The SERIOUS Wheel & Tire Thread

Real tech discussion on design, fabrication, testing, development of custom or adapted parts for Pontiac Fieros. Not questions about the power a CAI will give.

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Atilla the Fun
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Re: The SERIOUS Wheel & Tire Thread

Post by Atilla the Fun »

I've made no secret that for me, cheap performance over-rides all other concerns, including looks.
I would not even use the center caps.
If WCF is correct that a 17x9 +45 barely fits the rear, then a 17x10 +46 would be 13.7 mm into the strut. Or really, 13.7 mm from going on.
So the +23.8 is the 10" to try. It'll be out past the bodywork a bit, requiring mild flaring.
I'm thinking 275/40s on the rear, and 225/45s up front on 8s, probably MB "Weapon"s.
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Re: The SERIOUS Wheel & Tire Thread

Post by The Dark Side of Will »

Atilla the Fun wrote:If WCF is correct that a 17x9 +45 barely fits the rear, then a 17x10 +46 would be 13.7 mm into the strut. Or really, 13.7 mm from going on.
So the +23.8 is the 10" to try. It'll be out past the bodywork a bit, requiring mild flaring.
If the -46 doesn't fit, it can be spaced out until it's a perfect fit. If the -23.8 has clearance to spare, it ca *not* be spaced *in*.
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Re: The SERIOUS Wheel & Tire Thread

Post by Atilla the Fun »

I'm in Utah. It's outright blatantly illegal in Utah to have wheel spacers of any kind. So 8.5 mm out is the lesser of 2 evils. Especially since it'll improve stability. Especially since it'll take flares your way also, just my flares will look 8.5 mm more macho.
Far cheaper than making cast spacers, then welding those to the wheels, then putting the wheels on a lathe to turn down the welds, making them invisible and theoretically helping the balance.
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Re: The SERIOUS Wheel & Tire Thread

Post by The Dark Side of Will »

I was referring to spacing for testing. The whole point of this thread (I thought...) was to figure out what's actually the most that can be run.
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Re: The SERIOUS Wheel & Tire Thread

Post by Atilla the Fun »

So if I read this right, we're gonna test WCF's claims about fitment?
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Series8217
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Re: The SERIOUS Wheel & Tire Thread

Post by Series8217 »

I've run 17x8.5+50mm on the rear of an '88 Fiero with with adjustable coilover sleeves (removed the factory spring perch) and 12" Corvette rotors. I mention the rotors because I'm not sure if the hat thickness is the same as stock rotors and could affect spacing. I had to grind the upright and the strut mounting ears to get the wheels to fit without rubbing. If they were 18's I think it would be OK without grinding since it would clear the strut mounting ears. The shape of the inside wheel lip would also affect fitment since that is what interfered. It could be slightly different between wheels.

Based on this, I'm pretty sure WCF's specs are accurate since the inside edge of my rims were within a few mm of the 17x9-45mm that WCF tested. Keep in mind the fitment could vary quite a bit between wheels depending on the actual lip profile since the lip is the part of the wheel that interferes.

I think the 17x9-45mm may be what Chris West is currently running on his car. They are TSW wheels; I don't remember which style but he's had them for awhile.
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Re: The SERIOUS Wheel & Tire Thread

Post by Atilla the Fun »

What / where do I search for pics of his stuff?
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Re: The SERIOUS Wheel & Tire Thread

Post by The Dark Side of Will »

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Re: The SERIOUS Wheel & Tire Thread

Post by The Dark Side of Will »

http://www.rimsntires.com/specs.jsp

*Very* swift wheel/tire calculator, with graphical displays to compare two different wheel/tire combos from a fitment perspective.
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Re: The SERIOUS Wheel & Tire Thread

Post by Series8217 »

Atilla the Fun wrote:What / where do I search for pics of his stuff?
Chris West owns West Coast Fiero. There are probably some pics on the web site.

Here's one from before he finished the decklid:
Image
It's an 86 SE if I remember correctly.

I don't know where to find recent pics but I'll try to take some more next time I go to WCF.
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Re: The SERIOUS Wheel & Tire Thread

Post by Series8217 »

I really want to fit 285s on the back end of my Fiero, but it just doesn't look like an 18x9.5 wheel is going to fit without some flares in the rear, and that's more work than I want to do right now.

My current plan is some Motegi MR116s in 17x7 and 18x9 with some Hankook RS3s in 275/35/18 and 215/45/17. If I could take some more damn weight off the rear I could put 225s up front. I haven't scaled my red car, but my silver car was at 42.4/57.6 with me in it. My red car has lighter seats, flywheel and intake manifold, but it also has a full interior, lighter battery, heavier exhaust, radio, speakers, etc. I can't imagine the weight distribution is any better.

215/45/17 front with 275/35/18 rear results in a tire width distribution of 43.9/56.1, but with the fronts being a smaller diameter (24.6 vs 25.6) that should reduce the contact patch size a bit to make it perform more like a 205. At least that's what I'm hoping. Otherwise I'm going to need a gutted decklid (maybe!) or a lighter motor (not likely).
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Motegi MR116 for 215/45/17 and 275/35/18
Motegi MR116 for 215/45/17 and 275/35/18
motegi mr116 17x7-48 and 18x9-45.jpg (88.56 KiB) Viewed 8109 times
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Re: The SERIOUS Wheel & Tire Thread

Post by The Dark Side of Will »

Series8217 wrote:I really want to fit 285s on the back end of my Fiero, but it just doesn't look like an 18x9.5 wheel is going to fit without some flares in the rear, and that's more work than I want to do right now.
Have you thought about welding extensions on the "taco clamp" flaps on the strut? This would push the strut further inboard closer to the frame rail and allow more backspacing... I think it would be good for 18x10 with ~50mm offset in an early car... an '88 might be able to manage a 10.5 w/ 55mm offset because the upper strut mounts are already further inboard.

I've been thinking about designs for a bolt-in assembly that would allow this also.
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Re: The SERIOUS Wheel & Tire Thread

Post by Series8217 »

The Dark Side of Will wrote: Have you thought about welding extensions on the "taco clamp" flaps on the strut? This would push the strut further inboard closer to the frame rail and allow more backspacing...
I don't want to screw up the already bad rear camber curve by decreasing the strut angle.

Also, wide high offset wheels in 5x100 are not available except at custom wheel prices ($750+ per wheel) -- that's just too much for me to justify on the Fiero.
I think it would be good for 18x10 with ~50mm offset in an early car... an '88 might be able to manage a 10.5 w/ 55mm offset because the upper strut mounts are already further inboard.
I think a 10.5" wide wheel with a 55mm offset would still require a fender flare if it has a correspondingly wide tire. An 18x10 /w 55mm offset would probably be ok. It would stick out the same as the 18x9-45mm.

Work does make such a wheel; the Work VS XX. It's available in 18x7.0 5x100 with a 51mm offset (might need a 5mm spacer) and 18x10.0 5x100 with a 58mm offset. They actually go up to 64mm with an 18x10.5. It might fit.

I would rock those in gold if I could justify the expense, but at $900+ each I don't see myself doing that with a Fiero. It is the "ultimate" solution though.

I ended up ordering some of the 18x9-45mm wheels. I'll take some pics and measurements of the test fit later this week when they come in.
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Re: The SERIOUS Wheel & Tire Thread

Post by fieroguru »

It is more work, but on the 88's you can pull the suspension inboard with shorter lateral links, relocating the top of the strut (to help keep the angle near stock), tweak the trailing link slightly for clearance and get shorter axles... but with these mods a 18 x 10.5 with 56ET will fit under the stock panels.

Without any mods:
Image

With the shorter lateral links (couldn't get the camber perfect until I relocated the top of the strut).
Image
Image
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Re: The SERIOUS Wheel & Tire Thread

Post by The Dark Side of Will »

Series8217 wrote:I don't want to screw up the already bad rear camber curve by decreasing the strut angle.
The "strut angle" is from the top pivot to the lateral link outer pivots... That mod would have no effect on camber curve. It would change the motion ratio *slightly*, but not much.
Series8217 wrote:Work does make such a wheel; the Work VS XX. It's available in 18x7.0 5x100 with a 51mm offset (might need a 5mm spacer) and 18x10.0 5x100 with a 58mm offset. They actually go up to 64mm with an 18x10.5. It might fit.

I ended up ordering some of the 18x9-45mm wheels. I'll take some pics and measurements of the test fit later this week when they come in.
Let us know how those work out.

I have 16x8-25 wheels and 245/50 tires on The Mule right now. They don't need fender flares. A 10" wheel with 50mm offset or 10.5" with 56 offset would have the same front spacing as the 8-25's and therefore would not need fender flares either.
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Re: The SERIOUS Wheel & Tire Thread

Post by The Dark Side of Will »

fieroguru wrote:With the shorter lateral links (couldn't get the camber perfect until I relocated the top of the strut).
Could also have elongated the camber adjustment holes in the strut, but that would leave you with less "kingpin" angle than stock, which is not desirable.
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Re: The SERIOUS Wheel & Tire Thread

Post by Series8217 »

The Dark Side of Will wrote:
Series8217 wrote:I don't want to screw up the already bad rear camber curve by decreasing the strut angle.
The "strut angle" is from the top pivot to the lateral link outer pivots... That mod would have no effect on camber curve. It would change the motion ratio *slightly*, but not much.
You're right; it would just change the motion ratio a bit, and have some effect on strut side load.

I expect to have to relocate my e-brake cable to clear the 18x9-45mm wheels I ordered; it's only about 12mm from my 17x8-48mm wheels. The next point of interference is the trailing link. Wheel diameter and inner profile will play a role in that clearance. I'll see how it looks with the 18x9-45mm.
I have 16x8-25 wheels and 245/50 tires on The Mule right now. They don't need fender flares. A 10" wheel with 50mm offset or 10.5" with 56 offset would have the same front spacing as the 8-25's and therefore would not need fender flares either.
Pics? Also what camber setting?
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Re: The SERIOUS Wheel & Tire Thread

Post by Series8217 »

Another set I considered was these (see attached image).

In the rear (18x9.5), they stick out 6mm past Will's 16x8-25.

Unfortunately, they aren't available in a 7" width for front fitment. The 8" wide with 48 mm offset will poke out an extra 6mm past my 17x7-42mm wheels. It might be OK.
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xxr wheels.png
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Re: The SERIOUS Wheel & Tire Thread

Post by Series8217 »

fieroguru wrote:It is more work, but on the 88's you can pull the suspension inboard with shorter lateral links, relocating the top of the strut (to help keep the angle near stock), tweak the trailing link slightly for clearance and get shorter axles... but with these mods a 18 x 10.5 with 56ET will fit under the stock panels.

Without any mods:
Image
According to my calculations, the face of that wheel should be within 1mm of the face of Will's 16x8-25mm wheels. I suspect Will's wheels are mismarked for offset, his hub conversion (for the 5x115 pattern) reduced the hub-to-hub width of the rear suspension, or the picture isn't representative of what it will look like with the tires mounted..
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