2016 Yaris MOT adviseries

[preperationlaunch]

22 hours ago, BobHos said:

To my simple mind it seems that in "B" mode the engine may still be connected to the drive train and drives motor/gen 1 as a generator feeding power back to the battery causing increased "engine braking"

In the case you describe, MG2 captures the power, feeds it to MG1 which then forces the ICE to spin.

[Cyker]

It's worth noting that not all the HSDs work the same way too!

I've noticed subtle differences in behaviour with my colleague's Auris and my Mk4 Yaris.

Two examples:

1) His Auris has virtually no simulated engine-braking when off-accelerator, and will coast for ages. My Yaris OTOH has a noticeably higher simulated engine-braking, akin to 3rd/4th gear off-accelerator, and will not coast anywhere near as far.

2) The Auris has much more regen in B-mode - I think it must go to maximum regen before using the ICE to bleed off more speed. The Yaris OTOH doesn't regen any more than when you off-accelerator normally, and instantly spins up the ICE. When we both coasted down a hill in B, his Auris got 5 blocks of charge, whereas the Mk4 didn't get a single one!

 

 

21 hours ago, Cowgirl said:

I’m new to hybrids and automatic cars, so stupid question, can you change gears from Drive to B while moving or should you change gears at a complete stop?

You can switch to literally anything other than P at any time (Although I'd not recommend going into R at high speed  ) - All the other modes are not 'real' and are just you telling the computer what direction to feed power via an inconveniently large lever - There are no mechanical linkages or anything like you'd get in a real autobox.

P is the only exception, as it engages a wedge that locks the whole drive train up and stops it moving.

[Stopeter44]

11 minutes ago, Cyker said:

1) His Auris has virtually no simulated engine-braking when off-accelerator, and will coast for ages. My Yaris OTOH has a noticeably higher simulated engine-braking, akin to 3rd/4th gear off-accelerator, and will not coast anywhere near as far.

2) The Auris has much more regen in B-mode - I think it must go to maximum regen before using the ICE to bleed off more speed. The Yaris OTOH doesn't regen any more than when you off-accelerator normally, and instantly spins up the ICE. When we both coasted down a hill in B, his Auris got 5 blocks of charge, whereas the Mk4 didn't get a single one!

That's interesting. I just used "B" mode for the first time, on the Yaris IV, and it brakes pretty hard, I mean it slows the car down on reasonably steep hills way better than my 208 EAT6 pushed into manual mode and two gears down from what the auto trans would do by itself. 

I'm thinking that what @BobHos is experiencing in his 2016 Yaris III, sounds like the difference between your friend's Auris and the Yaris IV.

[TonyHSD]

34 minutes ago, Cyker said:

It's worth noting that not all the HSDs work the same way too!

I've noticed subtle differences in behaviour with my colleague's Auris and my Mk4 Yaris.

Two examples:

1) His Auris has virtually no simulated engine-braking when off-accelerator, and will coast for ages. My Yaris OTOH has a noticeably higher simulated engine-braking, akin to 3rd/4th gear off-accelerator, and will not coast anywhere near as far.

2) The Auris has much more regen in B-mode - I think it must go to maximum regen before using the ICE to bleed off more speed. The Yaris OTOH doesn't regen any more than when you off-accelerator normally, and instantly spins up the ICE. When we both coasted down a hill in B, his Auris got 5 blocks of charge, whereas the Mk4 didn't get a single one!

 

 

You can switch to literally anything other than P at any time (Although I'd not recommend going into R at high speed  ) - All the other modes are not 'real' and are just you telling the computer what direction to feed power via an inconveniently large lever - There are no mechanical linkages or anything like you'd get in a real autobox.

P is the only exception, as it engages a wedge that locks the whole drive train up and stops it moving.

Once when I was looking for an address and driving slow I mistakenly hit the P button on my Prius instead of hitting the hazard lights button and guess what happened , I kissed the steering wheel, what a nasty surprise, the P locked the transmission and the car stopped unexpectedly sharp, thanks god no one was behind. 😂👍 Lesson learned hard way 😉,  I still do sometimes now with my Auris but at higher speeds instead of ev button I push the P but nothing happens just the sound warning. 

[Cyker]

Ouch! Must have been going fairly slow at least, as I didn't think it would let you go into P when moving at all! (Smeg knows what it does on the Mk4 with its gigantic shift lever! Probably just flash all the warning lights at me like it's xmas!)

Good thing it didn't snap the pawl off too - I remember a few people who got rear-ended in P mode having that happen to them (Which is partly why I have joined the darkside and just use the brake hold...)

 

25 minutes ago, Stopeter44 said:

That's interesting. I just used "B" mode for the first time, on the Yaris IV, and it brakes pretty hard, I mean it slows the car down on reasonably steep hills way better than my 208 EAT6 pushed into manual mode and two gears down from what the auto trans would do by itself. 

I'm thinking that what @BobHos is experiencing in his 2016 Yaris III, sounds like the difference between your friend's Auris and the Yaris IV.

Yeah, the B-mode in the Mk4 is really really harsh - It's what it uses to slow the car down when using the cruise control too, which is why I normally click it off well in advance and take over when I see a stoppage!

 

 

 

 

[BobHos]

Looks like I've really started something with my comments about my experience of increasing fuel economy by using "B" mode for  predictive slowing/stopping. It certainly works for our main mode of urban travel. I need to see how it performs on longer out-of-town journeys. Despite all the advice and explanations I have a funny feeling that it may well be beneficial there too. The problem as I see it is that we do not really fully understand the intricacies and fine detail of exactly how the components and their controls interact in practice. We have theories and paradigms but we do not have access to the fine detail of the overall system as designed and constructed by Toyota. Fiendishly clever these Chinese (sorry Japanese).

Something that has been bothering me has been the assumptions and comments that regenerative braking (in "D" mode) is only initiated when the brake pedal is depressed. I did not think that was the case and today I tried it and found, as I expected, that normal regen. braking takes place as soon as the accelerator is released. I also found that whilst driving down a moderate incline when I released the accelerator there was a small amount of regen. current indicated on the hybrid system indicator dial ("charge") but when I then selected "B" mode the regen. current was significantly greater. The hybrid Battery was not in a fully charged condition so I hope to try the same thing again when it is. My paradigm is that in engine breaking ("B") mode) the kinetic energy of the moving vehicle/parts is transferred to drive the engine and coupled M/G1. If the hybrid Battery is fully charged there will not be electrical regen. current fed to the Battery but the inertia and resistance of the engine, etc will provide braking.

As I say I do not have detailed knowledge of how the system actually works but, like others, I have my own idea or paradigm. The way to prove or disprove a paradigm is to test and observe which I certainly intend to do.

 

[preperationlaunch]

14 hours ago, BobHos said:

Something that has been bothering me has been the assumptions and comments that regenerative braking (in "D" mode) is only initiated when the brake pedal is depressed. I did not think that was the case and today I tried it and found, as I expected, that normal regen. braking takes place as soon as the accelerator is released. I also found that whilst driving down a moderate incline when I released the accelerator there was a small amount of regen. current indicated on the hybrid system indicator dial ("charge") but when I then selected "B" mode the regen. current was significantly greater. The hybrid battery was not in a fully charged condition so I hope to try the same thing again when it is. My paradigm is that in engine breaking ("B") mode) the kinetic energy of the moving vehicle/parts is transferred to drive the engine and coupled M/G1. If the hybrid battery is fully charged there will not be electrical regen. current fed to the battery but the inertia and resistance of the engine, etc will provide braking.

As I say I do not have detailed knowledge of how the system actually works but, like others, I have my own idea or paradigm. The way to prove or disprove a paradigm is to test and observe which I certainly intend to do.

 

You have a light amount of regen in D, this is to emulate coasting in a normal ICE car. People expect it and it makes the transition safer, as you don't have people wondering why the car isn't slowing down with their foot off the accelerator. This drag is caused by MG2 charging the Battery.

Interestingly, if the Battery is at the SoC limit, there is minimal to no regenerative drag.

Coasting with a minute amount of accelerator pressure to engage a glide (no regen, but no acceleration) is a common hypermiling technique with the Hybrid.

In B-mode, if you're above about 35mph, the maximum current to the Battery is limited to around 25 Amps on a long descent, the engine starts spinning immediately via MG1 to provide a load for the rest of the energy being generated by MG2 (the bigger motor attached to the wheels). The speed of the ICE increases as the battery fills up.

This Prius thread has some detailed description on some of the mechanisms https://www.priusonline.com/threads/b-mode-and-how-prius-cvt-hsd-integrates.18907/ The Yaris uses essentially the same drivetrain as the Gen2 Prius, albeit with smaller more efficient motors, with a reduction gear to allow higher speed in EV mode.

 

 

 

[BobHos]

1 hour ago, preperationlaunch said:

You have a light amount of regen in D, this is to emulate coasting in a normal ICE car. People expect it and it makes the transition safer, as you don't have people wondering why the car isn't slowing down with their foot off the accelerator. This drag is caused by MG2 charging the battery.

Interestingly, if the battery is at the SoC limit, there is minimal to no regenerative drag.

Coasting with a minute amount of accelerator pressure to engage a glide (no regen, but no acceleration) is a common hypermiling technique with the Hybrid.

In B-mode, if you're above about 35mph, the maximum current to the battery is limited to around 25 Amps on a long descent, the engine starts spinning immediately via MG1 to provide a load for the rest of the energy being generated by MG2 (the bigger motor attached to the wheels). The speed of the ICE increases as the battery fills up.

This Prius thread has some detailed description on some of the mechanisms https://www.priusonline.com/threads/b-mode-and-how-prius-cvt-hsd-integrates.18907/ The Yaris uses essentially the same drivetrain as the Gen2 Prius, albeit with smaller more efficient motors, with a reduction gear to allow higher speed in EV mode.

Thanks for that info. P 

Paradigm shift already (but that is what paradigms are all about)- I thought when I was coasting down on "B" mode the engine (and M/G1) was still coupled to the drive train and the additional regen. current was coming from M/G1 to charge the battery but you say that the engine must be uncoupled from the drive train in this situation and M/G2 provides braking by regen. current being fed into the battery or, if the battery is fully charged, being used to spin the engine via M/G1. - Interesting. Obviously, for the fully charged battery scenario, fuel efficiency will not be improved.

Haven't looked at the info. on the site you have recommended yet but I will.

 

 

 

[BobHos]

26 minutes ago, BobHos said:

 

I have read the article you mentioned P. and it is very detailed and interesting. I still think that using "B" mode for the type of journeys we predominantly make provides extra fuel efficiency (ref the 2 carefully executed test runs I did a couple of days ago (10mpg saving)). I also feel that using "B" mode for predictive slowing/stopping on longer out of town journeys probably would not deliver the same level of fuel consumption improvement. Overall, though use of the enhanced regenerative braking of "B" mode will result in less wear of mechanical  brake parts. Interestingly one comment in the report alluded to the possible problem of following drivers being unaware of vehicle slowdown due to absence of brake warning lights during "B" mode slowdown. I have been aware of this and always ensure that there is sufficient distance between my car and following cars before selecting "B".

[preperationlaunch]

1 hour ago, BobHos said:

Paradigm shift already (but that is what paradigms are all about)- I thought when I was coasting down on "B" mode the engine (and M/G1) was still coupled to the drive train and the additional regen. current was coming from M/G1 to charge the battery but you say that the engine must be uncoupled from the drive train in this situation and M/G2 provides braking by regen. current being fed into the battery or, if the battery is fully charged, being used to spin the engine via M/G1. - Interesting. Obviously, for the fully charged battery scenario, fuel efficiency will not be improved.

Haven't looked at the info. on the site you have recommended yet but I will.

No, that's where it gets really tricky and interesting.

The engine, MG1 and MG2 are always coupled through a planetary gear set. MG2 can spin the wheels on it's own (EV mode). MG1 provides no resistance, and spins freely, therefore, the ICE doesn't turn. EV mode top speed is limited by the maximum speed at which MG1 can spin freely.

When a current is applied to MG1, this will cause the ICE to spin. The same works in the inverse, MG1 must resist the ICE turning (generator mode) to allow the ICE to drive the wheels.

This is old, but still representative of what happens in the planetary gear set in different situations.

http://prius.ecrostech.com/original/Understanding/WhatsGoingOnAsIDrive.htm

 

[preperationlaunch]

Wear on brake parts is one of your least concerns on the Hybrids. It's not unknown to get 100k out of a set on a Prius. It's actually more of a problem that they can get grabby from surface rust not getting knocked off quickly.

Out of curiosity, what was your overall figure with the 10mpg increase? I'm currently averaging around 60mpg in city/motorway use with careful use of heating when the engine is still warming up, and ECO mode switched on around town, always in D though.

[BobHos]

12 minutes ago, preperationlaunch said:

Wear on brake parts is one of your least concerns on the Hybrids. It's not unknown to get 100k out of a set on a Prius. It's actually more of a problem that they can get grabby from surface rust not getting knocked off quickly.

Out of curiosity, what was your overall figure with the 10mpg increase? I'm currently averaging around 60mpg in city/motorway use with careful use of heating when the engine is still warming up, and ECO mode switched on around town, always in D though.

About 50mpg

[BobHos]

1 minute ago, BobHos said:

About 50mpg

That is non - eco mode

[BobHos]

35 minutes ago, BobHos said:

That is non - eco mode

Sorry - The figure of 50mpg is our overall mpg and that is a combination of my wife's more aggressive driving mode and my conservative driving mode. For the careful pair of identical run tests (apart from "B" mode for one) the consumption for the "B" mode run (non ECO) was 68.9mpg.

[BobHos]

On 3/2/2022 at 1:31 PM, preperationlaunch said:

Wear on brake parts is one of your least concerns on the Hybrids. It's not unknown to get 100k out of a set on a Prius. It's actually more of a problem that they can get grabby from surface rust not getting knocked off quickly.

Out of curiosity, what was your overall figure with the 10mpg increase? I'm currently averaging around 60mpg in city/motorway use with careful use of heating when the engine is still warming up, and ECO mode switched on around town, always in D though.

Hi P meant to get back to you sooner to tell you the test runs I did a few days ago were in ECO mode, not non- ECO as I had told you.

The actual test results were:-

• 
• Registered Member
• •  85
• First Name:P
• Toyota Model: Looking
• Toyota Year: Non
• Location: Other/Non-UK

Posted Tuesday at 04:09 PM

@BobHos for some concrete figures I've acquired on my Yaris mk3 for you.

Coming down a reasonably steep hill at 40-50mph, I've noted some of the figures coming through my ScanGauge.

At approx 40mph, below the EV cut off, max regen into the Battery is about 50 amps sustained using the cruise control to maintain speed.

If I move into B mode, Battery charge current drops to approximately 25 amps, sustained and motor generator 1's current consumption increases as it starts to rev the engine. The engine goes from 0rpm to ~2000rpm. The engine starts spinning as soon as the gear selector is moved to B, irrespective of state-of-charge. Deceleration is greater than if using cruise control, but regeneration is significantly reduced.

Above the approximately 45mph cut-off, MG1 spins the engine at 992rpm anyway, to stop MG1 from spinning too quickly. (Plantary gears are magic).

For comparison, max regen current I see is generally around 100 amps under heavy braking, but this tails off and clearly can't be sustained for long.

This journey has been repeated dozens of times with similar results.

Equally, around town, B-mode will not engage the ICE in a power-wasting scheme at lower speeds, it's smart enough not to. You may well be finding that you're simply benefiting from putting slightly more power into the Battery around town. Light braking which isn't enough to engage the friction brakes will probably net you similar gains.

As another matter of interest, and one @TonyHSD alludes to, when the battery is 'full' at Toyota's ~80% limit, the car is very eager to discharge itself, and will continue to spin the engine on the flat, as well as being somewhat more spirited in how much power the electric motors will provide.

 

[BobHos]

3 hours ago, BobHos said:

Hi P meant to get back to you sooner to tell you the test runs I did a few days ago were in ECO mode, not non- ECO as I had told you.

The actual test results were:-

• 
• Registered Member
• •  85
• First Name:P
• Toyota Model: Looking
• Toyota Year: Non
• Location: Other/Non-UK

 

Posted Tuesday at 04:09 PM

@BobHos for some concrete figures I've acquired on my Yaris mk3 for you.

Coming down a reasonably steep hill at 40-50mph, I've noted some of the figures coming through my ScanGauge.

At approx 40mph, below the EV cut off, max regen into the battery is about 50 amps sustained using the cruise control to maintain speed.

If I move into B mode, battery charge current drops to approximately 25 amps, sustained and motor generator 1's current consumption increases as it starts to rev the engine. The engine goes from 0rpm to ~2000rpm. The engine starts spinning as soon as the gear selector is moved to B, irrespective of state-of-charge. Deceleration is greater than if using cruise control, but regeneration is significantly reduced.

Above the approximately 45mph cut-off, MG1 spins the engine at 992rpm anyway, to stop MG1 from spinning too quickly. (Plantary gears are magic).

For comparison, max regen current I see is generally around 100 amps under heavy braking, but this tails off and clearly can't be sustained for long.

This journey has been repeated dozens of times with similar results.

Equally, around town, B-mode will not engage the ICE in a power-wasting scheme at lower speeds, it's smart enough not to. You may well be finding that you're simply benefiting from putting slightly more power into the battery around town. Light braking which isn't enough to engage the friction brakes will probably net you similar gains.

As another matter of interest, and one @TonyHSD alludes to, when the battery is 'full' at Toyota's ~80% limit, the car is very eager to discharge itself, and will continue to spin the engine on the flat, as well as being somewhat more spirited in how much power the electric motors will provide.

 

Sorry P I meant to quote actual test figures for my test runs on 28.2.2022  but they did not go into my post (newbie error).

The results were 59mpg in D mode ECO (first run) and 68.3mpg in B mode ECO(second run). Conditions were dry and outside temperature was 10 deg. (Heater blower?)

I subsequently repeated the runs yesterday and the results were 56.3mpg in B mode ECO (first run and 57mpg in D mode ECO (second run).Conditions were wet and outside temperature was 6 deg. Heater blower and wipers were  on.

I repeated the test runs today and the results were 63.4mpg in D mode ECO (first run) and 62,2 mpg in B mode ECO (second run). Conditions were dry and outside temperature was 10 deg. (Heater blower off).

All test runs were predominantly on 40mph roads and each run started and ended at the same location. Trip average speeds were 23mpg for all runs.

On reflection I now think that for the first tests on 28.2.2022 The engine  may not have been at a reasonable operating temperature for the first test run (D mode).

The subsequent test runs yesterday and today were with the engine warmed up properly and indicate very little difference between mode D and mode B mpg figures. The lower figures yesterday could have been as a result of low ambient temperatures and operation of heater blower and wipers.

I also paid particular attention to the interaction of brake pedal and regen. braking and, as you said, "soft" application of the brake pedal does indeed result in increased regen. current.

In conclusion I now feel there is little benefit in me continuing to apply B mode control for anticipated braking. It probably will make little or no difference to fuel efficiency or brake pad/disc wear. Besides there is the potential issue of following cars being unaware of increased slowing due to lack of brake lights initially.

 

[TonyHSD]

👏, 
let say B mode it’s not an selective option for extra regenerative braking but only as an engine brake, a safety option when going downhill and for some reason you may loose standard brakes or you just want to ease the work of the brakes and your right foot, flip to B and after a while select D again and that’s all.
D - drive

R- reverse 

B- brake 

P- parking 

N-Neutral 

In full electric cars B act as extra brake too and also extra regenerative power to top up the Battery but also not recommended to use as the car become more unnatural to drive and you have to be very gentle with accelerator, otherwise you will be killing your free rolling, something important for the overall efficiency. 👌

 

[Red_Corolla]

Bob, your tests are never going to be representative because the test period is far too short and I suspect you're trusting to the trip computer to calculate the results, which is fallible in itself.

The only way to get a representative result is to stick to the same driving method over the course of using up a full tank of fuel, then calculate using miles travelled Vs refill quantity and repeat the whole thing for the next test. Obviously you're not going to use it all in one day and other factors will skew the results, but it's still many times more accurate than a quick half hour run and then look at the computer.

Remember that D is by far the more mechanically sympathetic, so that's the one you want to use as long as you're satisfied and convinced with regards to the efficiency.

[BobHos]

7 minutes ago, Red_Corolla said:

Bob, your tests are never going to be representative because the test period is far too short and I suspect you're trusting to the trip computer to calculate the results, which is fallible in itself.

The only way to get a representative result is to stick to the same driving method over the course of using up a full tank of fuel, then calculate using miles travelled Vs refill quantity and repeat the whole thing for the next test. Obviously you're not going to use it all in one day and other factors will skew the results, but it's still many times more accurate than a quick half hour run and then look at the computer.

Remember that D is by far the more mechanically sympathetic, so that's the one you want to use as long as you're satisfied with the efficiency.

I agree that a 2 longer test trips would be more accurate but only if the conditions for both trips was exactly the same which becomes more difficult when the trip increases. Using  full tanks of fuel and computing average mpg for total distance driven (average since refuelling) using both driving methods (with and without B mode) might not give an accurate comparison either since it is nigh impossible to ensure that driving conditions were more or less the same for both tests. I was very careful to try to ensure that my test runs were more or less the same in terms of time, acceleration, speed, slowing and stopping, etc. 

[BobHos]

Once again I want to thank everyone for their feedback, comments and information. As you know doubt have gathered I was not really a Toyota enthusiast/expert and only posted on the site initially because I was surprised that my wife's Yaris was reported as having flaking front pads and advisory issues with front suspension arm pins and bushes at 17,000 miles. I have certainly enjoyed driving the Yaris and understand a lot more of the detailed operation of the Toyota hybrid system  (struggled a bit initially comprehending the dynamics of the planetary gearing and all associated components, controls and sequences).

I am a Subaru enthusiast (for well over 30 years), or was until I sold my Forester last year so I drive the Toyota more now and enjoy it . I miss the "Scooby Doo" though. I was hooked with Subaru's low c.of g. and AWD performance over 30 years ago when I hit a right angled bend, at a speed I should never have been able negotiate it, and sailed round no bother at all. They are cars that are so sure - footed under all conditions.

 

Don't suppose I should really be saying that on a Toyota enthusiast site. Anyway I like Toyotas as well.

[Stopeter44]

5 minutes ago, BobHos said:

struggled a bit initially comprehending the dynamics of the planetary gearing and all associated components, controls and sequences).

Yes, that bit took some time to register for me. That planetary gearset is just a wonder, originally I shunned the hybrid solution thinking it was over complicated comped with ICE or pure electric, but once how it works registers in the grey matter has convinced me that for many people the hybrid is best compromise for now.

[Cyker]

The HSD is quite unique as it's the only variable ratio drivetrain that doesn't rely on friction to work. (At least that I know of...!)

This makes it incredibly reliable and long-lived as there are no friction surfaces to wear out over time.

[BobHos]

Speaking of lower c. of g. and AWD does anyone have any experience of the new Yaris Cross AWD (if it is available yet)?

[TonyHSD]

1 hour ago, BobHos said:

Speaking of lower c. of g. and AWD does anyone have any experience of the new Yaris Cross AWD (if it is available yet)?

It will depend for what use do you really want to have awd. Usually the awd in Toyota hybrids is weak and nothing to compare with Subaru, Audi , Mitsubishi and most other real awd systems. It relays on small e motor attached to the rear axle and controlled independently when needed. Some versions like Prius always start with its rear wheels and immediately torque is delivered from front motors. Many says that they can feel the difference when you drive hybrid awd in comparison with fwd and I will agree with that but does it really worth getting in over the fwd , I am not so sure. When grip is needed a good tyres choice is more important and the fwd will get you exactly to the same place where awd hybrid will do. If you enjoy faster turnings and don’t mind spending extra ££££ and sacrifice some mpg then awd might be the one to get, otherwise the standard fwd is good enough. 
No offence to all awd owners, it’s only my personal opinion. ✌️ Enjoy your hybrids 🏁🏎✅

[BobHos]

17 minutes ago, TonyHSD said:

It will depend for what use do you really want to have awd. Usually the awd in Toyota hybrids is weak and nothing to compare with Subaru, Audi , Mitsubishi and most other real awd systems. It relays on small e motor attached to the rear axle and controlled independently when needed. Some versions like Prius always start with its rear wheels and immediately torque is delivered from front motors. Many says that they can feel the difference when you drive hybrid awd in comparison with fwd and I will agree with that but does it really worth getting in over the fwd , I am not so sure. When grip is needed a good tyres choice is more important and the fwd will get you exactly to the same place where awd hybrid will do. If you enjoy faster turnings and don’t mind spending extra ££££ and sacrifice some mpg then awd might be the one to get, otherwise the standard fwd is good enough. 
No offence to all awd owners, it’s only my personal opinion. ✌️ Enjoy your hybrids 🏁🏎✅

what you say about  winter tyres is correct they do help  2 wheel drive cars in snow but when it comes to ice the awd system is vastly superior (with or without winter tyres,