Jump to content
SAU Community

Recommended Posts

What happens if I run 18 x 8? Should I be going 235/45/18 instead?

For M35's... (speedo values are based off the OEM speedo calibration for MY NM35)

STOCK RS

17" rims = 55 sidewall (total tyre height is 668mm) - speedo reads 10% fast

18" rims = 45 sidewall (total tyre height is 677mm) - speedo reads 8.7% fast

19" rims = 40 sidewall (total tyre height is 679mm) - speedo reads 8.3% fast

20" rims = 35 sidewall (total tyre height is 680mm) - speedo reads 8.2% fast

The ~10mm extra total height over the stock RS 17's fills out the wheel arch perfectly (particularly if you have lowered your suspension 20-25mm)

  • 1 month later...

For M35's... (speedo values are based off the OEM speedo calibration for MY NM35)

STOCK RS

17" rims = 55 sidewall (total tyre height is 668mm) - speedo reads 10% fast

18" rims = 45 sidewall (total tyre height is 677mm) - speedo reads 8.7% fast

19" rims = 40 sidewall (total tyre height is 679mm) - speedo reads 8.3% fast

20" rims = 35 sidewall (total tyre height is 680mm) - speedo reads 8.2% fast

The ~10mm extra total height over the stock RS 17's fills out the wheel arch perfectly (particularly if you have lowered your suspension 20-25mm)

oh on this i think for the arx its +5 on the sidewall for each..

mine are 19" with a 45' sidewall.

and against the informeter with a GPS HUD dispaly it was i think 3-4km out at 100km/h

oh on this i think for the arx its +5 on the sidewall for each..

mine are 19" with a 45' sidewall.

and against the informeter with a GPS HUD dispaly it was i think 3-4km out at 100km/h

Would probably work out the same for RS and RX's

but your running a 19 and a 45 sidewall

thumbsup.gif.....but I am running a 245 as well!....more width....higher wall!

I may even go to a 35 sidewall if the new diff's throw out my speedo!wacko.gif....more go!

Edited by Jetwreck

nup....standard size for the AR-X is 225/55 18"

Yes, I know... I was referring to the speedo accuracy.

Mine reads 10% high according to GPS, as have most other RS's I have been in, so adding the extra diameter will get the speedo reading close to what Aaron stated.

Yes, I know... I was referring to the speedo accuracy.

Mine reads 10% high according to GPS, as have most other RS's I have been in, so adding the extra diameter will get the speedo reading close to what Aaron stated.

oh....yeh the speedo is good in the AR-X until about 95km/h's....after that it out.....what's confusing is that the Infometer was spot on to my GPS.

Yes, I know... I was referring to the speedo accuracy.

Mine reads 10% high according to GPS, as have most other RS's I have been in, so adding the extra diameter will get the speedo reading close to what Aaron stated.

well yeh, if it makes any difference mine is a 235/45... which was lucky coz no chance am i getting a 245/45 under my guards at my height.

but yeh, comparing with scotts even, im kind of glad that my speedo is only 3-4k's out..

well yeh, if it makes any difference mine is a 235/45... which was lucky coz no chance am i getting a 245/45 under my guards at my height.

but yeh, comparing with scotts even, im kind of glad that my speedo is only 3-4k's out..

Rolling diameter, not tyre width :)

235 or 245 shouldn't make a difference to your speedo.

  • 1 year later...

ok so if i change the 265 for something smaller will that be ok. and i just read about roling diameter being different from front to rear am i going to have a prob with this? and i just found out the rears are 18x9.5 + 38 offset running 265/35/18 and the fronts are 18x8.5 + 34 offset running 235/40/18. is this going to cause probs?

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



  • Similar Content

  • Latest Posts

    • Here's the chart for fuel pressure vs. current draw, assuming your base fuel pressure is 3 bar and you run like 0.5bar boost on WOT, you should only momentarily hit 9amps here and there. (Ignore my prev post, I cannot read a chart these days it seems)
    • Those comp test results are not hideous. Whether they are accurate or not (ie, when that comp tester says 140 psi, is the real pressure120, 140 or 160?) is unknown to us. The state of the battery used to crank it over is unknown, etc etc. Many people around here would say that the absolute values and the spread are perfectly fine to just add boost and keep going. I personally would be happier with a narrower spread than that, but even the diff between 125 and 145 is not terrible. That one cylinder at 125 though, has probably copped some damage relative to the others. You should inspect the valves seeing as you've got it open. Do you know how to measure installed ring gaps? That, and an inspection of the rings themselves, is how you will determine whether they need to be replaced. If you're not good to do these things, take the block and the pistons and rings to a shop that is, and ask them for the go/no-go on them. Do the bores need a hone at all? If so, you might well be justified in getting some different pistons in order to get away from the ring supply problem. Whether you're happy to spend a lot more money right now, on more gear, rather than less money, but an amount that looks stupid given that you will only get a handful of rings in exchange for that money, is for you to decide.
    • also possibly backed up to my filler and shat down it! 🤣
    • Ok so i would love some advice here please, i purchased an R33 a few months back and its had a few mods done to the engine, its an RB25det running a Master ECU, 1200cc injectors, bigger turbo, oil cooler, oil filter relocation kit, Spool H-beam rods, acl/ross pistons. When i removed the motor from the vehicle (as its getting a respray) i thought i would compression test it and these are the following results. Cylinder 1-145psi, Cylinder 2-143psi, Cylinder 3-125psi, Cylinder 4-145psi, Cylinder 5-140psi, Cylinder 6-135psi this test was done with the motor on the ground and powering up the starter motor. I dropped the sump and found broken oil squirters on cylinder 3,5 and 6. I was told my rings are probably worn so i stripped the motor completely to get a new set of rings for it. The trouble is no one has these rings anywhere and they have to be custom made by Ross over in the states and will cost about $600+$200 delivery. My question is how can i tell if my rings are at fault and if they are still ok and is this price ok for a set of rings?
    • What sold me on Trailer Park Boys is this scene: Great stuff, just stay clear from the new Netflix production.
×
×
  • Create New...