[rajushank84]

Hi,

A couple of questions for tyre/wheel/handling experts, I apologize if a topic exists for this but I tried searching and didn't find any topic.

So I understand a square setup has less tendency to understeer, and I'm looking to reduce the understeer I feel with my stock runflats on my BMW.

Question (1):
- Setup A - square with 245/40/18 all around
- Setup B - staggered with 245/40/18 in front, 265/35/18 in the back

Here, is setup A still going to have less understeer than setup B because of being "square"? Or, will both these setups have the same front-end grip due to having the same tires up front? (i.e will the extra grip in the rear push the car further / encourage you to take a corner even faster, resulting in understeer?)

In other words, does square setup still have a grip/understeer advantage over staggered EVEN IF the tires in the front are the same in both cases?

Question (2):
If my square setup is mounted on different width wheels, will it still handle as neutral as mounting them on the same wheels i.e:
Setup A - 245/40/18 mounted on 18" wheels with 8" width
Setup B - 245/40/18 mounted on 18/8 wheels in front and 18/8.5 wheels in rear

Thanks in advance.

[Macfreak7]

Hi,
I'm assuming the BMW in question is your 335i? Does it have ZSP? What is your current tire set up?
Back in the day, I used to drive an E90 330i equipped with Sport Package which included sport suspension as well as staggered wheel sizes. The set up was as follows:
Front: 225/40 R18 - Rear: 255/35 R18.
Considering this is what BMW used, I would not go for what you have mentioned. 245 in the front and 265 in the rear is way overkill, IMHO. Besides 18s already fill into the wheel arches quite well.
To (kinda) answer your question 1, despite having a staggered set up my car would understeer (at BMW CCA auto crosses, for example). However I think the culprit in my case may have been Active Steering which would alter the steering ratio at various speeds. If you don't have Active Steering then I'd suggest this staggered (225 + 255) set up which *should* give better cornering and handling ability over the standard squared set up.

Question 2: If you're going for 225 / 255 on 18" wheels as suggested above, then you will need wider wheels for the rear tires, ie. 18x9.5. Front 225mm will fit on 18x8 wheels.
So in a nutshell:
Fronts : 225/40/18 on 18x8 wheels
Rear : 255/35/18 on 18x9.5 wheels

Hope this helps!

[rajushank84]

Originally Posted by Macfreak7

Hi,
I'm assuming the BMW in question is your 335i? Does it have ZSP? What is your current tire set up?
Back in the day, I used to drive an E90 330i equipped with Sport Package which included sport suspension as well as staggered wheel sizes. The set up was as follows:
Front: 225/40 R18 - Rear: 255/35 R18.
Considering this is what BMW used, I would not go for what you have mentioned. 245 in the front and 265 in the rear is way overkill, IMHO. Besides 18s already fill into the wheel arches quite well.
To (kinda) answer your question 1, despite having a staggered set up my car would understeer (at BMW CCA auto crosses, for example). However I think the culprit in my case may have been Active Steering which would alter the steering ratio at various speeds. If you don't have Active Steering then I'd suggest this staggered (225 + 255) set up which *should* give better cornering and handling ability over the standard squared set up.

Question 2: If you're going for 225 / 255 on 18" wheels as suggested above, then you will need wider wheels for the rear tires, ie. 18x9.5. Front 225mm will fit on 18x8 wheels.
So in a nutshell:
Fronts : 225/40/18 on 18x8 wheels
Rear : 255/35/18 on 18x9.5 wheels

Hope this helps!

Thanks! But I think both my questions are still unanswered. No, this is for my F30 328i, where the OEM wheels range from 17" to 20".

Perhaps I should rephrase both questions and remove the specifics, I apologize for not being clear.

Question 1: On any given car (lets say my 328i), will having a staggered setup versus square setup both with the same front wheels & tires, have any difference in the tendency to understeer?

Question 2: On any given car, does doing a square setup on the exact same wheels have any difference from doing a square tire setup with wheels of slightly different width? (lets say 8" and 8.5")

[Macfreak7]

There are too many variables (such as engine power/suspension set up/RWD vs FWD/air pressure in tires etc), to answer your questions for "any given car". If you could make it specific and tell us what exactly you're trying to do then maybe there could be a more specific answer. From what I gather you're trying to reduce understeer?

To understand your question 1 more clearly, you basically want to know about the impact on tendency to understeer if you keep the front tires and wheels the same and only change the rear sizes to a wider set up? All else equal, on a RWD car you will understeer more with a staggered set up. Have you tried different air pressure levels in front / rear tires? to reduce understeer if that's what you're trying to do, go with slightly less air pressure in the front.

Question 2 completely went over the top, sorry!

In general, changing the sizes of tires / wheels to impact understeer should be done as the last resort. Before that you could rather try reducing the air pressure in the front tires, or try using grippier tires in the front (run flats are too hard usually). Or even change your suspension set up.
Finally, check out this thread for more info.
http://www.team-bhp.com/forum/tyre-a...overrated.html

Cheers!

[karan561]

Originally Posted by rajushank84

Hi,

A couple of questions for tyre/wheel/handling experts, I aplologize if a topic exists for this but I tried searching and didn't find any topic.

So I understand a square setup has less tendency to understeer, and I'm looking to reduce the understeer I feel with my stock runflats on my BMW.

Question (1):
- Setup A - square with 245/40/18 all around
- Setup B - staggered with 245/40/18 in front, 265/35/18 in the back

Here, is setup A still going to have less understeer than setup B because of being "square"? Or, will both these setups have the same front-end grip due to having the same tires up front? (i.e will the extra grip in the rear push the car further / encourage you to take a corner even faster, resulting in understeer?)

In other words, does square setup still have a grip/understeer advantage over staggered EVEN IF the tires in the front are the same in both cases?

Question (2):
If my square setup is mounted on different width wheels, will it still handle as neutral as mounting them on the same wheels i.e:
Setup A - 245/40/18 mounted on 18" wheels with 8" width
Setup B - 245/40/18 mounted on 18/8 wheels in front and 18/8.5 wheels in rear

Thanks in advance.

Im running on staggered setup of 225/45 front & 245/40 rear on OE 18"ers (style 397)

You can read more about my upgrade from runflat to tubeless type here;

http://www.team-bhp.com/forum/tyre-a...k-com-usa.html

Also, Can you please share more details about your model that is a sportline or an M sport, as the style 397 are 8" wide & you cant go any wider than 245 rubber.

[rajushank84]

Thanks, Macfreak7 and karan561!

Originally Posted by Macfreak7

To understand your question 1 more clearly, you basically want to know about the impact on tendency to understeer if you keep the front tires and wheels the same and only change the rear sizes to a wider set up? All else equal, on a RWD car you will understeer more with a staggered set up. Have you tried different air pressure levels in front / rear tires? to reduce understeer if that's what you're trying to do, go with slightly less air pressure in the front.

That's exactly what I'm looking for! Just curious, any idea WHY a staggered setup will still understeer more than setup with all other factors being equal and same front tyres? Intriguing to me..

My car is a base 328i with the M Performance Suspension. Currently it has the stock wheels and tyres (17/7.5 wheels, 225/50/R17 runflats). Yes, I've tried playing around with air pressure already.

The runflats lose grip very easily with my style of driving - understeer sometimes, oversteer sometimes.

I'm looking to upsize a little bit, change to non-runflats, some max performance tyres since it rarely rains where I live. I'm thinking Michelin PSS, considering Bridgestone RE11As as well.

I'm torn between:
Option 1 - get 18" wheels (thinking factory style 397 wheels - 18/8"), go square with 245/40/R18 all around.
Option 2 - get 19" wheels - factory style 403 rims, but those are staggered rims. I'll have to go staggered if I get these, probably with 245/40 in front and 265/35 in rear.

I tend towards a square setup because the idea of eliminating understeer is attractive. My previous car, an E90 335i (forgot what wheels/tires it had except I know it had the sports package) had absolutely no understeer or oversteer to the extent that I pushed it. I would love to get that level of grip again. That car used to tramline a lot so I'm kinda used to tramlining and can deal with it.

So.. between Option 1 and Option 2 above, I posted Question 1 because I was wondering if I would get the same level of understeer with both. Sounds like no, I'd still be better off with a completely square setup. Except the fact that I'll be stuck with 245 as max width if I get those specific wheels.

Question 2 is (to rephrase it yet again ) - is there any difference between mounting square tires in square wheels vs non-square wheels ? I found the answer to this on another forum (m3 forum) last night, sounds like the answer is: There wont be any noticeable difference in handling but tire wear will be uneven since the tires will be stretched to a different extent, so rotation will no longer consist of just pulling out the wheel and mounting it. So if going square, square wheels are best.

... so, from all of the above, Option 1 (18" wheels square setup) sounds attractive to me. Only thing holding me back is the thought that I'll be spending all this money and not getting much bigger wheels (the bling factor of bigger wheels and "paisa vasool" factor) . Having said that, I can't think of any performance/real reason (other than looks) to get 19"s.

Oh and I'm not looking at aftermarket alloys because I like the OEM look. I did look at a few Avant Garde, Linea Corsa and a few others that almost match the look I want, but the OEM look is perfect for what I'm looking for.

By the way, @karan561 I think I saw your car on f30post or e90post.

[karan561]

Originally Posted by rajushank84

Thanks, Macfreak7 and karan561!
I'm torn between:
Option 1 - get 18" wheels (thinking factory style 397 wheels - 18/8"), go square with 245/40/R18 all around.

^ This is the best option IMO as this will reduce the understeer which you seem to be facing & the rear 245s will provide ample grip to put down the power. Another great advantage is that you can get to shuffle your tires periodically & hence longer life which in staggered you cant.

Originally Posted by rajushank84

By the way, @karan561 I think I saw your car on f30post or e90post.

Yes, i have a few active threads on f30post

[Macfreak7]

Originally Posted by rajushank84

Thanks, Macfreak7 and karan561!



That's exactly what I'm looking for! Just curious, any idea WHY a staggered setup will still understeer more than setup with all other factors being equal and same front tyres? Intriguing to me..

My car is a base 328i with the M Performance Suspension. Currently it has the stock wheels and tyres (17/7.5 wheels, 225/50/R17 runflats). Yes, I've tried playing around with air pressure already.

The runflats lose grip very easily with my style of driving - understeer sometimes, oversteer sometimes.

I'm looking to upsize a little bit, change to non-runflats, some max performance tyres since it rarely rains where I live. I'm thinking Michelin PSS, considering Bridgestone RE11As as well.

I'm torn between:
Option 1 - get 18" wheels (thinking factory style 397 wheels - 18/8"), go square with 245/40/R18 all around.
Option 2 - get 19" wheels - factory style 403 rims, but those are staggered rims. I'll have to go staggered if I get these, probably with 245/40 in front and 265/35 in rear.

I tend towards a square setup because the idea of eliminating understeer is attractive. My previous car, an E90 335i (forgot what wheels/tires it had except I know it had the sports package) had absolutely no understeer or oversteer to the extent that I pushed it. I would love to get that level of grip again. That car used to tramline a lot so I'm kinda used to tramlining and can deal with it.

So.. between Option 1 and Option 2 above, I posted Question 1 because I was wondering if I would get the same level of understeer with both. Sounds like no, I'd still be better off with a completely square setup. Except the fact that I'll be stuck with 245 as max width if I get those specific wheels.

Finally you give us some details about your set up.

Sounds like you are sure you want to upsize, I would suggest going for a staggered set up.
Why?
Because you're going for non-runflats, which means your tires will provide a lot more grip and most likely eliminate any understeer that you're facing right now, especially if you're going for the Michelin PSS. (effectively all else is NOT equal in this scenario). If you're worried about not being able to rotate tires then you may want to consider that BMW doesn't really recommend rotating tires to begin with. Besides if you get high performance tires then typically they tend to be directional which means you won't be able to rotate them even if it's a square set up.
Also, your previous E90 with sport package more than likely had a staggered set up. However, you can't compare the two cause the handling dynamic of both cars is quite different, and my guess is that this is the root of your problem. To put it bluntly, the E90 is a better handling car.
Finally, not that it really matters but a staggered set up is more aesthetically pleasing, esp. on a RWD car.

Long story short > my suggestion is for a staggered, 225 in the front and 255 in the rear, primarily if you're going for the Pilot SS, which in my experience are fantastic - quiet and super grippy.

Enjoy!

[rajushank84]

Originally Posted by Macfreak7

Finally you give us some details about your set up.

Hey, I intentionally avoided giving more details in my original post, to avoid digressing from the specific questions I posted and keep it as objective as possible / other factors out of it .

I'm still going back and forth on this!! Also, I wonder if getting five wheels & tires (if I go square) instead of a spare wheel / donut would be a good idea..

[VeyronSuperSprt]

Originally Posted by rajushank84

Hi,

A couple of questions for tyre/wheel/handling experts, I apologize if a topic exists for this but I tried searching and didn't find any topic.

So I understand a square setup has less tendency to understeer, and I'm looking to reduce the understeer I feel with my stock runflats on my BMW.

Question (1):
- Setup A - square with 245/40/18 all around
- Setup B - staggered with 245/40/18 in front, 265/35/18 in the back

Here, is setup A still going to have less understeer than setup B because of being "square"? .

Yes

Originally Posted by rajushank84

Or, will both these setups have the same front-end grip due to having the same tires up front? (i.e will the extra grip in the rear push the car further / encourage you to take a corner even faster, resulting in understeer?)

No

Originally Posted by rajushank84

In other words, does square setup still have a grip/understeer advantage over staggered EVEN IF the tires in the front are the same in both cases?

No

Originally Posted by rajushank84

Question (2):
If my square setup is mounted on different width wheels, will it still handle as neutral as mounting them on the same wheels i.e:
Setup A - 245/40/18 mounted on 18" wheels with 8" width
Setup B - 245/40/18 mounted on 18/8 wheels in front and 18/8.5 wheels in rear

No. Setup A will be marginally more neutral.

[rajushank84]

Thanks @VeyronSuperSprt! That's what I figured too, in fact I couldn't find anything conclusive on this on other forums too.

[9thsphinx]

Sorry for reviving an old thread but does a staggered setup for a quasi SUV make sense? A friend is planning on upgrading the rear tires on the Creta to 235/55/R17 while leaving the front to the stock 215/55/R17.

Any potential advantages except the obvious better grip? Or should he stick to the stock square?

[reignofchaos]

Originally Posted by 9thsphinx

Sorry for reviving an old thread but does a staggered setup for a quasi SUV make sense? A friend is planning on upgrading the rear tires on the Creta to 235/55/R17 while leaving the front to the stock 215/55/R17.

Any potential advantages except the obvious better grip? Or should he stick to the stock square?

Wider rubber at the back makes sense only when you have a RWD car, putting tonnes of torque down. Creta is FWD, a staggered setup makes absolutely no sense on a Creta.

[SKODA_RS]

hi guys,
I have a Peted Laura TSi(320bhp)
I have a query regarding the tyre setup, so i thought this is the right thread to ask such a question.Pls move to appropriate section if necessary.

Here are a few details of the Laura TSi Tyre Setup:
1)OEM setup : 195/65R15 Alloy Wheels and GoodYear NCT5 tyres

Now,in a hurry i have upgraded to the following setup on My Peted Laura(320bhp):

225/60R15 Yokohamas C-Drives on all 5 Tyres keeping the Stock Alloys.

After driving the modified car before and after the mods,even in stock form the 225/60 tyres were a bit too heavy, i and petes also found out this setup to be a tad too heavy.

Though this C-drives setup has upped the comfort level, the Bilestein struts and H&R springs have reduced the comfort. So on this tyre setup i have got a sweet spot in handling and comfort.

So a thought came to my mind after reading this thread, " Why not staggered tyre setup for Laura? "

The idea for going for a staggered tyre setup is to reduce the heavy weight of the current c-drives and still put down power efficiantly,in a maximum possible way.

Its a FWD car putting down 320bhp, so the setups in my mind are as follows:

Option 1) Front: 225/60R15 (Rubber pls suggest)
Rear : 205/65R15(Rubber pls suggest) (Weight Savings from current setup)

Option 2)Front : 215/60 R15 (Rubber pls suggest)
Rear:same as front.

Option 3)Front : 205/65R15 (Rubber pls suggest)
Rear: same as front.

Last Option: Upgrading the Rims(which i dont want to )
At the Max i can go for 16 inch rims.


So, pls suggest a good staggered tyre size setup for My Laura.
Awaiting responses as i am totally confused.

[batterylow]

Originally Posted by SKODA_RS

Option 1) Front: 225/60R15 (Rubber pls suggest)
Rear : 205/65R15(Rubber pls suggest) (Weight Savings from current setup)

So, pls suggest a good staggered tyre size setup for My Laura.
Awaiting responses as i am totally confused.

I don't know about the other options but a set up with wider front tires doesn't exactly look good, a square set up would look much better.