10" wide front wheels, can be made to work!
#1
10-12-2009, 03:01 PM
10" wide front wheels, can be made to work!
It's not easy though... and tolerances are *really* tight!
Here are some specs:
Front:
Wheels - CCW C10. 18"x10", 7.25" backspacing.
Alignment - -3.2 deg camber
Ride Height - 115mm (to appropriate measuring point beneath car).
required conditions to acheive above values:
2.5" diameter springs,
GT3 Control arm shims - 11mm / 12mm (depending on side) -
Mode Camber plate,
Upper strut mount holes *elongated* 3/8" inch.
Side Radiator outboard mounting point moved forward 1"
Fender Liner reshaped with heat - pulled - ziptied to brackets in front which are pushed forward.
Parts of Fender liner cut away at outside edges, near side marker lights.
Fender lip rolled on the inside more aggressively than the factory roll.
The end result is about 4.6mm of clearance between hard parts of the wheel and suspension strut. There is less clearance between tire and liner at full lock (they touch), but at heavy loads, in tight corners, triming the right amount (and location) of fender liner has prevented any further melting of plastic onto the tires edge. In the end, it just barely works.
The performance improvement, once the dampers and alignment were dialed into the new contact patches, was tremendous! The class lap records at Sears Point were shattered, using this setup. A significant retuning of the front suspension and mild tweaking of the rear was needed, going from a 235 r-comp on 8" rim, to the 265 r-comp on 10" rim. With the old settings, the car was very difficult to drive with the additional front end grip.
So, Heavy, if you're willing to put in the effort, these can be made to work! =) If not, the 9.5" wide rim, in 7.25" backspacing, will probably give most of the grip of the 10", with a little loss in feedback, etc. It would require much less effort to squeeze it in though.
(Link to original 10" thread... https://www.6speedonline.com/forums/...s-too-big.html )
Picture from Turn-2 at Sears, shown below.
Here are some specs:
Front:
Wheels - CCW C10. 18"x10", 7.25" backspacing.
Alignment - -3.2 deg camber
Ride Height - 115mm (to appropriate measuring point beneath car).
required conditions to acheive above values:
2.5" diameter springs,
GT3 Control arm shims - 11mm / 12mm (depending on side) -
Mode Camber plate,
Upper strut mount holes *elongated* 3/8" inch.
Side Radiator outboard mounting point moved forward 1"
Fender Liner reshaped with heat - pulled - ziptied to brackets in front which are pushed forward.
Parts of Fender liner cut away at outside edges, near side marker lights.
Fender lip rolled on the inside more aggressively than the factory roll.
The end result is about 4.6mm of clearance between hard parts of the wheel and suspension strut. There is less clearance between tire and liner at full lock (they touch), but at heavy loads, in tight corners, triming the right amount (and location) of fender liner has prevented any further melting of plastic onto the tires edge. In the end, it just barely works.
The performance improvement, once the dampers and alignment were dialed into the new contact patches, was tremendous! The class lap records at Sears Point were shattered, using this setup. A significant retuning of the front suspension and mild tweaking of the rear was needed, going from a 235 r-comp on 8" rim, to the 265 r-comp on 10" rim. With the old settings, the car was very difficult to drive with the additional front end grip.
So, Heavy, if you're willing to put in the effort, these can be made to work! =) If not, the 9.5" wide rim, in 7.25" backspacing, will probably give most of the grip of the 10", with a little loss in feedback, etc. It would require much less effort to squeeze it in though.
(Link to original 10" thread... https://www.6speedonline.com/forums/...s-too-big.html )
Picture from Turn-2 at Sears, shown below.
Last edited by itacud; 10-12-2009 at 03:05 PM.
#2
10-14-2009, 01:38 AM
Wow, fitting a 10" wide wheel in front is insane. BTW, is the 265 within spec for the overall diameter?
#3
10-14-2009, 06:48 AM
Excellent!!!!! Congrats on the lap records man. I'm looking at tire sizes now. What suspension are you running again? And do you think that camber plates that allow more aggressive neg. camber would have helped some? I'm not interested in Mode if you can only get 1-1.5* of negative camber?
Also what do you mean by elongating the strut mount holes.
Mechanical grip FTW!!!!!!
Also what do you mean by elongating the strut mount holes.
Mechanical grip FTW!!!!!!
#4
10-14-2009, 10:14 AM
Itacud,
Widening the front track on 911s is one of the best handling upgrades you can make. In your case you get an improvement of almost 3% in lateral grip just by increasing the front track (increasing backspace), add to that the wider contact patch and increased camber.. you add up quickly to maybe 10% + even with same tires.
Congrats on braking the records!
Widening the front track on 911s is one of the best handling upgrades you can make. In your case you get an improvement of almost 3% in lateral grip just by increasing the front track (increasing backspace), add to that the wider contact patch and increased camber.. you add up quickly to maybe 10% + even with same tires.
Congrats on braking the records!
#6
10-14-2009, 12:42 PM
WOW! Great job and congrats on the records, that is really impressive!
Makes you wonder whats next huh?
11"!
Makes you wonder whats next huh?
11"!
#7
10-14-2009, 09:55 PM
It's not easy though... and tolerances are *really* tight!
Here are some specs:
Front:
Wheels - CCW C10. 18"x10", 7.25" backspacing.
Alignment - -3.2 deg camber
Ride Height - 115mm (to appropriate measuring point beneath car).
required conditions to acheive above values:
2.5" diameter springs,
GT3 Control arm shims - 11mm / 12mm (depending on side) -
Mode Camber plate,
Upper strut mount holes *elongated* 3/8" inch.
Side Radiator outboard mounting point moved forward 1"
Fender Liner reshaped with heat - pulled - ziptied to brackets in front which are pushed forward.
Parts of Fender liner cut away at outside edges, near side marker lights.
Fender lip rolled on the inside more aggressively than the factory roll.
The end result is about 4.6mm of clearance between hard parts of the wheel and suspension strut. There is less clearance between tire and liner at full lock (they touch), but at heavy loads, in tight corners, triming the right amount (and location) of fender liner has prevented any further melting of plastic onto the tires edge. In the end, it just barely works.
The performance improvement, once the dampers and alignment were dialed into the new contact patches, was tremendous! The class lap records at Sears Point were shattered, using this setup. A significant retuning of the front suspension and mild tweaking of the rear was needed, going from a 235 r-comp on 8" rim, to the 265 r-comp on 10" rim. With the old settings, the car was very difficult to drive with the additional front end grip.
So, Heavy, if you're willing to put in the effort, these can be made to work! =) If not, the 9.5" wide rim, in 7.25" backspacing, will probably give most of the grip of the 10", with a little loss in feedback, etc. It would require much less effort to squeeze it in though.
(Link to original 10" thread... https://www.6speedonline.com/forums/...s-too-big.html )
Picture from Turn-2 at Sears, shown below.
Here are some specs:
Front:
Wheels - CCW C10. 18"x10", 7.25" backspacing.
Alignment - -3.2 deg camber
Ride Height - 115mm (to appropriate measuring point beneath car).
required conditions to acheive above values:
2.5" diameter springs,
GT3 Control arm shims - 11mm / 12mm (depending on side) -
Mode Camber plate,
Upper strut mount holes *elongated* 3/8" inch.
Side Radiator outboard mounting point moved forward 1"
Fender Liner reshaped with heat - pulled - ziptied to brackets in front which are pushed forward.
Parts of Fender liner cut away at outside edges, near side marker lights.
Fender lip rolled on the inside more aggressively than the factory roll.
The end result is about 4.6mm of clearance between hard parts of the wheel and suspension strut. There is less clearance between tire and liner at full lock (they touch), but at heavy loads, in tight corners, triming the right amount (and location) of fender liner has prevented any further melting of plastic onto the tires edge. In the end, it just barely works.
The performance improvement, once the dampers and alignment were dialed into the new contact patches, was tremendous! The class lap records at Sears Point were shattered, using this setup. A significant retuning of the front suspension and mild tweaking of the rear was needed, going from a 235 r-comp on 8" rim, to the 265 r-comp on 10" rim. With the old settings, the car was very difficult to drive with the additional front end grip.
So, Heavy, if you're willing to put in the effort, these can be made to work! =) If not, the 9.5" wide rim, in 7.25" backspacing, will probably give most of the grip of the 10", with a little loss in feedback, etc. It would require much less effort to squeeze it in though.
(Link to original 10" thread... https://www.6speedonline.com/forums/...s-too-big.html )
Picture from Turn-2 at Sears, shown below.
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#8
10-15-2009, 02:03 PM
Hah hah! I think more like within a tenth or two, plus or minus! =) That was one faaaaast cabrio you drove.... =) I meant to ask, is it the newer direct injection engine model?
#9
10-15-2009, 02:08 PM
Excellent!!!!! Congrats on the lap records man. I'm looking at tire sizes now. What suspension are you running again? And do you think that camber plates that allow more aggressive neg. camber would have helped some? I'm not interested in Mode if you can only get 1-1.5* of negative camber?
Also what do you mean by elongating the strut mount holes.
Mechanical grip FTW!!!!!!
Also what do you mean by elongating the strut mount holes.
Mechanical grip FTW!!!!!!
#10
10-15-2009, 02:14 PM
Yeah, it was a 265/35, so about the same diameter as the 295/30 rear. (25.2")
#11
10-15-2009, 02:16 PM
Itacud,
Widening the front track on 911s is one of the best handling upgrades you can make. In your case you get an improvement of almost 3% in lateral grip just by increasing the front track (increasing backspace), add to that the wider contact patch and increased camber.. you add up quickly to maybe 10% + even with same tires.
Congrats on braking the records!
Widening the front track on 911s is one of the best handling upgrades you can make. In your case you get an improvement of almost 3% in lateral grip just by increasing the front track (increasing backspace), add to that the wider contact patch and increased camber.. you add up quickly to maybe 10% + even with same tires.
Congrats on braking the records!
#12
10-15-2009, 02:41 PM
Thanks Heavy. It was a fun weekend! I'm using Moton three-way adjustables. But, any coilover with < 2.5" diameter springs should work. I haven't found any camber plates for our AWD front ends that allow more than 1-1.5 deg of neg camber on their own (w/o using shimmed control arms). We can't properly use the reversible camber plates that the 2WDs can use. But, since the camber plate isn't up against the inside of the fender well completely, I just had the alignment tuning slots at the top (where the upper strut mount is bolted to the chassis) elongated with a dremel - just enough to push the upper strut-mount as inboard as possible.
#13
10-15-2009, 03:50 PM
I found that shifting anywhere above 6500 was fine -- it would always be in the meat of the torque curve -- so focusing on really nailing the redline shifts wasn't important, but an early downshift was important -- falling below 4000 rpm was costly.
#15
10-15-2009, 11:05 PM
Damn that's crazy.. I'm running 255's on a 9.5 inch wheel with -3 degrees camber, rubs on full lock right now already but that really doesn't matter! Would love to go wider, maybe i'll try it out for VIR in November, i'm itching for a 2 flat LOL!