Today I test fit my new rims. I was aware that I would need to take some material off of the hub for clearance issues in the rear.

The wheels are c6's. 18x10.5 rear w/ 54mm offset; 17x9.5 front w/ 56mm offset. My car is lowered 1.75 inches all around w/ k sport springs.

I'm definatly going to need a set of spacers for the rear.

My question is that the inner lip of the rim is sitting fairly close to the front spindle. I'm talking this is about .5 inches from the spindle. How close is TOO close? It appears nobody on here had any issues with this but feedback is appreciated. IMO I think I may need a small spacer for the front depending on how these tires fit up.

I don't yet have my tires but they should arrive tomorrow.
BFG G-force TA KDW NT fronts 255/40/17
BFG G force TA Drags rear 275/35/18

Do you think I'll be ok or am I in for a world of pain?

 

anybody?

 

Nice set up. The rims will fill those tire widths well (the 275's won't be wrinkling at all though with a 10.5" wide rim, not that it matters with a drag radial though).

I assume this is the upper arm of the spindle? (between the abs sensor / hub and the upper A arm; near the wheel's inboard edge at the TOP of the wheel's inner diameter).

If so don't sweat it... that distance doesn't change with suspension changes. Lowered or not, full droop or normal ride height, if it fits, it fits. Sorta of like calipers inside a wheel... 1/2" is plenty since they don't move relative to eachother.

BTW, 17x11 fit upfront with 36mm backspacing (that's how most guys run 17x11's up front... with 36mm offsets and no spacer, or 56mm offsets with spacers). Remember though, that's on 11" rims. With 9.5" wide rims you have 0.75" less rim PER SIDE... which is 19mm closer to the spindle.

If you have 17x9.5" rims with 56mm offsets (20mm closer than 36mm offset)... you're 1mm closer to the spindle than guys running 17x11's with 36mm offset. Meaning? You'll be fine.

 

Why's that? They should fit fine the way they are if you're willing to "massage" the inner wheel well a touch.

The issue here is the same one guys with 17x11" rims run into when using 315 tires (although to a lesser extent). Do you go with ~54mm offset and tuck them in deep and "massage" the inner fender well? Or do you run say a 1/2" spacer to split the difference? Or do you go with a 36mm offset (stock ZR1 size) and roll the wheel well lip a touch?

Depends on the width of the stance you want (varries ~1") and what you want to do to the car.

With 275's on a 10.5" rim I'm a bit suprised you need any spacer though... maybe just a touch of the BFH and you'll be fine. Did you actually mock it up to check if it hits anywhere? (check at full compression, not just ride height or full droop... you'll probably want to pull the spring and jack the rear up to see what travel you have... and were it eveually hits ).

 

i just threw on my c6 rims on my 97 z, and they were 17x9.5 wrapped in 275/40/17 and fit absolutely perfect, no mods of any kind were called for.

 

That is GREAT news for the front. Yes, that is the upper arm of the spindle. I will have my tires mounted tomorrow and i"m just waiting on my rear spacers then I'll be in business.

With the DR's mounted on the rear, I presume that the tire will be resting on the LCA's preventing any rotation. I COULD notch them, but that's risky business. I'd imagine with the spacer, it should sit pretty. The fronts were what was scaring me.

Oh yes, there will be pics. It's been raining all day here in Detroit. Hopefully she'll be on the road come friday. This car is LOW. I stand about 6'2 and the roof is level with my waist.

 

That rear wheel calculates out to a 7.84" backspace. There is no reason for the tire to be anywhere near the LCA. I run the 17x11.0" 50mm wheels, with a 7.93" backspace, and 315/35-17 tires (BFG Drag Radials) and the only place that is close to rubbing is the inner fender, not the LCA.

 

I could be wrong cuz I'm no expert, but i'm confident that metal piece is the LCA that the inner lip of the rim is resting on. Regardless, a spacer will take care of the issue out back.

 

If the LCA is an issue (your LCA mounting point could be welded closer to the wheel hub I suppose), you can also take care of it with a rod-ended LCA.

The aluminum-bar shaft will be narrower than the large stamped stock LCA's, and the rod end eyelet can be mounted almost flush to the inner side of the bracket, and a spacer on the otherside of the eye (basicly you buy or make aftermarket LCA's and instead of mounting it "centered" in the bracket, use offset spacers to bring it inboard about an inch)... that gives you at LEAST an inch more clearance between the backside of the tire and the outter edge of the LCA.

I know it sounds like more effort than it's worth, but the LCA change can reduce the weight of the rear a few pounds, make your alignment a bit more adjustable, and give you better "articulation" (more control without binding at extreme angles). The main benefit though would be not needing a spacer (and possibily longer lugs). Hub-centric spacers, or at the least a lug-centric spacer isn't all that cheap and just adds more weight... a cheap slotted spacer will make everything clearance ok, but if I've heard mixed reviews of such set-ups due to vibrations at high speeds. The lighter the spacer, the less likely that will happen though. Spacers aren't horrible, but going without and lightening the drivetrain a touch is a way better option IMO.

If you have plans on an LCA change, spacers probably won't be nessesary. Though to be honest, I'm still surprised your rims are backing in that far. Wierd.

 

i agree it seems strange.

however, my tires are in and these G force KDW's are SWEET. The front mounted up with no problem. Some minor rubbing during full turn, but i'll live with it. With any luck and weather permitting, it'll all be done tomorrow. I'll follow up with pix

 

Even without spacers, the LCA should be well inboard of the tire. Something doesn't sound right there.
The only area you should have issues with in the rear is the bump stops.
With 17 x 11s at 7.75 BS I had to grind almost half of the stop away or the wheel would hang up on it when the car was raised.
No one mentioned it yet, but you may also need an adjustable panhard bar to center the axle so you do not rub the wheelwell with the front inside edge of the tire.

 

So far, my findings are 100% ok with the front tires. Minor rubbing, but not a problem.

the rear, however, is another story. as the sticky writeup states.. 1.25 spacers do the trick. they do, but they are also excessive. because I have been unable to locate a decent set of .75 spacers.. i ordered 1 inch spacers.

I was driving in some heavy traffic the other day and seen a crater in the road coming my way.. i did what i could to avoid the hole but my rear right tire caught it and my inner fender cut a nice chunk out of my brand new DR

I may have to take some material off the inner fender. I'm hoping between that and this reduced spacer, it won't happen again. Honestly, I won't buy another tire until I'm certain that I have this licked.