My E350 has staggered sized (wider rear) wheels, why ?

John Laidlaw

Senior Member
Joined
Nov 15, 2013
Messages
26,373
Reaction score
9,163
Location
Wirral
Your Mercedes
Land Rover Discovery 4
To be fair, mine is a saloon and Carl's is an estate, so the coupe might be different? Not sure on that....
 

C350Carl

Senior Member
Joined
Feb 16, 2014
Messages
4,580
Reaction score
898
Location
Middle East
Your Mercedes
BMW 740Ld xDrive
I meant to say. My C350 also had a space saver and I had HK in that. But it was again an Estate.
 

Craiglxviii

Senior Member
Joined
Sep 6, 2015
Messages
17,781
Reaction score
7,426
Location
Cambs UK
Your Mercedes
970 Panamera Turbo; W221 S500L AMG Line, C215 CL500, W251 R350L AMG Line, plus several more now gone
Damn, I was told no spare by the lying, cheating, salesman and I believed him...
Feel a tw*t now, I'll have to investigate a skinny on the web.
I've always had an uneasy feeling about goo as a sole solution (pun intended)!

If you have Bluetec in the 212 facelift, there is no room in the saloon for a spare wheel as the pig weewee tank takes up the volume of the wheel well. On the 213 they have made provision for this is a proper place. On the 212 estate I believe there is spare volume under the load space floor around the wheel well.
 

Headhurts

Senior Member
Joined
Jul 24, 2014
Messages
1,048
Reaction score
330
Location
Norwich, Norfolk
Your Mercedes
Mercedes GLC300 2021
If you have Bluetec in the 212 facelift, there is no room in the saloon for a spare wheel as the pig weewee tank takes up the volume of the wheel well. On the 213 they have made provision for this is a proper place. On the 212 estate I believe there is spare volume under the load space floor around the wheel well.

Nope!

No space on my S212 for spare wheel, unless I am missing something obvious.

I rarely lift the floor cover though.


Sent from my iPad using Tapatalk
 

Frosty149

Senior Member
Joined
Jan 9, 2017
Messages
2,363
Reaction score
761
Location
Garden of England
Your Mercedes
W207 '63 E350 coupe amg sport
If you have Bluetec in the 212 facelift, there is no room in the saloon for a spare wheel as the pig weewee tank takes up the volume of the wheel well. On the 213 they have made provision for this is a proper place. On the 212 estate I believe there is spare volume under the load space floor around the wheel well.

Ok,
So I took the bags of sand general ****-shat out of the boot and had a peep...
You're right there's a tank avec yes yes!
No room for any type of spare.
No ****** jack either!
 

John Laidlaw

Senior Member
Joined
Nov 15, 2013
Messages
26,373
Reaction score
9,163
Location
Wirral
Your Mercedes
Land Rover Discovery 4
It ****ing is!
Guess you've a **** tank then
 

Craiglxviii

Senior Member
Joined
Sep 6, 2015
Messages
17,781
Reaction score
7,426
Location
Cambs UK
Your Mercedes
970 Panamera Turbo; W221 S500L AMG Line, C215 CL500, W251 R350L AMG Line, plus several more now gone
Ok,
So I took the bags of sand general ****-shat out of the boot and had a peep...
You're right there's a tank avec yes yes!
No room for any type of spare.
No ****** jack either!

No ****ing jack because there's a compressor and a tub of ****ing goo!

The pigpiss tank takes up the spare wheel well totally (its 24 litres...) so no roomeven for a spacesaver. But tbh the goo will do almost anything the spacesaver will. I was sceptical until I saw the warranty data for a million cars worth of goo.
 

Craiglxviii

Senior Member
Joined
Sep 6, 2015
Messages
17,781
Reaction score
7,426
Location
Cambs UK
Your Mercedes
970 Panamera Turbo; W221 S500L AMG Line, C215 CL500, W251 R350L AMG Line, plus several more now gone
Hey it missed that one!!!^^
 

John Laidlaw

Senior Member
Joined
Nov 15, 2013
Messages
26,373
Reaction score
9,163
Location
Wirral
Your Mercedes
Land Rover Discovery 4
Somewhat redundant word in MB world...
 

Submariner1

Senior Member
Joined
Sep 3, 2016
Messages
4,688
Reaction score
785
Location
Windsor Berkshire
Your Mercedes
CL500 2009 5.5
Sorry Craig this is a fallacy.
A wider tyre has a different shaped footprint but not a significantly larger one (as long as tyre pressures are equal).

In other words increasing a tyres width by 20% does not give a 20% bigger footprint, just 20% wider and 20% shorter. The governing factor for footprint is tyre pressure. The higher the pressure the smaller the footprint (for a given weight).

I very rarely fail to see your logic. But I am struggling with this one.
I assumed just by calculation when they went from say 18" to 19" tyres MB adjust the rolling radius by a reduced tyre profile. So fundamentally the RR is the same or very close. So your wider tyres still have the same or extremely close RRs.

Thus assuming the RR is the same, then the contact area front to back on the road (pressure adjusted) is the same.
Therefore when you move from 255 to 285 you have 30 mm x the front to back dimension more touching the road.

The knowledgeable salesman he was a rare breed, said wider tyres have pros and cons ... better grip in the dry and slightly less in the wet. ( yes more because of the extra footprint, but less because you lower the contact pressure. ( namely weight of car stays the same .. larger footprint equals lower lbs / square inch).

TBH I have no technical expertise in this area, but I accepted one SL500 that the Option date on that build had closed (saved me a 2 months wait) it had all my selected options, but not the staggerred wheels. When the car came they said they had to get a new Info Plate inside the petrol flap, as they were fitting the bigger wheels so the pressures were incorrect.
Hence I assume this pressure adjustment would ensure the same front to back footprint dimension was retained, ergo you would get an 11.7% increase in road contact?

I do conceed that there is a probability that the wider tyres need a higher pressure just to keep the centre of the tyre inflated enough so it doesnt collapse and hence your theory could be correct.

But I do struggle with the concept especially as most of the big v8 AMGs have wider staggered tyres, surely they are looking for better traction/grip?
 

Craiglxviii

Senior Member
Joined
Sep 6, 2015
Messages
17,781
Reaction score
7,426
Location
Cambs UK
Your Mercedes
970 Panamera Turbo; W221 S500L AMG Line, C215 CL500, W251 R350L AMG Line, plus several more now gone
Better dynamics when cornering allowing for increased grip to cope with those bigger ANG hosses
 

John Laidlaw

Senior Member
Joined
Nov 15, 2013
Messages
26,373
Reaction score
9,163
Location
Wirral
Your Mercedes
Land Rover Discovery 4
:confused:Yip try some spirited cornering with near 560 horses and skinny tyres and see how you get on...
 

LostKiwi

Senior Member
Joined
Aug 25, 2006
Messages
31,326
Reaction score
21,574
Location
Midlands / Charente-Maritime
Your Mercedes
'93 500SL-32, '01 W210 Estate E240 (RIP), 02 R230 SL500, 04 Smart Roadster Coupe, 11 R350CDi
Ok Sub...

The only thing holding your car up is the tyre. The tyre has a sidewall that compresses unless filled with air so the only thing really holding the car up is the air.

Now air compresses and we see this from the way the tyre bulges at the bottom (if it didn't the tyre wouldn't deform). The tyre will therefore deform by an amount dependent on the weight on the tyre and its static pressure. Notice it doesn't depend on width.
As the weight is borne by the air inside the tyre the pressure measured in psi will result in a footprint which is also independent of width. The clue is PSI. Pounds per square inch. Only a change in PSI (either through less tyre pressure or more weight) will change the tyre deformation and contact patch size.
This is why we increase tyre pressure for increased loads. The extra weight will alter the deformation of the tyre and its contact patch hence allowing more heat build up. Increased tyre pressure counters this by reducing the contact patch and deformation hence allowing less heat build up.
The wider footprint will have benefits in lateral stability of the tread but will have REDUCED traction in the fore and aft plane, especially in wet conditions.

It seems counter intuitive but its true.

http://www.autospeed.com/cms/article.html?&title=Tyres-Grip-and-All-That&A=108915
 
Last edited:

You lost your key ? Or maybe you need a spare! Your vehicle imobilliser does not respond anymore? WE CAN FIX THEM ALL !! Mobile ! Save Time and Increase Profits With us !
Top Bottom