Hey guys
Could running 235/40/18s on a Gen II throw the speedo out, it seems to be a bit out when comparred to a few GPS units and driving next to a friend.
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Hey guys
Could running 235/40/18s on a Gen II throw the speedo out, it seems to be a bit out when comparred to a few GPS units and driving next to a friend.
u will be travelling faster than what ur speedo shows.
I didn't think wider tyres mattered.
I thought it was just the height or the rim size that would change the speedo
Peter "SLIXX"
A 235/40 has a larger rolling circumference than the std 225/40 of the Gen 2. So speedo will be out a little.
YepQuote:
Originally Posted by 03blk
40% of 225 = 90mm sidewall height (stock)
40% of 235 = 94mm sidewall height
Enough to affect speedo by a small amount
Sent from my Galaxy Nexus using Tapatalk 2
As everyone here has posted :) 235/40R18 will be 1.26% greater in size!
Here's a link with a handy calculator so you check what different sizes will do.
Car Bibles : The Wheel and Tyre Bible Page 4 of 4
I had 235/40/18 and I was 7k's out going by my GPS to the speedo,when i was doing 100k's on the speedo the GPS showed 93k's ???? and the higher I went the bigger the margin IE: conrod straight......
Mps speedos seem to suck to begin with too... Mine with stockers used to 100 when doing 95 according to wife's rav4 and mrs garmin...
Sent from my iPhone
by law all speedos have to be accurate or read up to 10% faster than actual speed
if anything, running 235/40 will likely correct your speedo :)
as Sam said though I believe its 8%, could be wrong.
Really anyone who tries to argue their way out of a speeding fine using speedo inaccuracy is an idiot. All you do is make yourself look more guilty.
For example, in my car to do more than 100kmh my speedo shows 110kmh. So right there I know I am speeding, the speedo says so. Do what the speedo says, no chance of being booked.
Since my car is still 3-4ks slow @ 100ks on the speedo with 235/40/18 you wont have a issue ;)
Brad I just set my GPS at 100k's because that is the correct reading and you can't go wrong providing you have some sort of GPS ????? I have purposely driven through speed traps using it without any problems so when the GPS was doing 100k's and the car speedo does 106 to 107k's. I have been fine and I have asked some of my cop mates and they said it was fine, it's a true reading then it comes down to the radar gun if it's correct :p. You don't win, so far so good been through plenty through Qld and now Darwin using the GPS true reading.Quote:
Originally Posted by bd581