Hi all

I have question about tire size.....has any one tryed to fit 225/45/18? Instead of skoda recomended 225/40/18 ? Comments recomendedfrom lowered superb owner but alos other coments are welcome...

225/45/18 is a very uncommon size. 235/40/18 is more common.

Edited 23 March, 201214 yr by digidoctor

Won't it make the speedo read wrong aswell, admittedly only slightly??

Won't it make the speedo read wrong aswell, admittedly only slightly??

Yes, it will. But given the fact that, almost, all cars shows a "false" speed, I think that the size mentioned, acctually will make it more presise. (?)

True, it's because car makers don't want people seeing them because their cars told them they weren't speeding when they were. My classic cars have inaccurate speedos aswell, but I don't think it was intended :p

If you use Tom Tom or other navigation youcan easely see speedo is wrong. Normaly we all are driving slower then in reality...i heard something about 3% mistake.....

What about ABS or ESP errors in case of diferent tire size? Is it true or false?

really noone have switched to 225/45/18 ?

True, it's because car makers don't want people seeing them because their cars told them they weren't speeding when they were. My classic cars have inaccurate speedos aswell, but I don't think it was intended :p

The regulations are precise on this point. The Road Vehicles (Construction and Use) Regulations 1986, as amended, allows the use of speedometers that meet the requirements of EC Community Directive 75/443(97/39) or EC Regulation 39. Both the EC Directive and the ECE Regulation lay down accuracy requirements to be applied at the time of vehicle approval for speedometers. A vehicle meeting these requirements would not be able to travel at a greater speed than that shown on the speedometer and a driver could not, therefore, inadvertently exceed speed restrictions, so NO manufacturer will produce speedometers that read slow (i.e., will show 30mph when the true speed is 33mph).

The leeway allowed by regulation is 10% + 2mph (4kph). IOW, when a car's speedo is showing 30mph, it must be travelling at at least 25mph - at 40, at least 34mph - at 50 43mph and so on. The plus side is that the tolerance works both ways, so that an actual 30mph can read 35mph, an actual 40mph could read as 46mph and so on. That's why most speed traps, cameras, etc. don't result in prosecutions if the actual speed was within the 10% + 2mph (4kph) boundary. Construction tolerances are 5 per cent plus 10 kph.

Ray