Jump to content
SAU Community

Recommended Posts

Hey guys,

I have an r32 GTR, it currently has R34 GTR rims with 245/40/18 Bridgestones all round.

I've had some camber issues (now fixed) so the fronts were chewed on the inside.

Anyway, can I fit 245/45/18s to replace the 2 damaged tyres? Will this effect my AWD (as I'll still be running 2x 245/40/18s)

And finally assuming they are suitable should the 245/45/18s go on the back or front?

Thanks!

Ali.

Link to comment
https://www.sau.com.au/forums/topic/211709-2454018-vs-2454518/
Share on other sites

Hey guys,

I have an r32 GTR, it currently has R34 GTR rims with 245/40/18 Bridgestones all round.

I've had some camber issues (now fixed) so the fronts were chewed on the inside.

Anyway, can I fit 245/45/18s to replace the 2 damaged tyres? Will this effect my AWD (as I'll still be running 2x 245/40/18s)

And finally assuming they are suitable should the 245/45/18s go on the back or front?

Thanks!

Ali.

You can fit whatever size tyres you want...

Eg. you want 245/40/18s, the middle number, 40 has to be the same FRONT AND REAR.

Otherwise you f**k up your Centre Transfer Case.

I have got,

FRONT

235/45/17R

REAR

245/45/17R

1st mesurement is for the width of the tyre.

2nd mesurement is for the height of the tyre.

3rd mesurement is for the wheel size.

:blink:

Edited by (00)SKYLINE(00)
You can fit whatever size tyres you want...

Eg. you want 245/40/18s, the middle number, 40 has to be the same FRONT AND REAR.

Otherwise you f**k up your Centre Transfer Case.

I have got,

FRONT

235/45/17R

REAR

245/45/17R

1st mesurement is for the width of the tyre.

2nd mesurement is for the height of the tyre.

3rd mesurement is for the wheel size.

:blink:

lol cool.

So thats a no go for the 245/45/18 pair with a 245/40/18 pair.

Centre transfer case sounds expensive....

You can fit whatever size tyres you want...

Eg. you want 245/40/18s, the middle number, 40 has to be the same FRONT AND REAR.

Otherwise you f**k up your Centre Transfer Case.

I have got,

FRONT

235/45/17R

REAR

245/45/17R

1st mesurement is for the width of the tyre.

2nd mesurement is for the height of the tyre.

3rd mesurement is for the wheel size.

:blink:

yes and no, the profile is relative to the tread width (245/45 = 45% of 245). the thing that affects the AWD system is overall rolling diametre difference between front and rear. for example the difference of the rolling diametre of a 225/45 and 245/45 is almost as much as the difference in rolling diametre as a 245/40 and 245/45. so basically the profile value is not the only thing u have to look for to determine 2 matching tyres for the front and rear.

lol cool.

So thats a no go for the 245/45/18 pair with a 245/40/18 pair.

Centre transfer case sounds expensive....

LOL! Yes please have matching / the right tyres for you GTR and yes Centre Transfer Case sounds expensive.

yes and no, the profile is relative to the tread width (245/45 = 45% of 245). the thing that affects the AWD system is overall rolling diametre difference between front and rear. for example the difference of the rolling diametre of a 225/45 and 245/45 is almost as much as the difference in rolling diametre as a 245/40 and 245/45. so basically the profile value is not the only thing u have to look for to determine 2 matching tyres for the front and rear.

Sure.

I was just making sure that IOWNU's tyre height is the same cuz another member did a similar thing and but put his Silvia S15 rims on his GTR and his drive train had problems of couse. LOL!

haha fair enough, was just trying to clear it up for anyone that read it and misunderstood what u said.

:whistling: Thanks dude! Always up for learning whats right and wrong.

Thanks for the input fellas. :rofl:

No probs! :rant:

You can fit whatever size tyres you want...

Eg. you want 245/40/18s, the middle number, 40 has to be the same FRONT AND REAR.

Otherwise you f**k up your Centre Transfer Case.

I have got,

FRONT

235/45/17R

REAR

245/45/17R

1st mesurement is for the width of the tyre.

2nd mesurement is for the height of the tyre.

3rd mesurement is for the wheel size.

:P

that is wrong. the middle number as you call it is the aspect ratio. it's a percentage of the width. so on it's own it means nothing. your fronts have a sidewall of 105.75 and your rears have a sidewall of 110.25 so you almost certainly have different overall diameter tyres front to rear. as for how much difference is too much, personally I have no idea, but for me any difference is undesirable so I just stick with the same size front and rear.

that is wrong. the middle number as you call it is the aspect ratio. it's a percentage of the width. so on it's own it means nothing. your fronts have a sidewall of 105.75 and your rears have a sidewall of 110.25 so you almost certainly have different overall diameter tyres front to rear. as for how much difference is too much, personally I have no idea, but for me any difference is undesirable so I just stick with the same size front and rear.
yes and no, the profile is relative to the tread width (245/45 = 45% of 245). the thing that affects the AWD system is overall rolling diametre difference between front and rear. for example the difference of the rolling diametre of a 225/45 and 245/45 is almost as much as the difference in rolling diametre as a 245/40 and 245/45. so basically the profile value is not the only thing u have to look for to determine 2 matching tyres for the front and rear.

:)

on a side note: old guy at work who brought his 4-door awd skyline over from NZ when he moved over had alot of problems when he changed tyres

(from memory he bought new tyres for front when back were still old or something) and it screwed it up totally so yeah - tolerances might be small!!

on similar note, my 32R currently has 255/40/17 on rear (nankang) and 245/45/17 on front (contisport).. so my rolling diameter is 102 rear vs 110.25 front.. not good at all.. would like to know if my car symptoms is due to this and attesa..

speedo needle is constantly bouncing (original broken cables replaced with 2nd hand item)

car tends to pull left/right at will randomly without turning steering (no steering wheel shudder even under braking and car does not pull left/right if checking for alignment etc)

does this sounds like attesa having issues due to different rolling diameters..

on similar note, my 32R currently has 255/40/17 on rear (nankang) and 245/45/17 on front (contisport).. so my rolling diameter is 102 rear vs 110.25 front.. not good at all.. would like to know if my car symptoms is due to this and attesa..

speedo needle is constantly bouncing (original broken cables replaced with 2nd hand item)

car tends to pull left/right at will randomly without turning steering (no steering wheel shudder even under braking and car does not pull left/right if checking for alignment etc)

does this sounds like attesa having issues due to different rolling diameters..

nope. sounds like other issues.

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

    • If as it's stalling, the fuel pressure rises, it's saying there's less vacuum in the intake manifold. This is pretty typical of an engine that is slowing down.   While typically is agree it sounds fuel related, it really sounds fuel/air mixture related. Since the whole system has been refurbished, including injectors, pump, etc, it's likely we've altered how well the system is delivering fuel. If someone before you has messed with the IACV because it needed fiddling with as the fuel system was dieing out, we need to readjust it back. Getting things back to factory spec everywhere, is what's going to help the entire system. So if it idles at 400rpm with no IACV, that needs raising. Getting factory air flow back to normal will help us get everything back in spec, and likely help chase down any other issues. Back on IACV, if the base idle (no IACV plugged in) is too far out, it's a lot harder for the ECU to control idle. The IACV duty cycle causes non linear variations in reality. When I've tuned the idle valves in the past, you need to keep it in a relatively narrow window on aftermarket ecus to stop them doing wild dances. It also means if your base idle is too low, the valve needs to open too much, and then the smallest % change ends up being a huge variation.
    • I guess one thing that might be wrong is the manifold pressure.  It is a constant -5.9 and never moves even under 100% throttle and load.  I would expect it to atleast go to 0 correct?  It's doing this with the OEM MAP as well as the ECU vacuum sensor. When trying to tune the base map under load the crosshairs only climb vertically with RPM, but always in the -5.9 column.
    • AHHHH gotchaa, I'll do that once I am home again. I tried doing the harness with the multimeter but it seems the car needed a jump, there was no power when it was in the "ON" position. Not sure if I should use car battery jump starter or if its because the stuff that has been disconnect the car just does send power.
    • As far as I can tell I have everything properly set in the Haltech software for engine size, injector data, all sensors seem to be reporting proper numbers.  If I change any injector details it doesnt run right.    Changing the base map is having the biggest change in response, im not sure how people are saying it doesnt really matter.  I'm guessing under normal conditions the ECU is able to self adjust and keep everything smooth.   Right now my best performance is happening by lowering the base map just enough to where the ECU us doing short term cut of about 45% to reach the target Lambda of 14.7.  That way when I start putting load on it still has high enough fuel map to not be so lean.  After 2500 rpm I raised the base map to what would be really rich at no load, but still helps with the lean spots on load.  I figure I don't have much reason to be above 2500rpm with no load.  When watching other videos it seems their target is reached much faster than mine.  Mine takes forever to adjust and reach the target. My next few days will be spent making sure timing is good, it was running fine before doing the ECU and DBW swap, but want to verify.  I'll also probably swap in the new injectors I bought as well as a walbro 255 pump.  
    • It would be different if the sealant hadn't started to peel up with gaps in the glue about ~6cm and bigger in some areas. I would much prefer not having to do the work take them off the car . However, the filler the owner put in the roof rack mount cavities has shrunk and begun to crack on the rail delete panels. I cant trust that to hold off moisture ingress especially where I live. Not only that but I have faded paint on as well as on either side of these panels, so they would need to come off to give the roofline a proper respray. My goal is to get in there and put a healthy amount of epoxy instead of panel filler/bog and potentially skin with carbon fiber. I have 2 spare rolls from an old motorcycle fairing project from a few years back and I think it'd be a nice touch on a black stag.  I've seen some threads where people replace their roof rack delete with a welded in sheet metal part. But has anyone re-worked the roof rails themselves? It seems like there is a lot of volume there to add in some threads and maybe a keyway for a quick(er) release roof rack system. Not afraid to mill something out if I have to. It would be cool to have a cross bar only setup. That way I can keep the sleek roofline that would accept a couple bolts to gain back that extra utility  3D print some snazzy covers to hide the threaded section to be thorough and keep things covered when not using the rack. 
×
×
  • Create New...