Up Front with Fuchs & Boots

On a street 911sc, with 911 7x16 Fuchs upfront, you can't get any more tire than with the six inch wide rims. So what's the point of using 7" upfront? Is the cost of extra unsprung & rotational weight *really* worth the slightly wider track of the front end? Is the tire geometry better on a 7"?
. ..It seems the engineers at Porsche thought the sixes were fine all the way up to 89(?) even when they bumped the rears up to 8x16. Hmmmm Any experts out there, on this?

I'm no expert, but I think the answer is yes: better geometry on the 7's, especiallly if you're following the common practice of putting 205s in front. The sixes came with 185s, which are appropriate to that rim size, in terms of sidewall flex, etc., but most people opt for 205s because they're commonly available, and they fit under the fenders.

I think the weight difference comes more from the larger tires than it does from the larger Fuchs, but I may be mistaken about that.

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Jack Olsen
1973 911 T (3.6) sunroof coupe
jackolsen@mediaone.net

[This message has been edited by JackOlsen (edited 04-01-2001).]

I'm talking '80 vintage (SC or Carrera.) They came stock with 205/55's on the 6x16 Fuchs upfront. So no tire difference is realizable on the 7x16's. ..w/o bodywork, or different wheels. Putting 7's upfront is so popular, yet I'm not sure why.

Aside : (re. previous post) We all know Jack has ADD when it comes to those big bumpered, non-3.6L 911's from the 80's

[This message has been edited by island911 (edited 04-01-2001).]

The 7" Fuchs are better than the 6" given the same tire size. Jacks right. The sidewall is pinched when 205s are mounted on 6"ers. When put on 7s the sidewall is more vertical and can "work" better. Also the tread contact patch makes better contact with the ground. It effectively makes the tire wider and the sidewall stiffer. There are similar problems associated with too narrow a tire for a given wheel width where the sidewall is stretched too far. The difference in weight between the 6s and 7s is quite minimal.

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Tyson Schmidt
72 911 Cabriolet
92 C-2 Cabriolet

Hey you guys are forgeting the probably favorite reason. They look COOL! Or IMHO the 7" looks better than a 6"

Randy Jones
1971 911

Is it worth it? If you already have 6 and 8", I doubt it. I have 205's on my 6" Fuchs and if they are pinched, it aint by much! Porsche would not let cars off their line with serious handling issues such as incorrect tire/rim width. I have put 225's on 6". Now that's pinching. The rears have more of an problem with oversized tires from the weight and acceleration placed on them. It seems 7" would benefit from 215 sizes, but fitment is an issue.

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8 9 9 1 1, The last of the line.

I just put 7 & 8s on with 225/50 front and 245/45 rear on my 85 Carrera and the car handles outstanding with no body mods.I had 17" ruf rims before and this is now a much better handling car.

The reason 7's and even 8's were not standard on the front of 911's is $$$. They are better from a handling point of view. Sizes up to 235/45 and 245/40x17 on 8" rims are commonly used by enthusiasts and racers on the front of the SC/Carrera models. The extra wt is a minus but only a small one relative to the better mechanical advantage which the 7 or 8" rim can provide on the tire. For a given tire size a bigger rim will stretch the tire carcass more, giving a wider cross section and a lower profile, the tread does not change but the transfer of forces has better angulation(mechanical advantage)with a wider rim. As Mully pointed out you also have the option of using a nominally wider tire ie 225/50 vs 205/55 to further enhance handling.

I believe the 7" rims up front will also lessen the under steer due to the wider track between the outside tire edges on the front. That is what I was told, when I was complaining about my '85s under steer (I didn't experience this under steer in my '73 911). Therefore, I went searching for some 7's and 8's. I found some 7's and 9's with 205/55 and 245/45. Now it under steers BADLY. My car handles better now before 6's & 7's.

I will be getting some 225/50 and 245/45 soon.


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Nick Hromyak
'85 Carrera