Fitting the wrong size tyres....on purpose!

[Mactech]

Now I certainly do not know better than Mercedes when it comes to the correct tyres for the GLE, but I do know what suits my specific set of circumstances best.

That’s why I have ended up with a new set of Avon’s finest ZX7 tyres in a size larger than Mercedes fit.

The size has gone from 265 to 275/45/20. The width has actually increased by just 8mm and the change of diameter is within the new tyre to worn tyre region.

I have some prior convictions for using odd tyres on cars. I developed a road car that ran 17” front and 18” rear. I ran my S Class on 20” front and 21” rear and have even run race cars with a different compound on each corner to suit a specific circuit!....and they all worked.

I have worked with Avon on many racing car projects over the years and have found them to be at least the equal, and often better than the ‘premier’ brands….and British.


So I found myself with some, shall we say, cost effective 275 tyres to fit the GLE.

I have already run this size on my W164 ML for some years previously and seen only benefits.

So the reasons I am not conforming to Mercedes recommendations on tyre size are:

· Cost. Most ‘MO’ tyres in 265 size are around £200 each. The Avons were certainly not anything like that! Generally 275 tyres are about 20% cheaper than the much rarer 265’s.

· The wet grip rating on the Avon’s is A, two grades better than the outgoing Pirelli Scorpion Verde. They do feel great in the wet.

· The efficiency rating is also 2 grades better. That is yet to be proven

· The noise exterior noise was also rated as lower which has translated to a reduced cabin sound level at 70mph on my favourite bit of dual carriageway from 64.1 to 62.4DB. The GLE is a quiet car

· Being a few mm wider and having rim protection edges has made the car more kerb tolerant. Not wife proof….but better!

· The small extra diameter has corrected the speedo, which now reads true to GPS readings.

· The ride comfort has gone up a notch, with at least a 25% reduction in he odd roll stiffness ‘jiggle’ at low speed.

· I have yet to try the ultimate dry grip, but if it is a good as the change to these tyres made on my previous Audi A6, then it will be fine. Not planning any trackdays in the GLE!

Any downsides? Not as yet, but I’ll keep you posted.

But don’t just take my word for it, look up some reviews on the Avon ZX7

Avon ZX7 Tyres at Blackcircles.com

 

[zipdip]

Well I needed a set of tyres for my W221 S320, 15 months ago,and decided I had a gut full of the supposed leading brands,they cost a lot,and for my sort of driving they just did not seem cost effective,not lasting that long,so I looked around and asked a tyre fitter what he would recommend and he said Nexen,he said that the 255x45x18 N Fera SUV 4 was a great tyre,normally fitted to 4x4's they are fitted as new to the Porsche 4x4,so I bought a set £80 a corner,well 13,000 later they tyres have loads still left on them,ok not the wrong size tyre but they are the best tyre I have had on this car,the worst being the P zero's they were crap.

 

[moog999]

Wrong tyre size might be a get out clause for any insurance pay out in some circumstances?

 

[Petrol Pete]

I replaced like for like on my old C55 only later to realise that the old rears I took off were 255 when stock spec was 245 but once I checked that the stock rear 8.5 inch rims were technically good for 255 width tyres that I had fitted it stopped worrying about it. the difference in width is negligible anyway.

 

[m2287]

View attachment 75176 Now I certainly do not know better than Mercedes when it comes to the correct tyres for the GLE, but I do know what suits my specific set of circumstances best.

That’s why I have ended up with a new set of finest ZX7 tyres in a size larger than Mercedes fit.

The size has gone from 265 to 275/45/20. The width has actually increased by just 8mm and the change of diameter is within the new tyre to worn tyre region.

I have some prior convictions for using odd tyres on cars. I developed a road car that ran 17” front and 18” rear. I ran my S Class on 20” front and 21” rear and have even run race cars with a different compound on each corner to suit a specific circuit!....and they all worked.

I have worked with Avon on many racing car projects over the years and have found them to be at least the equal, and often better than the ‘premier’ brands….and British.


So I found myself with some, shall we say, cost effective 275 tyres to fit the GLE.

I have already run this size on my W164 ML for some years previously and seen only benefits.

So the reasons I am not conforming to Mercedes recommendations on tyre size are:

· Cost. Most ‘MO’ tyres in 265 size are around £200 each. The Avons were certainly not anything like that! Generally 275 tyres are about 20% cheaper than the much rarer 265’s.

· The wet grip rating on the Avon’s is A, two grades better than the outgoing Pirelli Scorpion Verde. They do feel great in the wet.

· The efficiency rating is also 2 grades better. That is yet to be proven

· The noise exterior noise was also rated as lower which has translated to a reduced cabin sound level at 70mph on my favourite bit of dual carriageway from 64.1 to 62.4DB. The GLE is a quiet car

· Being a few mm wider and having rim protection edges has made the car more kerb tolerant. Not wife proof….but better!

· The small extra diameter has corrected the speedo, which now reads true to GPS readings.

· The ride comfort has gone up a notch, with at least a 25% reduction in he odd roll stiffness ‘jiggle’ at low speed.

· I have yet to try the ultimate dry grip, but if it is a good as the change to these tyres made on my previous Audi A6, then it will be fine. Not planning any trackdays in the GLE!

Any downsides? Not as yet, but I’ll keep you posted.

But don’t just take my word for it, look up some reviews on the Avon ZX7

Avon ZX7 Tyres at Blackcircles.com

Ermmmmm, can you get me one of those body kits (without the wing) at a “cost effective price”

 

[fabes]

I put those Avon's on our QQ rears late last year.
Same will be going on the fronts before we go to France in the summer

They are doing well so far

 

[Mactech]

Ermmmmm, can you get me one of those body kits (without the wing) at a “cost effective price”

So long as you can provide your car in the condition shown here so we can fit it, then I'll see what I can do!
It's a bit more than a body kit....but the lights and the door handles are standard...errr ...and that's about it
Here, the composite roof panel and rear quarters and being bonded to the roll cage....sorry bodyshell...

 

[brucemillar]

What a great pic. Gives an insight into just how much work goes into "prepping" one of these cars. Some people.......... think you just drive them at speed, through the nearest Halfords then
wait and see, what bits have stuck to the bodywork
.

 

[oldguy57]

Ermmmmm, can you get me one of those body kits (without the wing) at a “cost effective price”

Go on you need the wing as well...

 

[Mactech]

You probably want one of those interior mirrors too!
Our Northern Irish driver Stephan Kane said " Aye cun see nothin' in ma merse" so we gave him this 'panavision' one to see through all the roll hoop tubes. He rarely gets overtaken now.....

 

[Mactech]

What a great pic. Gives an insight into just how much work goes into "prepping" one of these cars. Some people.......... think you just drive them at speed, through the nearest Halfords then
wait and see, what bits have stuck to the bodywork
.

Yes, that was the result of almost 3 months solid work of two of the best guys in the business at M-Sport in Cumbria.
It was another 2 months before the prototype had a nice big turbo V8 under the bonnet, 400mm further back and 200mm lower than the production car

 

[m2287]

Yes, that was the result of almost 3 months solid work of two of the best guys in the business at M-Sport in Cumbria.
It was another 2 months before the prototype had a nice big turbo V8 under the bonnet, 400mm further back and 200mm lower than the production car
View attachment 75181

Could you imagine a project thread on something like this!!!!!

 

[oldguy57]

Yes, that was the result of almost 3 months solid work of two of the best guys in the business at M-Sport in Cumbria.
It was another 2 months before the prototype had a nice big turbo V8 under the bonnet, 400mm further back and 200mm lower than the production car
View attachment 75181

I bet the bill was eye watering.

 

[Mactech]

I bet the bill was eye watering.

Yep! They had to pay me for overseeing it..

 

[Mactech]

Just a quick update on the new Avon ZX7 tyres as I got to drive a couple of hundred miles on dry roads over the weekend.
The dry grip is really high with very progressive breakaway if you push them to hooligan limits and the dry braking is immense.
The pressures are now reduced to 2.2 bar and the ride comfort is fine. If I'm being really picky then the the steering input response time has increased very slightly (typical of a wider tyre on the same size rim)...but this is an SUV not a race car. The flip side of that is that the straight line stability is demonstrably improved and the car now ploughs a really straight furrow in high speed cruise with virtually no small correction inputs required.
I re-measured the cabin noise today (on the same bit of road, but this time properly dry!) and got constant readings below 62db at 70mph.
The officially makes it the quietest car I have ever owned (including my S class and Lexus) and the quietest I have every measured...and that includes a few current Bentleys
The slightly wider tyres appear to at least as efficient as the 265 Pirelli tyres as I got little over 40mpg on a known stop/start 70 mile A road route today which normally returns just under that figure....so the signs are good.
Overall I'm very pleased and just hoping I have to wait a really long time to tell you how they are wearing

 

[kid-jensen]

I always put wider size tyres on my cars for reasons of improved grip, ride and wheel-rim protection.

The ML is by far the most difficult car I've ever had to judge the position of the tyres vs the kerb, and my alloys are too rare to "park by ear" like someone with an "X" chromosome might do.

Without exception, I've always found a wider tyre gives better grip, less road noise and a smother ride than the "approved" fitment.
285/50/18's are "just right" on the ML in terms of dynamic compromise and protection of the alloys.

I'll accept the fuel consumption may be up a bit, but not significantly....