hi i have been building my car over the last few years and am getting close to fininshing and need to sort some wheels and tyres. i would like to fit 20" wheels all round. with prob 235 or 245 tyres up front and 295's ot the rear. i have found quite a bit of info regarding 17 and 18" wheels but not so much on 20's maybe my search terms need a bit of adjusting or not haha anyway i found this.

20
Tire width (mm) 225 245 255 265 275 295
Aspect ratio 25 25 20 20 20 20
Tire diameter (in.) 24.42 24.82 24.01 24.17 24.33 24.64
Actual speed (60 mph indicated) 59 60 58 58 59 59
Front wheel offset (mm) 31 38 44 50 57 63
Tire clearance, outside (in.) 0.22 0.24 0.23 0.21 0.24 0.23
Tire clearance, inside (in.) 1.78 1.26 0.77 0.29 -0.24 -0.73
Rear wheel offset (mm) 19 25 31 38 44 50
Tire clearance, outside (in.) 0.24 0.23 0.22 0.24 0.23 0.21
Tire clearance, inside (in.) 2.26 1.77 1.28 0.76 0.27 -0.21


what i get from this is that i need a 295,20,20 tyre to keep as close to the factory wheel height and a wheel with a 50mm offset to fit the 295 tyre on the back.

i have emailed quite a few wheel companies and the last one emailed back with this info.

Sorry for late reply.
for your car application, we do have some a good wheels in sale
1.
WORK BR II
WORK BRII 20 x 8.5 30 5 - 114.3
WORK BRII 20 x 9.5 30 5 - 114.3

Price $ 4,950 delivered to your door.

2.
WORK BRIII
WORK BRIII 20 x 8.5 30 5 - 114.3
WORK BRIII 20 x 9.5 30 5 - 114.3

price $ 4,950 delivered to your door.


by the looks of it they are saying the wheel size i need is a 20 x 9.5 30 5 - 114.3

Im guessing that the 30 is the offset.

so i researched further and found that some guys on this site say that on a 9.5" wide rim they wouldnt put a tyre any wider that 275...

I just want to clarify that i will be purchassing something that will fit the car and tyres that i want.


so do i need to go upto a 10" rim on the back to fit the 295? and if so what offset will i need? the chart that i pasted above tells me wheel height, tyre width,tyre wall size and also offset of the wheel but not rim width.

hope my info is clear enough for everyone to understand.

Cheers Mark

 

This thread will be moved to the suspension/wheels/tires section...

If I remember correctly, Tire Rack is the sponsor of that section and can answer questions for you.

 

www.EscaladeForum.com

 

You haven't found info on it b/c 20s are not a good fitment option for the FD - if the intent is to drive it anyway. If you are making a show car, then I still think it isn't a good fitment option and will look cartoonish but its your car so... Have fun.

 

Dont do it.

 

As said before a 20" wheel COULD fit if you found a tire with a REALLY low sidewall ratio however it will ride horrible and even the smallest potholes will probably ruin the rim. A 10" is suggested for a 295 tire and probably a +40-45 offset would be best for the rear. Front +50 all the way.

In the end don't do it. 18-19 really is the max you can go for both practical and aesthetic reasons. The car is just too small for a 20'" rim. A buddy of mine had 20" on his Z. I swapped it on one side and it was just wrong in so many ways that aren't even opinion based.

Edit: a +30 offset will not work on a stock body in any way, shape or form unless the wheel is 7" wide. I had rubbing issues with a 265tire and a +37 offset.

 

right cheers for an actual answer worth reading! i have been running 19's for about 5 years now with no probs so maybe i will stick with them.

I will go with a +50 offset on the front and +40 - 45 on the rear. Thank you!

will i need a 9 or 9.5" rim on the front? I will go for a 10" on the back. is the offset marked on the wheel somewhere or can it be measured or?

Cheers

 

You measure from the inside of the mounting surface to the inside edge. This is called backspacing for some wheels. The offset is the distance from the mounting surface the the midline of the wheels width.

Also something to keep in mind is that the stock rear trailing arms are a bit wider than after market ones. Also for the rear, a 285 tire on a +40 10" and a 295 tire with a +45 should fit exactly the same with relation to the fender. The 295 will just take up more room inside. After market trailing arms may be needed.

As for the front. I personally use 18x10 all round with a +50 right now. I would, however, prefer a 8.5-9.0 in the front for tracking issues on the road. The car likes to drive itself with 10" in the front. Another thing to keep in mind if the vehicle is more for drift purposes (ie higher neg camber) then a lower offset may be used. It will however not fit on a normal alignment. I just know some folks like the cambered look and a +45 18x10 on a 295 with -3 camber leaves a .5-1cm gap on an unrolled fender.

 

Awesome thanks again! so if i was to go 19's all round would the same offsets apply? and will the 8.5 to 9" with 285's fit under the guards at the front? the guards have been rolled many years ago but it was just the very inside lip. i am happy as to do a bit more rolling if needed!

i like the info on the aftermarket trailing arms! thank you. do you run them yourself? i will google them... do you know a website that sells good ones by any chance?

do you run 285's all round?

nah not into drifting as such so will just be running whatever camber is best to get even tyre wear!

Cheers Mark

 

 

 

http://www.punchinthefacetoallyouloo...***.co.upyours!

Thanks to the guy who moved the thread to the right spot and to exedus for some help and usefull info.

Cheers Mark

 

A 285 is for a 9.5 rim mostly. It ill be too wide for an 8.5 and hairy on a 9. The offset is ONLY affected by the width of the wheel and "backspacing".

For the trailing arms.....www.rx7.com and rx7store both carry them.

I run 285/30-18 +50.5mm on my CCW sp500's. The front is the max I'd go in every direction but the rear definitely has room to grow. I use a 5mm spacer that reduces offset to +45 and could still go another +5 with unrolled fenders. Keep in mind that a 285/30-18 is slightly smaller than stock diameter.

265/30-19 on a 9.5 rim with a +50 front and +40 rear is pretty much the only way you'll be able to go without some issues. Will be about .4" taller than stock.

 

yeah i emailed rx7.com and pettit. pettit is $199 for a kit and you can offset the trailing arm to create more room. still waiting to hear back from the others. thank you.

so i can run a 265,30-19 on a 9.5 rim with a +50 offset. awesome thats sorted thank you again.

just with the rear will a 295-30-19 on a 10" rim with a +40 offset not fit?

I will be getting a set of trailing arms to make more room either way!

Cheers Mark

 

i just got this email back from ccw.

18's maybe sounding better and better for fitment!

if you are going to run a 9.5" front you will want it to be in the 50-56 mm offset range
the 19x10 will need to be at no more than +50mm, as you will rub the trailing arms
offset arms will gain you approx 6mm clearence to the inside, and may give you room to run an 11" wide wheel at +45mm

295 30 will be a little tight, and may need some fender rolling depending on your right hight and camber settings

wheels will run 2800 for the set in 19", in an all polished finish
to do the spokes black and leave the lip polished can be done but it is a lot of handwork, and will run 125 per wheel

to get a firm quote on shipping i'll need the full street address, but i expect that wheels alone will run around 580-640

keep in mind that an 18" setup may be an easier fit as the tire will be shorter (a 285 30 18 on an 18x10 is an easy fitting setup on a stock car)

 

The 18x10 +50 is exactly what I run but I suggest that with a 295 tire, a rear offset of +45 with unrolled fenders would be ideal. Rolled in the rear would be a +40. I strongly suggest for a non tracked car to not go over 9.5 with a 265 tire for tracking issues driving down the road. I have a set of 255/40-17's that feel just perfect for the front. I pretty much have to have tow hands on the wheel at all times with a 285 tire in front. This is not bump steer as it does it with just minor lines in the road.

When I ordered my CCW's they really liked the idea of +50 all round but I wish I had gone to a 10.5 or 11" +45 in the rear over the +50 10". (10.5" isn't usually available but they happen to have the blocks there in short supply when I asked.)

In the end I think you'll really like a good quality set of 18's from a good company like CCW.

 

Thanks heaps for your help. I have decided on the following....


18x9.5 +50 to run a 265-30-18 on the front
18x11 +45 (running pettit's offset aftermarket trailing arms) and a 295-30-18

Price is $3575 us$ delivered to my door here in new zealand! whis works out to be $4,713.57 NZ$ Which i think is a pretty fair price.

I am looking at mickey thompson street slicks on the back and am unsure of what tyre to put on the front yet! so many choices haha

Thanks again!

Cheers Mark

 

MT ET streets are VERY aggressive and VERY soft. You won't get more than a couple thousand Km out of them unless I'm thinking of a different tire. Also you may have to roll the fender with that wheel and I'm pretty sure 11" is in the neighborhood of a 315 tire which is VERY hard to fit stock. Just look at kevin doe's thread.

https://www.rx7club.com/suspension-wheels-tires-brakes-20/fitting-315s-stock-body-fd-904367/

 

right thanks for that link. i had a good read and am not keen to go to that much drama! lol ccw can do the 10.5" rim. i noticed that kevins rim ended up being 10.75" but with a different offset(cant remember what tho, will look again later) so a 10.5" rim should bolt on with a little fender rolling and hopefull thats about it correct? nothing is ever as simple as it seems sometimes even when you have all the info infront or you it still needs beating into your head lol

 

right some more info from wheel suppliers.. all the info seems to conflict against each other. one person says this will fit other say no.....

this is the last sizing and whatnot i have got.


"quote"
Please note that, by using 9.5 and 10.5 wheels, it required to roll you fender or guard for front and rear

And possibility to put camber kit for front and rear.

The price for 18” is $3,990 including GST and delivered to your door for black, gunmetal, silver, etc with polish lip finish.

The recommended offsets for

- Front 18x9.5 +30

- Rear 18x10.5 +30

"endquote"

I told the guy that i had been recommended to run a +50 for the front and + 45 for the back and his reply was you want +30 all round or the tyres will rub on the inside....

should i stick with the +50 & +45 still or?

Cheers Mark

 

'the guy' is completely wrong and obviously has little to no knowledge of what will fit properly on an FD.