discussion about outside wheel overheating under throttle

[nomis3613]

It's a tuning aspect which rears its head in various threads from time to time: why can high LSD Accel cause the outside wheel to go red before the inside wheel? What does it mean?

Some people believe the outside is spinning, others think it is just because of the combination of engine torque and the extra weight on the outside wheel.

Here are my observations:
- in-game manual specifically says that the blue/red indicator is tyre temperature
- I have seen tyres "heat" from combined braking and cornering, wheelspin, etc- but never from cornering alone (using a DS3 controller)
- Wheelspin leaves skidmarks, but I have never seen hard cornering leave skidmarks.
- using a high LSD Accel setting, I have seen the outside wheel start smoking and cause skidmarks earlier than the inside wheel (can post pics if required). The temperature indicator showed the outside wheel going red first, soon followed by the other wheel.
- on RWD cars, high LSD Accel settings reduce exit understeer, and it feels like the traction is helping to rotate the car (as opposed to GT4 where high LSD Accel can make the car exit understeer)

Discuss!

 

[Adrenaline]

I'm not sure what you want us to discuss? You about summed it up.
My only qualm is that I have seen the front tires heat up on corner exit of a RWD under throttle, without skid marks. Meaning, that based on my best recollection, you can overheat them in hard cornering.

 

[xSTIG_JUNIORx]

It's a tuning aspect which ...

- Wheelspin leaves skidmarks, but I have never seen hard cornering leave skidmarks.

...

Discuss!

I can help you to see hard cornering leaving skidmarks, let me know if you're interested.

👍

 

[nomis3613]

I'm not sure what you want us to discuss?

Perhaps stuff like this

My only qualm is that I have seen the front tires heat up on corner exit of a RWD under throttle, without skid marks. Meaning, that based on my best recollection, you can overheat them in hard cornering.

Aha, so do you think it's the outside wheelspinning with high LSD Accel? Or it's just the extra weight causing the outside to overheat? (or something else?)

I can help you to see hard cornering leaving skidmarks, let me know if you're interested.

👍

Yep, interested!

Just wondering, is it with a wheel perhaps?

 

[Adrenaline]

I think it's literally just 'sliding' the front wheels.
The same as a real car. The tires can 'slide' without leaving tread marks.

 

[CSLACR]

It can't be wheelspin, the closer to a locked differential you get, the more impossible it becomes to spin either tire without spinning both.
The outside tire lights up first because it's the grip tire. If the inside tire cannot spin without also spinning the outside tire, the outside tire slides (heats) first. Like you said, it's from having the differential to tight.

I think it's literally just 'sliding' the front wheels.
The same as a real car. The tires can 'slide' without leaving tread marks.

Yes, that would be the devil in understeer. And you won't fix it by adjusting the LSD if it's non-drive wheels, you must have a look at suspension settings if this happens.
Very easy to do with NASCAR's.

 

[Adrenaline]

understeer...you won't fix it by adjusting the LSD if it's non-drive wheels...

I disagree. RWD LSD can have major effects on the front tires.

 

[CSLACR]

I disagree. RWD LSD can have major effects on the front tires.

It can, but you shouldn't even consider it.
LSD should be used for the sole purpose of getting every last pony possible to the pavement.
Suspension should be used to dial out steering issues.

If my front end is sliding, and I make the rear slide more to match, does my front end have more grip?
No matter what, you never take rear grip off a rwd car, you add front grip. If you can't add anymore front grip, then you drive with understeer. If you want to go fast, that is.

 

[Adrenaline]

I'm not sure why you automatically assume that adjusting the LSD removes rear grip?

 

[xSTIG_JUNIORx]

xSTIG_JUNIORx
I can help you to see hard cornering leaving skidmarks, let me know if you're interested.
____________


Yep, interested!

Just wondering, is it with a wheel perhaps?

With pleasure mate, yes it it with a wheel.

Would you send me a friend request, to xSTIG_JUNIORx and title it - Hard cornering - or something else that lets me recognise you.

👍

 

[nomis3613]

I think it's literally just 'sliding' the front wheels.
The same as a real car. The tires can 'slide' without leaving tread marks.

Cool. I'm gonna go a bit off topic here...but... it seems to me that DS3 users are giving a helping hand by the game not letting you scrub out the front tyres through too much steering angle. But wheel users have to set their steer angle correctly. Is this perhaps the situation you are talking about, or have you seen the fronts overheat in other cornering situations (except while applying brakes, of course)?

It can't be wheelspin, the closer to a locked differential you get, the more impossible it becomes to spin either tire without spinning both...

I totally agree with you if we're talking passive LSDs in real life. GT5 may be different thought. Even without any wheelspin, when the LSD setting causes the outside to heat up first, it feels to me that the thrust is somehow causing a yaw moment. What do you think of the cars' behaviour when the outside tyre heats first in GT5? (hope this doesn't sound patronising or argumentitive, I'm genuinely interested to hear your theories)

With pleasure mate, yes it it with a wheel.

Would you send me a friend request, to xSTIG_JUNIORx and title it - Hard cornering - or something else that lets me recognise you.

👍

Cheers, I'll send you a friend request next time I fire up the PS3.

 

[dr_slump]

There's a thing which is way more strange: The overheating inside front tire!
It happens on my Nissan Skyline KPGC10 '70 and a few other cars.

 

[Stotty]

This has been bugging me for some time...

I have a replay of my TVR Speed 12 spinning and smoking it's outside rear tyre only (whilst loaded) on corner exits... and leaving a thick black line from just the outside tyre.

This should not be possible under any circumstances.

 

[Adrenaline]

Cool. I'm gonna go a bit off topic here...but... it seems to me that DS3 users are giving a helping hand by the game not letting you scrub out the front tyres through too much steering angle. But wheel users have to set their steer angle correctly. Is this perhaps the situation you are talking about, or have you seen the fronts overheat in other cornering situations (except while applying brakes, of course)?

I've only used DS3 for 2 things. Old school grinding at Indy for $$, and once at a friends house doing a drifting seasonal. So unfortunately I can't really say, but it does sound logical, as I assume DS3 limits are 90 degrees, where the wheel can easily go beyond that. But that's purely a guess.

If you want to simulate this, the best way would be... Off the top of my head,
Take the CLK Touring car(on default suspension) to Deep Forest. The 2nd to last 90 degree turn (after the kind-of-straight-a-way, up the hill, just after the very last tunnel) and purposely enter the corner with too much speed, crank the wheel as far as you can and try to make that corner. The front tires will both turn bright red and you'll just fade off the track into the grass.

There was another car that consistently did this too, but I can't recall at this time.

Either way, the point I'm trying to make, is that you can overstress the front tires, by sliding them and skid marks are not always present.

 

[oatmeal so good]

LSD in this game can be tuned oddly. For the outside wheel to spin faster than the inside, it would first have to overpower the clutch discs in the LSD.

 

[Basilea]

When I started playing around with LSD settings, my goal was to set Accel to the point where the inside spin just disapears and the outside spin (or turning outside red) is as minimal as possible!
But now I believe that it hasn't a big impact whether the outside turns red or not and you get faster laptimes the higher Accel you have! With Initial the fastest laptimes I get with the lowest value (this gives the LSD the most time to have an effect)! But you can controll inside or outside spin with Initial! The higher it is the faster it locks the LSD! The Accel doesn't lock the LSD at all in my opinion, it only gives power either to the inside or to the outside!

 

[CSLACR]

I'm not sure why you automatically assume that adjusting the LSD removes rear grip?

The statement was made with the assumption of starting from a proper LSD in which both tires spin at as close to the same time as possible.
If your diff is to loose or to tight, then adjusting it could benefit both the front and rear.

I totally agree with you if we're talking passive LSDs in real life. GT5 may be different thought. Even without any wheelspin, when the LSD setting causes the outside to heat up first, it feels to me that the thrust is somehow causing a yaw moment. What do you think of the cars' behaviour when the outside tyre heats first in GT5? (hope this doesn't sound patronising or argumentitive, I'm genuinely interested to hear your theories)


Cheers, I'll send you a friend request next time I fire up the PS3.

Well, without wheelspin, the outside tire(s) has to heat up first, that's where all the weight and grip is.
And I'm speaking 75% of what I know from real world, and 25% what I've experienced in-game. That said, I'm fairly new to seriously tuning in any GT game, as they never worked properly from what I've seen.
I know in last weeks WRS I ended up with a very different tune from some of the competitors, but ended up with my best personal lap to date, IMO.

So if anyone is saying it's different in the game from real life, I'll gladly try it out, as I've only tuned a few cars, and a lot of tuning in GT is just driver preference, and from what I've seen, doesn't translate to more actual cornering grip.

This has been bugging me for some time...

I have a replay of my TVR Speed 12 spinning and smoking it's outside rear tyre only (whilst loaded) on corner exits... and leaving a thick black line from just the outside tyre.

This should not be possible under any circumstances.

Can't argue that...
I should say with a high differential, it is possible (I think) to slightly spin the outside wheel without spinning the inside wheel, because of the grip being used for cornering, but it would have to be a very small amount of wheelspin, and a very stiff differential... But I don't know for sure, just sounds possible to me.

https://www.gtplanet.net/forum/showthread.php?p=5405057#post5405057

Takata NSX, R1's, 545HP.
Would greatly appreciate feedback from anyone interested.
It's sharp, responsive, and borderline twitchy, I know this, but I loved it.

 

[nomis3613]

There's a thing which is way more strange: The overheating inside front tire!
It happens on my Nissan Skyline KPGC10 '70 and a few other cars.

Hmmmm...at what stage of cornering? Old cars only? Cambered or flat corners? Any other common denominators?

...smoking it's outside rear tyre only (whilst loaded) on corner exits... and leaving a thick black line from just the outside tyre.

This should not be possible under any circumstances.

LSD in this game can be tuned oddly. For the outside wheel to spin faster than the inside, it would first have to overpower the clutch discs in the LSD.

Yeah, there's some crazy magic going on inside Polyphony's LSD!

Take the CLK Touring car(on default suspension) to Deep Forest. The 2nd to last 90 degree turn (after the kind-of-straight-a-way, up the hill, just after the very last tunnel) and purposely enter the corner with too much speed, crank the wheel as far as you can and try to make that corner. The front tires will both turn bright red and you'll just fade off the track into the grass.
...
Either way, the point I'm trying to make, is that you can overstress the front tires, by sliding them and skid marks are not always present.

Cool, I'll give this a try. Totally agree that skid marks do not go hand-in-hand with overheated tyres (as seen when turning while braking, even with a DS3)

But now I believe that it hasn't a big impact whether the outside turns red or not and you get faster laptimes the higher Accel you have! With Initial the fastest laptimes I get with the lowest value (this gives the LSD the most time to have an effect)! But you can controll inside or outside spin with Initial!

Yeah, that's what I've found. Using LSD Initial to overheat the outside reduces power understeer IMHO.

For the few FWD cars I've tuned though, the effect doesn't work as well (if at all) I reckon.

 

[CSLACR]

So how would one be sure the outside tire was the only one spinning?
I ask because if you're cornering hard, the inside tire would take longer to smoke and leave marks than the outside with weight on it.
I'm just guessing off reality, but PD's screwed up worse with tuning...

 

[Adrenaline]

So how would one be sure the outside tire was the only one spinning?
I ask because if you're cornering hard, the inside tire would take longer to smoke and leave marks than the outside with weight on it.
I'm just guessing off reality, but PD's screwed up worse with tuning...

Set your LSD to 5/60/5 and watch the outside burn away all by itself.
Depending on the car and set up, the inside tire can take a looooong time to ever even heat up on the indicator. I'm not sure if this is what you're asking though?

I've also seen people use 1 tire on asphalt 1 on grass, to compare LSD lock up times.

 

[Basilea]

So how would one be sure the outside tire was the only one spinning?
I ask because if you're cornering hard, the inside tire would take longer to smoke and leave marks than the outside with weight on it.
I'm just guessing off reality, but PD's screwed up worse with tuning...

No they didn't IMHO... all settings work, in a own way, but they work!

What I, as a non car/tuning genius in real life, wonder is, how is a LSD supposed to work? I read some thing but still not sure... let's try, when you drive on a straight line the LSD is locked and then you turn in and it opens at some point and then it locks again on exit, is this correct so far?
Now in game, what you can change is the initial, regulates when (early when still turning or late when already on the straight) it locks on exit and with accel where it sends the power to (and therefore a high value makes the outside spin, because it sends too much power to the outside) while cornering. So in the end the diff is never really open. And the decel has barely an impact at all with ABS at 1.

 

[Adrenaline]

I think DeAccel has a huge impact.
As for RL LSD's... There are so many different types, it's best to just read the wiki for a short explanation of how each one works.

 

[articzap]

No they didn't IMHO... all settings work, in a own way, but they work!

What I, as a non car/tuning genius in real life, wonder is, how is a LSD supposed to work? I read some thing but still not sure... let's try, when you drive on a straight line the LSD is locked and then you turn in and it opens at some point and then it locks again on exit, is this correct so far?
Now in game, what you can change is the initial, regulates when (early when still turning or late when already on the straight) it locks on exit and with accel where it sends the power to (and therefore a high value makes the outside spin, because it sends too much power to the outside) while cornering. So in the end the diff is never really open. And the decel has barely an impact at all with ABS at 1.

It depends on what type of LSD it is. They all work differently.

Torsen? Quaife? Clutck pack?

 

[CSLACR]

It depends on what type of LSD it is. They all work differently.

Torsen? Quaife? Clutck pack?

Well the general idea is the same.

LSD's are used to keep one wheel from spinning more than another.

What I, as a non car/tuning genius in real life, wonder is, how is a LSD supposed to work? I read some thing but still not sure... let's try, when you drive on a straight line the LSD is locked and then you turn in and it opens at some point and then it locks again on exit, is this correct so far?
Now in game, what you can change is the initial, regulates when (early when still turning or late when already on the straight) it locks on exit and with accel where it sends the power to (and therefore a high value makes the outside spin, because it sends too much power to the outside) while cornering. So in the end the diff is never really open. And the decel has barely an impact at all with ABS at 1.

It's supposed to be:
Inital is how much constant slip is allowed, 5 should be only in extreme cases, 60 would be constantly engaged.

When a car turns, one wheel has to move faster than the other, (outside) So you can't just locked them as a solid axle, or the car wouldn't turn worth crap.
You can't let them free, because then only the inside wheel spins under acceleration.

Accel would be how much force will be applied to stop either wheel from spinning faster than the other.

Decel is the same, but works under engine braking and cornering, and is more useful in cars with engine's that decelerate quickly, because it keeps the engine deceleration and braking from spinning and/or locking one rear wheel (the inside) without or before the outside wheel.

Hope that was the question.

edit: other than Jeep's, I can't think of any vehicles that comes with or uses a limited slip that fully locks. And even them you either manually lock, or on new ones I think you can push button lock.

Set your LSD to 5/60/5 and watch the outside burn away all by itself.
Depending on the car and set up, the inside tire can take a looooong time to ever even heat up on the indicator. I'm not sure if this is what you're asking though?

That was my question for the game. I never tried the extremes, but managed to fiddle myself faster somehow, but do you have an answer why some people say higher diff is more grip, and I find better results on a lower diff?
I never had the time to analyze why I run faster times with lower diff's.

 

[Adrenaline]

Well the general idea is the same.

LSD's are used to keep one wheel from spinning more than another.



It's supposed to be:
Inital is how much constant slip is allowed, 5 should be only in extreme cases, 60 would be constantly engaged.

When a car turns, one wheel has to move faster than the other, (outside) So you can't just locked them as a solid axle, or the car wouldn't turn worth crap.
You can't let them free, because then only the inside wheel spins under acceleration.

Accel would be how much force will be applied to stop either wheel from spinning faster than the other.

Decel is the same, but works under engine braking and cornering, and is more useful in cars with engine's that decelerate quickly, because it keeps the engine deceleration and braking from spinning and/or locking one rear wheel (the inside) without or before the outside wheel.

Hope that was the question.

edit: other than Jeep's, I can't think of any vehicles that comes with or uses a limited slip that fully locks. And even them you either manually lock, or on new ones I think you can push button lock.

That was my question for the game. I never tried the extremes, but managed to fiddle myself faster somehow, but do you have an answer why some people say higher diff is more grip, and I find better results on a lower diff?
I never had the time to analyze why I run faster times with lower diff's.

If by 'higher diff' they mean a higher initial setting, then I believe you get more 'acceleration' and they're just using 'grip' as a general term. As you stated above, 5 is an open diff, 60 is constant engaged and the closer to locked you go, the better straight line launch you'll get.

By 'Lower Diff' I assume you mean, an LSD Initial of 8-12, in which the car handles better, because it's more 'open' and like you've stated above, locked diffs don't turn worth a crap.

That's my take on the GT5 LSD anyways.

 

[CSLACR]

If by 'higher diff' they mean a higher initial setting, then I believe you get more 'acceleration' and they're just using 'grip' as a general term. As you stated above, 5 is an open diff, 60 is constant engaged and the closer to locked you go, the better straight line launch you'll get.

By 'Lower Diff' I assume you mean, an LSD Initial of 8-12, in which the car handles better, because it's more 'open' and like you've stated above, locked diffs don't turn worth a crap.

That's my take on the GT5 LSD anyways.

That's exactly my take. 👍
But that matches reality if I'm not mistaken. Which is almost odd for GT.

 

[Adrenaline]

Lol. As far as I can tell, the Accel setting is the only one that's commonly accused of 'unrealistic'. By my theory, all the Accel setting does, is apply power to a specific tire. 5 sends it all to the inside tire, 60 sends it all to the outside tire. The 'sweet spot' seems to be different for every car, but you want to try and give equal power to both wheels, or depending on driving style, you can get better corning ability by giving the outside tire just a little bit more than the inside, which helps 'steer' the car with the LSD. Heavy footed people will want to give more to the inside tire, to avoid spinning on hard corner exits.
But, as always, this is just my take on the GT5 aspects of LSD; I don't claim it as scientific fact.

 

[CSLACR]

Lol. As far as I can tell, the Accel setting is the only one that's commonly accused of 'unrealistic'. By my theory, all the Accel setting does, is apply power to a specific tire. 5 sends it all to the inside tire, 60 sends it all to the outside tire. The 'sweet spot' seems to be different for every car, but you want to try and give equal power to both wheels, or depending on driving style, you can get better corning ability by giving the outside tire just a little bit more than the inside, which helps 'steer' the car with the LSD. Heavy footed people will want to give more to the inside tire, to avoid spinning on hard corner exits.
But, as always, this is just my take on the GT5 aspects of LSD; I don't claim it as scientific fact.

It's also exactly the same as my take.
I've yet to deviate from the Inside/Outside at the same time approach, it works better than all the others I've tried so far.