Ropski

I'll apologize in advance, none of the stickies sizing charts ect... will open on my Mac and searching freezes my computer... no idea why, but it lets me post. Budget build and I am also not very knowledgeable on wheel fitment, suspension setups.

93" FD Koni Yellow shocks, planning on Tien S springs.
Wheels I'm looking at are Konig SSM 18x8 +45 front 18x9 +50 rear. Want to run BFG G-Force T/A KW2 275/35 on rear. I don't really want to roll/flare stock fenders, will rubbing/clearance be an issue for stock body?

Rxmfn7

iTrader: (4)

Those sizes will fit no problem, are are pretty well on the conservative side. The wheels will still look sunken in. Also, 275 is a bit large for the 9" wheel. It will work, but its not really optimal. I know you just asked about fitment and not really opinions, but Konig is a pretty cheap wheel, and if it were me I wouldn't put them on an FD. I know not everyone wants to spend, or can afford super high end wheels, but there are a few offerings from brands such as enkei which are well priced and much better quality, that I would look into. They offer better fitment options as well. Just throwing it out there..
If however, you are dead set on these wheels, the 18x9+22 rears will fit with a 255/35 tire, but I would suggest a fender roll. For the fronts the 18x8 +35 would still fit fine and look a bit better. Again, just my opinion. Your original sizes will fit with no issues, for a quick answer to your question.

Ropski

I know they're pretty cheap, I'm not necessarily set on them. Like I said, I really am not a big wheel guy lol. Offsets, Spacing... May as well be greek to me. The other wheels I'm looking at are XXR 926 18x8.5 F 18x9.5 R 35+ offset, but they're quite heavy. I don't do any Auto-X, maybe the occasional drag, but mainly just looking for something to have decent fitment, not look rediculous, and be able to put the power down better than the 225's I'm rockin now. If I had $3k laying around, bet your *** I'd have some SSR's on it.

Rxmfn7

iTrader: (4)

Are you set on new? Every once in a while some good used wheels pop up for sale. I have no affiliation with the seller, but in this thread, last post he has a set of RPF1s with near new star specs for sale for a really good price:

https://www.rx7club.com/wheels-tires...m-rpf1-988574/

Tires alone cost more than that when new.

Ropski

Not necessarily, as long as they look sexy I guess. I sent a PM to the guy selling Work Meister SP2's in the wheels/tire section. They're 18x8/9 staggered, but that would definitely be a + instead of Konigs.

ZDan

I'm liking the OP's preference for +45/+50 offsets a *lot* better than +35/+22...

IMO, 245/35-18 on +45 front and 265/35-18 or 275/35-18 on +50 rears would be a great fitment, shouldn't rub with no fender rolling required.
Hate to see unnecessarily low offsets, particularly up front where scrub radius is affected (greater kickback, less real "feel" with offsets further removed from stock +50).

For visual reference, here's my car with 245/40-17 on 17x8.5 +40 up front, 275/35-18 on 18x9.5 +45 in back.


255's up front tweaked the front fender lips, but 245s with 5mm more offset should fit without any issues.
In back, I think 265 on +50 should be no prob at all. 275 maybe a little riskier without rolling (my rears are rolled).

For functionality and aesthetics, I like reasonable, stockish offsets, though I know for a lot of people, the lower-offset and pokier the better...

Rxmfn7

iTrader: (4)

^Thats fair. As I mentioned, his original offsets are perfectly safe and would work fine. I only suggested the lower ones for aesthetics, which is a personal preference. Im definitely not a "lower offset and pokier the better" person, but I like the wheels as flush as you can get them without really causing issues. To be fair, just for comparisons sake lets take your 17x8.5+40 fronts, and compare it to the 18x8 +35 that I suggested. The 18x8 +35 pokes a whopping 4mm more than an 8.5+45.. so at that point I think we're splitting hairs. For the rear, a 18x9 +22 compared to your 17x9.5+ 45 pokes 17mm more. Given that Id suggest a 255 tire for that, vs your 275, were taking maybe 7mm less fender clearance in the rear. So, I really dont think we're that far off

ZDan

255 on +22 is going to be 13mm closer to rubbing than 275 on +45, 18mm closer than 275 on +50. Aside from aesthetics, another reason I'm not a fan of low offsets is that you can't run tires as wide as with higher offsets.

If you want to run 275s with stock unrolled fenders, +50 should work. +22 definitely won't! You'd have to go down to 225s to have the same fender clearance on +22 offset as 275 will have on +50.

Rxmfn7

iTrader: (4)

^ Youre not taking wheel width into consideration when doing your calculation of offset. But anyway, Im not fully disagreeing with you, but at the same time given his original wheel specs, I personally wouldnt recommend running a 275 on a 18x9, which is why I suggested the 255. In the widths he chose, Id do a 235/255 stagger. If he would want a 275 rear Id step up to a 9.5-10.5 wide wheel and try to be in the +40 to +45 offset, as you said.

ZDan

It's the tire that's gonna rub, but anyway, if we look at the outer wheel lip, 9" +22 is going to stick out 22mm further vs 9.5" +50.

50mm - 22mm - (9.5" - 9")/2 = 28mm - 6.35mm = 21.65mm

Anyway, 275 on 9", 9.5", 10", whatever, without rolling fenders, I'd say +50 is a definite fit, +45 a likely fit, +40 or less is likely to rub.

9" is the min width for 275, but it is a valid fitment.

Rxmfn7

iTrader: (4)

^Yep, agreed. Not sure what we're arguing about lol. I was just referring to your above statement where you said "255 on a +22 is going to be 13mm closer to rubbing than a 275 on a +45". In that example I was assuming the 255 would be on the 18x9 +22, and the 275 was on your reference picture of the 95 +45, in which case the outside lip of the wheel itself would be 17mm further outboard, and then running a 20mm narrower tire, 10mm more clearance on each side, would only really give you about an 7mm difference in outboard tire clearance.

Those 17" PF01s that you posted, are you currently running those in 18x9.5 all around, or am I thinking of someone else?

ZDan

You don't go by outside wheel lip position to get tire location, you have to take the wheel position as a whole. Outside lip moves in with 9" wheel, but inside lip moves out by same amount. I.e., they cancel as far as tire position is concerned.

255 on +22 is going to stick out 45mm - 22mm - (275-255)/2 = 13mm more vs. 275 on +45.

I'm running 245/40-17 on 17x8.5 +40 fronts and 275/35-18 on 18x9.5 +45 rears in the pic above.

Ropski

This is what I was talking about... this all just went right over my head haha. But it's making a bit more sense now.

ZDan

Here's a site that will help visualize impact of wheel/tire sizes and offsets:
www.willtheyfit.com

Rxmfn7

iTrader: (4)

Not trying to be argumentative, as I think we both have a grasp of what we're trying to get across, but again.. you aren't taking wheel width into consideration when posting this calculation. The 255 on a +22 is on a 9" wheel, whereas the 275 is on a 9.5. Your calculation does not account for that. As you said above, we agree that when talking wheel only a 9.0 +22 will place the outside lip 17mm further out than the 9.5 +45. If you were running the same size tire on each, you would agree that the edge of that tire would also be ~17mm further out, agree? Now taking into consideration the narrower 255 on there, you would have approximately 10 less mm on each side, which would equal out to ~7mm more poke on the outside.

Your calculation just takes the difference in offset and subtracts half of the difference in wheel width, but not accounting for the ~6mm more outside clearance you get by using the 9" wheel as opposed to the 9.5. (1/2" is approximately 12.7mm/2 = 6.3mm. Subtract this from your 13mm, and we come to the same conclustion of 7mm)

Ropski

Making more sense now. So Lower the offset the further the outer lip is from the hub? And vice versa higher offset. 18x9 35+ offsets with 255's would be about the same distance to the fender as 275's on a 9" +45 offset correct? If I am doing this math correctly that is...

lOOkatme

iTrader: (19)

The tire mounts to the wheel and it is mounted in a way that is centered on the wheel. If you mount a 18x9.5" wheel with +38MM offset using 255/35/18 tire the tire will sit in the same exact location as mounting a 255/35/18 tire on a 18x10 +38MM wheel. The tire will be stretched more but be in the same exact location.

Running the widest possible front wheel will give you the best handling vehicle given the tire is installed with a slight stretch and fits correctly.

running a 255 35 18 tire on a +22MM offset wheel is not going to fit in the front. no way, no how, unless you either do a fender flare/pull, or go with wide body fenders and it would be flush then.

If I were the op I would run a 18x9.5" wide wheel front and rear, or a 18x9.5" front and 18x10" rear if the op decides to stagger. I would run a +40 to +50MM offset front and rear or go a little more aggressive in the rear with a +45 to +38MM. I would run a 245/35/18 all around or 255/35/18 all around or a mix match of these. Most aggressive I would go is 255/35/18 front 265/35/18 rear which may require a fender roll.

depending on tire selection you can get more or less aggressive with the offset.

Front tire selection and offset
245/35/18 front I would run a 18x9.5 +50 to +38MM (+35MM might fit with a roll?)
255/35/18 front run 18x9.5 or 10 +50 to +45MM (might need a roll)
265/35/18 front run 18x9.5 or 10 +50 or +45MM (will need a roll, taller tire)

I am running 18x10's all around on +38MM offset with rolled fenders all around and might have my front fenders pulled a little. I am running 265/35/18 tires and I hit the fender liner front and rear when making tight turns. I recommend a 255/35/18 tire in the front but I got such a good deal on the tires I made it work.


Wheel calculations.

I ran my 18x9.5" +45MM with 265/35/18 tires. the tires have a tread width of 9.7 or so, from the hub the top outer edge of the tire is located 78.19MM from the hub with a 25.3" diameter tire and worked with rolled fenders.

I had 18x8.5 +30MM with a 235/40/18 tire on the front as well with another set of wheels. tread width was 8.4" on so from the hub it was located at 76.68MM from the hub 25.4" diameter.

I have seem some people run a 275/40/17 with +45Mm offset which means max with rolled fenders might, tread width of 10.3" and is located from hub 85.81MM from hub with a 25.5" diameter tire. that i would consider to be the most aggressive you can get with rolled fenders up front.


So to the op.

Are these wheels going to be for performance? Looks? or both? Are you going to roll your fender lips?

Rxmfn7

iTrader: (4)

^Yep. Offset is the distance from the hub mounting point, to the centerline of the wheel. So lets say you have an 8" wheel with a 0 offset. The centerline of the wheel will be directly above the hub mounting surface, so you will have 4" of wheel on each side of the centerline (Just to avoid any confusion, wheel widths/diameters are talking from the actual tire bead mounting point. A 8" wide wheel will actually be about 9" wide from outside lip to ouside lip). A factory wheel on a FD is 8" wide with a 50mm offset, meaning the centerline of the wheel is 50mm further inboard from the hub mounting surface.

Ropski

Mainly for looks right now. It's seeing mostly street use, cruises/local meets, occasional drag few times a year, (I will have DR's on stock wheels for the back if that ends up being a semi regular thing) not too much excitement where I'm located. The car is just about to go my buddies shop to be rebuilt, ported, tranny swapped ect... so my money as of now is going all into making a solid motor, which is why I didn't plan rolling the fenders and/or going with a set of nicer, higher quality wheels. Later down the line I will upgrade them to a nicer set.

SoOo another set I've been looking at (friend of a friend is selling)

18" 8.5+38F - 245 should clear
18" 9.5+40R - 265 will be close

My main concern was the rear being and able to run as wide as possible for the time being, in the future when the wheels/tires are upgraded I have my eye on the FEED Fenders.

Rxmfn7

iTrader: (4)

^Those sizes will work well. I would still advise a roll on the front fenders though. Its quite easy to catch the fender lip, dependent on ride height and suspension stiffness. You also mention alot in running the widest rear tire possible, which isn't necessarily a bad thing, but just keep in mind a good high end tire in a smaller size will almost always outperform a cheaper tire in a wider size. So, dont skimp out when it comes to tires. Something like a star spec, RS-3, Advan AD08, etc in a 255-265 will provide much more grip than a run of the mill tire in even a 295 or something.

Ropski

I don't plan on skimping on tires. I had 275 BFG G-Force T/A KDW's on my 04 GTO in the rear and loved them. Lots of grip on the street, actually decent tread life and I can get them relatively cheap from a friend who works at a local tire shop. I just have always preferred a set of good wide rear tires. I'm used to domestics with 285-315's so I'm guessing old habits just die hard haha.

Rxmfn7

iTrader: (4)

Nothing wrong with that. With the right offsets you can fit a 285 tire up front and up to about a 305 or so under the rear of an FD with stock fenders.

ZDan

That is because the bulk of the tire *does not care* what the wheel width is. Where the tread of the tire is located depends only on wheel *offset*, and not on wheel width.

Only the bead of the tire is that additional 6.35mm inboard. It where rubbing is a possibility, nearer to the tread, wheel width is much less relevant to clearance (except in cases of extreme stretch/poke where the wheel itself is capable of hitting the fender lip).

Online Wheel & Tyre Fitment calculator. Offset, Tyre stretch and Rolling Radius calculator