wanklin

iTrader: (2)

It'll look good. The stock wheels are +50mm so you are going to be a little closer to the lip than stock; however, keep in mind that you will be changing scrub radiuses a bit.

FDdragon

ok, i must be missing something. I did an oil change on my FD today and thought id take a look at my wheel offset, sizes and such and noticed that in front i have 17X8 +34 offset with 1"spacer...in the rear i have 17X9 +38 offset with a 1/2"spacer and the wheels fit fine with no rubbing on the fenders.

this is confusing to me because if i did my math right (i suck at math so if im wrong then please forgive me) that would mean that my front wheels would (with spacers) be at 17X8 +9 offset and the rear would be 17X9 +26 offset. Technically this is what my wheels are sitting at right? this is because i am using spacers so the point where my wheels mount are at +9 and +26 offset. am i completely wrong?

i am confused because i thought the factory offset was +50...which would mean that my current setup would not fit at all. any thoughts on this?

blackoutz

Ill wait for Wanklin to replt to that one. Good point though. What are scrub radiuses??
thanks

wanklin

iTrader: (2)

Your math is close enough since the offset shifts by the width of the spacer, and no they should not fit with proper tires. The spreadsheet is based off of outer-edge setups leaving only a hair between the tire and fender; CCW 18x10 +50 track package, 18x10 +42 and others.

The factory setup is conservative and does not represent the out limits. The spread sheets are however, and according to the data on which the application is based, you should not be able to run much more than about +30 in the rear and +18 up front w/ stock lips.

Either fender work has been done to your car, your car has abnormally large fender clearance, the spacers are not as thick as advertised or you are running a drift setup.

FDdragon

i dont know what the previous owner had done to the car but i am running the current wheel sizes and 235/45 in front and 255/40 in the rear. it doesnt look like anything was done to the fenders but ill try to find out. i did take a tape measure and measured the spacers and they were 1" and 1/2".

yeah, the numbers dont make sense but if they work then ill have an easier time finding new wheels and with a deeper lip. ill probably go down to a wheel shop tomorrow and see if they have any wheels these low offsets and see if they fit. if so then im in luck i guess.

thanks man!!

GoodfellaFD3S

iTrader: (213)

A question for Jim/Rob/whoever is an expert about this stuff.

I picked up a set of Fikse Profil 5s in 18x9 +38 and 18x10 +44. Using both spreadsheets, it looks like a 265 in front will fit, but a 285 in the back won't fit? Ideally, I'm probably looking at 245/35 in front and 285/30 out back. I might push it to a 295/30, but it appears that won't work.

wanklin

iTrader: (2)

The front spacing is close to the limit so you will make a judgment call based on nominal tire widths. Peter Hahn was running 18x10 +42s in the rear, unrolled, but I think he was using 275mm wide tires (maybe 285, Peter, correct me if I'm wrong). His setup is just about flush with his unrolled lips and leaves very little space between the tire and trailing arms.

Your proposed 285s will stick out about 3-5mm more on each side so, in theory, they should fit, and the sheet agrees. 295's may be possible with modified lips, and shimmed (to the inner limit), aftermarket trailing arms (you might research Gene Felber's setup) and perhaps a little sledging of the inner wells, but it is definitely pushing it. I wouldn't recommend trying to shoehorn the 295s since they will weigh more and give you only a few mms of rubber when all is said and done since the wider tires will be slightly contracted by the fixed 10" rim bead width.

Howard Coleman

iTrader: (6)

this is a long thread and it is my first visit but i thought it might be worthwhile to share my setup.

my background is roadracing and my FD is getting close to being complete for dual street and road racing usage.

we all have differing objectives w our FDs. having raced for 22 seasons and hung up spending my entire spare time at the track i am not interested in doing a track only car.... cage, fuel cell, trailer etc. i want a car that i can do a few track days and lay down some fast laps but also enjoy just cruising.

suspensions and tires were always number one on my agenda when i was racing. i was sponsored by Hoosier and they would make tires for me for each of my races. i would spend most of my time looking at them after sessions. i also used softeners on them. i slept w them.

anyway i have finalised my 08 tire sizing. my car runs very close to 54% rear weight. i run 18 X 9.5 fronts and 18 X 10.5 rears which i consider to be the optimum sizing for my application. front offset is 40, rear 30. i run small rear fender flares as i needed about 5/8 of an inch w my Toyo 285s. i run 25 inch ride height front and rear.

i will run sizing that will deliver tread width equal to my wheel width: 265 front and 295 rears.

the operative concept for me, since tires are number one in my book, was that i would not base my sizing on the body but on performance.

i will be running a UTQG around 140-160 and may shave a few tires.

i will also be running the 08 Silver State Classic in Sep.

here's a pic of my flares... i did the work and am happy w the result. final paint still awaits.



hc

FDdragon

so i have a question which might seem stupid but i just want to make sure.

if i have two wheels, 18x8 and 18x8.5, both with the same offset (+35) and both using 225/40 tires....will moving up from 18x8 to 18x8.5 be that big of a difference?

just from thinking about it I only see a slight difference...and after using the spreadsheet it showed only about 1/4" difference. i plan on running the 18x8.5's in the front. (currently on 18x8 +34 offset with no problems). the width should still be the same because I am running 225 tires right?

just thought id ask. thanks guys!

wanklin

iTrader: (2)

Negatory, it will not be the same. Tire width is affected by rim width. Stretch the tire beads another .5 inches apart and the tire width will increase slightly. Your front spacing will increase by about 1/4" as you say, but why not go with a higher offset so you can put at least some 245-255s up front? A 225 tire is a bit underkill for this application.

dhays

iTrader: (1)

I have been sweating this and am still unsure. I've checked out both the "Will these tires fit" and the "FD Wheel and Tire sizing" spreadsheets and they seem to imply that they will work.

Here is what I'm looking at.
Enkei RZ-5 18"x8.5" 42mm offset Gunmetal rims
Dunlop SP Sport Maxx 245/35-18 tires

As near as I can tell, these should fit.

One of the reason I'm looking at the Enkei rims is that the 42mm offset is closer to the 50mm offset of stock rims than the 38mm offset of either the ASA JH8 or the Kazera KZ-A. Tire rack does have the ASA and Kazera on sale now for pretty good prices and they are both lighter than the relatively heavy Enkei's.

I actually went to two tire dealerships yesterday, and in both cases they said that the 18"x8.5" would not fit and that I would need to run 235s instead of 245s. One place actually said that the offsets for the FD weren't 50mm but were I think 38 and 42. I looked at the book they had and they were right, that is what it said. I left in confusion.

Will the Enkei's fit with those tires? Any other affordable suggestions on rims? Tire Rack seemed to have the best selection and prices, anywhere else you might recommend?

wanklin

iTrader: (2)

Those tire shops are incorrect. The spreadsheets were put up to answer questions like these, and as long as you are using properly sized tires they can, with fair certainty, be trusted. In my opinion, if you are going to spend the money on after-market wheels you should at least end up with 255mm rear and 245mm front tires minimum.

dhays

iTrader: (1)

Thanks a lot for the response Rob. You seem to have a wealth of good information. Here are my thoughts about tire size, maybe you can tell me if I'm deluded or not.

I don't want to go too wide since we have a lot of rain here in the PNW. I want to go bigger than the stock 225s, but don't want to create hydroplaning problems. I also would like to be able to rotate tires front to rear, hence the equal size front and back. I think that 245 should be plenty of grip for my purely street purposes.

Any suggestions on other affordable rims or sources?

wanklin

iTrader: (2)

Haha, well thanks but I'm just regurgitating dimensions. If a different look is what you are after you may think about getting some J-spec 16" or 17" wheels to keep the OEM look (contact FDNewbie). If you are looking for something more flashy there are tons of brands out there, but unfortunately most budget wheels are significantly heavier than stock. The best thing to do is just scour the web and magazine advertisements until you find a wheel that fits your style and budget. The Tire Rack is a good go-to, but there are hundreds of businesses out there that specialize in wheel sales. I wish I could be of more assistance, but I'm a pretty boring guy as far as wheels go [I stuck with widened 17" stockers].

dhays

iTrader: (1)

17" is better than my stock 16". I'll check on the cost of the stock J-spec 17", but I'll bet it is a lot more $$$.

mdpalmer

iTrader: (24)

^^ Huh? 17" stock FD wheels? How did you get stock FD wheels to be larger diameter and wider?? Details please, as I would love to have that on my car.

wanklin

iTrader: (2)

Later model RX-7's came with 17" wheels standard which are slightly different in design to our USDM 16" standard equipment.

I wouldn't get too excited. Once you've paid to import the wheels and widen them and make hubcentric spacers you could purchased a set of Fiks's or BBS's, which most people would rather have anyhow.

s1mpsons

iTrader: (5)

I have a question regarding wheel hub fitment. Will a wheel with the following dimension fit my FD: 17x8.5, 5x114.3, e48, 73hb. I am just not sure about the "73hb" measurement. I ran all the dimensions in the spreadsheet and there was sufficient clearance, however that was assuming a 245/40/17 tire size. I plan on running 245/45/17 Azenis RT615's. I notice that if you play with tire width in the spreadsheet, clearance measures don't change accordingly. Anyone care to weight in on this.

Thanks,
Jake

pinkston

iTrader: (1)

so if i get a 18x10 for the rear will it work with a stock rx7 body or ami going to wide here i know the sheet is up but i wanted to ask you guys its easier im lost in that sheet or like a 18x10.5 my car will be throwing down some big numbers so i need all the tire i can get lol thanks guys

fd3virgin

i have searched and read and the more i read the more confused i get.
so i need help.
wheels 18x9.5 +38 offset front
18x9.5 +38 offset rears

i want to run 265 in the front and 285 in the rears. i have tein has and will run about 25 inches from fender to floor. would the 265 require fender rolling? from what i have read the 285/30 should clear the rear.

thank you so much. i want to run r comps b/c i have reo1rs on my civic and they only make up to a 265 max rear. kvn

s1mpsons

iTrader: (5)

I really would like to know how to change sizes on this spreadsheet and have clearance measures change too?!?!?! If you play with tire width in the spreadsheet, clearance measures don't change accordingly. Has anyone editted this spreadsheet to fix this?

I am now looking at Enkei RPF1 17x8.5 40mm all around. I am curious what are my best tire size options. I am think 245/40/17 front and 275/40/17 rear. My math shows me that I will have rear tire clearances of .22'' on the outside and .58'' on the inside. Can some check my math on the 275/35/17 tire clearance in the rear please????? Is this an acceptable clearance. Thank!

I would think going as wide as possible (without rubbing of course) all around would give the most traction. Do FD's allow for more tire width clearance in the rear?

wanklin

iTrader: (2)

^ The tire calculator portion is just there to help you determine proper tire widths for your rims. As long as you are using tires that are properly sized the rim measurements will be all you need. Ideally the tires should be almost flush with the outer face of the rims.

s1mpsons

iTrader: (5)

"Ideally"????? Ideal for what? I want max traction and min weight. I know that it sacrifices a little steering feedback, but I definitely don't need heavy 10.5" wide wheels to match the width of a 275 tire.

PS: I know the rounding/side-wall-bulge takes a little away from the contact patch/traction, but it's can't be worth all that extra wheel weight!


Enkei RPF1 17x8.5 40mm all around. Front tires will be 245/40/17 and rear tire will be 275/35/17. It looks like I will have the following tire clearance:

rear outside (in.) 0.22*
rear inside (in.) 0.58*
front outside (in.) 0.32
front inside (in.) 1.18

*To calculate the rear clearance I subtracted 0.6" to both rear outside and rear inside clearances which were calculated automatically in the spreadsheet using 245/40/17 tire measurements.
0.6 in = [(275 mm-245 mm)/2] / 24.5 mm/inch

gracer7-rx7

iTrader: (16)

^^might want to talk to these guys:
https://www.rx7club.com/a-138/

FurryRoadkill

hey, i've looked at the spreadsheet, and i've already asked another memeber and they said this setup woudnt work. But i just read that someone was running a setup similar to the one i want and it works so... i'll ask.

I would like to get some wheels that are 18" x 8" with 35mm offset for the front and rear. The tires i'm looking to get are 225/40/18s. Will this fit? if not with those tires.. is there any way to make it fit??


if not then what about some18"x8"s with 40mm offset front and rear with the same tires???