched off. Then there is the assist feature which locks brake pressure so that the brake pedal can be released without releasing the brakes.

Long and short of it is that the parking brake is not much use in cleaning up discs.

 

[Caramaddy]

QUOTE: "
"There is an argument that the occasional bit of charging into the battery rather than constant draining helps to overcome the Peukert effect which limits the battery's ability to deliver all the stored energy. Yes Peukert is associated with lead acid batteries but it is also seen to a lesser degree with LiIon batteries as well. The more the battery is caned, the less of the stored energy you can get is the basic law!
Indeed, it has been said that the most efficient roads are not that are level but have slight hills to go up and down. I was doing some postgrad work on this and there certainly on first inspection seemed to be some validity in it. The batteries get a break and seem to respond better as a result."

That is interesting as I was told by an old Tutor:-

"The brain is like a battery, it is at its most efficient when it is able to charge and discharge. Talking is important but so is listening!"

 

[Gomev]

I think it's hilarious the Chinese call regen KERS!!!? KERS was a system developed for F1 "Kinetic energy recovery system" which used a vacuum flywheel ("kinetic energy") and revolves at up to 64,500 rpm. Note "Kinetic" which is the energy of something MOVING. Regen is simply converting the "Kinetic" energy of the car (slowing down) into electrical energy (in the battery)
.......

I think KERS is perfectly fine and describes exactly what is happening. Regen, a contraction of regeneration is used widely for many things such as urban regeneration etc. Are we actually RE generating something or simply generating electricity by converting the "Kinetic" energy of the moving car into electrical energy.
My vote is for KERS as the official description and regen as colloquial usage.

 

[Geoffers]

I find level 3 regen on an MG5 about equivalent to a diesel engine breaking, in fact, when the battery is fully charged (and hence no room to store any more energy) the lack of regen I find quite alarming, when I take my foot off the pedal, and the car doesn't slow down as much as it should.

Borrowed a friends Audi ICE automatic the other day, frightened myself witless at the first junction when the car didn't slow at all!

 

[pollenface]

Been using kers3 normal for nearly 40,000kms and tyres don't look concerning

 

[Billymanta]

Thanks for the prompt and helpful reply.?


Appreciate this useful info, thank you ?

Totally agree - it’s ether KERS wearing rear tyres or brakes wearing front tyres - slowing the car down does this - there’s no difference.

 

[nexia201]

I dont think kers has to do with tyre wear , my fronts lasted 64k kms , the rears i have to change every 30k kms and they are as bald as an egg . The problem i see is that the driven wheels lets say in town every take off it tries to wheel spin or slide ( wr have crappy road surface ) yesterday i changed my 3rd rear sets and this time i put 225/45r17 and seem to grip much better , lets see how long these last

 

[Verdigris]

I dont think kers has to do with tyre wear , my fronts lasted 64k kms , the rears i have to change every 30k kms and they are as bald as an egg . The problem i see is that the driven wheels lets say in town every take off it tries to wheel spin or slide ( wr have crappy road surface ) yesterday i changed my 3rd rear sets and this time i put 225/45r17 and seem to grip much better , lets see how long these last

But you're driving a rear wheel drive car. The MG5 is front wheel drive.

 

[CanyonReveller]

I dont think kers has to do with tyre wear , my fronts lasted 64k kms , the rears i have to change every 30k kms and they are as bald as an egg . The problem i see is that the driven wheels lets say in town every take off it tries to wheel spin or slide ( wr have crappy road surface ) yesterday i changed my 3rd rear sets and this time i put 225/45r17 and seem to grip much better , lets see how long these last

My car had covered 16k miles when I bought it and was near the end of two sets of front tyres. The el cheapo tyres on the front would wheel spin even at the gentlest takeoff. I switched out to Goodyear Vectors, and they're still practically brand new after 10k miles and never wheel spin unless you're really trying.

What I'm trying to say is that I agree; driving style and crappy slipping tyres are the main reason for fast tyre wear. It's much easier to accidentally wheel spin on crappy tyres in an EV due to the massive amount of torque available. Nothing to do with KERS.

 

[andymgzs]

Hi
I saw a post recently that suggested that KERS resulted in the tyres wearing quickly, especially if you use KERS 3. I usually drive Normal and 3 but after seeing that post I've switched to 2. I do a lot of miles 44k since November 21. Have changed fronts once (Falken-good)and rears will need changing soon. Should I stick with 2? Thanks

The alternative is use the brakes or go into the back of someone. Take your pick!

One foot driving ensures maximum life of brakes and tyres.

One down side is cheap disks rust and corrosion is the end of them - not wear.

 

[Andypandy]

Hi
I saw a post recently that suggested that KERS resulted in the tyres wearing quickly, especially if you use KERS 3. I usually drive Normal and 3 but after seeing that post I've switched to 2. I do a lot of miles 44k since November 21. Have changed fronts once (Falken-good)and rears will need changing soon. Should I stick with 2? Thanks

Just put the Kers on adaptive.

 

[johnb80]

Just put the Kers on adaptive.

Thats not an option.

 

[Spinynorman]

Partly OT but relevant in a small way…
My year 3 service came back with a brake pad change recommended warning!
Now I’m disabled and only drive once or twice a week for a few miles and in 3 years have only done 1,600 (yes 1.6k) miles!!
I think the dealership is talking ‘bollards’ and trying it on and if I were fit, I’d have the pads off for inspection myself.
Plus are they telling me they spent time taking off two front wheels/callipers for no extra fee?
They also said my A/C needed recharging…more ‘Horlicks’, IYAM
My year four is coming up soon and I’m tempted to ask them to prove the state of my pads to me with video of them dismantling the callipers etc ??

 

[Verdigris]

I had most brake problems with cars that haven't been used much.

Do you mainly use KERS for braking?

 

[kevin ellard]

I had most brake problems with cars that haven't been used much.

Do you mainly use KERS for braking?

He's only done 1600 miles in 3 years. He doesn't mainly do much braking at all.

 

[Spinynorman]

He's only done 1600 miles in 3 years. He doesn't mainly do much braking at all.

Nice one! It’s only town/urban travel - most 6-8 mile trips into town on Eco mode so KERS 3 all the way or normal mode if I forget to change it over.
Thought KERS was like engine braking on an ICE car..?