What's The Point In

[Chris81]

You know the ones - under all Yaris front bumpers there is a strip of plastic attached to both sides. They make the front overhang of the car so low that they easily catch on kerbs when parking in certain car parks. You have to make sure not to drive too far into they bay to avoid any scraping.

Our car park at work is like that and practically all other cars have sufficient clearance at the front to clear a standard kerb whereas a Yaris would catch it. Why is the Yaris so different??

[Gnome]

Basically, so if it bottoms out, it's scratches the plastic, and not your nice shiney front bumper. ;)

[YarisGLS]

Usually cars have these to reduce turbulence air flow... some to avoid hot air from radiator gets to the front of the car (at stand still), some for reducing the amount of air going to the bottom of the car at speed, so to gain more stable handling...

Or as Johnathan said, for sacraficing when you gone too far up at a Kerb!

I like them there though, makes the car looks lower :)

[rickster]

anybody have a set? need them for my new tte bumper, old 1s are nackered

[Al J]

Yeah, as already said, they are a great warning that you're about to start bending metal. They don't do much for airflow on a Yaris. :P

I wonder if there's a Yaris in the country that hasn't got serrated bottom edges on those pieces of plastic. Nearly lost a finger once!

[smilybrad]

The plastic bits will have an effect on the aerodynamics of the car as the are placed to divert the flow arround te front wheels.

Not sure if this is the main reason for them but as the car is tall and quite blunt i'd suggest their for increasing high speed stability by diverting air arround the front wheels.

If they were just for indicating when the car was too close to the ground etc then it would just run across the whole width of the car.

[Al J]

No, sorry, I just can't buy that. Not on a Yaris.

Still, each to their own opinion.

[forde]

Just cos its not fast doesnt mean it dont need stabilising.

Also, pretty much every car has those on the bottom of the bumper anyway so no big deal.

[smilybrad]

125 Mph is PLENTY fast enough to need them, as a general asumption of thumb aero starts to have an effect around 60mph+

Most cars will be aero tested during their development and manufactures don't just stick bits of plastic on cars with out a very good reason!

maybe someone should try asking toyota directly, but i'd put money on them having an effect on the cars aerodynamics!

Brad =)

[T V O R]

No, sorry, I just can't buy that. Not on a Yaris.

Still, each to their own opinion.

but i'd put money on them having an effect on the cars aerodynamics!

I agree with the aero dynamics.

Just because it’s a Yaris doesn’t mean it has to have the characteristics of a house brick on the motorway.

Car manufacturers spend millions on development and wind tunnel testing to maximum fuel efficiency (coefficient?)

At 70mph you may be surprised at what can drag you down (window open, sunroof up etc)

The parts department at Mr. T would be able to give the official answer to their use.

[Ryan1985]

If they were just for indicating when the car was too close to the ground etc then it would just run across the whole width of the car.

If they are for diverting wind round the front wheels at high speed why don't they run across the whole width of the car?

The parts department at Mr. T would be able to give the official answer to their use.

They don't know their bum from their elbow!

[Al J]

125 Mph is PLENTY fast enough to need them, as a general asumption of thumb aero starts to have an effect around 60mph+

Most cars will be aero tested during their development and manufactures don't just stick bits of plastic on cars with out a very good reason!

maybe someone should try asking toyota directly, but i'd put money on them having an effect on the cars aerodynamics!

Brad =)

But they have them on 1 litre Yarii which are not known for doing 125mph. As they wind tested the car, why didn't they change the design at that stage?

Oh and they do stick bits of plastic on their cars for no real reason...

they're called roof spoilers. :P

I agree with the aero dynamics.

Just because it’s a Yaris doesn’t mean it has to have the characteristics of a house brick on the motorway.

Car manufacturers spend millions on development and wind tunnel testing to maximum fuel efficiency (coefficient?)

At 70mph you may be surprised at what can drag you down (window open, sunroof up etc)

The parts department at Mr. T would be able to give the official answer to their use.

Yes, but opening a window or the sunroof means the air hits the inside back window instead of going past the car so it's like a huge air brake. That makes sense.

Citing these tiny bits of plastic as anything other than cosmetic or for under front valance protection, doesn't.

Besides, look at their position and angle. Hey, maybe they are teeny little air brakes! I'd imagine they added to the cd of the car by a small fraction, if anything but then so do the door mirrors, handles and even the aerial. At normal speeds they simply wouldn't matter in my opinion.

Even vans can do 70.

[smilybrad]

But they have them on 1 litre Yarii which are not known for doing 125mph.

Like i said aerodynamics come in to play MUCH! earlier then 125mph.

Oh and they do stick bits of plastic on their cars for no real reason...

they're called roof spoilers. :P

Actually most factory roof spoilers do have an effect on the cars aero dynamics, just like the rear diffuser on the new renault clio has an effect (Trust me i have spoken to people who designed it).

Yes, but opening a window or the sunroof means the air hits the inside back window instead of going past the car so it's like a huge air brake. That makes sense.

Besides, look at their position and angle. Hey, maybe they are teeny little air brakes! I'd imagine they added to the cd of the car by a small fraction, if anything but then so do the door mirrors, handles and even the aerial. At normal speeds they simply wouldn't matter in my opinion.

One thing i would like to point out is that the angle at which air hits parts of the car isn't the same as direction the car is traveling. just because the car is traveling in a straight line doesn't mean that the air hitting the wing mirrors or the plastic bits in front of the wheels is parallel to the

direction of movement.

The angle at which the air hits rear wing of a formula one car is different to the free stream flow infront of the car. (FACT)

Aerodynamics is a lot more complex then you may think. Just because those little bits of plastic are at an angle to the rest of the car doesn't mean they are at the same angle to the flow of air that is passing over them, and there is alot of work in motorsports to control the flow around the front tyres which is why i am certain they are there for a purpose.

Even vans can do 70.

Yes they do and thats why the aero of new vans are optimised around the other main criteria.

Lorries only do 60mph but the adjustable roof things have a huge effect on the drag coefficient!!!

Brad =)

[Al J]

Yes, some of what you mention is agreed but you're confusing your physics, I'm afraid mate. The air that reaches the rear wing of an F1 car obviously has been severely compromised due to it first having travelled over the car. No-one is going to dispute its effect.

We're talking about the front of the vehicle and, I'm fully aware that a canard fin (fitted on some racing sports cars for over forty years) can make a difference but we really are talking chalk and cheese here.

Very often, designs or additions to the rear or roof of cars (normal road cars, not performance ones) is to move air further away from the back of the vehicle, causing less turbulence. I suspect that on the Clio has more to do with keeping the back of the car cleaner than it has about keeping it on the ground.

Of course, when Toyota do a P2 version of the new Yaris and it has pop-up front and rear diffusers, depending on its speed, I'll have to retract all of this!

Meanwhile, just watch out for those kerbs.

[Chris81]

Well quite a debate has opened up here since my original post! I doubt they have much to do with aerodynamics especially if you compare the shape of the Yaris to loads of other cars on the road that are just as high and narrow and don't wander all over the road as soon as you hit 70mph. As I said, from a quick straw poll in the work car park most cars front bumpers can clear a kerb with room to spare but I've got to be careful to stop just shy of the kerb to avoid a scrape. But hey they must be there for a reason! And airflow seems to be the only explanation, unless Mr. T has a huge problem with car owners overhanging kerbs in car parks!!

I agree with whoever said that your local toyota dealer wouldn't have a clue - they'll just make something up on the spot - thats what they usually do when you ask them to explain something. I bet if we went and asked our local dealer we'd have at least a handful of different explanations.

[PhillWalker]

I had to have mine removed as it caught on my drive every morning when driving off the drive!

[Gnome]

I think they're teeth, added by the Toyota Performance department, to make the Yaris look mean!!!

Or... They're upside-down eyebrows.

Or... They serve the purpose of solely creating debates like this...

[Chris81]

I had to have mine removed as it caught on my drive every morning when driving off the drive!

Now we're getting somewhere!!! Did you take them off or did Toyota? Have you noticed the car driving any differently since they were removed?

[PhillWalker]

I had to have mine removed as it caught on my drive every morning when driving off the drive!

Now we're getting somewhere!!! Did you take them off or did Toyota? Have you noticed the car driving any differently since they were removed?

No difference Whatsoever! I got my brother to do it, he works for toyota, but all it is is a couple of bolts which you can use a 10mm spanner on . Needed to do the same on both my yaris's old and new. They are just a pain those scuff pads!

[rickster]

fancy selling them?

[alanbradley]

Do you want a proper answer?

Small flaps like those can smooth arflow around the front wheels by up to 10% at motorway speeds. This lowers wind noise, imroves fuel consumption and, yes, "makes it faster".

The back ones (yes, I've broken them again - now knackering the second set) do a similar job.

There...

A

[T V O R]

Yes, there are back ones as well, just in front of the rear wheels under the car, like mini spoilers.

I would put money on the fact they are there for some sort of aero dynamics especially at motorway speeds.

I also think the rear spoiler is not just for cosmetic reasons. OK, it won’t give any down force but I think it could reduce any vacuum effect to the rear of the car at higher speeds.

Whatever the reasons, I think the whole effect looks smart

[Gnome]

Do you want a proper answer?

Small flaps like those can smooth arflow around the front wheels by up to 10% at motorway speeds. This lowers wind noise, imroves fuel consumption and, yes, "makes it faster".

The back ones (yes, I've broken them again - now knackering the second set) do a similar job.

There...

A

My answers are far better... :D

[Yaris SR Kid]

Do you want a proper answer?

Small flaps like those can smooth arflow around the front wheels by up to 10% at motorway speeds. This lowers wind noise, imroves fuel consumption and, yes, "makes it faster".

The back ones (yes, I've broken them again - now knackering the second set) do a similar job.

There...

A

My answers are far funnier... :D

[smilybrad]

So does this mean that people are agreeing that they are for arodynamic reasons??

Al J i'm looking at you.....

Brad =)