PDA

View Full Version : 17's and Speedo Readings.


Loz
16-02-2006, 22:28
i have 17's on my car, will my speedo read out higher or lower than the actual speed i am travelling?

thanks

Lawrence
Zollo
17-02-2006, 09:58
Presuming you've got a Williams or Valver and are going to 205/40/17 tyres, it'll over read by a couple of mph. Plus speedos generally read a little higher anyway...
J o n
17-02-2006, 11:05
more importantly though if you came accross a valver on 15's it would blow you into the weeds... 17's slow you down and add weight... okay to have on a torque monster turbo, but not on a valver dood! get some turbines on there! :lol:
Lunner
17-02-2006, 13:01
Will actutally make the speedo more or less spot on, will still read slightly higher tho.

At 60mph, with 15's on my speedo is about 5mph off from GPS, off as in reads 65 when you are doing 60 on the GPS
Zollo
17-02-2006, 13:23
Oh yeah, it'll make it under read! :D
Lunner
17-02-2006, 13:26
As above, doubt they will ahve enough effect to actually make it under read, will prolly read spot on or just slightly over read
Loz
17-02-2006, 19:50
so when i belt it in 2nd it reads 63, then flat out it reads 135, will that be the de-cat and IK adding power?

so if my 17's make my speedo read under, i am actually going faster?
Lunner
17-02-2006, 20:26
No that will be the speedo being wrong and over reading :roll:

The 17's will make the speedo read just over or spot on......not being rude, but have you not read anything i've posted above?
Loz
17-02-2006, 20:32
yeah i did read the posts, but some were saying it reads over and some say under...
Lunner
17-02-2006, 20:34
Some werer talking bullshit, i'm talking truth, based on GPS and personal experience
MAXIBOY
17-02-2006, 21:23
try this for all your tyre size needs http://www.rochfordtyres.co.uk/tyrecalc.asp
Zollo
18-02-2006, 11:05
yeah i did read the posts, but some were saying it reads over and some say under...

Erm, I corrected myself, so nobody was saying it would over-read :wink:


Some werer talking bullshit, i'm talking truth, based on GPS and personal experience

Yeah, cheers.
Lunner
18-02-2006, 18:22
Thats ok, sorry it was blunt, was in a foul mood, lol
david932
19-02-2006, 20:44
unless the rsi has the same final drive as the valver(?) it would affect both cars differently.