Lightweight wheels

I decided to put my car on a diet: drilled disks, aluminum IRS trailing arms (in the works), and a set of five Mahle cast magnesium 4-lug wheels with slightly smaller tires. These Mahle wheels (nicknamed "gasburners" in the trade) only weigh about 9 pounds each.
With 185/60X15" tires the wheel/tire combined weight should be at least 10 pounds per wheel less than the 5 1/2" x 15" steel Mangel wheels with 165/65x15" tires for a total weight reduction of 50 pounds.

There are Pedrini (Italian company) copies of gasburners in cast aluminum that are heavier, and the 4-lug forged aluminum alloy Fuchs wheels are heavier still.

Just posting this as an FYI to those of you who may be thinking about weight reduction.

I saved 110 pounds from my IM in one simple step.....I left my wife at home....but the road is lonely when you're by yourself.

The first Corvairs were considered too light in the front and lead shot weight canisters were added to later convertible models, (approx 50 lbs) to each corner. It greatly improved the ride, handling and stopping ability. The 66 Corsa was a true performer with this set up. I removed the weights from my convert to reduce the weight and quickly put them back, what a difference. I believe the replica is already lacking weight (at least in the front) to give it a good ride and I am adding weight to see if it makes a diference. Just a thought and my opinion, I appreciate and certainly am not challenging your knowledge George.

Power to weight ratio is a well understood principle. In the current issue of Kit Car magazine, the show at Carlisle, Pa., featured one of many Lotus 7 clones which featured a 240 hp Honda S2000 engine in a package weighing less than a thousand pounds. No performance figures were offered in the article, but one can only speculate what it must be like to floor it in this little number. Reducing unsprung weight isn't a bad plan either, come to think of it.
John H.
still truckin' along with my little 1776

Bill,
There are classifications of weight loss in motor vehicles. There is sprung and unsprung weight.

George is reducing his unsprung weight. This improves response and performance of the suspension.

Sprung weight is the weight being supported by the suspension. This includes passengers and ballast. This weight affects the power to weight ratio, acceleration and to some extent handling.

Although these may be light cars, decreasing the unsprung weight can greatly improve the cornering and road response. This may allow George more flexibilty in balast use and placement without losing performance.

(Message Edited 10/3/2002 12:23:01 PM)

Corvairs - shades of Ralph Nader. My first was a '64 convertible with 4-speed; traded that in on a '65 Corsa 140 convertible with 4-speed; traded that in on a '66 Corsa 140 coupe with 4-speed. Three years ago I gave away a cherry low-milage '66 Corsa 4-speed coupe to a local Corvair club guy because I had one of Ted Trevor's Crown conversion kits (350 V8 in rear seat) and realized that if I built the conversion I'd probably kill myself with it (see, we do get smarter when we get older, just not much). I had also lost some garage storage space and didn't want the car sitting out in the weather.

Late Corvair Corsa 140's were neat cars; '65 had the old transmissions but '66 and later used the Chevrolet Saginaw V8 4-speed adaptation (which is why the V8 converted Corvairs were possible).

Bill, also note that in the current IM cars the engine/transaxle is moved forward about 2 7/8" farther than in a pan-based replica, making the stock IM weight distributrion about 57% rear and 43% front. I added a large capacity gas tank, heavier rack-and-pinion steering unit, FM stereo/tape deck and dual speakers in kcik panels, and full sized spare up front (spare is not standard). So my car's weight distribution may be more like 55/45, which isn't bad for a rear engined car.

Anyone on this forum been brave enough to get the back end of these cars to slide out. I've gone around corners at some pretty high speeds and the back end tracks like it's on rails. Interestingly, it's the front end that feels like it's going to go. Maybe it's just too light in the front end.

When banging into a right turn, try downshifting to second gear and dropping the clutch. Now slam the gas and steer with the throttle.

I wouldn't try drifting the car unless you can see whats coming the other way. When the rear breaks loose it will come around pretty quickly. Try a tight exit ramp (cloverleaf) early in the morning on a weekend, you might back into the guardrail.
Better yet, try a racetrack close to you. Summit Point in WV has what they call "friday at the track" where for a price you can drive the road course there under semi-controled conditions. I don't know about other areas, but i doubt Summit is alone in this as most road courses need all the revenue they can get.
ed

Kudos to Erik for 'splainin' the difference between sprung and unsprung weight.
BUT, there is also a very fine line between slidin' and rollin'
There's a break point where tire adhesion gives way to tire buckle.
Neither will improve your track times and the later will require even more 'splainin'
MM
RIP '60 356B

I've experienced both a little push, and some oversteer in my car. The push is typically at lower speeds. I've hung the rear out a little and had to gather it back up with the throttle. However, there is no question that under racing conditions these cars tend to oversteer, meaning the rear will hang out on you. Yes, if you are seriously outside the envelop, the rear will come around. You can take it out on a skip pan in a shopping mall to experiment. At slower speeds on a tight turn, you may push, especially if there is a little dirt/sand on the road. But take it up to like 35 mph, and you will notice it's the rear that wants to come around.

I have only rolled two cars. A 1968 Renault R10(rear engine), and a 1969 beetle. Both had less to do with tire buckle than with staying on the road.

(Message Edited 10/4/2002 7:56:08 PM)

I thought that only the five lug mahle wheels were light and called gasburners..?

www.terovirta.com/volks/VolksWheelsGasBurner.html

www.terovirta.com/volks/VolksWheelsMahle.html

www.terovirta.com/volks/VolksWheelsPedrini.html

Right you are, the 5-lug Mahles are magnesium and called "gasburners" and the 4-lug Mahles are aluminum. I just picked up a set of Mahles and have a set of Fuchs on the way (both 4-lugs). I also have a set of four "Western" (also called MacAfee) 4-lug aluminum wheels and chromie 4-lug Mangels currently on the car. Maybe I should go into the wheel business...