quick tyre question please...
Hi there
My '93 300ges has 255/60/18s on it at the moment.
Can I change all four to 255/70/18 without complications please?
(Wheel clearance, gearing, steering etc etc??)
All advice very gratefully received as always
OE68
Theo had some real input on this about the tolerance in increased circumference
The tyre sizes for the different G models have the same circumference: for example 265/ 60 R18 = 265/ 70 R16. You can fit larger tyres but you have to adjust the settings both for the instrument cluster and transmission module. The reason: the ESP tolerates a deviance in the tyre circumference of about 2%. The difference between 265/60R18 (2367 mm) tires and the popular upgrade 275/70R18 (2590 mm) is about 10%. Without adjustment the ESP will interfere in faster turns. There are a number pre-programmed tyre sizes in the G-electronics (and that varies depending on model year), it has been disucssed on this forum before (and there is more if you google it).
I promoted the thread that had that information.
I also did some calcs of my own, because I wanted to 'gear up' my 4 speed auto 460 by putting larger wheels on that. Larger circumference wheels would mean faster for the same rpm. But the calcs showed bugger all difference realistically, so I didn't buy the spacers and the longer wheel bolts to try it. No ESP or DTC to worry about on the 460.
(edit: I was thinking of puttingn wider 463 wheels onto my 460, but the circumference increase was only about 5%, increasing my cruise speed from 60mph to 63mph. not worth it)
This was the thread for that: http://www.gwoa.co.uk/content/bigger-wheels-460
I'm definitely no expert but I don't think so.
I also have a 463 G300 SWB and according to the Owner's Manual the orginal wheels/tyres should be 225/75/16
Those you have on at the moment already have a 2.6% greater circumference which is more than the recommended - although probably not critical on a 1993 vintage model with not so many electrical sensors.
The ones you want to fit have a 9.4% greater circumference than those listed in the handbook. So, at the very least there would be a 9.4% difference in the speed you are showing compared with originals. I don't think this is an accepted excuse should you trip a speed camera
Useful calculator which allows you to compare 3 different sized wheel/tyre combinations here:-
https://www.tyresizecalculator.com/tyre-wheel-calculators/tire-size-calc...
No doubt someone will be along shortly to say that they've got even bigger wheels/tyres with no problems
Thank you both.
True, I was looking for lower revs on the motorway...
Although not what I was hoping, this information is good to know and really useful.
The thought was being driven by the need for one new tyre - need one, why not five?!
Sounds like I should stick with what I have.
Best wishes to all