campbesl

I'm interested in hearing your opinion about how changing wheel offsets affects handling of a car.

Yesterday on my '06 C2S coupe I swapped out my 19" OEM Lobster Forks (Fr 8" ET 57, R 11" ET 67) for 19" Champion wheels (Fr 8" ET 46, R 11" ET 55). The fronts moved outward 11mm while the rears moved out 12mm. I noticed an immediate change in handling. It now seems to turn much more readily and quickly. It's not twitchy by any means but I was surprised by how such a small change could make it turn more quickly and feel 'lighter' on the turn-in.

How does it work that changing the offset causes the steering response to change so noticeably?

Scott

chuuey

The wider track surely aids in agility, but you might be feeling the (assumed?) drop in unsprung weight which, depending on the amount, is very noticeable.

campbesl

So my 997 is now quicker and more agile! Sounds like the goal of a company that I do consluting consulting work for.

There is definitely a drop in unsprung weight and I think that I can discern that too.

pilfer

light wheels are a revelation. I remember noticing a huge difference with forged wheels on my old S4. I didn't notice as much when I got new wheels on my GTS as I think Porsche CL wheels are pretty light and might even be forged?? I've had spacers on a few cars and always did it simply for looks, never noticed improved handling with spacers alone.

kru911

According to Otto Fuchs ...the OE Spyders are "exclusive forged wheel(s)"
https://www.fuchsfelge.com/en/wheel-...wheel-380.html

pilfer

I believe it, they were surprisingly light. Not as light as the BBS I have on now but not what I was expecting.

sandwedge

Don't forget that you also reduced unsprung weight on each corner of the car by close to 10 lbs. Someone correct me if I'm wrong but aren't the lobsters among the heaviest stock wheels pushing 30 lbs each? Your Champions (I've had two different sets of them) should be closer to just over 20 lbs each.

Sorry. Posted this before reading the whole thread. Already addressed obviously.

wjk_glynn

Can’t speak to the accuracy of the weights listed in the following, but they put Lobsters in line with the rest of Porsche’s 19” cast rims.

https://rennlist.com/forums/944-turb...l-weights.html

http://www.944racing.de/wheelweights.php

Karl.

kru911

Definitely, not as light as BBS monobloc wheels. If of any further interest, Otto Fuchs support emailed me the weights last year.
8.5J - 36948 10,3 kg (~22.7 lbs)
11J - 36949 12,0 kg (~26.5 lbs)

Petza914

I've had all of these wheels on my 997s. All of them worked perfectly on the car EXCEPT the ADV1s with the et42 offset. Tires were all the same make, model, and size and alignment settings weren't changed, but the ADV1 wheels not only stuck out past the fenders but also severely limited the high-speed stability of the car, even at 85 mph, making it want to dart left and right. The current Forgelines drive better at 130 mph than the ADV1s did at 85, so I'm m not surprised by your findings based on my personal experience.


Champion RS171 Wheel Specs
Front - 19" x 8.5" with 53mm offset
Rear - 19" x 11.5" with 62mm

GT3 Wheels
Front - 19" x 8.5" with 53mm offset
Rear - 19" x 12" with 68mm offset

ADV1 Wheels
Model ADV05 Mv1 SL (forged 1 piece lightweight)
19x8.5 with 42mm offset
19x11 with 52mm offset
Finish: Brushed & cleared

Forgeline SC1 Forged Monobloc
Finish: Brushed & Cleared
Front - 19" x 8.5" et 50mm
Rear - 19" x 12" et 74mm