[kayotik]

Because the first thread got too large, this one had to be made. Please do not spam in this thread or you will be dealt with swiftly and harshly.

For the WHEEL FITMENT SPREADSHEET, LOOK HERE: http://my.is/forums/f95/wheel-fitment-spreadsheet-376266/

Okay, here's the definitive guide to all the wheel offset and fitment questions. Here's the real way to figure out whether your wheels will fit!

EDIT: Thanks to NeoVB for this excellent link to help visualize wheel parameters - Wheel / tire size calculator / comparer - RIMS-N-TIRES

These limits are the practical extremes with good alignments. You can buy more fender room with camber or rolling or pulling. In front, you can buy more room with shorter overall tire diameter (<25") The closer you get to these limits, the more likely you will need to stretch a tire to fit the fender side. Drop does not determine what size wheels fit. Put too aggressive a wheel, and one day, you WILL bend your fender when you take the wrong turn with a good bump if you exceed these limits.

Measuring in mm from the face of the hub:
Front fender limit: +65mm
Comments:
| +65 | Stretch tire and/or roll fender. Need fender liner mod. Do not exceed tire diameter of 25"
| +55 | Fender liner mod if going for a wide or tall tire. Do no exceed tire diameter of 25.2"
Front inner suspension upright limit: -155mm
Comments:
Need spacer if this number is exceeded. If close, do not use lip weights on wheels

Rear fender limit: +68mm
Rear fender limit w/ shaved lip: +75
Comments:
Need to stretch tire to a certain degree if very close to these numbers
Rear inner suspension coil lmit: -183mm
Comments:
Several factors matter as you approach this limit. You may need to limit the amount of suspension travel. You may need to stretch tire. And you cannot run as aggressive camber. I've been able to actually scrub tire well before this limit (@ -175mm) with track cornering loads on the spring and inner forward tub.

Equations to figure out wheel lip placement relative to limits:

Outer lip: (Wheel Width * 25.4) / 2 - Wheel Offset
Inner lip: (Wheel Width * 25.4) / 2 + Wheel Offset
Note: Inner lip is related to backspacing but backspacing takes into consideration the wheel lip thickness, which is usually another 1/2" or 12.7mm.

Examples:
Front wheel size: 8.5" +45
Fender: 8.5 * 25.4 / 2 - 45 = 62.95 (< 65 - OK)
Suspension: 8.5 * 25.4 / 2 + 45 = 152.95 ( < 155 - OK)
Rear wheel size: 9.5" +55
Fender: 9.5 * 25.4 / 2 - 55 = 65.175 (< 68 - OK)
Suspension: 9.5 * 25.4 / 2 + 55 = 175.65 (< 190 - OK)

 

[Powerdrift]

It looks like I may need to do some modifications for this, so if I do, what would it be?

Work Emotion XD9 Bronze

17x8.5 +42 215/45/17
17x9.5 +44 225/40/17

(the tires can be changed if a different size would be better)

 

[white_is]

It looks like I may need to do some modifications for this, so if I do, what would it be?

Work Emotion XD9 Bronze

17x8.5 +42 215/45/17
17x9.5 +44 225/40/17

(the tires can be changed if a different size would be better)

8.5 * 25.4 / 2 - 42 = 65.95
8.5 * 25.4 / 2 + 42 = 149.96

You'll need to roll the fenders and probably reshape the fender liners. Use and heat gun and a wet rag to push the liner out of the way and hold it while the liner cools and hardens into place.

9.5 * 25.4 / 2 - 44 = 76.65
9.5 * 25.4 / 2 + 44 = 164.65

Should be fine with just a roll. You'll need to probably trim the bumper tabs a little but your tire size will help with that.

As long as you can roll or can get your fenders rolled you'll be fine.

 

[VLXIS300]

The above info's a little confusing for me, but here's the set up I want, something not too aggressive since I plan to track and drive hard around corner will this set up do it all?

SSR Type-F
18x8.5 30 rear
18x8.5 48 front

 

[Rabbit-is300]

Ok, so here is what i came up with.

18x8.5 +38 front
18x10 +32 rear

So I calculated.
8.5*25.4/2 - 38 = 69.95 which is great than 65mm. FAIL! lol so i'll need a roll and fender mod and I'll be good.

Rears calculated
10*25.4/2 - 32 = 95 which is much greater than 75. Which means I'll need a fairly agressive pull of 20mm. Just under one inch. Am I correct on that? I'll more than likely have to mod the bumper tabs as well. Now this is assuming stock camber correct?

 

[twestman]

Ok, so here is what i came up with.

18x8.5 +38 front
18x10 +32 rear

So I calculated.
8.5*25.4/2 - 38 = 69.95 which is great than 65mm. FAIL! lol so i'll need a roll and fender mod and I'll be good.

Rears calculated
10*25.4/2 - 32 = 95 which is much greater than 75. Which means I'll need a fairly agressive pull of 20mm. Just under one inch. Am I correct on that? I'll more than likely have to mod the bumper tabs as well. Now this is assuming stock camber correct?

The aggressiveness of the rear versus the non-aggressiveness of the front will make it look like a funny car. Just FYI. The front will fit just fine if you are lowered any amount, because the negative camber will give you extra clearance. I'd run a 225/40r18 up front and a 245/35r18 out back. Depending on how low you are, you can pull your fenders about 10mm and run -3* of camber, and get away with running a 245. I've done it rub-free for about 9 months now.

 

[Rabbit-is300]

The aggressiveness of the rear versus the non-aggressiveness of the front will make it look like a funny car. Just FYI. The front will fit just fine if you are lowered any amount, because the negative camber will give you extra clearance. I'd run a 225/40r18 up front and a 245/35r18 out back. Depending on how low you are, you can pull your fenders about 10mm and run -3* of camber, and get away with running a 245. I've done it rub-free for about 9 months now.

I had the offsets backwards. The front is +32 rear is +38. I know what you mean about the aggressiveness of the front. I'm getting them used and getting a damn good deal. Thats why I'm doing it that way. They come with 5mm and 10mm spacers as well. So I'll probably run spacers up front to help make them flush. The front tires are 225/40/18 so I'm good there. The rear is 255/40/18. I really don't want to change the tires though. I kind of want an aggressive wheel with a little meat and a decent ride without having to run a 35series tire. I'll have to do some work to get them fitting good but its ok. I"m just curious how much work i'll have to do. I almost wish I went with a more aggressive offset. Somewhere in the low 20's.

As for being lowered. I'm stock - tucked. Depends on how much I want to go lol i'll be on K-Sport air suspension setup. I'm in Iraq right now I already have the kit its just waiting on me to get home to install it.

 

[twestman]

I had the offsets backwards. The front is +32 rear is +38. I know what you mean about the aggressiveness of the front. I'm getting them used and getting a damn good deal. Thats why I'm doing it that way. They come with 5mm and 10mm spacers as well. So I'll probably run spacers up front to help make them flush. The front tires are 225/40/18 so I'm good there. The rear is 255/40/18. I really don't want to change the tires though. I kind of want an aggressive wheel with a little meat and a decent ride without having to run a 35series tire. I'll have to do some work to get them fitting good but its ok. I"m just curious how much work i'll have to do. I almost wish I went with a more aggressive offset. Somewhere in the low 20's.

As for being lowered. I'm stock - tucked. Depends on how much I want to go lol i'll be on K-Sport air suspension setup. I'm in Iraq right now I already have the kit its just waiting on me to get home to install it.

Oh, well you'll be fine as far as tire size in the front. The rear.... is an inch and a half taller than stock... Which is seriously HUGE on an IS300. Not sure you will realize this until you've done it. You will run into serious clearance problems when you lower your car. You'd have to drive around at stock height all day. Air will temporarily solve that issue but I'd go with a 245/35 just for clearance sake and trust me (been running 245/35 on shitty roads for over a year now)... You won't even notice a 35 series sidewall on a 245 tire. It's nearly the same size sidewall as a 225/40. If you went low-20's for offsets, you'd need more stretch and much smaller tires.

 

[Rabbit-is300]

Hmmm, thanks for the help. I'll have to look into that.

 

[BangurangRufio 808]

need help, how to make this work

Volk GT-C
19x9.5 +33
19x10.5 +34

and what size tires do I run?

stock-tein drop springs, thank you for your help much mahalos

RUFIO

 

[Rabbit-is300]

For the front you're looking at 83.2mm. Thats much greater than the 65mm they're talking about. So you're looking at a little bit of work to get them to fit. The rear is 94mm. Again way over the limit they talk about. A flat roll and a pull is going to be needed. The tires, I would suggest 225/35/19 up front and probably a 245/35/19 in the rear.

I am just learning this so let an expert help you, but I'm learning so I wanted to give it a shot. I know I have 19's now before I put the vs-xx's on and thats the tire size I run with no issues. Of course you're running a more aggressive size. The rear you can probably roll/pull 10mm and a lil bit of camber.

Again, just learning so please correct me if I'm wrong.

 

[twestman]

need help, how to make this work

Volk GT-C
19x9.5 +33
19x10.5 +34

and what size tires do I run?

stock-tein drop springs, thank you for your help much mahalos

RUFIO

You're not going to want to run that setup with springs.... No sir.

 

[BangurangRufio 808]

You're not going to want to run that setup with springs.... No sir.

will the suspension be too soft and the tire/rim would grab?

 

[iculkn]

With a 1.5 drop will these fit with no problem?

Wheels F - 19x8.5 38 offset R- 19X9.5 40 offset
Tires: F-225 R-245

or will 19x8.5 38 offset work better all around?

 

[twestman]

will the suspension be too soft and the tire/rim would grab?

It's not how soft it is, but more of how you cannot adjust your ride height and camber to fit it. Just so you know, it would be considered a pretty aggressive wheel setup.

I've got some new wheels on order in 18x9.5+27 and 18x10.5+30. My tire sizes are 215/35 and 225/40. I also plan on possibly spacing them out to an 18x9.5+22 and 18x10.5+25. We'll see. My rear camber is maxed out in the negative at -5.5* (if that helps).

 

[twestman]

With a 1.5 drop will these fit with no problem?

Wheels F - 19x8.5 38 offset R- 19X9.5 40 offset
Tires: F-225 R-245

or will 19x8.5 38 offset work better all around?

Yup the staggered setup will work perfectly.

 

[LEXziLLa]

Offset Guru's... Plz help a Wheel noob!

ok b4 i start this... yes i searched the stickies.. but i just dont get this offset thing...

i got a set of rims 18" X 8" with 35 offset front and back... i want a Flush setup with a bit of aggressiveness.... im not lowered.. But i plan on dropping the car within the next 30 days... please help me out on what tire size i should use in the front and back...( + spacers if needed).. thanks in advance!

 

[twestman]

ok b4 i start this... yes i searched the stickies.. but i just dont get this offset thing...

i got a set of rims 18" X 8" with 35 offset front and back... i want a Flush setup with a bit of aggressiveness.... im not lowered.. But i plan on dropping the car within the next 30 days... please help me out on what tire size i should use in the front and back...( + spacers if needed).. thanks in advance!

I have an aggressive setup for you (but it will only look good lowered a lot and with coilovers).

Front: 18x8+35 ->
-Run a 20mm spacer (bolt-on type)
-205/40r18 tires (try to find and use narrower tires for gained clearance and more stretch. IE Nankang NS-II)
-Roll fenders flat, mold and push liners up
-Run -2* of camber

Rear: 18x8+35 ->
-Run a 30mm-35mm spacer (bolt-on type)
-205/40r18 (run narrow)
-Roll fenders flat, flare 10mm, trim bumper tab
-Run -3* of camber

You can still rotate tires. Boom. Done.

 

[redlex15]

Blitz Technospeed Z1

19x8.5 +41 225/35/19 Advan Neova AD08
Fender = 66.95 <65 not OK
suspension = 148.95 <155 OK

19x9.5 +45 ? Advan Neova AD08
Fender = 75.65 >68 not OK
suspension = 165.65 <190 OK

I'm using the 225 from my previous wheels so the front tire is set. I know that 225 on an 8.5 is barely a stretch if any at all.

What size for the rear should I use to match the appearance of the front?
245/35/19, nice because I THINK it would match how the front looks

or 255/30/19, nice because its wider yet the OD is closer to that of 225, but not sure if it will fit with the amount of fender work i'm limited to doing.



Fenders will be rolled but can't be pulled due to the cosmetic only Rspec fender flares.

Lowered on Tein Comfort Sport Coilovers.

 

[twestman]

They'll fit just fine. Roll your fenders flat, and run 255's to keep the OD the same. Otherwise it might look goofy with a thinner tire on the back.