315/30/18 OR 315/35/18 - Advice Needed

[MaxxdOut]

Setting a new wheel tire package for my O4 vert and I could use some assistance.

Problem Statement:
- I'm having a difficult time deciding on sidewall height.

Option 1: 315/30/18
- this option will bring me slightly shorter in total tire height than stock. Stock = 25.7 in (total tire height) VS ~25.4

Option 2: 315/35/18
- this option will bring me ~1 in taller than stock. Stock = 25.7 VS 26.7

Background Details and Assumptions:
- Convertible
- Currently on factory wheels and tires
- New rear wheels will be 18x10.5. Offset = 22
- Rear tires will be R888R's
- The car will be lowered. However, I have not determined what springs I will put on it. I plan to retain my factory struts/shocks. Perhaps down the road I may go coilovers, but I'll cross that bridge later.
- Expect I will need to shave or replace my IRS bolts
- Car use - Street car, weekend cruiser. I do drive it hard very hard and like a stiff and compliant drive.
- Fenders are factory un-rolled.

Open Questions:
1) with the 315's, I presume I will need to roll the fender. I was considering using the Eastwood Fender Roller. Any recommendations pro or against this approach?

2) I am torn between the 30 and 35 sidewall tires. Any recommendations on commonly used tires? I am seeing both from the posts that I read.

3) I haven't determined my lowering approach as of yet. Any recommendations in this area are greatly appreciated. I realize this has a contributing factor towards tire selection and avoiding rubbing. I like a low, stiff, yet streetable car.

4) With lowering considerations in mind, should I plan to purchase anything else to correct my geometry? E.g., Camber/Caster plates, etc.

5) with my offset of 22. Will I need spacers for clearance? If so suggestions on size to avoid rubbing with 315's?

Guidance, and pictures of your setup are greatly appreciated!

Thanks in advance!

 

[LS WUT]

So I’ve ran to many sets ups on all of my cars. However are you running 315’s because you think they’ll grip more? Is it more for the look of how big they’re? What’s your power level? As for springs, I’ve had great results with H&R springs. I’ve personally never owned a VERT, so I’m not sure how much help I can provide there. I’ve run 255/55/15. I’m currently running 305/35/18 Mickey Thompson drags on my white car. They fit nixe and snug and I didn’t have to cut the IRS bolt, or even run a lower profile bolt. I did run 315/35/17 on some cobra R replicas.

 

[LS WUT]

 

[MaxxdOut]

So I’ve ran to many sets ups on all of my cars. However are you running 315’s because you think they’ll grip more? Is it more for the look of how big they’re? What’s your power level? As for springs, I’ve had great results with H&R springs. I’ve personally never owned a VERT, so I’m not sure how much help I can provide there. I’ve run 255/55/15. I’m currently running 305/35/18 Mickey Thompson drags on my white car. They fit nixe and snug and I didn’t have to cut the IRS bolt, or even run a lower profile bolt. I did run 315/35/17 on some cobra R replicas.

Regarding the 315 section width. Its all looks TBH. I could be persuaded to go 305 is the 315's create too much of a problem.

Concerning H&R's - they seem to be the common approach. Did you the Sport Springs?

 

[LS WUT]

Regarding the 315 section width. Its all looks TBH. I could be persuaded to go 305 is the 315's create too much of a problem.

Concerning H&R's - they seem to be the common approach. Did you the Sport Springs?

315’s is generally about looks, as is 335 in my personal opinion. I’m not knocking it. I love the look. That’s why I asked purpose. Yes, H&R race springs are awesome. They’re pricey, but they’re worth it. I’ve got eibach sportline for my GT500, and my
Black coupe I haven’t Installed yet because I wanted to try them out. I’d say if you had 315’s and spacers to prevent cutting the knuckle they would Stick out a bit and might look strange.

 

[MaxxdOut]

315’s is generally about looks, as is 335 in my personal opinion. I’m not knocking it. I love the look. That’s why I asked purpose. Yes, H&R race springs are awesome. They’re pricey, but they’re worth it. I’ve got eibach sportline for my GT500, and my
Black coupe I haven’t Installed yet because I wanted to try them out. I’d say if you had 315’s and spacers to prevent cutting the knuckle they would Stick out a bit and might look strange.

Yeah its 100% looks. I have always loved a big booty Terminator.

Can you elaborate on your statement regarding cutting the knuckle? It is my understanding the only things I will need to be mindful of are 1) IRS bolt. I plan to pick up a low profile one. 2) The possibility I will need to roll the fenders some, and 3) I know some people have had rubbing issues somewhere else near the rear bumper (location and resolution I am not clear on - Hence my concern with the 315/35's vs the 315,30's).

 

[TerminatoRS]

Shitty pics, but maybe they’ll help…
H&R race springs with isolators installed
Chrome wheels are 315/35/18 TQ
Black are 305/35/18 Nitto 555RII

 

[TerminatoRS]

Can you elaborate on your statement regarding cutting the knuckle? It is my understanding the only things I will need to be mindful of are 1) IRS bolt. I plan to pick up a low profile one. 2) The possibility I will need to roll the fenders some, and 3) I know some people have had rubbing issues somewhere else near the rear bumper (location and resolution I am not clear on - Hence my concern with the 315/35's vs the 315,30's).

1 - Yes, get low pro bolts.
2 - I doubt you'll need to roll the fenders unless you go low low. My fenders aren't rolled and I've never had any indications of even coming close to rubbing on them. It seems the folks who roll are dropped low or running 335s with spacers or both.
3 - Some folks have issues rubbing on the rear inside lower edge of the fender well.

The bottom line is that not all IRSs are created equally in that they're not necessarily centered under the ass end of the car. Some rub, some don't (mine doesn't with 315s). Some rub on one side, but not the other. Doesn't seem to be a one size fits all scenario unfortunately.

 

[MaxxdOut]

Shitty pics, but maybe they’ll help…
H&R race springs with isolators installed
Chrome wheels are 315/35/18 TQ
Black are 305/35/18 Nitto 555RII

Thank you!

Both of those pictures are with 315/35's?

Did you roll your fenders and install shaved IRS bolts?

Any other rubbing issues or modifications needed to make it work?

 

[MaxxdOut]

1 - Yes, get low pro bolts.
2 - I doubt you'll need to roll the fenders unless you go low low. My fenders aren't rolled and I've never had any indications of even coming close to rubbing on them. It seems the folks who roll are dropped low or running 335s with spacers or both.
3 - Some folks have issues rubbing on the rear inside lower edge of the fender well.

The bottom line is that not all IRSs are created equally in that they're not necessarily centered under the ass end of the car. Some rub, some don't (mine doesn't with 315s). Some rub on one side, but not the other. Doesn't seem to be a one size fits all scenario unfortunately.

Thanks for sharing your experience. From everything I'm reading I'm hearing the same. I would love to avoid rolling if I can, but I'll do it if I have to.

What are people doing if they are rubbing on the rear inside lower edge of the fender well?

 

[TerminatoRS]

Both of those pictures are with 315/35's?

Did you roll your fenders and install shaved IRS bolts?

Any other rubbing issues or modifications needed to make it work?

One is a 315 and one is a 305.
Just low pro bolts.
No sir!

What are people doing if they are rubbing on the rear inside lower edge of the fender well?

I believe they're just buzzing the spot down with a wheel or Dremel tool.

 

[MaxxdOut]

One is a 315 and one is a 305.
Just low pro bolts.
No sir!

I believe they're just buzzing the spot down with a wheel or Dremel tool.

Sorry - I misread your post. You clearly said which wheel / tire setup.

Thanks for your help!

 

[MaxxdOut]

Shitty pics, but maybe they’ll help…
H&R race springs with isolators installed
Chrome wheels are 315/35/18 TQ
Black are 305/35/18 Nitto 555RII

Are you running 275/35/18's OR 275/40/18's in the rear.

If you have 275/35/18's I'm guessing you have a slight rake (~1 inch taller) in the rear.

 

[TerminatoRS]

Are you running 275/35/18's OR 275/40/18's in the rear.

If you have 275/35/18's I'm guessing you have a slight rake (~1 inch taller) in the rear.

You mean in the front? 275/35/18
Let me see if I have any pics.

 

[TerminatoRS]

275/35 and 315/35

 

[MaxxdOut]

275/35 and 315/35

Looks killer! Are those AFS’s?


Sent from my iPhone using the svtperformance.com mobile app

 

[LS WUT]

1 - Yes, get low pro bolts.
2 - I doubt you'll need to roll the fenders unless you go low low. My fenders aren't rolled and I've never had any indications of even coming close to rubbing on them. It seems the folks who roll are dropped low or running 335s with spacers or both.
3 - Some folks have issues rubbing on the rear inside lower edge of the fender well.

The bottom line is that not all IRSs are created equally in that they're not necessarily centered under the ass end of the car. Some rub, some don't (mine doesn't with 315s). Some rub on one side, but not the other. Doesn't seem to be a one size fits all scenario unfortunately.

This right here, sorry got caught up with work.

 

[01yellercobra]

Friend of mine is running CCW 18x11's with 315/30/18 Falkens. He had to have his fenders rolled for just a smidge more clearance.

As mentioned, every car is different. The IRS in my 01 was centered. In my 04 it's roughly a quarter inch to the passenger side. I run a spacer on the driver side to give the tire more clearance equal to what the passenger side has.

You're going to have to mount your set up on the car and go from there.

 

[TerminatoRS]

Looks killer! Are those AFS’s?

Yes sir! Had them for probably 10 years now.

 

[Santiago]

I would recommend 35s That’s a 315/30/18 and most times I wish I had 35s