Wheel/Tyre Upgrade

[nismovzr2003]

Hey guys,

Currently running V7 STI 5x100 17x7.5 rims with 225 45 R17's on my 98 Coupe in order to clear the brembos. I've been investigating replacement options, in particular going to a 8.5" or 9" rim in order to run a 245 tyre.

At present, with my current camber setup I've got approximately 15-20mm clearance in the front between the strut and the inside of the tyre, rears approximately 10-15mm clearance.

Is there a minimum clearance you must maintain in order to not have any contact between the strut and inside tyre wall?

At the moment I've roughly worked out that I'll need to run something around a +30 offset in a 8.5" rim, or 22-25 offset for a 9" rim. Does this sound about right?

I understand that fender flares are most likely required, or depending on the right offset with probably a 8.5" rim you might be able to get away with some fender work only without the need for flares.

If anyone has had previous experience with running larger rim/tyre combinations and what was involved, any help and/or advise would be greatly appreciated.

Cheers

[GC8E2DD]

How much camber are you running currently? I remember having the exact same combo (V7/225-45) on my coupe at a street sprint once and the rears kept smashing into the guards in potholes. It was scary! You might be up for a wide body graft. NotAWhiteGTB had a hook-up for the S5/6 WRC guards locally if you wanted to go crazy.

[nismovzr2003]

 GC8E2DD said:

How much camber are you running currently? I remember having the exact same combo (V7/225-45) on my coupe at a street sprint once and the rears kept smashing into the guards in potholes. It was scary! You might be up for a wide body graft. NotAWhiteGTB had a hook-up for the S5/6 WRC guards locally if you wanted to go crazy.

I'm running -2 front, and -1 rear.

[Tony]

For what it's worth, I was running 17x8.5 +48 with 240 slicks on my car. Had to run a 3mm slip-on spacer in the rear to clear the strut (well it did clear without the spacer, but only just, like 2mm!, so chucked the spacer on for a little more room).

My rear guards were pumped out as much as possible before they started looking like sh*t (all folded and wavy etc) and I ended up with no contact with the guards - although I was running far more than road car camber (-3 in the rear), so with less camber it may be a bit harder to get the clearance you need with standard guards. Fronts are easy enough to pull out, and I ground the inner lip off to make some extra room - plus running -4.5 camber helps (again, prob not ideal for a road car though).

I am now running 18x9 +20 (again with 240 slicks) and they sit out of the guards a whole lot more so have got bolt on flares to get around that problem (along with a bit of cutting & welding in the rear to get the required clearance).

[Guest]

 Tony said:

For what it's worth, I was running 17x8.5 +48 with 240 slicks on my car. Had to run a 3mm slip-on spacer in the rear to clear the strut (well it did clear without the spacer, but only just, like 2mm!, so chucked the spacer on for a little more room).

My rear guards were pumped out as much as possible before they started looking like sh*t (all folded and wavy etc) and I ended up with no contact with the guards - although I was running far more than road car camber (-3 in the rear), so with less camber it may be a bit harder to get the clearance you need with standard guards. Fronts are easy enough to pull out, and I ground the inner lip off to make some extra room - plus running -4.5 camber helps (again, prob not ideal for a road car though).

I am now running 18x9 +20 (again with 240 slicks) and they sit out of the guards a whole lot more so have got bolt on flares to get around that problem (along with a bit of cutting & welding in the rear to get the required clearance).

Far less pornographic without pics huh.

[Tony]

 evowrx said:

Far less pornographic without pics huh.

haha, yeah no pics as its not quite finished yet, plus only just finished fixing crash damage. Cars still on stands and I cant put it on the ground since I don't even have a full set of tyres fitted to the rims at this stage (only have one I borrowed to set the car up with, check clearance etc). Soon hopefully...

[nismovzr2003]

 Tony said:

For what it's worth, I was running 17x8.5 +48 with 240 slicks on my car. Had to run a 3mm slip-on spacer in the rear to clear the strut (well it did clear without the spacer, but only just, like 2mm!, so chucked the spacer on for a little more room).

My rear guards were pumped out as much as possible before they started looking like sh*t (all folded and wavy etc) and I ended up with no contact with the guards - although I was running far more than road car camber (-3 in the rear), so with less camber it may be a bit harder to get the clearance you need with standard guards. Fronts are easy enough to pull out, and I ground the inner lip off to make some extra room - plus running -4.5 camber helps (again, prob not ideal for a road car though).

I am now running 18x9 +20 (again with 240 slicks) and they sit out of the guards a whole lot more so have got bolt on flares to get around that problem (along with a bit of cutting & welding in the rear to get the required clearance).

Cheers Tony.

Going back to my current situation, with my 5x100 17x7.5 running 225 45 r17 tyres, ive got approximately 15-20mm in the front and 10-15mm in the rear in relation to strut inner tyre clearance.

I roughly worked out that i'd need to run a +35 or +30 offset in a 17x8.5 or 18.8.5 to maintain the inner clearance especially with running a 245 tyre, does this sound right?

You mentioned your rims were a +48 offset and still had clearance? Im now wondering if ive worked things out incorrectly?

Any help would be awesome.

Cheers

[Guest]

I use this:

http://www.willtheyfit.com/

[nismovzr2003]

 evowrx said:

I use this:

http://www.willtheyfit.com/

Yeah thats what i used.

Going to a 18x8.5 with a +35 offset, this will move 5.3mm further away from the strut, with my current clearances and going to a 245 tyre i should be able to maintain enough clearance between the strut and the inside of the tyre.

Does this sound about right?

[GC8E2DD]

Just keep in mind they need to fit over the dynamic range of the strut too. If they hit the inside of the guard on compression it is dangerous.

[Tony]

 nismovzr2003 said:

Cheers Tony.

Going back to my current situation, with my 5x100 17x7.5 running 225 45 r17 tyres, ive got approximately 15-20mm in the front and 10-15mm in the rear in relation to strut inner tyre clearance.

I roughly worked out that i'd need to run a +35 or +30 offset in a 17x8.5 or 18.8.5 to maintain the inner clearance especially with running a 245 tyre, does this sound right?

You mentioned your rims were a +48 offset and still had clearance? Im now wondering if ive worked things out incorrectly?

Any help would be awesome.

Cheers

Nah, you would have worked it out correctly. The higher the offset, the more the wheels will sit in-board, hence my +48 at 8.5 wide having minimal clearance to the strut (on the rear), so that's why I used the 3mm spacer. Higher offset also means less wheel/tyre sitting out from the guards so easier to make them fit before having to use flares/widebody etc. Anything over 8.5" wide on a GC8 is going to have to be lower offset (generally in the 30s) otherwise you do run into the inner clearance issues. So yeah, if your new wheels offset is +35, then you will fine for inner clearance, and just have to worry about outer clearance.

[nismovzr2003]

 Tony said:

Nah, you would have worked it out correctly. The higher the offset, the more the wheels will sit in-board, hence my +48 at 8.5 wide having minimal clearance to the strut (on the rear), so that's why I used the 3mm spacer. Higher offset also means less wheel/tyre sitting out from the guards so easier to make them fit before having to use flares/widebody etc. Anything over 8.5" wide on a GC8 is going to have to be lower offset (generally in the 30s) otherwise you do run into the inner clearance issues. So yeah, if your new wheels offset is +35, then you will fine for inner clearance, and just have to worry about outer clearance.

Cheers for all the help Tony, much appreciated!