Jump to content
SAU Community

Recommended Posts

spaz moment, the 235/40 compared to the 45, this will increase spedo reading yes?

i know only by likr 3-4% but i have a 10% speedo error (always reading to high) anyway

Edited by GH05T

The higher profile will make the car go faster than the speedo is reading, so if your speedo currently reads higher than you're actually doing, it will correct this somewhat...but rather negligible as you say.

Let's not use confusing terms that could be interpreted differently.

Speedo runs off the gearbox output shaft, so it takes its reading based solely on engine rpm and the gear selected, irrespective of what's happening at the tyres and diff. Therefore, 2000rpm in 5th will always make the speedo read the same speed (say ~80km/h) no matter what size tyres or diff ratio you have.

Increase your tyre diameter and the vehicle physically goes faster but the speedo reading stays the same. So if your speedo reads high, putting on larger tyres will make it more accurate. If it reads low, putting on larger tyres will make it more inaccurate.

Manufacturers usually calibrate the speedo to the standard tyre diameter and make it read a little bit high so that they aren't responsible for people's speeding fines.

  • 2 weeks later...
  • 2 weeks later...

received the tires, unfortunately i stuffed up the tire speed calculation (yep did it backwards in my head....derp).
my speedo error reads to high already, the new diameter for my wheels means it will now read higher again not lower so they really dont suit which sucks.

still unfitted
which sucks cos the tread pattern looks so nice

re listed in sa :P

http://www.sau.com.au/forums/index.php?app=forums&module=post&section=post&do=new_post&f=12


Edited by GH05T

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Latest Posts

    • Hi. Yeah thanks. Car is already at tuners and it staying there to resolve "many" issues they do not like. So it is in a good hands. Getting a good tune on that Nistune ECU too so the car would be good. Just needs a little tune up and love.
    • Probably gonna remove manifold and turbo. I’m not sure if I can get M12 x 1.5 air tight. Could use high temp Loctite 246 or something similar, but I don’t know. Maybe it’s just best to remove everything again and weld an 1/8NPT on there instead.
    • Yeah, saw the ratios, not impressed. Would like the punch I have in the first gears now. With those ratios it won't be the same.  Also want the h pattern gearing, or at least a quiet gear set that don't need to come apart for service each year. Looks like the only "reasonable" way Is a 8hp70 transmission, but where is the fun in that🤷‍♂️
    • Hey mate, really appreciate the help. Have been looking pretty extensively myself and was certain they were retro fitted, but then ended up finding a 4 door with what looks like the same side skirts or at least the closest I’ve seen. The photos from the Offset Kings event at Sunrise 2016. https://fatlace.com/offset-kings-okayama-at-sunrise/
    • Isn't there a PAR engineering gearset that has closer to stock ratios? And they claim they'll do whatever ratios you want.
×
×
  • Create New...