Hi

need some professional advice

have 2004 350z with VDC

would the following work?
front - 225/40/18
rear - 245/45/18

TIA

 

The rear tires are 40.5 mm taller than the front. That’s way too tall.

 

thanx

much appreciated

 

It will probably work but may not be the optimal setup. The majority of VDC problems stem from people having the fronts as tall or taller than the rears. I've only seen a few cases of people having the rears significantly taller than the fronts and none of them reported any problems. There has to be a point where too much difference causes a problem though.

Better safe than sorry - try to stick to the stock stagger of around 0.5 to 0.75".

 

Mine was shorter in the front for a week or so , the VDC just about everytime i turned thought i was sliding and hit whatever brake it needed to. ABS also flipped out a bit .

 

The fronts are supposed to be shorter. Did you change just the fronts or rears? That has been known to cause problems.

 

i just put 245/40/18's on my fronts still have the stock 245/45's in the back and they work great vdc has been good and handling has been well improved.

 

No, don't run this size on the front (225/40-18). Your fronts should be 225/45-18.

If you run 225/40-18, you will be OK driving in straight line, but the first time you push this setup "hard" into a turn, you will experience something you never want to happen. VDC (along with TCS) will activate for no good reason. You will feel as though you have no control of the car, and this is only because you have the wrong sized tires.

--Spike

 

Good choice of tire size!

That works because your new 245/40-18" tires have the same overall diameter as 225/45-18 tires.

--Spike

 

thanks man i gotta admit your post inspired me to go bigger up front. After what you said about eliminating understeer etc. im in love with my setup now i cant wait to get the rears in and really take it to the limit >

 

Thanks for kind words. Truthfully I was a little surprised that this setup (square widths- 245/40-18 front and 245/45-18 rear) improved the car's handling so significantly. As you point out...you really notice the improvement. I'm thinking it isn't so much the staggered setup (I don't think it is as simple as a linear relationship between the width of the fronts and the rears) that detemines under/neutral/over-steer, but instead it's what you mount on the front.

Of course 225's on the front are prone to understeer. My thought is that 245's on the front resist understeer, no matter what width you mount on the rear (with stock engine power, suspension, etc.) With this in mind, I really want to test the front 245's with 275's on the rear. I think this setup will remain fairly neutral because 245's on the front will grip adequately to avoid understeer. But... I'm only guessing here.

If you run "all square" (i.e., 245's all around), you can expect this setup to handle very well and neutrally until you begin experiencing more tread wear on the rears, which is a natural progression and will result in oversteer (and oversteer is not something you want). A better scenario is installing new wheels (e.g., Nismo or equivalent wheels - 18/8.5" front and 18/9.5" rear) that accomodate 245/40-18" front and 275/40-18" rear tires. With this setup, you will hardly be able to "plow" the 245/40-18" tires (this width tire on the front prevents understeer), but the arrangement allows rear tread wear without experiencing a dangerous level of oversteer.

The downside of 18/8.5" front and 18/9.5" rear wheels that accomodate 245/40-18" front and 275/40-18" rear tires is co$t. You could run "all-square" 245/40-18" front and 245/45-18" rear tires on stock Nissan wheels (and replace the rears at very frequent intervals to avoid wear and oversteer) many times for what the larger wheels and rear tires cost for a one-time installation. The Nismo install with wheels, tires, sway bars, and suspension could easily cost $4k plus. You could replace your tires on the OEM setup many times for that price.

Sorry for the long post (probably so long that many skipped reading it),

--Spike

 

naww i read every word lol. Good points kinda helped me understand more points on the understeer over steer etc. Im very new to sports cars im used to skinnys up front and straight slicks in back pulling the front wheels lol. I gotta say though im hooked on the twisties more then i ever was on the strip. I just cant afford new wheels etc. especially since i think the 06 wheels do so much for the look stock. Plus i hardly ever spin my rear tires. I know they will wear faster being a rear wheel drive period, but i dont think it will be near as bad as some. I think ill stick to the square setup maybe go 255's on the back or somethin when i replace them i still have the stocks on the back. So with the re01-r's on front and stock on back it still handles great with no overstear so hopefully ill be alright when i just replace the back with 245's i need a 45mm sidewall in back with this setup right spike? thanks bro.

 

and im not meaning to hijack the thread OP just nobody has posted in here much to help you out that much. I figured by my questions it is helping you as well. sorry if you think i was trying to hijack.

 

i'm cool with it

having read a number of threads where guys have lost control due to VDC cutting in, i wanted to make sure

tyre guy has stock rear size but fronts are 225/40/18, hence i thought i'd ask the pro's over here

so, if i went with 245/40/18 front and 245/45/18 rear, would that be ok?

thanx

 

yeah thats what me and spike is running right now and neither of us have had a problem yet.