Offset help

[speedyblue]

Just for the record. Running a 235 wide tyre on 0 offset rims will just rub on the guards. Lipping the guards fixes this. Running the same tyres on a 12.5mm offset will only just comfortably clear the spring perch on the rear and barely fits the front (so close that I wouldn't run them) so in my experience, if you aren't running coilovers and don't want flares, aim for a +5mm to +7mm offset in the rim.

[veritech-z]

Talking about offset in regards to fitment will only be useful if you also tell the width. An 8 inch wheel at 0 offset has just enough backspace to clear the strut assembly, but a 10" wheel at 0 offset will have too much backspace to fit. Backspacing is a more useful measurement when trying to fit wheels on a car. The reason using 0 offset works most of the time is because people rarely use wider than 8" wheels on their Z's.

[webdawg1]

This word file might help out a little bit...If you know your total rim width, backspace...etc..etc. Then you should be able to figure out what your offset should be or at least get you in the ballpark.

webdawg1

How to Measure Wheel BackSpace (Offset).doc

[veritech-z]

Or you could read post #21, where I explained it already...total rim width is advertised width plus 1", an S30 Zcar can have a maximum backspace approaching 4.5". Say you've got a 15X8" Watanabe that you want to use. Total width of an 8" wheel is 9", divided by 2 gives you 4.5". This wheel will fit in a 0 offset. Say you want a newer style wheel, like an Impul Hoshino Racing RS-III in a 17X8, but the offset of this wheel is +38. Well, convert 38mm to inches, and this is the thickness of the adapter that will be required to space out your hub and correct the offset to 0. (for the record, that is 1.5"). If you are buying wheels that are custom, just do the math and make sure that your resulting backspace won't end up being more than 4.5" and you will be fine. If it is more than 4.5", determine the difference between your calculated backspace and 4.5", and convert that to millimeters. Put a negative sign in front of it, and that is your required offset. For instance, that same watanabe, but in 15X9: (9"+1")/2=5" 4.5"-5"=-.5" -.5"X25.4=-12.7mm (which can be rounded to -13mm). Your required offset for this wheel would be -13mm.

[S30TRBO]

Looking in 240zzt's gallery, his rear Wats are 9.5" and he is using 245/45ZR16 Fuzion tires. According to the specs for that tire at the Tire Rack, the approved rim widths are 7.5-9.0". So his wheels are wider than the tires were designed to fit.

You did your research and so did I. I originally went to Tires Plus and they tried to mount them but didn't feel comfortable installing these tires on my Wats. I called around a bunch of places and the guys over at Mr. Tire that install big 20"+ wheels on SUV's using a Cheetah said to bring them by and it wouldn't be a problem. They didn’t have to use the Cheetah but mounted them normally and they went on flawlessly, $20 later they were mounted. I talked to Joji from Wheel Choice because I said no one over here wants to mount them on my side of the world. He laughed and he said they mount them like that in California all the time. The problem is on the east coast the stretch look isn't as popular as on the west coast.

Even if safety and tire wear wasn't a concern (and it is), here's a thought: If one of those tires develops a small leak and gets a bit low on pressure, the tire could easily pop itself off the bead, since it is stretched so tight. And if it does, that is one very expensive wheel that will hit the pavement.

Safety, Safety blah blah blah they are on the rears and you know what it’s “All about the Look” right daddz. The fronts are not stretched and that’s where the most safety concern would come in IMHO. I don’t plan on running these on the track and if it blows I’ll cross that bridge when it comes.

In most parts of the world, the tire dealers would not be allowed to do stuff like that. And the car wouldn't pass inspection that way most anywhere but here in the USA.

This was started in Japan and occurs on a daily basis and in my case the stretch is very minor compared to some wheel and tires combos that the Japanese run in country.

I think Joe would have been better off with a 255/40/16 or 265/40/16 but these sizes are so oddball that his next choice should have been an 8.5" or 8" wide wheel.

Those tires are unobtainable. However a 265/45/16 are but they are competition and not street tires. With 500hp these won’t last long anyways hehehe muhahaha :devious: :laugh:

240ZTT's car does not need coilovers to run those wheels and tires. Watanabe's like his (typw r) are designed to have flares and a stock suspension. Go to the web site and you will notice they all have a 4.5" backspace. The 9.5" wheels have a -19 offset, thus requiring flares.

I beg to differ. Try fitting these on a stock suspension. The stock lower spring perch will rub on the tire. An 8.5” 0 offset can be run using 245 in the rear and a 225 in the front any bigger and the lower valance will need to be removed because the tire will rub when turning.

you know what is the width, and the offset for that rims

Fronts:

225/50/16

16x8.5” -6 offset

Rears:

245/45/16

16x9.5’ -19 offset

[S30TRBO]

On a side note. My buddy just emailed me, his Wats are for sale on Ebay:

[Walter Moore]

Vehicle Inspections???

We don't need no stinking vehicle inspections! The righteous citizens of the state of Indiana rose up and told the legislature where to stick their vehicle inspections way back in the 70's, just after they banned daylight savings time!!!

What did you say? Indiana has daylight savings time AGAIN!!! OH NOOOO...

Where have all our righteous citizens gone??? NO NO NO:eek:

[zguitar71]

I beg to differ. Try fitting these on a stock suspension. The stock lower spring perch will rub on the tire. An 8.5” 0 offset can be run using 245 in the rear and a 225 in the front any bigger and the lower valance will need to be removed because the tire will rub when turning.

Fronts:

225/50/16

16x8.5” -6 offset

Rears:

245/45/16

16x9.5’ -19 offset

I have personally seen these exact size wheels and tires on stock suspensionad Z's before. I run 15x7 wheels with a -12 offset and 264/36/15 (odd size, Goodyear calls them 23x9x15) cantilever race tires, they do not rub my stock suspension in the front or rear and they do not rub the front valance either, some of that could be from the small diameter of the tire too.

[S30TRBO]

I have personally seen these exact size wheels and tires on stock suspensionad Z's before. I run 15x7 wheels with a -12 offset and 264/36/15 (odd size, Goodyear calls them 23x9x15) cantilever race tires, they do not rub my stock suspension in the front or rear and they do not rub the front valance either, some of that could be from the small diameter of the tire too.

Correct you are I was mislead.

[240ZX]

Just a small correction regardings veritech-z's comment about offset. Positive offset is when the mounting flange is closer to the hub and negative offset is when the mounting flange is closer to the outside of the wheel....not the other way around!

Tom

[Victor Laury]

Tom, I read your post twice, maybe I didn't read it right?

Positive Offset - Think of the honda next to you at the light. His wheels are +40 offset.

And then there is Negative offset, as perfectly demonstrated by the REAL "TYPE R's" in this case 14X9 @-19 RS Watanabe Type R

[240ZX]

Tom, I read your post twice, maybe I didn't read it right?

Positive Offset - Think of the honda next to you at the light. His wheels are +40 offset.

And then there is Negative offset, as perfectly demonstrated by the REAL "TYPE R's" in this case 14X9 @-19 RS Watanabe Type R

Yah, you read it right.....just had a senior moment:stupid: .....my mistake and appollogy to veritech-z!