Fuch 6s vs 7s up front

[Another911]

Like dozens of previous contributors, I wanted to increase wheel sizes on my ‘89 Targa from 16x6/7 to 16x7/8. It seemed universally accepted that 7s fit up front so I did just that. The problem is that the outside tire wall now sits 1/4” beyond the outside fender edge. There are no spacers on the hub. I do not want to go back to the flat-faced 6’s up front, so any advice to remedy the situation would be wonderful!

[Bill Verburg]

Originally Posted by Another911

Like dozens of previous contributors, I wanted to increase wheel sizes on my ‘89 Targa from 16x6/7 to 16x7/8. It seemed universally accepted that 7s fit up front so I did just that. The problem is that the outside tire wall now sits 1/4” beyond the outside fender edge. There are no spacers on the hub. I do not want to go back to the flat-faced 6’s up front, so any advice to remedy the situation would be wonderful!

Pics would be informative What size tire is on the wheel?

Are you sure that it's a Fuchs ET23.3 7 that is the issue? A 911 ET10.6 8 would be more likely to cause that sort of issue in front

[996AE]

no issues on my 1988 911 with 911 off set 7&8s.

205 and 225s

[racer]

What size tires? Still 205's on the 7's or with the 225s if they were previously on the rear or were they mounted up "naked" to check fitment first?

IIRC, an '89 came with 6" front and 8" rears.. so.. do you really have the factory 8s and put them on up front?

[Another911]

Bill Verburg - thanks for the reply. I am sure that it is ET 23.3 7 that is on.

[Another911]

[Another911]

[Another911]

Here is another ‘84 Targa with 16x6 on front. You can see in pic the tire side wall less than an inch inside the out fender. Going to 16x7 would move the sidewalk out an inch causing same problem.

[Another911]

[Another911]

Both cars in the pics have 205s

[Bill Verburg]

It's sure that 205/55 on 7ET23.3 can be tight, for the same nominal 205/55 x16 tire the sidewall is moved out .5" +/- by the 7 compared to the 6.

There are some production variances that can cause the fit to be better or worse but 7ET23.3 w/ 205/55x16 should be doable

Things that help are to run a little extra negative camber(this pulls the top of the tire in and allows more room as the assembly moves through it's arc and roll or trim the lip

[racer]

I believe the usual caveats about 7" front is

1) Ride height
2) Camber
3) Fender lips to be rolled
4) Tire size: some cars fit a 205, some a 215, others a 225. (some of this is tire brand/shape dependent)

I agree, the blue car image does seem to stick out farther than most I've seen but some is the angle of the photo too.

I had issues on my track 911SC running 225's on 951 7"s and 951 8"s on the front (same et as the 911 7"s). Had to smash the lip pretty well. Car was lowered and stiffened. Never rubbed on the street, only high load / compression corners on the track.

[Bill Verburg]

Originally Posted by racer

''''
I had issues on my track 911SC running 225's on 951 7"s and 951 8"s on the front (same et as the 911 7"s). Had to smash the lip pretty well. Car was lowered and stiffened. Never rubbed on the street, only high load / compression corners on the track.

all the 7s have ET23.3 and, yes, the 944/951 8s also have ET23.3 but it's the combination of width ET that makes or breaks a fit

225/on an 8 w/ the the right ET fits fine evn on a really low car. But the ET needs to be in the range 25 to 30

here's some frontspace data for Fuchs 6, 7 & 8, I generally use 88.9mm as a maximum
6ET36 49.1mm fits fine
7ET23.3 74.5mm fits but is close to lips and usually requires camber and/or lip clearancing
8ET23.3 87.2mm (951 part#) really, really tight always requires a lot of work to use
8ET10.6 99.9mm (911 part #) I've never seen this work, though some claim to

[Another911]

Bill - doing the math I believe the 7s should be 1” out from 6s: centerline + .5” plus reduced offset +.5” (36mm -23mm). Am I off in my comparison of the two wheels? Another thought - are all hubs the same? My wheel hub looks to be perfectly flush with the brake caliper. Are there shorter hubs that still allow enough wheel clearance for brake calipers?

[Another911]

[Bill Verburg]

Originally Posted by Another911

Bill - doing the math I believe the 7s should be 1” out from 6s: centerline + .5” plus reduced offset +.5” (36mm -23mm). Am I off in my comparison of the two wheels? Another thought - are all hubs the same? My wheel hub looks to be perfectly flush with the brake caliper. Are there shorter hubs that still allow enough wheel clearance for brake calipers?

Yes the 7 wheel edge sits out 1" more than the 6 but the nominal tire sidewall only moves ~.5" The fit is further complicated because the 6 doesn't stretch the side wall as much as a 7

Here's how they compare, the upper section in silver is the wheel, the next in green is a nominal 205 tire, the next section in yellow is the installed tire here stretched to ~208mm on a 6 and ~218mm on a 7. On the far right is the deltas which are also listed in the lower right blue section

[Bill Verburg]

Originally Posted by Another911

Bill - doing the math I believe the 7s should be 1” out from 6s: centerline + .5” plus reduced offset +.5” (36mm -23mm). Am I off in my comparison of the two wheels? Another thought - are all hubs the same? My wheel hub looks to be perfectly flush with the brake caliper. Are there shorter hubs that still allow enough wheel clearance for brake calipers?

There are different hubs but only the very early ones are thinner. From '73 they are all the same(actually earlier but the part #s are more muddled the further back you go), in '73 the part # was .04 they got up to .06 in '89 but dimensionally it was still the same as the .04 & .03

[Another911]

Bill - super helpful...thank you!

[DanielDudley]

A lot of the aftermarket 17 inch wheels have offsets that will allow you to run more tire without significant clearance issues. If you want to run more tire and have a crisper sidewall, that is the way to go. You can run a 944 16x8 inch wheel up front and a 911 turbo 9 inch wheel in the back and get the tire widths you want, but there aren't as many if those 8 inch wheels hanging around as there used to be. If you want to run a 225 and a 245, that is the only way I think you can do it with Fuchs.