Tyre wear at Indy

[Anghammarad]

Could someone who knows about these things explain to me how come the inner (left) front wheel is worn out the quickest when driving around the Indy Speedway. It seems completely illogical.

 

[Hig-GT]

This has been discussed before. Weight transfer occurs on the inside front and outside rear. So a left turn will wear the front left and the rear right (& vice versa for a right turn)

 

[Anghammarad]

But certainly the outer front must experience as much weight transfer as the outer rear?

 

[Hig-GT]

In your instance, as you turn left, the weight is supported by the rear right tyre, because this weight is supported by the rear right tyre, less weight is put onto the right front tyre (because the back right is doing some of the work that the front right would usually be doing). This then results in the weight being shifted over to the front left causing corner weighting. Hence more tyre wear on front left & rear right.

I think its all based around trying to keep the weight supported by each axle there abouts the same.

 

[Anghammarad]

OK, fair enough. But if the weight is supported by the outer rear, why then is the inner front wearing out? There can't be much weight on that one.

 

[Hig-GT]

To keep it simple say your car weighs 1800KG. The front supports 900KG & the rear supports 900KG, thus meaning that each wheel is supporting 450KG. As you turn left the weight shifts to the right, mainly onto the rear right hand side (with a slightly stiffer set up), so now the rear left is supporting, say, 350KG whilst the rear right is now supporting 550KG.

Because of the weight being supported on the rear right, the front right only takes on 350KG so the front left has to pick up the slack so is now taking on 550KG like the rear right.

(Not the best example but stick with it)

The extra weight that weight transfer has now put on these tyres (front left & rear right) pushes them into the ground more, putting more force on the tyres, thus causing more tyre wear because the tyres have more work do to.

Don't forget the front left is turning into the corner, it is the main tyre for turning into a left corner, so that already has forces going through it from trying to turn, throw in the extra weight pushing it down etc. etc.

Hope that explains it a bit better.

 

[CivicInLake]

I dont see how.

 

[Anghammarad]

Even so, the weight transfer must surely be greater between the outer and inner wheel pairs than between wheels on the same side when turning into a corner like Indy. In your example the two outer wheels support maybe 550/650 front and rear and the inner ones 350/250 which would mean that the outer tyre still gets a higher load than the inner one.

 

[ElSecundo]

From Dodge's crew chief before the 2009 Indy 500:

HOW MANY LAPS CAN YOU RUN BEFORE YOU ARE STARTING TO SEE SIGNIFICANT TIRE WEAR? "Right now, we're getting about eight or nine laps out of a set of tires and then the right-front is usually corded. On our Mobil 1 Dodge, we've only seen the right-front start to cord. We've seen a little bit on the right-rear. The left sides are fine. I think the right-front (tire) is going to be the one all the crew-chiefs are going to be concerned with because it does the most work and has the most load. That's the tire that is under the most pressure and gains the most heat."

You get the wear in the right front because the right front loads heavily under braking, more than the right rear does when it comes out of a corner. The left front shouldn't be wearing out faster than other tires, so if it is, it may have to do with the suspension setup (camber and toe).

 

[Hig-GT]

On my example:

On the front axle the front left takes more weight.

On the rear axle the rear right takes more weight.

It's not just as simple as oh the car flops over to one side during a corner.

 

[Anghammarad]

On my example:

On the front axle the front left takes more weight.

On the rear axle the rear right takes more weight.

It's not just as simple as oh the car flops over to one side during a corner.

The centrifugal "force" when turning must be greater than the weight shift between front and rear. I can appreciate the idea that the fronts take a higher load when braking into a turn, which obviously is not applicable here, but I still don't understand how the inner wheel can have a higher load when the "force" is clearly directed in the opposite direction.

 

[ElSecundo]

It doesn't. If it's wearing more, it's not because of a higher load.

But these guys are definitely braking going into the corners at Indy.

 

[Hig-GT]

Note the slightly stiffer set up ...

I don't brake into corners at Indy, my Ford GT, Toyota GT-One & X1 go round on full throttle ... (Perhaps learn to tune your cars better / drive better so as to not brake at Indy ... lol!)

Do some research on it yourself if you refuse to listen

Download the - Suspension & Brake Tuning Guide from the link below & read the section on spring rates, that explains all this.

https://www.gtplanet.net/forum/showthread.php?t=135268&highlight=scaff+tuning+guide

 

[ElSecundo]

If you push down at one corner of a car, it lifts at the opposite corner. You'll find examples of this wherever you go to look at racing pictures. Every time a wheel lifts in a corner (no load), the wheel at the opposite corner is the wheel that's most heavily loaded.

I've read Scaff's guides before, and while thumbing through them again, I don't see anything that would indicate wheels at the opposite corners are the most heavily loaded.

Please point out the page in the guides that would indicate this.

 

[TenEightyOne]

I have to say that all the Nascar interviews I've seen over the years support the idea that on ovals the inside front (left front) gets the least wear.

The front right and rear left get even wear and are the 'pivot' point for the car. The rear right gets the most load from the sprung mass and has the additional problem of being powered longtitudinally.

This doesn't apply in GT5 though! Why not? Ah, well...

GT5 doesn't allow independent setup of each wheel. This means that one of your front tyres will always be disadvantaged when turning. It seems (in my own opinion from my own experience over many years of GTx) that the car is borne by the outside wheels in a turn and that the inside turning wheel 'drags'.

If you camber your outside front by 1.5' to give you good grip on the outside tyres when you run the banking (just an arbitrary example) you'll camber your inside by 1.5' too. This is without doubt a Bad Thing. You'll be running that tyre on its "corner". Messy.

It's logical therefore that the inside front will wear quickly on an oval under certain conditions. This is one of the ways in which GT5 demonstrates that the mechanical simulations ain't all that.

It's still a lot of fun though

 

[Hig-GT]

Page 17 (for a right hand bend)

"As the body rolled to the left, the rear spring, being stiffer, held up the body
more then the outside front. This produces an equal and opposite force
downward, forcing the tire into the ground more. This also REDUCES the body's
weight over the front left, because the back left is doing some of the work the
front left would have been doing. This results in some of the body weight being
shifted toward the INSIDE FRONT (this is where corner weighting, or wedge,
comes into play). These results in the total weight supported by each axle
remaining the same. Because the front tires are closer to an even bias of
weight, they are closer to their optimal traction, and can produce more lateral
force then the rear."

Please note as I did say twice I did say for a stiffer set-up!

 

[Anghammarad]

Which side gets the higher load?

 

[ElSecundo]

I have to say that all the Nascar interviews I've seen over the years support the idea that on ovals the inside front (left front) gets the least wear.

The front right and rear left get even wear and are the 'pivot' point for the car. The rear right gets the most load from the sprung mass and has the additional problem of being powered longtitudinally.

This doesn't apply in GT5 though! Why not? Ah, well...

GT5 doesn't allow independent setup of each wheel. This means that one of your front tyres will always be disadvantaged when turning. It seems (in my own opinion from my own experience over many years of GTx) that the car is borne by the outside wheels in a turn and that the inside turning wheel 'drags'.

If you camber your outside front by 1.5' to give you good grip on the outside tyres when you run the banking (just an arbitrary example) you'll camber your inside by 1.5' too. This is without doubt a Bad Thing. You'll be running that tyre on its "corner". Messy.

It's logical therefore that the inside front will wear quickly on an oval under certain conditions. This is one of the ways in which GT5 demonstrates that the mechanical simulations ain't all that.

It's still a lot of fun though

Thanks, that's an explanation that makes good sense. 👍

I'm with you -- even if the simulation aspect isn't perfect, it doesn't take away from the fun of it. I'm having a blast!

 

[Hig-GT]

Which side gets the higher load?

OMFG! How many times! I said on a stiffer set up! I also said it depends on set up! If you have a 2CV with pillows either side for suspension then it will flop around! But you don't set your car up like that for racing do you!

 

[Anghammarad]

Where have I talked about setups? Regardless of which car I use, be it stock or completely tuned, I will always get more wear on the inside front tyre on Indy in GT5.

Why does it matter if I have pillows or steel bars, the weight transfer will still be _mainly_ inside to outside, not rear to front.

 

[ElSecundo]

Page 17 (for a right hand bend)

"As the body rolled to the left, the rear spring, being stiffer, held up the body
more then the outside front. This produces an equal and opposite force
downward, forcing the tire into the ground more. This also REDUCES the body's
weight over the front left, because the back left is doing some of the work the
front left would have been doing. This results in some of the body weight being
shifted toward the INSIDE FRONT (this is where corner weighting, or wedge,
comes into play). These results in the total weight supported by each axle
remaining the same. Because the front tires are closer to an even bias of
weight, they are closer to their optimal traction, and can produce more lateral
force then the rear."

Please note as I did say twice I did say for a stiffer set-up!

Well, you read it, but it's not saying that the right front wheel is where the load is -- not at all. The right front (inside front in this case) is still the wheel with the lightest load on it.

The stiffer rear spring just means that less load is taken off the right front, but the right front is still the wheel under the lightest load.

But I do agree with the gist of what you're saying, that a stiffer setup helps to keep the right front from lifting.

 

[ASH32]

Could this problem be the same one as the one that makes hard tyres wear quicker than softs if the tyres are skidding too much?

 

[TenEightyOne]

Hi-GT's example is for a RIGHT-HAND bend... i.e running an oval in reverse. Some people are extrapolating the result the wrong way.

The weight transfer to the inside front (wedging) is done by humans with ballasting - it is NOT a natural part of the intertia transfer in the corner.

The centripetal inertia will always push the weight (if not the mass) to the outside tyres in a corner. Suspension setups can attempt to keep the inside tyres in contact with the road but they can't stop the intertia transfer that loads the outside up.

As a very famous engineer once said; ye cannae change the laws o'physics, Jim.

The stiffer setup is, as said, the way to go... up until the point where the stiffness causes sliding. This is why oval setups are so much different (IRL) to road setups.

 

[ElSecundo]

Hi-GT's example is for a RIGHT-HAND bend... i.e running an oval in reverse. Some people are extrapolating the result the wrong way.

The weight transfer to the inside front (wedging) is done by humans with ballasting - it is NOT a natural part of the intertia transfer in the corner.

The centripetal inertia will always push the weight (if not the mass) to the outside tyres in a corner. Suspension setups can attempt to keep the inside tyres in contact with the road but they can't stop the intertia transfer that loads the outside up.

As a very famous engineer once said; ye cannae change the laws o'physics, Jim.

The stiffer setup is, as said, the way to go... up until the point where the stiffness causes sliding. This is why oval setups are so much different (IRL) to road setups.

Yes, I think the waters are getting muddied because the tuning guide and the example at Indy are turning two different directions.

So if I can clarify, Hi-GT was saying that the right rear (at Indy) was loading, as was the left front. I'm saying that the left front at Indy is not loading, it's unloading.

His interpretation from the tuning guide is that the stiffer rear springs put a greater load on the left front tire at Indy, causing unnatural wear. I contend that the guide is not saying that, that the stiffer rear springs only prevents more severe unloading at the left front -- but that the left front continues to be the wheel supporting the lightest load in the corner at Indy, no matter how the car is sprung.

 

[JJ72]

the above post is correct, no need to go into deep physics stuff, it's just basic common sense!

Stiff suspension will decrease the difference in load between inner and outer tires, but the outside tire should always bear more load.

I do have a theory regarding the situation: in real life oval setups are asymmetrical, the inner tire is ran with positive camber so it stays flat to the banking's gradient, however GT5's setup is always symmetrical, so the dynamic negative camber of the inside tire is almost double that on a normal course, which creates severe wear on the inside of the inner tire. We don't know how GT5 measure tire wear (does it draw the average wear rate between outer, centre and inner wear, or shows the part with most severe wear, or there is only one point of measurement only?) but I will assume the tire wear display is caused by concentrated wear on the inside of the inner tire, but theoretically most of the inner tire is not doing much, the centre and outside may seldom be part of the contact patch at all.

 

[ElSecundo]

I do have a theory regarding the situation: in real life oval setups are asymmetrical, the inner tire is ran with positive camber so it stays flat to the banking's gradient, however GT5's setup is always symmetrical, so the dynamic negative camber of the inside tire is almost double that on a normal course, which creates severe wear on the inside of the inner tire.

Bingo, and I think this is essentially what TenEightyOne is saying, too. I think you guys are spot on. 👍 It's a suspension setup issue (that can't be addressed because each wheel can't be tuned independently), not a loading issue.

 

[Forcone]

I don't understand how anyone can think that the inner front tyre could have more load on it in a corner than the outer one? I've read my share of physics but can't get my head round that thought, must be some higher level stuff.

 

[SJames052]

Wow, this is an intriguing question. Has anyone tried running the oval in the opposite direction to see if the tire wear pattern is the same? I also wondered if, apart for the tire indicator, a player could feel which wheels were slipping. Also, is the wear caused more by the forward motion or by the side-to-side slippage?

 

[caladina]

the inner corner tyre will wear more due to
a, the brakes being applied while turning, thus causing the inner unloaded tire to skid
b,the unloaded tire (inner) is so unloaded that it will skid or scrub without the need for brakes to make it do so,
c, you are running the kerbs on the apex and the developers have given these more wear aggression, codemasters got this right in one of the driver/toca games, you could do a wheel spin one tyre on the kerb and it would shread very quick
d, you pitstop dude on the inner front is puffin muffins, give him a slap and make him go sweep the shop.

i have run indy flay out and the inner front is the only one not to burn out, the other three do

btw, red is for over heated and white/blue is ok, just checking you reading the correct badger