Why staggered tires?

gknight8 · 05-20-2008

Why do we have staggerred tire sizes between the front tires and rear tires? Is it okay to put let's say 225/40-18 all he way around? Or do I need to put 255/35-18 on the rear?

Ikarus · 05-20-2008

Quote:

Originally Posted by gknight8

Why do we have staggerred tire sizes between the front tires and rear tires? Is it okay to put let's say 225/40-18 all he way around?

You would change the driving dynamics of the vehicle such that the rear would have less traction and would come around more easily in corners. Depending on your driving style, this could be a disaster waiting to happen. It is not recommended, to say the least.

**DansSlk** · 05-20-2008

255's are not OEM for the back wheel's on your car so you don't have to put them on but you do have to put the MB sized wheel's on.

225 will be a hell of a mess.

**Driller** · 05-20-2008

I run 225's, on stock wheels, all around for my winter tires. No problems to speak of! For my summer shoes, I keep the 225's up front and grow to 255's in the rear.

*easty* · 05-20-2008

The staggered arrangement promoted under steer which is much is to recover from than over steer. it's not a huge problem though if your not pushing the car in say winter conditions.

**richard_leeds** · 05-20-2008

Apologies for showing my ignorance as a fair weather driver who's cautious about going too fast around corners...

Quote:

Originally Posted by Driller

I run 225's, on stock wheels, all around for my winter tires. No problems to speak of! For my summer shoes, I keep the 225's up front and grow to 255's in the rear.

Winter tyres on steel rims or cheap alloys? I guess you don't use low profile but have higher profile on smaller rims to give the same overall diamter as OEM?

Quote:

Originally Posted by easty

under steer which is much is to recover from than over steer.

Understeer is easier or harder to recover ?

**DansSlk** · 05-20-2008

Quote:

Originally Posted by richard_leeds

Understeer is easier or harder to recover ?

Understeer is much easier to cope with, you simply turn into the corner more.

Oversteer especially on the SLK that tends to fight as much as it can then snap away is horrible to cope with unless your expecting it because the tail tries to overtake the nose and you have to be sharp on the correction unless you want to be sideways or worse backwards.

Thats why i would never run 225's on the rear

Ikarus · 05-20-2008

Quote:

Originally Posted by richard_leeds

Understeer is easier or harder to recover ?

As entertaining as I find TopGear - one of my main gripes with them is their glorification of oversteer, as evident in this video:

YouTube Video

I very well understand this is all tongue in cheek, but their depiction of what can and often will happen if a car oversteers is trivialized to the point that it's almost criminal. It is also reflected in their car tests. If they can't manage to have the rear come out causing a wall of smoke and tire squeal, they will generally label a car as "boring".

**DansSlk** · 05-20-2008

It's funny whenever i have had a car spin out and i admit sometimes I've cocked it all up and it does happen i find that so much velocity is lost in the spin or the slide that you get very little motion left at the end of it all.

Very embarrassing experience.

**richard_leeds** · 05-20-2008

Quote:

Originally Posted by DansSlk

... explanation ...

Cheers Dan, that's what i thought but you were much more succinct than my rambling answer

Quote:

Originally Posted by DansSlk

Very embarrassing experience.

The perfect response came from a friend of mine with a Caterham. He did a pure 360 when pulling away from lights in the wet. Little old lady in a little old car pulls up awfully concerned... "are you alright?" she asks. He came out with the line .... "oh, its OK, she's a bitch in the wet"

*easty* · 05-20-2008

I think it comes down to if the wheels are turning and the car is slowing it will grip and turn in an under steer scenario. obviously if there is a wall prior to the car gripping it doesn't matter. But with over steer it takes action from the driver to correct.

Ikarus · 05-20-2008

Quote:

Originally Posted by easty

But with over steer it takes action from the driver to correct.

Indeed, and the action it takes is counter-intuitive to most inexperienced drivers. In order to straighten the car in an oversteer situation, lifting off the accelerator is counter-productive, since this will make the car lift up in the back, so it'll lose even more precious grip. Instead, one needs to turn the steering wheel into opposite lock and modulate the accelerator to straighten it out.

**DansSlk** · 05-20-2008

This is why the traditional driver training is useless, nearly every country offers advanced driver training and practically the first thing you learn is how to recover an over-steering car (or at least it was when i took the test) so why the hell don't they include all that stuff as standard and perhaps we might get some safer driver's.

And its not helped by TV as Ikarus pointed out, i can think of no situation that i want the tail to step out of line for, it is totally counter-productive to getting somewhere in a hurry and making it sound like a good thing is IMHO a very bad idea, it's the last thing you want young drivers trying to copy.

The driving instructor's themselves don't help either by hammering it into people that if you get into trouble you stand on the brakes.

**Dolebludger** · 05-21-2008

As I also drive a Honda S 2000, I am very familiar with the problems of having the "tail step out" version of over steer. We have a whole generation of drivers who have driven nothing before except FWD vehicles. They are not prepared to sense when this is coming on, or how to prevent it. First, if a car comes stock with larger tires in the rear, there is a reason for this, and you don't want to change this. Second, you must develop a sense of how far you can "push" you car on a corner while keeping your rear end from breaking out. Third, you must know how to correct this problem -- if you are on a curve to the right and your rear heads left, you need to steer to the left and get off the throttle, with no braking.

There has never been a FWD sports car, and there will never be one. But driving a RWD sports car is a whole different experience from driving a FWD sedan or hatch. With RWD, you must learn to "feel" when your rear tires are heading in the opposite direction of your turn, and take the action described above to stop this, before accelerating again. If driven correctly, no FWD car will ever corner as well -- or pull as many gs -- as a RWD car will. But if driven incorrectly, cornering in a RWD car can be a disaster. If you are the recent owner of an SLK or any RWD sports car, you must learn to "feel" what your rear tires are doing on corners, and learn to respond correctly.

And this is what I have to say about that!

Ikarus · 05-21-2008

Quote:

Originally Posted by Dolebludger

There has never been a FWD sports car, and there will never be one.

Hardly. BMW is the only RWD team in the current WTCC and it is trailing two out of the three competing FWD teams in the ranking (Seat, Chevrolet, Honda).

gknight8 · 05-22-2008

Okay, so I guess I should keep the staggered tires and not go with the same size, thanks for the info guys!

**Driller** · 05-22-2008

[quote=richard_leeds;69934]Apologies for showing my ignorance as a fair weather driver who's cautious about going too fast around corners...

Winter tyres on steel rims or cheap alloys? I guess you don't use low profile but have higher profile on smaller rims to give the same overall diamter as OEM?

I use my stock staggered wheels with 225/40/18 all around.

**Dolebludger** · 05-22-2008

Ikarus:

I know there is no universally accepted definition of the term "sports car", and I know that many competitive events now exist where FWD cars are competing successfully. I was merely applying my own definition of "sports car" (and that of many others, I must confess) in excluding any FWD car. But contrary intelligent opinions do exist.

Ikarus · 05-22-2008

Quote:

Originally Posted by Dolebludger

I was merely applying my own definition of "sports car" (and that of many others, I must confess) in excluding any FWD car.

Fair enough, but what is your definition of sports car?

Just don't say that it cannot have FWD by definition, because that makes it a somewhat circular argument.

**richard_leeds** · 05-22-2008

Quote:

Originally Posted by Driller

I use my stock staggered wheels with 225/40/18 all around.

ah... penny drops .... you have stock 225 front and back... my 350 has 225 front, 255 rear (from memory)

05-20-2008	#1 (permalink)
gknight8 SLK World Member Join Date: May 2008 Vehicle: SLK280, E550 Other Toys: BMW Motorcycle, 32' power boat Posts: 36 Country: Thanks: 0 Thanked 0 Times in 0 Posts	Why staggered tires? Why do we have staggerred tire sizes between the front tires and rear tires? Is it okay to put let's say 225/40-18 all he way around? Or do I need to put 255/35-18 on the rear?

05-20-2008	#3 (permalink)
DansSlk Dude Join Date: Jun 2006 Location: Wales Vehicle: 05 B55S (Brabus 6.1 S) Posts: 6,795 Country: Thanks: 96 Thanked 225 Times in 177 Posts	255's are not OEM for the back wheel's on your car so you don't have to put them on but you do have to put the MB sized wheel's on. 225 will be a hell of a mess. __________________ One thing you will learn with German cars - If it's simple it ain't happening.

05-20-2008	#5 (permalink)
easty Moderator Join Date: Jun 2006 Location: Montreal Vehicle: ///AMG Posts: 2,075 Country: Thanks: 17 Thanked 19 Times in 9 Posts	The staggered arrangement promoted under steer which is much is to recover from than over steer. it's not a huge problem though if your not pushing the car in say winter conditions. __________________ "I'm not a roman mum, I'm a kike, a yid, a heebie, a hook-nose, I'm kosher mum, I'm a Red Sea pedestrian, and proud of it!" Life of Brian To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts.

05-20-2008	#9 (permalink)
DansSlk Dude Join Date: Jun 2006 Location: Wales Vehicle: 05 B55S (Brabus 6.1 S) Posts: 6,795 Country: Thanks: 96 Thanked 225 Times in 177 Posts	It's funny whenever i have had a car spin out and i admit sometimes I've cocked it all up and it does happen i find that so much velocity is lost in the spin or the slide that you get very little motion left at the end of it all. Very embarrassing experience. __________________ One thing you will learn with German cars - If it's simple it ain't happening.

05-20-2008	#11 (permalink)
easty Moderator Join Date: Jun 2006 Location: Montreal Vehicle: ///AMG Posts: 2,075 Country: Thanks: 17 Thanked 19 Times in 9 Posts	I think it comes down to if the wheels are turning and the car is slowing it will grip and turn in an under steer scenario. obviously if there is a wall prior to the car gripping it doesn't matter. But with over steer it takes action from the driver to correct. __________________ "I'm not a roman mum, I'm a kike, a yid, a heebie, a hook-nose, I'm kosher mum, I'm a Red Sea pedestrian, and proud of it!" Life of Brian To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts.

05-20-2008	#4 (permalink)
Driller SLK World Member Join Date: Jun 2006 Location: Calgary, Alberta Vehicle: 2005 SLK 55 Posts: 88 Country: Thanks: 2 Thanked 1 Time in 1 Post	I run 225's, on stock wheels, all around for my winter tires. No problems to speak of! For my summer shoes, I keep the 225's up front and grow to 255's in the rear.

05-20-2008	#13 (permalink)
DansSlk Dude Join Date: Jun 2006 Location: Wales Vehicle: 05 B55S (Brabus 6.1 S) Posts: 6,795 Country: Thanks: 96 Thanked 225 Times in 177 Posts	This is why the traditional driver training is useless, nearly every country offers advanced driver training and practically the first thing you learn is how to recover an over-steering car (or at least it was when i took the test) so why the hell don't they include all that stuff as standard and perhaps we might get some safer driver's. And its not helped by TV as Ikarus pointed out, i can think of no situation that i want the tail to step out of line for, it is totally counter-productive to getting somewhere in a hurry and making it sound like a good thing is IMHO a very bad idea, it's the last thing you want young drivers trying to copy. The driving instructor's themselves don't help either by hammering it into people that if you get into trouble you stand on the brakes. __________________ One thing you will learn with German cars - If it's simple it ain't happening.

05-21-2008	#14 (permalink)
Dolebludger Elite SLK World Member Join Date: Feb 2008 Location: Yukon, OK Vehicle: '07 SLK 280; '04 C 320, '01 Honda S 2000, '98 Ford Ranger truck. Posts: 569 Country: Thanks: 40 Thanked 77 Times in 52 Posts	As I also drive a Honda S 2000, I am very familiar with the problems of having the "tail step out" version of over steer. We have a whole generation of drivers who have driven nothing before except FWD vehicles. They are not prepared to sense when this is coming on, or how to prevent it. First, if a car comes stock with larger tires in the rear, there is a reason for this, and you don't want to change this. Second, you must develop a sense of how far you can "push" you car on a corner while keeping your rear end from breaking out. Third, you must know how to correct this problem -- if you are on a curve to the right and your rear heads left, you need to steer to the left and get off the throttle, with no braking. There has never been a FWD sports car, and there will never be one. But driving a RWD sports car is a whole different experience from driving a FWD sedan or hatch. With RWD, you must learn to "feel" when your rear tires are heading in the opposite direction of your turn, and take the action described above to stop this, before accelerating again. If driven correctly, no FWD car will ever corner as well -- or pull as many gs -- as a RWD car will. But if driven incorrectly, cornering in a RWD car can be a disaster. If you are the recent owner of an SLK or any RWD sports car, you must learn to "feel" what your rear tires are doing on corners, and learn to respond correctly. And this is what I have to say about that!

05-22-2008	#16 (permalink)
gknight8 SLK World Member Join Date: May 2008 Vehicle: SLK280, E550 Other Toys: BMW Motorcycle, 32' power boat Posts: 36 Country: Thanks: 0 Thanked 0 Times in 0 Posts	Okay, so I guess I should keep the staggered tires and not go with the same size, thanks for the info guys!

05-22-2008	#17 (permalink)
Driller SLK World Member Join Date: Jun 2006 Location: Calgary, Alberta Vehicle: 2005 SLK 55 Posts: 88 Country: Thanks: 2 Thanked 1 Time in 1 Post	[quote=richard_leeds;69934]Apologies for showing my ignorance as a fair weather driver who's cautious about going too fast around corners... Winter tyres on steel rims or cheap alloys? I guess you don't use low profile but have higher profile on smaller rims to give the same overall diamter as OEM? I use my stock staggered wheels with 225/40/18 all around.

05-22-2008	#18 (permalink)
Dolebludger Elite SLK World Member Join Date: Feb 2008 Location: Yukon, OK Vehicle: '07 SLK 280; '04 C 320, '01 Honda S 2000, '98 Ford Ranger truck. Posts: 569 Country: Thanks: 40 Thanked 77 Times in 52 Posts	Ikarus: I know there is no universally accepted definition of the term "sports car", and I know that many competitive events now exist where FWD cars are competing successfully. I was merely applying my own definition of "sports car" (and that of many others, I must confess) in excluding any FWD car. But contrary intelligent opinions do exist.

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