Trouble with the Curve

[Grim_Reaper]

Just thought I would share a story and see if anyone else has had similar experiences in their mustang.


A few weeks ago my father and I went for a nice cruise through Sequoia Natl Forrest/Park and Kings Canyon Natl Park. Obeying the speed limits of both areas, I gotta say the car was a blast to drive! It handles the curves, twists, switchbacks, and bumps so well.

After exiting Kings Canyon we headed south on 265 (I think that's the road) and kinda picked up the pace a little bit. Now let me pause here and say that my car is the Base GT with stock wheels and tires, and that the only suspension mod are the Eibach Sportline springs. So picking up the pace, playing follow the leader behind my dad in his 14 GT C/S, we start hitting some curves, s-turns, and sweepers. On one of the downhill left exit sweepers I encountered severe understeer that almost led me straight off the road right at the bottom of the hill where it started to go back uphill. The tires eventually caught which led to the rear end coming around the right side fairly quickly so I counter steered and eased off the throttle, making sure not to panic and stab the brakes. The car fish tailed a little bit and I broke the center line but never lost control.

I am sure the cause of this incident could be chalked up to a number of reasons like driver error, stock tire grip quality, road conditions, etc but I gotta say all in all I was both surprised but the understeer and also the cars stability during the corrections. I feel like in the last gen this would have been a lot worse.


Thoughts?

Sponsored

 

[Mustm26]

curves

On our Honeymoon 32 years ago we drove down into Kings Canyon in a rented Ford Escort. It was a blast driving thru all those switchbacks but my new Wife was not thrilled about it as she gets car sickness easily. But what a road down to the river!!!!! Most awesome switchback road I've ever driven on!!!

 

[arrow94]

I have a base gt as well and it does tend to understeer a bit. One thing my father taught me, downhill corners are a no no at high speed.
With this car i noticed braking later and harder right before corner entry moves the weight forward and allows the front tires to grip through the corners much better.
Anyways im glad you managed to get out of it trouble free!

 

[Mustm26]

A rear wheel drive is always going to understeer a bit no matter what the performance suspension compared to a front wheel drive car more common these days that can have severe oversteer.

 

[Grim_Reaper]

On our Honeymoon 32 years ago we drove down into Kings Canyon in a rented Ford Escort. It was a blast driving thru all those switchbacks but my new Wife was not thrilled about it as she gets car sickness easily. But what a road down to the river!!!!! Most awesome switchback road I've ever driven on!!!

I agree! Very beautiful drive throughout the entire park. I usually get sick too if I am riding, but not when I have control.

I have a base gt as well and it does tend to understeer a bit. One thing my father taught me, downhill corners are a no no at high speed.
With this car i noticed braking later and harder right before corner entry moves the weight forward and allows the front tires to grip through the corners much better.
Anyways im glad you managed to get out of it trouble free!

Yeah hopefully the new suspension setup and 285fr 305rr Hankook Ventus hook up better. I will take note of the braking advice though and remember that next time.

A rear wheel drive is always going to understeer a bit no matter what the performance suspension compared to a front wheel drive car more common these days that can have severe oversteer.

Yeah my last car was a 2013 WRX with 265 Nittos on all four corners so I am still getting used to the RWD and crappy base tires. Sure are fun though for some tire roasting.

 

[Norm Peterson]

A rear wheel drive is always going to understeer a bit no matter what the performance suspension compared to a front wheel drive car more common these days that can have severe oversteer.

Pretty sure you've got this backwards. FWD cars inherently understeer because the front tires are overworked (they carry well over half of the car's weight, all of the power, and most of the braking). Severe oversteer in a production car is seriously frowned upon.

You can trick them into oversteering by playing around with suspension and tire pressure tuning efforts, but that's really a different thing because now you've become the car's "chassis engineer" with different goals in mind than making it drivable by the country's least skilled driver. Think autocross.


Norm

 

[Norm Peterson]

Thoughts?

I know it's asking a lot, but did you happen to notice whether the stability control system was doing anything during all of this?

I'll add road crown and road camber and the possibility of front suspension bottoming to your list of contributing causes.


Norm

 

[Hack]

Was it really hot and your tires got overheated greasy/slippery? Cold or wet on the curve but not everywhere else?

You say you were following your dad. Does he have better tires than you? Your car should out-corner a 2014, everything else equal.

 

[Mustm26]

understeer vs oversteer

Norm Peterson:
you said:
retty sure you've got this backwards. FWD cars inherently understeer because the front tires are overworked (they carry well over half of the car's weight, all of the power, and most of the braking). Severe oversteer in a production car is seriously frowned upon.:

I am more sure than you Norm that I have it correct. I am 65 and have owned since new 4 vehicles with FWD and 8 with RWD. ALL the FWD ones oversteered, not severely but they did. All the RWD vehicles, including a 1998 Corvette understeered not severely but they did.

Ask your associates, I am 100% sure I am correct.

 

[arrow94]

no need to argue guys. The reason for the understeer wasnt front or rear wheel drive, but too high of a speed entering a downhill corner.

 

[ForTehNguyen]

base GT tires arent great either, 235 width all seasons? If you get some wide pilot super sports, the car will be transformed and will feel like a different machine. I eventually want a 285 square setup

 

[Todd15Fastback]

Norm Peterson:
you said:
retty sure you've got this backwards. FWD cars inherently understeer because the front tires are overworked (they carry well over half of the car's weight, all of the power, and most of the braking). Severe oversteer in a production car is seriously frowned upon.:

I am more sure than you Norm that I have it correct. I am 65 and have owned since new 4 vehicles with FWD and 8 with RWD. ALL the FWD ones oversteered, not severely but they did. All the RWD vehicles, including a 1998 Corvette understeered not severely but they did.

Ask your associates, I am 100% sure I am correct.

Norm is 10000% correct.

 

[Allstar71]

Actually, most if not all cars are now setup from the factory to understeer. Their thought is that understeer is much easier to deal with for the average driver. With tweeks to the suspension you can get a car to act how you want it to. Usually the goal is a neutral car although with improper driving techniques the car can understeer or oversteer simply because of a mistake on the part of the driver.

Sure you can force and oversteer with power but the chassis is setup from the factory to understeer.

Car that understeers:
Stiffen up the rear suspension either with sway bar and/or springs

Car that oversteers:
Stiffen the front suspension either with sway bar and/or springs.

Alot of people don't realize the changes they are making to a cars handling when they throw suspension mods at a car. Spring rates and swaybar rates should be changed based upon what the car is doing not just because "stiffer springs will make it corner better".

 

[NotBlake]

The new mustang (like almost every street car) is set up for understeer from the factory as this is safer for untrained drivers than oversteer. I recently had Gran Turismo East do a custom alignment and they found -1.1 degrees average front camber and -1.8 degrees of rear camber. A heavily cambered-in rear setup is an easy way for a manufacturer to dial understeer into an otherwise neutral chassis. I had them take a full degree of camber out of the rear and the car feels fantastic.

 

[Iceman2733]

Get some wider tires on that car. My car with the stock base tires didn't handle well at all now the only thing k changed was tires and wheels and the car is soooo much better feeling in corners. I am running Nitto Invo 275front 285 in the rear

Sponsored