New tyres - which end?
Discussion
pmjg66 said:
totally disagree,a well sorted race/track car will be set up differently for dry or wet conditions ie different camber angles and spring rates and toe settings etc,etc.
A normal road car supplied to the general public will have settings for good tyre wear and safe handling ie no snap oversteer.
This is why ALL tyre manufactures also say new tyres should be fitted to the rear under all circumstances for ROAD use !
I understand what you're saying, but remember car manufacturers have to give advice to every single person on the planet, from 16 year old kids to 80 year old women. We're all petrol heads here and we're into this kind of stuff so we get it. A normal road car supplied to the general public will have settings for good tyre wear and safe handling ie no snap oversteer.
This is why ALL tyre manufactures also say new tyres should be fitted to the rear under all circumstances for ROAD use !
It is safer for the average driver to experience understeer than oversteer because understeer to the inexperienced driver will always be easier to control than oversteer.
Oversteer takes more skill to handle than understeer, but to the experienced driver oversteer 99% of the time will be the preferred scenario.
I'm not talking about like huge drifting oversteer. If you have it too extreme one way or the other its horrible. I'm talking about manageable oversteer. It's important to clarify that
A good friend of mine races Formula Atlantic (1.6L, 1200lbs, 268bhp full ground effects before they were banned) and had an opportunity to drive for Newman-Haas' Indy Car team which he turned down.
He is also a 16 time national champion karter, 8 time Duffy Kart Champion and has raced and won since he was about 4 years old.
I actually got into the discussion we are having on this board with him a while back and he 100% of the time prefers a car with oversteer as opposed to understeer. The guys who win in Formula Atlantic are the guys who can set the car up with a little bit of oversteer that would make a new driver very uncomfortable.
For the street you have to remember the politics. Tire companies are telling people what is safe for them given the fact not everyone out there is a petrol head or a track enthusiast. That doesn't mean it's what is correct when you get into the world of petrol heads / sports driving.
What I really like about this forum is how you guys can disagree and have it out in a respectful manner. I've been on so many forums where personal attacks are the norm so from an American to you Brits you guys really get my respect. I like you pistonheads!
Edited by Zero 1 on Thursday 3rd May 01:14
Zero 1 said:
Tire compound and tread levels affect braking more than any upgrade of rotors or pads. Think about it like this:
The front of a car is responsible for 70-80% of the load under heavy braking. If all that weight transfers to the front of the car and you have worn out tires at the front, and brand new rubber at the back, how well do you think the car is going to stop?
Now if you remember the original posters question was about a front wheel drive car, you are asking the front of the car on worn tires to handle the braking load, acceleration load (longitudinal) AND cornering loads (lateral). It is simply too much for the tire. Physics are physics.
The terms are coefficient of friction- Measure of the ratio at which a tire converts download to traction
and
Slip angle- difference between the direction the wheel rim is pointing and the direction the tire is traveling. This difference is reffered to as the slip angle. Tires have a range of slip angle where they deliver their maximum level of cornering traction.
Street tires tend to work over a wider range of slip angles and produce lower coefficients of friction. Slick tires (racing tires) tend to operate in a narrow band of slip angle and produce high coefficient of friction but drop off much faster once you exceed the limit.
Street tires tend to break away progressively so they are easier to control.
The bottom line is without tread you are asking the tire to do too much and you are exceeding it's capabilities of traction. There for you want more traction at the front ESPECIALLY on a FWD car where the tire is responsible not only for steering, but acceleration AND correcting the car once it has gone into an oversteer condition...
Where two new tyres are supplied, they should always* be fitted to the REAR of the vehicle irrespective of the orientation of the driven wheels i.e. front/rear wheel or all wheel drive.The front of a car is responsible for 70-80% of the load under heavy braking. If all that weight transfers to the front of the car and you have worn out tires at the front, and brand new rubber at the back, how well do you think the car is going to stop?
Now if you remember the original posters question was about a front wheel drive car, you are asking the front of the car on worn tires to handle the braking load, acceleration load (longitudinal) AND cornering loads (lateral). It is simply too much for the tire. Physics are physics.
The terms are coefficient of friction- Measure of the ratio at which a tire converts download to traction
and
Slip angle- difference between the direction the wheel rim is pointing and the direction the tire is traveling. This difference is reffered to as the slip angle. Tires have a range of slip angle where they deliver their maximum level of cornering traction.
Street tires tend to work over a wider range of slip angles and produce lower coefficients of friction. Slick tires (racing tires) tend to operate in a narrow band of slip angle and produce high coefficient of friction but drop off much faster once you exceed the limit.
Street tires tend to break away progressively so they are easier to control.
The bottom line is without tread you are asking the tire to do too much and you are exceeding it's capabilities of traction. There for you want more traction at the front ESPECIALLY on a FWD car where the tire is responsible not only for steering, but acceleration AND correcting the car once it has gone into an oversteer condition...
*where applicable
quoted by all tyre manufactures after extensive testing which relates to the OP.
pmjg66 said:
Where two new tyres are supplied, they should always* be fitted to the REAR of the vehicle irrespective of the orientation of the driven wheels i.e. front/rear wheel or all wheel drive.
*where applicable
quoted by all tyre manufactures after extensive testing which relates to the OP.
Read my post above P. *where applicable
quoted by all tyre manufactures after extensive testing which relates to the OP.
I'm speaking from about a decade now of racing experience in heavy FWD cars, and light weight RWD cars as well as mid engine two stroke 17,000rpm karts.
I try to associate with guys who are national champions or well respected in their fields to learn from the guys who did it themselves. This conversation has come up and between multi time national champion autocrossers, Formula Atlantic drivers, national champion karting drivers they all tend to prefer the oversteer side as opposed to understeer in both daily driver and racing situations.
Always do the research for your self. You should get new tires and mount them in both ways then go take a round about quickly or something and see how each behaved. Go do a track day and try the same thing and get up to speed see how the car reacts at the limit with it setup each way.
I think you would find that a little oversteer at 100mph is going to be a lot more comfortable than understeering at 100mph...
Edited by Zero 1 on Thursday 3rd May 01:21
WhoseGeneration said:
...the point is that tyre manufacturers are aiming this recommendation at the majority of their customers...
A valid point, publicly given advice will always tend towards idiot-proofing for the lowest common denominator.As far as I can tell the only real argument (other than joe average being more comfortable with understeer) for universally putting newer tyres on the rear is the (slim IMO) possibility of only one end aquaplaning, and even then its only valid for the same tyres - without testing how sure are you that new tyre A will clear more water than partially worn tyre B with a different tread pattern?
Personally I arrange my tyres front/rear in the way that gives the best handling (to my feel and driving situations), with most cars this tends to result in the better (not necessarily newer) tyres on the front. I had a pair of kingstars on an MX5 for a while (until I could afford to replace them), on the front they were a liability and borderline dangerous, on the rear it was a bit tailhappy in the wet but several orders of magnitude more controllable and predictable.
Edited by GravelBen on Thursday 3rd May 01:32
Zero 1 said:
Read my post above P.
I'm speaking from about a decade now of racing experience in heavy FWD cars, and light weight RWD cars as well as mid engine two stroke 17,000rpm karts.
I try to associate with guys who are national champions or well respected in their fields to learn from the guys who did it themselves. This conversation has come up and between multi time national champion autocrossers, Formula Atlantic drivers, national champion karting drivers they all tend to prefer the oversteer side as opposed to understeer in both daily driver and racing situations.
Always do the research for your self. You should get new tires and mount them in both ways then go take a round about quickly or something and see how each behaved. Go do a track day and try the same thing and get up to speed see how the car reacts at the limit with it setup each way.
I think you would find that a little oversteer at 100mph is going to be a lot more comfortable than understeering at 100mph...
Think you have not read the original posters question,no mention of track use or competition use or driving on the public roads road at 100 mph I'm speaking from about a decade now of racing experience in heavy FWD cars, and light weight RWD cars as well as mid engine two stroke 17,000rpm karts.
I try to associate with guys who are national champions or well respected in their fields to learn from the guys who did it themselves. This conversation has come up and between multi time national champion autocrossers, Formula Atlantic drivers, national champion karting drivers they all tend to prefer the oversteer side as opposed to understeer in both daily driver and racing situations.
Always do the research for your self. You should get new tires and mount them in both ways then go take a round about quickly or something and see how each behaved. Go do a track day and try the same thing and get up to speed see how the car reacts at the limit with it setup each way.
I think you would find that a little oversteer at 100mph is going to be a lot more comfortable than understeering at 100mph...
Edited by Zero 1 on Thursday 3rd May 01:21
the recommendation from all tyre manufactures as stated is on the rear for road use.I understand the race orientated driver will like a little over steer for the race track under certain conditions,but not for the general public.
Edited by pmjg66 on Thursday 3rd May 01:43
pmjg66 said:
hink you have not read the original posters question,no mention of track use or competition use or driving on the public roads road at 100 mph the recommendation from all tyre manufactures as stated is on the rear for road use.
I understand the race orientated driver will like a little over steer,but not for the general public or by car manufacturers.
I did read his original post and I still would run the new tires up front, especially on a FWD car. If a person doesn't feel comfortable doing this then they shouldn't. This is why it's so important to rotate your tires and adhere to basic maintenance. the recommendation from all tyre manufactures as stated is on the rear for road use.I understand the race orientated driver will like a little over steer,but not for the general public or by car manufacturers.
If the tires are worn to the point where they would cause an extreme condition at the front or the rear, you really should just replace them instead of trying to cut corners.
Zero 1 said:
I did read his original post and I still would run the new tires up front, especially on a FWD car. If a person doesn't feel comfortable doing this then they shouldn't. This is why it's so important to rotate your tires and adhere to basic maintenance.
If the tires are worn to the point where they would cause an extreme condition at the front or the rear, you really should just replace them instead of trying to cut corners.
Agree with that Zero,I rotate my tires every few thousand miles,all 4 down to approx 2mm If the tires are worn to the point where they would cause an extreme condition at the front or the rear, you really should just replace them instead of trying to cut corners.
of to get 4 new tyres soon 
pmjg66 said:
Where two new tyres are supplied, they should always* be fitted to the REAR of the vehicle irrespective of the orientation of the driven wheels i.e. front/rear wheel or all wheel drive.
*where applicable
quoted by all tyre manufactures after extensive testing which relates to the OP.
Mercedes put the cat amongst the pidgeons with advice, which I think has now been removed, in the C Class (W204) manual that said the car's electronic anti-skid system is so good that you might as well fit new tyres on the front. The tyre industry newspaper had a fit!*where applicable
quoted by all tyre manufactures after extensive testing which relates to the OP.
I also think you have to take the kind of tyres that are being fitted into account. On wifey's Honda Jazz, I replaced the front pair of original grippy Yokohama tyres with not so grippy Michelin Energy eco tyres at Costco. Costco will absolutely only fit the new ones on the back so I swapped them around when I got home as I reckon the half-worn Yoko's would still be as grippy as the new Michelin's.
I'm intrigued about the idea that a little bit of oversteer is safer than a little bit of understeer.
I can understand drivers preferring oversteer to understeer (especially male drivers where understeer is an insult to one's manliness). So what evidence do we have that oversteer is safer than understeer? I'm not talking about on the track or for braking distances, just specifically over v under in normal road driving.
BB
I can understand drivers preferring oversteer to understeer (especially male drivers where understeer is an insult to one's manliness). So what evidence do we have that oversteer is safer than understeer? I'm not talking about on the track or for braking distances, just specifically over v under in normal road driving.
BB
BertBert said:
I can understand drivers preferring oversteer to understeer (especially male drivers where understeer is an insult to one's manliness). So what evidence do we have that oversteer is safer than understeer?
IMO it gives a competent driver more control options for dealing with a situation.That aside, what I find with better tyres on the front is that rather than giving an oversteer bias it just goes some way toward neutralising the excessive understeer bias engineered into many modern cars.
BertBert said:
I'm intrigued about the idea that a little bit of oversteer is safer than a little bit of understeer.
I can understand drivers preferring oversteer to understeer (especially male drivers where understeer is an insult to one's manliness). So what evidence do we have that oversteer is safer than understeer? I'm not talking about on the track or for braking distances, just specifically over v under in normal road driving.
BB
If you had two choices of how to lose control of your vehicle: I can understand drivers preferring oversteer to understeer (especially male drivers where understeer is an insult to one's manliness). So what evidence do we have that oversteer is safer than understeer? I'm not talking about on the track or for braking distances, just specifically over v under in normal road driving.
BB
1) You're steering system fails completely and you can not turn the front wheels at all; 0% control.
or
2) Have a simultaneous blow out of both rear tires but still be able to steer the vehicle (and in this case lets assume the car is FWD)
Which would you choose?
I would feel safer 99% of the time with scenario #2
Personally I don't think you can apply over / understeer to normal road driving. They don't really happen at normal road speeds. I don't think anyone said it was safer directly, but that it allows the driver more control and therefor could be argued as safer. Provided the driver knows how to control it. There is no evidence that I know of personally that provides empirical data to support either.
Edited by Zero 1 on Thursday 3rd May 22:08
GravelBen said:
IMO it gives a competent driver more control options for dealing with a situation.
That aside, what I find with better tyres on the front is that rather than giving an oversteer bias it just goes some way toward neutralising the excessive understeer bias engineered into many modern cars.
Thats a really good point actually. My 96 Volvo 850 FWD would understeer like a pig. I remember one time switching the front worn tires to the rear and the fresh rubber up front and the car felt very neutral. It solved a lot of the innate problems of modern heavy FWD saloon cars. That aside, what I find with better tyres on the front is that rather than giving an oversteer bias it just goes some way toward neutralising the excessive understeer bias engineered into many modern cars.
Could the 'new ones on the front' contributors please watch this video (skip to 1m40s if you're in a rush) and get back to us? Thanks.
At work, but I assume thats the 5th Gear VBH clip where what the test really finds is the very specific speed/water depth window where you can make only one end aquaplane? IIRC she gives a quick twitch on the steering just before it 'suddenly spins' too.
If its a different clip I'll either delete this post later or just look like an idiot.
If its a different clip I'll either delete this post later or just look like an idiot.
GravelBen said:
At work, but I assume thats the 5th Gear VBH clip where what the test really finds is the very specific speed/water depth window where you can make only one end aquaplane? IIRC she gives a quick twitch on the steering just before it 'suddenly spins' too.
If its a different clip I'll either delete this post later or just look like an idiot.
It's a different clip.If its a different clip I'll either delete this post later or just look like an idiot.
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