dull performance with larger wheels

[sherco450]

shopping around the moment for a E320 w211 and are surprised on the dull performance testing various vehicles with 17 " 18 and 19' wheel /tyre combo... l couldn't imagine how the car would drive with 20" ..is it really worth the larger wheel or do you need 500hp to propel a car with anything larger than stock..

 

[martyp87]

I can't see how a set of 17" wheels over 16" would make much of a difference to be honest?

My CLK came with 16"s and I fitted a set of genuine 18" AMG alloys and didn't really notice a loss of performance, just a little more grip if anything. I was more surprised the ride quality didn't degrade due to the smaller profile tires.

Only sold them as they didn't really suit the car as its not an AMG and fitted some decent Pirelli tires to the stock wheels.

 

[Benzowner]

To maintain speedo accuracy, normally the larger the wheel, the lower the profile of the tyre to maintain same rolling circumference. So I cannot see much, if any difference in performance with larger wheels, it is only a visual thing IMO.

 

[LittleG]

My first Escort had 155/70/13 when I bought it, I then put 205/40/17 on didn't make much difference although wheel spinning was reduced

 

[SavMan]

The challenge is finding the sweet spot for any particular model the majority of cases smaller wheels will give reduced weight per axle. If you took a like for like wheel and the majority are cast alloys then expect at least 20-25% increase in weight going from 16 to 20 inch wheels which will work out about 4-5kgs per wheel/tyre combo per axle.
I wouldnt be surprised to find anything upto a 0.5 secs to 60mph.

 

[b1g1an]

You might lose a tiny bit on top speed due to extra drag/rolling resistance if they're wider but there won't be any noticeable difference in performance.

You would be able to notice if coincidently the ones you've tried on larger rims are knackered or the one on smaller rims has been tuned.

 

[joecash]

E320 dull performance? sherco, are you sure all the cars you were testing didn't have their brakes jammed on, had turbo problems, or were in limp mode as well as oversized tyres? or am I just a timid oldie?

 

[SavMan]

Interesting test on a VW Golf

Fitting 4 inch larger wheels

0.3 secs faster to 60 mph
1.1 secs faster to 100 mph
10% drop in fuel economy

The plus was an increase on the skid pan but the tipping point was 3 inch larger wheels, the 19inch wheels actually dropped down.

Effects of Upsized Wheels and Tires Tested - Tech Dept. - Car and Driver

 

[230K]

The important table from the link in the above post

230k

Sent from my GT-I9505 using MBClub UK

 

[bolide]

0.3 secs faster to 60 mph
1.1 secs faster to 100 mph
10% drop in fuel economy

In case you're reading that as a benefit of the bigger wheels, it's not. The standard wheels & tyres gave better results in all measured criteria apart from skidpan G readings

Interesting that R&T describes the skidpan readings as "Roadholding". I think European testers might use rather different criteria to determine roadholding

Nick Froome

 

[b1g1an]

All that table shows is they didn't use tires that gave the original aspect ratio and so changed the overall gearing which would indeed affect performance...absolutely nothing to do with the size of the rim and if they matched them exactly they'd all be the same give or take the consistency of the driver.

Put lower ratio tyres on the standard rims and it'll accellerate a lot quicker and vice versa.

 

[redbaron]

it also shows that heavier wheels = less performance... so very light larger wheels could be "better"

 

[bolide]

All that table shows is they didn't use tires that gave the original aspect ratio and so changed the overall gearing

I think the contrary is true. They changed the aspect ratio to give the closest match on gearing. Check them on a tyre size calculator and you'll see they're very close

Nick Froome

 

[SavMan]

In case you're reading that as a benefit of the bigger wheels, it's not. The standard wheels & tyres gave better results in all measured criteria apart from skidpan G readings

Interesting that R&T describes the skidpan readings as "Roadholding". I think European testers might use rather different criteria to determine roadholding

Nick Froome

I was not should have worded it clearer, if you see my earlier post I had said that bigger wheels would be heavier and slower.

 

[SavMan]

it also shows that heavier wheels = less performance... so very light larger wheels could be "better"

Problem is normally overall package so needs to include tyre weight but I do agree fitting lighter wheels would have negated the difference. Then again you could fit light weight smaller wheels and increase the difference.

 

[SavMan]

I think the contrary is true. They changed the aspect ratio to give the closest match on gearing. Check them on a tyre size calculator and you'll see they're very close

Nick Froome

Agreed

 

[Dieselman]

it also shows that heavier wheels = less performance... so very light larger wheels could be "better"

I can't see any metal wheel rim being lighter than the air in the tyre.

 

[markjay]

I can't see any metal wheel rim being lighter than the air in the tyre.

Bigger wheels = more alloy = more weight.

The weight of the rubber remains (about) the same because the rubber from the sidewall goes on to the tread.

So larger wheels = more overall weight = slower acceleration

This is of course assuming that the wheels upgrade was done correctly i.e. while retaining the original circumference.

 

[markjay]

There's more to a car's performance than acceleration and top speed..

It is also worth noting that lower profile tyres will have more rigid sidewall and therefore better cornering ability and better control through the corner (because the car will 'tilt' less on the more rigid sidewall and because the low profile tyre will deform less quickly and the tread stays 'flat' and in full contact with the road for longer before deforming and reducing friction).

On the other hand wider tyres will 'tramline' when driven in straight line making it more difficult to maintain directional stability at speed, and they are also far more prone to aquaplaning on wet road than narrower tyres.

As far as the golden point... up to a that point wider tyres will allow better traction of the rear wheels (on RWD cars) and prevent wheelspin hence produce better acceleration. Beyond that point they will simply be heavier and cause more friction so will slow the car down when accelerating compared to narrower tyres.

So wider / lower profile tyres affect the car's performance in several ways.

Said that... as other pointed out... I suspect that 99% of the buying public will never experience or notice any of these performance differences in their day to day driving, and that for them the larger wheels are purely for aesthetic purposes.

Nothing wrong with that, mind... metallic paint does not make the car go any faster either, and yet we happily pay extra for it.

 

[SavMan]

The weight of the rubber remains (about) the same because the rubber from the sidewall goes on to the tread.

One size change may not be huge but move 3 sizes and you could be looking at 1.5-2 kgs per tyre. Just looking at the Conti 2 specs from 17 to 20 inch you are looking at more than 2kgs difference.