Does This Size Look Legal ?

[Wacky Dee]

I'd like to order some wheels that I've seen on another SAU member's R34 GT-T but the rear rims are 18x9.5 and I'm afraid they might stick out from underneath the guard .. (same car as his) I don't want to get pulled over and defected because the rims are too wide

Also, can anyone tell me what the correct offsets would be for an R34 GT-T ?

Stock wheels are 17x7.5 with a 40 offset. The new wheels would be 18x8.5F and 18x9.5R - any ideas what the correct offsets would be ? I only have stock calipers

Attached is the image of the other gtt with these wheels - rears look like they're sticking out don't they?

[Mr. Keets]

A new wheel offset would help.Try this for guestimating what's possible

This is a useful site- Wheel offset calculator, also check the sticky on rims at the top of the suspension main page

[Wacky Dee]

Thanks for that .. the calculator is very handy but I'm not sure what to make of the results ... I'm not worried about the fronts as they're only 8.5, it's the rears that worry me (the new offsets are 35 on both front and rear)

According to the calculator the 9.5 rears would have 20mm less INNER clearance and would extend 30mm outside as well. Opinions ??

Edit: I've looked through the 16 pages of member posts on wheels and offsets last night ..unfortunately there's only 1 or 2 R34 GTT in there and no one posted any similar new rim sizes to what I'm getting.

Edited April 28, 2008 by Delta Force

[Mr. Keets]

They look a little wide in the rear. I've got a 32R so my experience with the 34T is limited. Don't worry you've only had the thread up for a while and there are plenty 34T owners lurking. GL

[Wacky Dee]

According to the wheel offset calculator the 18x9.5 +35 would add another 30mm to the outside wall .. and I've just done some rough measurements on my car and that seems to be sticking out about 15mm from under the guards

The 18x8.5 (+35) would add only 20mm which means they'd stick out only 5mm or so, so shouldn't be an automatic defect unless you run into a really nasty copper.

I guess I better stick to 18x8.5 on both fronts and rears since the offset is +35 in both widths. Grr! Wish i could get em today, alas no such luck.

Edited April 28, 2008 by Delta Force

[Mr. Keets]

There are always more rims in the sea...err sorry fish.

[Wacky Dee]

There are always more rims in the sea...err sorry fish.

Yeah I know .. it's just that these look really great on a black gtt (as seen in DOSKI's gallery) and the price cannot be beat I fink (<$900 for a set!!) ah well ..gotta keep on fishing ..err looking

[adam-__-]

When purchasing wheels, the "correct" offsets of the new wheel will have to be what it was from factory (in this case, +40). The car's suspension components were designed for a wheel with +40mm offset. Wouldn't matter what the width is because the same amount of force will still exert on the components in the same percentage (something like that ).

The front wheels with those offsets will stick out 17.7mm from where the current wheels are sitting. The rear wheels will stick out 30.4mm. From what I can see in the pics, it should be fine. Roll of the guards and it'll be perfect (no rubbing).

When getting new wheels, chances are you'll break the 'track' rule anyway. Without breaking it, your car's stance will look shit.

Edited April 28, 2008 by adam-__-

[dead32]

and what a great rule the "track" rule is!!! another 100year old law that doesnt mean anything on modern car's with modern brake symetry.

[Wacky Dee]

Just found this rather informative document on RTA's web site (NSW roads & traffic authority):

http://www.rta.nsw.gov.au/registration/dow.../vsi09_rev4.pdf

Basically what that document states is that wheels up to 26mm (1") wider than the widest optional wheel recommended by manufacturer are OK...... BUUUUUUT, there is another catch.

"An important requirement for all replacement wheels is that the wheel track must not be increased by more than 25mm beyond maximum specified by vehicle manufacturer".

From what I understand, "wheel track" refers to the distance from the center of the one wheel to the center of the wheel on the other side of the car. And from what I could google, the standard wheel track for the R34 GT-T is 1480mm at the front and 1470 and the back.

So um, anyone know what the 'widest optional wheel' (factory) is/was for the R34 GT-T when it was sold? Stock is 17x7.5 What about 'maximum wheel track' as specified by Nissan (or is that simply the 'factory' wheel track ie. the standard is the maximum)

And also, anyone know a wheel offset calculator that also gives you the change in wheel track at the same time??

Edited April 28, 2008 by Delta Force

[adam-__-]

The widest optional wheel for your model would be printed on the placard. On the side of your door.

I'll get back to you about the change in track from standard. Haven't actually thought about it.

Edit: Ah okay, did a little research to back up what I was thinking and I was right. With the track increase, you're not allowed to exceed 25mm. That means with your new wheels, you can't have the wheels sticking out more than 25mm on BOTH side. Just use the offset calculator as normal, if your wheels stick outwards more than 25mm for BOTH sides, the wheels are illegal.

Someone correct me if I'm wrong.

Edited April 28, 2008 by adam-__-

[adam-__-]

So for example, you're current and widest track wheel from factory is 17x7.5 with +40 offset.

You're wanting 18x9.5 +25 for example on the rear of your car. These will stick OUT ~40mm on EACH side. Your total track increase is 2x40=80mm. Therefore illegal.

[Wacky Dee]

The widest optional wheel for your model would be printed on the placard. On the side of your door.

Doesn't say anything other than tyre sizes ... there's an additional 'T135' and 'D70' or something along those lines...

[Wacky Dee]

So for example, you're current and widest track wheel from factory is 17x7.5 with +40 offset.

You're wanting 18x9.5 +25 for example on the rear of your car. These will stick OUT ~40mm on EACH side. Your total track increase is 2x40=80mm. Therefore illegal.

Edit: I believe that's completely wrong .. see explanation below.

Edited April 28, 2008 by Delta Force

[Wacky Dee]

think I've finally managed to wrap my head around the whole concept of a "changing wheel track", in relation to wheel offsets.

If your new wheels are WIDER (or narrower for that matter) than your stock wheels, but the OFFSET is the same - the wheel track does NOT change (it's just that the wheel sticks out further inwards and outwards as it's wider) - the centre of the wheel is still the same distance from the wheel mounting point (which does not change its location obviously)

If the OFFSET changes, then so does the wheel track ... ie. if offset is say 10mm more your wheel track becomes 20mm narrower (2x10mm for both wheel on each side). If your offest is 10 LESS, then your wheel track becomes 20mm wider.

So basically when they talk about 'wheel track must not be wider than 25mm' what they mean is your new wheels must not have an offset smaller than 12mm from the original eg. if the original offset is 40mm, any new wheel should not have an offset of less than +28mm otherwise the 'wheel track' will increase by more than 25mm

Now at the same time, you need to keep in mind that a wider wheel will provide less clearance for the strut housing. In short, I don't think there's a friggin chance in hell that 9.5" rears could fit without some extra work or risk of being defected.

Woohoo, I finally figured something out!! Yay for me. (I realize most of peeps here already knew all this, but it's very confusing for us newbs so maybe this helps someone like me)

Now as to the max legal WIDTH of a new non-stock wheel - it's simply, no more than 1" wider than the largest factory option (anything above that and you need an engi cert). So anyone know where to find out what Nissan's widest optional wheel was for the R34 GTT ? I'm guessing it couldn't have been more than 8.5" if the stock wheel is only 7.5" wide.

Edited April 28, 2008 by Delta Force

[adam-__-]

Ah yep, that makes sense. Sorry for giving false information. I'm sure it's not the first.

Edit: Here's a calculator for the track increase/change. What you said is right.

http://www.s4play.com/Tire-Wheel%20Combina...0Calculator.htm

Edit Edit: I just realised the above link is for "tire track" changes, not wheel. So to find out what the change in wheel track is, I think you just have to keep the same tyre width.

Edited April 29, 2008 by adam-__-

[Laurence]

rears look like they're sticking out don't they?

Not really, the tread of the tyre is covered from the top from what I can see. But my opinion matters a lot less than that of the local police. Maybe give them a yell and ask. They may be helpful or may tell you to jam it.

But styling wise the most important thing about your wheel offset is to match it front and rear, nothing looks weirder than flush 5mm clearance on the rear with the fronts sunken in an inch... I see it a lot here in Japan with VIP style Toyota sedans. It doesn't look very nice.