titleistaddict87

Anyone know? If so, please share! Thinking about swapping to GT4 rims on my Spyder vs. getting a set of lightweight Forgeline GA1Rs.

spyderphile

I believe these are the specs for Spyder:

20 x 8.5 - 23 lbs. 3 oz.
20 x 10.5 - 25 lbs. 9 oz.

Would be interested to know about GT4 as well. Would you know the specs of the Forgeline?

blacksheepSpyder

like this?

titleistaddict87

Very nice! Forgeline weights depend on model but from the various ones I've looked into around 19 lbs for the fronts and 20-21lbs for the rears so looking at maybe 4 lbs / corner for a total of 12 lbs weight savings?

spyderphile

4 lbs/corner (or close to) is a substantial saving. With PCCB, could make perceivable difference. The suspension could be tweaked to take advantage of the reduced unsprung weight as well.

titleistaddict87

Agree with the above ^^^^

GT4 wheel weights appear to be almost exactly the same as the specs posted for the Spyder wheels above.

spyderphile

Here are the GT4 specs:
20 x 8.5 61mm offset, 245/35 ZR20 23.24 lbs
20 x 11 50mm offset, 295/30 ZR20 25.86 lbs

Interestingly, Spyder's rear being half-an-inch less than GT4's, still weighs the same! Seems odd! The tires being wider, will add to unsprung weight though.

titleistaddict87

Wondering if 295s would fit on the 10.5 rear of the spyder wheel?

tq.3z

They will.

Alan C.

Also consider the Forgelines are forged and the GT4 wheels are cast. I've seen a few GT4s with broken wheels.

K-A

It's amazing how much of a difference lighter wheels make. I have HRE's which are a few lbs lighter than the stock 20's, and my car feels a lot more zippy than a standard 991 C2 in every direction thanks to them.

lovetoturn

A set of HRE R101 Lightweight wheels weight only 16 pounds front and 19.4 pounds rear. That is a total of 70.8 pounds compared to 98.2 pounds for the OEM wheels. That is a loss of 27.4 pounds just for the wheels alone! An expensive one, but a rather significant one.

spyderphile

Are lighter wheels more susceptible to failure? Does fragility increase with reduced weight, as they get punished with pot holes, bumps, dips, etc.? Forged process could be stronger than cast. With multiple pieces in a forged wheel, is the failure isolated to the individual piece, theoretically? I have been running Forgeline in S2000 for close to 10 years; have been extremely reliable.

aryork

Forged wheels designed for track or racing, in general, are not more susceptible to failure (on street or track). There is less material, but the material is much stronger due to the forging process that works the metal. The GT4 wheels are pretty decent for OEM in terms of weight. But reducing the rotating mass will definitely make the car feel more responsive.

spyderphile

Thanks.