Hi Guys Just want to ask few Questions

-Ok so i want to ask does having a Bigger tyre effect the speedo readings, But i thought the speedo reading on a Fabia Vrs are taken from the gearbox so what has that got to do with the tyre size.

-And the other questions is that i have fitted a 215/45/16 on standard Fabia Vrs Rim So its 10mm wider. I have worked out that the wheel height will increase by 4.5mm over standard recommended tyre size. Will i have any problems relating to speed ( i don't want a speeding ticket)

And one last thing

I Have had it since 65K had no problems (touch wood)

Thanks

Oh and one last thing M25 near Heathrow Black Fabia VRs 53 Plate with Briskoda.net Sticker In back window who was it lol On 01/Dec/10 About 2pm

Edited 1 December, 201015 yr by Guest

try this link

stick the 2 sizes in and it'll give you the difference in size and speed readings

If you cant be arsed then the calcutor says a difference of 9mm difference making the speedo read 1.5% slow so at 60 you'll actually be doing be doing 61mph and 70mph will really be 72ish

and the difference in size of tyres effects the rolling radius of the wheel which means that for every rpm of the engine the wheel is travelling less distance essentially effecting the gearing which is why the speedo reads incorrectly (i think!)

Edited 1 December, 201015 yr by PastyBoy

Thanks PastyBoy

I Have Had a Look And this is what it came up with

So i think i should be ok to run them. Not much Difference in speed

What do you guys Recommend should i replace them or should i keep em

Thanks

Edited 1 December, 201015 yr by Guest

Just want To ask one last thing. What about all the people that fit bigger wheels and tyres. Does that also effect the Speed Readings?

Thanks

Just want To ask one last thing. What about all the people that fit bigger wheels and tyres. Does that also effect the Speed Readings?

Thanks

It depends on the size of tyre they use - throw the details into the link in post #2 and you'll see for yourself.

Just want To ask one last thing. What about all the people that fit bigger wheels and tyres. Does that also effect the Speed Readings?

Bascially any change away from 16" rims running 205/45/16 tyres will affect your speed readings.

As an example if you put on a set of 17's you will need a lower profile tyres (40 or 35 rather than 45) to keep to over all rolling radius as near to the standard as possible.

On a similar bent if you put smaller wheels on (say 15" for winter wheels) you'd need to put on larger profile tyres (50 or 55) to keep everything the same

The calculator i posted will give you all the info you need.

Thanks PastyBoy

I Have Had a Look And this is what it came up with

So i think i should be ok to run them. Not much Difference in speed

What do you guys Recommend should i replace them or should i keep em

Thanks

Concidering the standard speedo is always over reading the speed - you will be good with the new tyre size for speed.

As a check - go for a drive with a satnav fitted you can see how close to the speedo your actual speed is. ( my guess is that the speedo will still read high )

That sounds ok will give the satnav try and see what it says

thanks for the helps guys

Just for your information- on the vRS, the speed is read from the ABS sensors I think. The reason iot also works from the gearbox is that the gearbox turns the wheels, so if you want to know how fast the wheels are turning you can just measure how fast the gearbox is turning and you get a speed reading. In the old days they used to run a cable off the gearbox to the speedometer, but now it's all done by tiny mice. :yes: