Guest alanq64 Posted December 28, 2005 Share Posted December 28, 2005 Okay, I got into trouble with my first post and hopefully I won't again. I've read through the posts and I'm looking for certain info. I have a 1976 280z 2+2. What is the widest 15" rim I can fit on the back of my z? What offset for the rear? What is the widest tire? I have a stock bodied z and have no plans on using flares. The front is not an issue as I plan on using a relatively narrow tire with the manual steering. Again, I hope that this is the right spot to post and yes, I'm looking for the easy answer. Thanks to anyone who helps and thanks to anyone who decides to correct me on how to do a search. Quote Link to comment Share on other sites More sharing options...
buZy Posted December 28, 2005 Share Posted December 28, 2005 There is no easy answer to tire selections. I wish there was. Make an offset flat board template. Search tire specs according to different rim widths. Mine are small but fit well for adjustments. 17x7 4.75 or 4.25 bs I think. There are many options.....Get creative. Good luck, Quote Link to comment Share on other sites More sharing options...
Guest ON3GO Posted December 28, 2005 Share Posted December 28, 2005 stock suspension a 8in or 8.5 to 9in is about max. with coilovers you can go to about a 10in or so. you might have the roll the fenders abit with either one depending on how low you go with the car and tire size. 275's and maybe a 285 is the widest ive seen on a stock flared Z car.. that was without tubing and etc. just coilovers and some x9 inch wide wheels. search its been posted on this site many times. mike Quote Link to comment Share on other sites More sharing options...
Here comes trouble Posted December 28, 2005 Share Posted December 28, 2005 Now just suppose, where you all gonna get one of those big wide obselete 15 inch tars. They are just about plentiful new as 8 track tapes and hen's teeth and a kind woman. I am stuck with some 15 inch wheels (Dayton cross lace wires and halibrand replicas) that are about impossible to obtain the 50 series 15 inch wide tires. Somehow I woke up in the 21st century where wheel diameter like a stagecoaches are in vouge Quote Link to comment Share on other sites More sharing options...
Guest alanq64 Posted December 29, 2005 Share Posted December 29, 2005 Now just suppose, where you all gonna get one of those big wide obselete 15 inch tars. They are just about plentiful new as 8 track tapes and hen's teeth and a kind woman. I am stuck with some 15 inch wheels (Dayton cross lace wires and halibrand replicas) that are about impossible to obtain the 50 series 15 inch wide tires. Somehow I woke up in the 21st century where wheel diameter like a stagecoaches are in vouge Haha, that's funny. I'm going with 15 or 16's. I'd like to use 245.50x16 or something comparable to that in 15's. I'm a big fan of the "How wide can I go and still stay stock?" way of thinking. Way back when, I used to own a 72 240z and really hated to sell it. Now about 20+ years later, with kids, I've gotten the bug and bought a 76 280z 2+2 (kids remember). I've done search after search.. How about any of you out there with 15 or 16 inch rims tell the rest of us what tire/rim combo you're using and what offsets? I say the rest of us but I really mean me.haha Just looking for ideas. Thanks to any who help and happy new year. Quote Link to comment Share on other sites More sharing options...
Guest 73LT1Z Posted January 2, 2006 Share Posted January 2, 2006 I'm working on wheel solutions as well, and did the angle metal attached to the brake drum (rear) and rotor (front) of a '75 280 (non 2+2). I found with a 24" tire, there is about 5.5" to the lower strut on the rear. Same tire up front, and about 4.75" to the lower strut. I made up a calculator (see screenshot attached) to determine wheel data for the front & rear, but it is on a proprietary program called Omniform. The basic math is this (I'm sure you can replicate this stuff with something else, there are 5 columns): Wheel Width | 0 Offset Backspace | Enter Offset in MM | Backspacing | Spacer Needed 0 offset is calculated as ((wheel width)+1) divided by 2. Backspacing is determined by this formula: ((0 offset backspace)+(offset in MM)) divided by 25.4 Spacer needed is then calculated: ((Backspacing)-4.5) value for front x 25.4 The formula adds 1 to the wheel width for the lips, so this gives a correct 0 offset value, since an 8" wide wheel is actually 9" wide. A lot of numbers, but it seems to work well. For instance, my +55mm OS TA wheels below in this formula have a 6.67" backspace & need a 55mm spacer for the front, and a 35.95mm one for the rear (same formula, subbed 5.25" for the 4.5 value). I have a set of 255/50/16 Pep Boys "W" speed rated tires (about 26" diameter) on 1995 Pontiac Trans Am wheels, 16x8 +55mm offset- LOTS of backspace- (see above)! I don't see this tire fitting under the fender, so I'm going to keep the wheels, sell the tires, and buy some adapters & 4 new "Z" rated 225/50/16 tires (this works out to abot $500 vs. $750 for new wheels, spacers, and tires). From what I've learned here and my measurements, I think this is about as big as you can go with the stock suspension & fenders. Ditto the stagecoach comments above . That is why I'm selling the 14x6 gold mesh wheels that came w/ my car- there are NO tires above an H speed rating in 14", and 15" is drying up as well. Glad you were able to rekindle your youth (some would call this a midlife crisis, I should know, I got to drive ML Crisis #2 today )- I had to sell an RX7 for the family reason, but the next one many years later got a Chevy 383 . Quote Link to comment Share on other sites More sharing options...
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