Wider tires on early 911...Custom offsets?

[Tremelune]

I have a 1970 911T that needs some new shoes, and I'd like to replace the wheels while I'm at it. I'm wondering if I can get a bit more tire under there by going with custom offsets. It seems like tires rub the fender lip but have room to spare inboard.

A fair amount of longhoods are sporting a square wheel and tire setup, or at least square wheels with slightly different tires. I like a square setup for rotation, but...it just feels weird on a 911 to me. My 2.2L engine isn't putting out much power, but that's liable to change in the future, and even still, the rear is ready to kick out some (no sway bars and ancient tires on 5.5x14 Fuchs—where'd these come from??).

I'm hoping to get a 205/55-16 up front and 225/50-16 in the rear, as that gives me access to more modern rubber. From what I've read, 7"-wide Fuchs in the stock offset will fit in the rear, and a 205-series tire probably won't rub (though some do). I'm wondering what it might look like to go 6" up front and 7" in the rear, or maybe even 7" up front and 8" in the rear.

Looking at this chart, it sure seems like I could squeeze an 8" rear (or at least a 7" wheel and 225 tire with room to spare) if the offset were something like 30-40mm (between the standard Fuch and the 911R):

[targa44]

With the 2.2, I would guess there's no oil tube issue in the right rear. I have a pair of special Fuchs on the rear - but it was just adding 1" inboard to the wheel. You might consider modifying the rears you have to accommodate the tire and spacing you need. Then, add a spacer as needed.

good luck,

[thetorch]

I have custom 7s (aluminum steelie look) on a narrowbody. The exact offset is not marked, but I believe they are about 40. They fit 205/60 R15s all around with no rubbing, though a spacer (7mm) is required in the rear, as well as longer studs. That's a difficult tire size to get now.

This is as wide as I think I can go, though maybe 225/50s might work in the rear. Your car's setup could be different.

I am considering getting rid of them -- I have another set of Fuchs I prefer the look of. The ride is quite a bit firmer going from 185/70 to 205/60. I don't think I would enjoy 225/50s, though that depends on how and where you drive.

[jpnovak]

225/50/16 on 16x7 rubbed high in fender wells on my 71. Paint burner... Even with tons of negative camber and stiff suspension.

Can't get 215s anymore.

205 is your default limit. honestly, a light car with relatively sticky 205 doesn't need more rubber.

[Tremelune]

I'd be fine with narrow tires, they just seem to fall under the category of "vintage". I have no need for the look of old tires, and it seems like tread patterns have come a long way to enhance grip, noise, and feedback since the 60s...

It doesn't seem easy to find good, modern tires narrower than 205...I think I'm mostly struggling with the mental block of having a square setup on a 911...It just seems weird when 80s cars I've had were like 225 up front and 275 in the rear (with a whole lot more power and flare, of course).

[Tremelune]

I'm basically chasing a 16" setup from what's stated in this thread:

When the factory fitted wider wheels on the early n/b they produced the Fuchs 7r wheel which is 7x15 ET49. The factory fitted 6.5mm spacers and 215/60 x15 tires. Others have used 7 - 16mm spcars w/ that wheel and 225/50 x15 tires.

Anyone ever get the spacing nicey nice in the rear...?

[75 911s]

Tremelune, I go into depth on fitting a 911R replica from Maxilite in my 75 build thread.

Spacer is 17 or 18mm depending on your car / tire / fenders rolled, camber etc. (For a LWB) I think the 7R with original 6.55mm spacer is for short wheel base cars with steel trailing arms.

I also helped with input into the design of the "Trick" offset Group4wheels Torque thrust wheels which are available in ET 32 which is perfect to run on a narrowbody 69-77 car.

If you have Instagram, you can see a video under my profile that shows the introduction to the Group4TTs with trick 7" wheel.

I run 225/50 with very little camber and slight rolled fender on my 75 with a very low stance. Here's the Fuchs replica (Back)15 X 7 49ET with a 18mm spacer (elephant tuner spacer kit) with a regular 6X15" Fuchs with a 205/50 in front



Here are the TT's with trick 32 ET 15X7 in back and standard 36 ET 15X6 in front. 225/50 and 205/50



If you are chasing a 16" setup, you would need to make custom wheels. 32 ET would be ideal but build at your own risk due to a wide array of fitment factors.

[Bill5900]

Duane, I’m not following which is which. The car in the photo has stock flairs? It’s a great looking set up and I like those wheels fully black.

[Showdown]

You don’t need a custom set up to run 16” wheels. On my 1977 I have rolled fenders and 1° of negative camber and my 6x16 (36mm offset) and 7x16 (23mm offset) Fuchs with 205/50/R16 Dunlop Dirrezzas fit nicely on my lowered car.

I don’t get any rubbing at all.

You could fit 8” wheels back there but you’d have to stretch your tires a bit like Singer but it may look odd to have that much wheel/tire extending past the fender lines…

In the background of one of the photos you can see I have a stack of pirelli tires (215/60/15 rear and 195/65/15 front) and those did rub even with negative camber. But then again those were balloons compared to the Dunlops.

[dwelle]

205/55-15 on 6x15 front and 7x15 rear. that's the happy place i found after trying a bunch of options. i have a 3.2 and don't need any more rubber on the rear.

you could run a 195 up front, i opted for square tires on offset wheels...

[Showdown]

Originally Posted by dwelle

205/55-15 on 6x15 front and 7x15 rear. that's the happy place i found after trying a bunch of options. i have a 3.2 and don't need any more rubber on the rear.

you could run a 195 up front, i opted for square tires on offset wheels...

This was one of the cars that made me really want wider and offset wheels. Such a good looking car!

[Bill Verburg]

Originally Posted by Tremelune

I have a 1970 911T that needs some new shoes, and I'd like to replace the wheels while I'm at it. I'm wondering if I can get a bit more tire under there by going with custom offsets. It seems like tires rub the fender lip but have room to spare inboard.

A fair amount of longhoods are sporting a square wheel and tire setup, or at least square wheels with slightly different tires. I like a square setup for rotation, but...it just feels weird on a 911 to me. My 2.2L engine isn't putting out much power, but that's liable to change in the future, and even still, the rear is ready to kick out some (no sway bars and ancient tires on 5.5x14 Fuchs—where'd these come from??).

I'm hoping to get a 205/55-16 up front and 225/50-16 in the rear, as that gives me access to more modern rubber. From what I've read, 7"-wide Fuchs in the stock offset will fit in the rear, and a 205-series tire probably won't rub (though some do). I'm wondering what it might look like to go 6" up front and 7" in the rear, or maybe even 7" up front and 8" in the rear.

Looking at this chart, it sure seems like I could squeeze an 8" rear (or at least a 7" wheel and 225 tire with room to spare) if the offset were something like 30-40mm (between the standard Fuch and the 911R):

If you don't mind spending some money you could fit 7 & 8 w/ 205/225 tires, given the drivetrain It's far better to go w/ 15s due to inertial and gearing efficiencies

front; fuchs 7x15ET23.3 can be used w/ a 205/50 tire w/o much issue so that would be a good spec, some gus want to use 225 up front and for that a 7ET25 would be ok and 8ET27 would be best.

rear; depends on what's in front if 7 205/50 is used 7 225/50 or 7 225/45 ET23.3 can be used here too but ET25 to 27 gives you a bit more room at the lips, The extra room isn't likely to be needed w/ these short tires. Better from a performance standpoint is 225/50 or 225/45 on 8, the 8 will want at least ET25 and again ET27 gives you some extra breathing room at the lips, though again the room isn't going to be critical w/ the short tires

If you insist on 16s for some reason the torque cost of an efficient 205/50 & 225/45 x16 over 205/50 & 225/50 x15 is ~22lb-ft, the cost of 205/55 and 225/50 x16 is 38.6 lb-ft

ETs for the 16s would be the same as for the 15s but the taller tires will require more room at the lips

[Tremelune]

Interesting.

Staggered wheels and same-size tires...Very E36 M3...I certainly won't be putting out more than a 3.2 any time soon.

I'm gonna stick with 15s...I wanted 16s solely because of better tire selection, but it's not like I'm racing, and a good GT all-season will probably do me well in the end, considering it does sometimes snow in the mountains, and I'm told these cars fair well if they're allowed to "move around".

Group 4 offers a 15lb aluminum alloy steelie in 15x6 ET23 (stock) as well as 15x7 ET32 (between stock and 7R), so I bought a set of those.

For tires I'm thinking Yokohama Avid Touring S in 195/65-15 and 215/60-15. I could do Pirelli P6000 with a 185/70-15 front (stock), but my experience with Pirellis is that they tend to run loud, and 185 to 215 seems like quite a stagger for a 100hp car...I have the Avids on my MGB, and I'm happy with them.

Fingers crossed!

[Showdown]

If you are interested in Pirelli P6000 I have a set with about 150miles on them (195/65/15 & 215/60/15) that I’d love to sell you for cheap. $600 for the set + shipping. They retail at $300+ per tire.

[Bill Verburg]

Originally Posted by Tremelune

Interesting.

Staggered wheels and same-size tires...Very E36 M3...I certainly won't be putting out more than a 3.2 any time soon.

I'm gonna stick with 15s...I wanted 16s solely because of better tire selection, but it's not like I'm racing, and a good GT all-season will probably do me well in the end, considering it does sometimes snow in the mountains, and I'm told these cars fair well if they're allowed to "move around".

Group 4 offers a 15lb aluminum alloy steelie in 15x6 ET23 (stock) as well as 15x7 ET32 (between stock and 7R), so I bought a set of those.

For tires I'm thinking Yokohama Avid Touring S in 195/65-15 and 215/60-15. I could do Pirelli P6000 with a 185/70-15 front (stock), but my experience with Pirellis is that they tend to run loud, and 185 to 215 seems like quite a stagger for a 100hp car...I have the Avids on my MGB, and I'm happy with them.

Fingers crossed!

The 215/60 is a tall and costly choice

you can save 23lb=ft by going w/ 205/55 & 215/50 Vredestein Sprint+ on those wheels and get much better grip

[Tremelune]

A 215/50-15 is a 23.5" diameter tire vs stock (185/70-15) being 25"...That's a almost a 7% reduction...That's not a problem? I've always read to try and keep it within 3%.

[dwelle]

60's are tall. i can recommend the yokohama advan fleva V701 (previously the Sdrive), that's what i've been running. plenty of grip, and the 50's were too short for my use/tastes...

[Bill Verburg]

Originally Posted by Tremelune

A 215/50-15 is a 23.5" diameter tire vs stock (185/70-15) being 25"...That's a almost a 7% reduction...That's not a problem? I've always read to try and keep it within 3%.

keeping the front and rear the same OD is only critical for AWD and ABS

keeping the front and rear close in OD is good practice and makes setup easier

the only other reason to be concerned about going w/ a shorter tire is speedometer accuracy, I rarely pay any attention to mine but others are more concerned, they are wildly inaccurate anyway

The #1 reason to go w/ a shorter tire is the increasingly steep torque cost incurred the taller the tire is, secondarily is the less dear but still costly inertial costs associated w/ heavier tires

The shorter the tire, to a point the easier it is to fit, the less torque loss and the the lower profile ratio allows for better grip

Too short makes for fitment issues and dragging tailpipes

Tire OD in the range 23 to 24 makes for a nice compromise from the stockish 25" tires, 23" was the shortest oe tire fitment ever to come from the factory

[mar2mar]

205/55/16 on Fuchs 16x7 (originally 16x6 with inner rim widened by 1") on all corners.

[mar2mar]

Front 15x6, 205/55/15
Rear 15x7R, 205/55/15