Carsy

I will need new tyres in the future.
I was dismayed to see that the 215/55/16 tyre is an unusual tyre size in Australia & costs around $250 each.
The common size in the same brand 215/60/16 is around $100 cheaper per tyre.
The tyre fitter stated that he could fit the larger 60 profile so long as the McPherson strut allows sufficient clearance.

I used the website here to calculate the differences.Please see results below.
http://www.exploroz.com/Vehicle/Tyres/SizeCalc.aspx

The obvious result is the the speedo will read 3% higher which may not be a problem as most cars have a 3% low reading.
The gearing should not be affected a great deal with a high torque diesel engine.
The car will ride a little softer which I will see as an advantage.
I need advice on how the larger rolling radius will effect the car stability control system.
Any advice welcome.

Results for your selected Wheel/Tyre 1 215/55/16
Rolling Radius 321.45mm
Circumference 2019.73mm
Diameter 642.9mm
Wheel Cover Size Size 001

Results for your selected Wheel/Tyre 2 215/60/16
Rolling Radius 332.2mm
Circumference 2087.27mm
Diameter 664.4mm
Wheel Cover Size Size 001
Differences between Wheel/Tyre 1 & 2
Rolling Radius 10.75mm
Circumference 67.54mm
Diameter 21.5mm
When your speedo reads 100km/hr you're actually at 103.24 km/hr

amdeutsch

Why not go with a 235/50 if you are going that route. If you want to stay with a narrower tire I'd suggest looking at 195 or 205/60

Carsy

Good advice , I will look into these options . Thank you.

e1000

215/55/16 would also be a lot closer than 215/60/16

nbturbos

Keep in mind the contact patch with a narrower tire will affect braking and traction around corners. I would opt with the same width and maybe a different brand tire that might be more cost effective.

C300Sport

At what percent of rolling diameter increase are we likely to start seeing issues with ABS, ESP, engine management, etc...

RLE

2% has always been the limit, according to the experts. You are going to notice the slower accelleration and your fuel economy may even drop a wee bit.

Your speedo will read lower than actual, not higher, (I know that's what you meant to say) and the days of German car speedos reading a bit high are over.

JoeVal

2% of what? Perhaps we can get some clearing up since the key to the stability and grip of the car lays on the design of the drive train and suspension, and with the change in tire geometry there will be a change in the relationship between the Center of Gravity and the center of Balance. Enough to a negative effect on cornering and sleek roads?

I either know what I'm doing or I only take advise from parties of my trust and confidence, and the tire store would be last in the line of uninterested parties.

Isn't the speedo electronic and reading rpm and shift engaged?




Mercedes, if a woman as complex and well appointed as the motor car must have driven poor old Daimler crazy...

Glyn M Ruck

John - Tirerack have tables of revs per mile of all tyres - Have a look there. 1010 Tires have excellent calculators you can play with. (Size effects on rolling circ/offset calcs etc.)

With some Aus conditions you might actually wish to go to a higher profile tyre for increased clearance beneath the car. This will have no negative effects on the ESP etc. as long as rolling circumference does not differ between front & rear tyres by more than about 2%. If it reads different front & rear wheel RPM it will throw a wobbly (thinks it's reading slip & can throttle back automatically etc). Handling differences will be insignificant on a diesel. Your Benz dealer can recalibrate your speedo with the STAR DAS to suite tyres with a greater rolling circumference. Your speedo averages data from the transmission output shaft sensor via the TCU & the LH front wheel ABS sensor.

For tar road use I would go to a wider, lower profile, more cost effective tyre - but that's me & I'm not sure of your percentage time spent on dirt. e.g. My 203 came standard with 205/55/16 - I removed the Conti crap on it and went to Michelin Pilot Exalto PE2's 225/50/16 at 15,000Km (an option new in Europe) - Now going to 245/40/17 on AMG wheels all round - all have the same rolling circumference.

Go well mate!

Sentosa

You have a A$65-A$70000 car and you're worried about paying $250 per tyre?

Sentosa

I have a set of brand new Bridgestone Turanza B300 205/55/16 91H that came off the C200 less than 24hrs after taking delivery. Here is the data against your originals. If you're interested PM me.
Tread Width (mm)205
Sidewall Aspect Ratio55
Rim Diameter (in)16
Tyre Diameter (mm)631.90
Tyre Diameter (in)24.88
Sidewall Height (mm)112.75
Sidewall Height (in)4.44
Tread Width (in)8.07
Tyre RPM @100 kph839.22
Tyre RPM @ 60 mph810.36
Speedometer 61.04 Error @ 60 mph
Speedometer101.74 Error @ 100 kphDifference -1.71%

Tread Width (mm)215
Sidewall Aspect Ratio55
Rim Diameter (in)16
Tyre Diameter (mm)642.90
Tyre Diameter (in)25.31
Sidewall Height (mm)118.25
Sidewall Height (in)4.66
Tread Width (in)8.46
Tyre RPM @100 kph824.86
Tyre RPM @ 60 mph796.49

Sorry that didn't come thru properly

Carsy

Thank you all for the good information.
Buying tyres to suit one's situation & personality is certainly an interesting excercise.

"You have a A$65-A$70000 car and you're worried about paying $250 per tyre?"

Yes Sentosa , I cannot help that I come from Scottish stock. We can chose our friends but not our genes.!!
It seems sensible (and interesting) to find a high quality tyre with a slight size differential that does the job well, & is 40% cheaper than the same brand specified because it used by a larger number of vehicles in a particular country.It is nice to beat the advertisers for a change. $600 a change Vs $1000.. You can buy your wife a couple of nights out for that. !!