luckett

Will these wheels fit on the front of a late offset car?

17x9.5 52 offset

I currently have the stock 16x7 wheels with a 55 offset.

By my calcuclations, the 9.5 inch wheel would put 1.37" more width on the outside and 1.13" more on the inside. It looks like it will fit based on my static measurements, but is there enough room under dynamic conditions?


What is the max width that you guys know of being used on the front?

ptk

My friend has the 8" rims and I thing this is top level. Wider one's can schratched when you will want to turn. I can be wrong but I thing that if you want wider rims in front you will have to modern front fenders. Why you want to have so wide rims in front?

luckett

What do you mean modern front fenders?

There should be room for much more that 8" on the front. What offset was your friend running?

Wider wheels-> wider tires->more grip->faster track speeds->more fun

bearone

i've got 7.5x17 on the front and 17x9's on the rear.

87951

Danno

"Will these wheels fit on the front of a late offset car?
17x9.5 52 offset
I currently have the stock 16x7 wheels with a 55 offset."

Yah, but you'll be limited to a 225/45-17 tyre. If you had 65mm offset like on the TurboS, you'll be able to run a 255/40-17 tyre (coilovers needed).

I'm current using a 17x10.5" in front...

luckett

I'm sure you do. How that is relevant, I'm not quite sure...

Serge944

With 6.75" backspacing on an early car (figure 8" backspacing on a late offset car), a 9" wheel with 255/40/17 will fit with stock springs. This also means that if you're pushing over 1.5" of frontspacing on a late car, youre gonna run into the fender.

Chris, your wheels have 2.7" frontspacing and will most likely rub on the outer well.

luckett

I neglected to mention that I have coilovers with 2.5" springs. I currently have 225s on the 16x7s and there is about 1.75" of space between the tire and spring and about 1.25" between the wheel and spring perch.

I've done a comparison to the spacing of your wheels Danno. I assumed that the other than the offset, the space avail. in the wheel well is the same. Is this a correct assumption?

The 16x7 55 offset wheels have a backspacing of 5.67 and frontspacing of 1.33. Your 17x10s have a backspacing of 6.63 and frontspacing of 3.87. The difference amounts to +0.96 of backspacing and +2.54 of frontspacing.

The 17x9.5s that I'm looking at have a difference of +1.13 backspacing, which might fit based on my measurement but exceeds the backspacing of your 17x10s by a bit. The frontspacing has a difference of +1.37, which should fit based on the 2.54 avail.

I'm summary (can't get it to format, but you get the idea):
wheel 16x7 17x10.5 17x9.5
frontspacing 2.17 3.87 2.7
backspacing 5.67 6.63 6.8

Looks like it might be a tight fit. Do you think it will fit?

Serge944

Chris, Danno never posted an offset on his wheels. He was merely quoting you.

Your wheels need a higher offset to fit and will rub the fender with a properly sized tire.

By my calculations, 2.7" front spacing, and 6.8" backspacing. Your backspacing will clear the springs by a LOT, at the cost of not clearing the fender.

luckett

I assumed he has a 35 offfset from the info I got from his website. If you take the difference in offset and add it to the 17x9.5 wheel, the frontspacing is 3.37 and the backspacing is 6.13. This is within the max tolerances defined by Danno' wheels (3.87/6.13).

Unless there is an error in the math somewhere...

luckett

There is currently 1.33 front spacing with the 16x7s and I measured a bit less than 1.5 of room avail. I think it might fit but, but that is probably being hopeful...

Serge944

Chris, Danno's car is early offset while yours is late offset. This makes a big difference!

Danno

"Unless there is an error in the math somewhere..."
"Chris, Danno's car is early offset while yours is late offset. This makes a big difference!"\

Yeah big difference, you need to add +29mm to the backspacing and -29mm to the frontspacing to convert my wheels to late-offset in your comparison table.. You really want to add +10-15mm to the stock offsets like Porsche did in going from Turbo to TurboS. I went from 23.3mm to 35mm offsets in front when going from stock 16x7 to 17x10.5" wheels. This adds 2.25" on the inside rim-edge and 1.25" on the outside*. I come within 0.4" of the coilovers on the inside with a 255/40-17 tyre. On the outside, it's pretty darn close to the fender lip as well. It does rub on uphill right-hand low-speed switch-backs with more than 20-25 degrees of steering (about 1/2 turn on steering wheel).

That's why I was saying you'll only be able to use a 225mm tyre with that wheel, because the outside edge of your tyre will be right about where mine is. If you use a 255mm tyre, you'll end up sticking out a bit and rubbing a lot more.

"I've done a comparison to the spacing of your wheels Danno. I assumed that the other than the offset, the space avail. in the wheel well is the same. Is this a correct assumption?"

Yup, I've got all the dimensions and clearances measured here: Wheels-FrontClearances.pdf. The equivalent dimensions on a late-offset 9.5" wide wheel will be around 7.5" backspacing and 2.5" front-spacing.

*There's a strange phenomenon that happens when you move the tyre's centerline in or out. It seems to make a bigger difference than tyre and rim-widths. I'm not sure why this is yet. Let's say you're running a 225mm tyre on 8" rims. Then you go up to a 255mm tyre and use a 9" rim with 12.7mm more offset. This theoretically puts all of the extra rim-width on the inside edge and both the outside rim-edge and tyre should be at the same location as the previous configuration. But somehow, you actually end up with MORE clearance than before... Conversely, moving the tyre's centerline outwards slightly seems to eat up clearances faster than you it should. I'm not exactly sure why that is yet... Perhaps something to do with the suspension geometry since the wheels move in an arc, not just up and down.... bizarre... ...

"What is the max width that you guys know of being used on the front?"
" Why you want to have so wide rims in front?"

Alan Coleman's running 18x12" all around with 315/30-18 tyres. Larger front wheels and tyres will reduce the understeering effect without risking lifting the inside rear tyre under cornering like if you used springs and sway-bars to tune out understeer. Until you've tried it, you have no idea what a 10" front rim does to transient response and cornering speeds.

At Laguna Seca about 5 years ago, I swapped my 16x7/8" Fuchs for a set of used HRE 16x10.25" wheels I bought from a racer. Did the swap during the lunch break and re-used my crappy SP8000 tyres. On the very first lap, I flew off the INSIDE of turn-1! The handling had improved so much, that my normal steering inputs were too much for the new configuration and it overreacted.

There's no longer a slight pause after steering inputs while the tyre's outer edge is pushed under the rim-edge and stretched towards in the inside. This 2" lateral movement of the sidewall has to take place BEFORE the tyre can pull on the rim and turn the car. With the wider rims, the sidewalls are already inside the rim edge and only have to move 0.5" before they pull on the rim. So turn-in and left-right transitions occur MUCH, much faster. Also the wider rim keeps the contact patch flatter since you don't have much sidewall distortion any more.

There was an EVO at last years OTC that was pulling 1.55-Gs of cornering on 140-treadwear street tyres! I gotta figure out a way to catch up to that kind of handling and cornering-grip. Perhaps going to Alan's 18x12" set-up all around is gonna be the secret...

bearone

cuz i haven't seen anyone post with anything bigger than 7/1/2's on the front without major mods.

Matt H

I have Boxster S 8.5s mounted up front and they work fine with no "mods" per se.
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