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Definitive wheel fitment guide for S30 Z cars ......creating a database?


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Hey guys!  For many years, the most commonly asked question (that doesn't seem to have a clear answer in many cases) is the ideal wheel size, offset & tire size used on our S30 Z based on whether the car has stock struts utilizing stock or aftermarket springs, a coilover conversion, stock fender lips, rolled fender lips or flares, suspension upgrades (bumpsteer spacers, adjustable control arms, etc.), ride height (from the rocker to the ground, and brakes (stock or upgraded), etc. 

 

Has anyone started (or considered doing) a master spreadsheet / Application Guide that has a column for each of these variables?  Do any of you web savvy guys know how to make some sort of page or table that people can enter what they have and maybe a spot to upload a side shot of the car?  Just a thought.  We can start here with this thread to post all those kinds of details on each members rides to start collecting data and then input it into some sort of database/sheet?  Just a thought.   Anyone have any additional input in this regard? 

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Problem is variance between tire and rim manufacturers. Some companies have very very loose grasps on the specs.

 

I had a tire in a 205 that was wider then a 225 in another manufacturer, even when you go to buy tires, the seller will usually comment on some manufacturers running wide. I imagine rims are a little more easily verified, but tires especially vary quite a large amount. 

 

In board offset determination would be very easily verified, outboard would be more problematic. You could generate some pretty good guidelines via crowd sourcing if everyone went out and physically recorded their setups, but if they just reply with the written specs you may run into some trouble.

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Maybe with google spreadsheet (like excel but online). I would prefer a table which you can sort for all details, like tire width or offset.

Possible columns could be: wheel width, offset, stock struts/upgrades, distance to strut/coil, distance to fender, fender status(rolled/stock/flared), tire size(split to width, diameter and cross-section), tire manufacturer,tire type, link to a picture and the other things you mentioned. But someone would have to moderate it.

 

I would love to see that.

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You would have to have alignment settings, and a measurement from the ground to a common point on the car? Possible the lip under the rockers right in front of the rear tires and right behind the front tires to account for how much lowering if any. Whether its a 240,260,280, not sure if there's any fender well clearance differences. Suspension components, tire brand, wheel brand and sizing. With adjustable suspension whether you centered the rear wheels in the opening.  It would need a lot of information to be very accurate with all the differences out there.

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And peoples definition of fitment can vary oh so very much. I think a 7 or 8 inch wheel with a 225 tire 50 sidewall in 0 offset fits pretty well for a non flared car. I've also had conversations where someone says their 9 inch wheel -15 with a 205 stretched with larger amounts of negative camber fits well on a non flared car. Kind of really depends on what you are going for.

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Even if the definition of fitment varies, a dedicated/somewhat uniform fitment guide could still be useful for many. I've spent days searching the internet looking at different wheel, suspension, bodywork setups. It would be nice to see a lot of different setups in one place. I don't think it could or should  be a substitute for measuring your own car.

Seattlejester makes an interesting point about the "definition of fitment". This is exactly why i personally would be interested in seeing the diversity of ideas out there.  However, I don't think a guide of any sort would fulfill the OP's quest for "clear" answers on "ideal" fitment, but data base of sorts would be pretty cool.

 

Saying all that.... I personally wouldn't have any interesting info to add or know how to setup such a guide. :P

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Too many variables to consider and too much  time to keep a spread sheet updated. How about a tutorial on how to measure  for wheel and tire fitment including special tools  required for checking spring/strut clearences? 

 

The tutorial could be posted in the FAQ section.

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Savage42-I would be happy to contribute to such a data base, but I'm not willing to start one. One field in the database should be for a link to a photo of a car with the referenced wheels and tires mounted. I think that there should be columns for both advertised offset and measured back spacing, since it is kinda hard to measure offset.

Edited by RebekahsZ
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Problem is variance between tire and rim manufacturers. Some companies have very very loose grasps on the specs.

 

Also, sellers often advertise the wheel will fit. I purchased some 17" with +25 offset and they hit the struts.  Seller was no help and suggested I use

spacers. So, try them on the car before putting tires on them.

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Too many variables to consider and too much  time to keep a spread sheet updated. How about a tutorial on how to measure  for wheel and tire fitment including special tools  required for checking spring/strut clearences? 

 

The tutorial could be posted in the FAQ section.

1. I think with Google Spreadsheets everyone who has the Link could insert data (if configured) and the moderating part would be small. On the other side, we could make a thread where we post the neccessary data and someone fits them into the sheet.

2. a template to print out/tinker with a scala to see the what measurements the wheel could have, would be nice too. The tire could be excluded.

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You are right about what tire sizes may fit, as they vary by manufacturer and also by what size a person is willing to stretch onto any given wheel size.  Instead of a just a "show your wheels" thread where everyone just throws a pic in the pot with limited info, maybe something a bit more defined and with more info would be the easiest way to get this kind of information narrowed down. 

 

Another option may be to pin a thread at the top of this forum and have one for each size (14" - 18") of wheel and each person can put a side picture of their Z.   (ie. Post your 15" wheel, size, offset and other info)

 

The following info would be helpful:

 

Wheel

Brand:

Size:

Offset:

Spacers: Y / N

Fenders: stock, rolled lip, flares

Springs: stock, aftermarket or coilovers

Control arms: stock or adjustable

Camber Plates: Y / N

 

Tires

Brand:

Model :

Size:

 

I think pics like a side shot of the car, pic of wheel/tire clearance to strut and a shot taken from the front & rear directly along the side of the car to show how much the wheel sticks out / sits inward / close to flush would be useful, as well. 

 

What do you guys think?  I know it'll take a little time for each person to put the info together, but would likely yield the best collection of information with the most ease & least amount of work.  With that resource, then an actual database/sheet could be put together. 

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My 0.02

 

I think it would be helpful to add info in addition explaining the list, as I have seen threads on forums, where people are unsure and they skip or leave it blank.

 

It would be nice if we had a rule where you cannot post until you have all your numbers/info, just so it has more complete entries.

 

Wheel

Brand: Who made your rim? If you have a model name or number that would be great

Size: In inches. Usually found on the rear of the wheel this will be two numbers: diameter followed by width, on some rims, the number may be in reverse, please correct and post in diameter by width format (e.g. 17x8). If you feel the wheel may be wider then advertised, break out the measuring tape :).

Offset: This is the distance from the hub center, this is usually provided in two numbers either as a + or - number or a inches of backspacing number. Please convert the number into mm. + numbers refer to the hub face being further outboard from the center of the rim, - numbers indicate the hub face being further inboard from the center of the rim (e.g. 8 inch rim with 0 offset has 4 inches of back spacing and is 4 inches from the the rear of the hub to the edge of the rim. 8 inch rim with -25 offset has 3 inches of backspacing). The conversion factor is 1 inch = 25.4mm. The offset number is usually stamped on the back of the wheel, if it is unavailable, next time you take your wheel off, flip it over and measure from the back of the mounting face to the edge of the rim in a vertical fashion, that is your back spacing. Take that number convert into mm and subtract half of the rim width that is your offset in mm.

Spacers: Y / N

Fenders: stock, rolled lip, flares

Springs: stock, aftermarket or coilovers, brand would be very helpful

Control arms: stock or adjustable

Camber Plates: Y / N

Camber specs: if available

Ride height: we should pick a common point like the distance from the rocker to the pavement, some piece of bodywork that most people don't change.

 

Tires

Brand:

Model :

Size:

Edited by seattlejester
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Should caliper type/brand/model number be added to the list?  

 

I know it made a difference with my Toyota front calipers. The 15" wheels  I had at the time I installed the Toyota calipers fit without any clearence problems, but when I installed a set of 15" Ansen slotted mag wheels   the mounting surface of the wheel rubbed on the  caliper body. A 1/8" spacer fixed the problem.

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