Early Track Widths

Jagshund · 08-17-2008, 09:07 PM

Does anyone know what year a 911 with the chassis number 305 101 would be? I've got the track widths from the manual (pg. 1029 of 1075 in the 65-71 manual, for those who have that version) and it states that prior to chassis no. 305 101 the track widths were as follows:

f 1337 mm
r 1317 mm

and from chassis 305 101 on the numbers were as follows:

f 1353 mm
r 1321 mm

These numbers are for the standard 911; the 911S and 911T have different figures for each but I'm not getting into that right now. Just curious to know exactly when Porsche decided to enlarge the trackwidths by roughly .5 inches and .25 inches . . . not that it matters . . . it's 0100 and I'm not really going to force myself to watch the Olympics . . .

tonythetarga · 08-18-2008, 04:35 AM

I have 305 100 listed for MY 1966 and 305 101 listed for MY 1967.

gestalt1 · 08-18-2008, 04:41 AM

does the track width include the tires? isn't the changing width just slightly wider tires being used?

Bill Verburg · Bill Verburg's Garage

the original O-series 911(Sept'64-July'67 production) came w. 4.5" , the A-series(Aug'67-July '67) have 5.5", the B-series(Aug'68-july'69) have 6" w/ veery slightly flared fenders

Jagshund · 08-18-2008, 11:05 AM

I've got a car with a build completion date of 22 Feb 68. I'm guessing that the FTW was 1353 (53.23); is the 'slight flare' of the B-series different than that of the 69- cars? I'm increasing the FTW of this car to 1465 (57.7 in) and am looking for a fender that's not too "out there" . . . okay, okay. A 2.25" increase on either side IS going to need something more than 'subtle' but you understand what I'm going for here . . . unless I can get away with having my tires stick out the sides. It used to be all the rage . . .

304065 · 08-18-2008, 12:13 PM

305101 is from September, 1966 as a 1967 Model Year. The change was probably made at the start of new production.

Remember that the wheel offset is another factor in the track width. The 911R used 7" rear wheels but has a narrower rear track because the extra inch is on the inside.

Jagshund · 08-18-2008, 01:58 PM

I was under the impression that they were taking the measurements from hub to hub?

304065 · 02:28 PM

Definition of track is distance between wheel centers. In offset wheels this is not the hub-to-hub distance.

Here is a thread where I post the track numbers:

225 tires on 6" rim??

Jagshund · 08-18-2008, 02:52 PM

Augh! That's a MATH PAGE. Don't you know that stuff doesn't have any application outside a classroom? Thanks for the info-

304065 · 08-18-2008, 03:13 PM

Hey, your data completes my question! (which was, did they change the track in '67-)

prior to chassis no. 305 101 the track widths were as follows:

f 1337 mm
r 1317 mm

and from chassis 305 101 on the numbers were as follows:

f 1353 mm
r 1321 mm

If you assume a normal used 4-1/2 with 42mm offset, then your rear track hub-to-hub is different by 4mm. The missing 4mm!

Jagshund · 08-18-2008, 03:31 PM

Guess this 1k+ page shop manual comes in handy every so often after all. A three year mystery solved!

304065 · 08-18-2008, 03:41 PM

What shop manual, the two-volume factory manual?

The "Slight flare" that Bill refers to is the LWB flare. All SWB fenders are the same (except the R).

Why are you increasing front Track? Are you bolting on an LWB suspension?

Jagshund · 08-18-2008, 05:14 PM

This could be a two-volume manual if it were printed out . . . it's a PDF of about 1075 pages in length titled "65-71 911 Workshop Manual WKD 480 520" and is about the best resource I've ever run into regarding SWB 911s. I'm not so certain I want to mention what I'm putting on this car just yet; need to put up an umbrella before the poo flinging starts . . .

I'll start a thread about it soon. If you're really curious, just send me a PM.