MarkT.Bevans

With the 78-89 911 body style what is better for performance handling 7"& 8" 16's or 7" & 8-8.5" 17's ???
Thanks in advance

Mark

Bill Verburg

Generally speaking the handling with 17's will be better, but if the O.D. of the tires is taller, then straight line acceleration will suffer. The main reasons for using 17s are big brake clearance and the lower profile tires which are available in the 17" sizes. The lower profile will give better turn in because of less sidewall deformation.

By the way there is a nice intermedite step of 8 & 9 x16 Fuchs with 225/50 and 245/45 tires.

Larger sizes of 17s can also be made to fit with some work I am using 8 & 9.5 x 17 w 235/45 and 275/40 rubber. It is possible to use 10s in the back

KOAN

Mark,
I had both 7 & 8 "16 Fuchs and 8 & 9 "17 Fikse on my '87 911, which was mostly a track car. The Fikses looked great, and they made the car handle much better. I didn't notice any decrease in straight line accel., and seemed to hit my shift points a little earlier due to higher exit speeds. The greater width of the Fikse may have been the factor which made more difference with handling, but the 17" really looked better. Unfortunately, money buys speed.

Chuck <img src="graemlins/yltype.gif" border="0" alt="[typing]" />

AES

The acceleration will only be affected by changes in overall height, as stated by Bill V. The height or in particular the rolling radis of the tire affects the overall gear ratio. A taller tire means a higher numerical ratio(less acceleration/more top speed(neglecting aero considerations) a shorter tire will have the opposite effect. The only way to get wider rubber without also getting a taller tire is to use lower profile tires on larger rims(the so called +1 or +2 concept).

Bill pointed out the shortest wide tire for a 911 ie the rear 9x16 with 245/45 tire.

Dave

Another detail to consider is the weight of the tire/wheel, as additional unsprung weight will reduce handling potential. Chuck Price's Fikses weigh even less than Fuchs IIRC, but if you are looking at a heavy cast wheel your results may differ from his.
Dave

993RS

Comparison of 17" vs 18" wheels. Accelerating from 60 to 120 mph will be about 2 seconds slower as tested on a 993 with a 3.8 300 hp engine when mounted with the 18" wheeels (French Porsche Magazine Flat6). Can imagine similar situation regarding the 16" vs 17". Much better handling with the larger wheels however.

George Stevens

[quote] With the 78-89 911 body style what is better for performance handling 7"& 8" 16's or 7" & 8-8.5" 17's ???
<hr></blockquote>

Mark

On a torsion bar 911 16's work very well, on my previous '77 Carrera 3.0 the best combination was 6" or 7" front with 205/55's and 8" rear with 225/50's

I would not recommend going over a 205 width at the front.

Personally I can't understand anyone changing beautiful forged Fuchs for cheap heavy one piece cast cup copies.....but hey it's your money!!!

AES

Kinesis and Fikse 17s are no heavier than comparable width Fuchs. However the larger tires are heavier. The additional weight does cause ~2-4hp loss on a dyno. This cannot be felt by the average driver. A small change in rolling radius can easily be felt by the average driver.

MarkT.Bevans

Thanks all. My thoughts were to go with newer 17" factory wheels. I have lifted those aftermarket cast wheels and they are too heavy for me. I have found a set off of a early C-4 and with spacers I believe I can stuff them under my 911 body. But seeing so many out there with 16's still I could not help but wonder.
Again Thanks
Mark

Dave

[quote] Personally I can't understand anyone changing beautiful forged Fuchs for cheap heavy one piece cast cup copies.....but hey it's your money!!! <hr></blockquote>
Thanks George, I couldn't agree more! <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />