why are 3 piece rims better then regular?

this is something that always bothered me.

I hated the messy look of all those bolts, I I thought all the extra hardware and seperate pieces defeated the purpose of a strong light wheel.

But these wheels are always at a premium...what gives?

thanks

Rim halves can be lightweight spun aluminum for dramatic weight savings in race cars. Separate rim halves provide flexibility in changing wheel widths and offset. Low production is one reason they're more expensive.

Two-piece wheels give the same appearance as 3-piece, but not as trick .... or as light.

Sherwood Lee
http://members.rennlist.org/911pcars

This month's European Car has very good article about wheels.

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1984 911 Cabriolet

Another thing about a 3-piece wheel...i think, is that the width can be changed if you want it to be changed...but that means swapping out the center piece.

"Another thing about a 3-piece wheel...i think, is that the width can be changed if you want it to be changed...but that means swapping out the center piece. "

Wheel width and offset is adjusted by changing one or both rim halves. The center section usually remains.

Sherwood Lee

so what are the 3 pieces...

first I see the face of the wheel (where the lugs go)

then the rim...

and then the width (bad english) part???

still confused and still don't know why they are expensive...you mean to tell me if a race team is going to change widths some poor sap has to undo all 50 bolt...then tighten them with even torque???

isn't this an unreliable system? why not just buy 2 sets of rims???

OK, 3 part rim:
-Central part-bolts to the hub
-inner rim half
-Outer rim half.
Advantages:
In racing, if you crash, you often only bend 1 lip, so you change only that part, which is cheaper.
You can make different widths with time as you amass parts, and tailor them to the car/tire/conditions.
That is to the best of my knowledge.
GeorgK

thanks george...

last question...I know how the central part is held to the outer rim half all the bolts...how are the ineer and outer rim halves held together?

or are the bolts go through the whole rim...
they seem thin to be keeping together something that goes under so much pressure and stress

thanks


[This message has been edited by 82SC (edited 04-27-2001).]

By all those little bolts!; except in the case of the one piece-three piece rice boy wheels

Sorry about that.
That is what I meant, the center stays. DUH!

Paul

I think on a street car, they are *not* better than good quality forged one piece wheels.

They add unneeded complexity, for purposes of looks only. They are more likely to leak. If they get damaged, replacing only the damaged part is not economically feasible (call BBS to get the parts and labor costs, ouch!). If they leak, they are a hassle, most shops won't touch them, and you have to send them to the mfr.

Not to say they are bad, I just don't think overall they are better for a street car than a quality one piece wheel.

IMHO, weight-wise, I don't think you can manufacture an equiv. wheel to factory Fuchs without going the 3-piece route. Is there a 1-piece wheel that's about the same weight as a Fuchs?

I agree, you're spending a bunch of money for the 50 bolt look. I hope that's not the only reason people buy these wheels.

The wheels on the rear of my 911 are 3-piece. What I wanted were the stock 9x15 and 11x15 Fuchs. I found the 9s but had to sit down and breath real hard when told the prices wanted for the 11s. A compromize was in order. With the 3-piece wheel I could get the Fuch center AND any offset and width that I wished for. I opted for 12" instead of 11" in order to better fit the 345s that I wanted to run. Yes, the wheels look different due to the bolts, but most don't notice. As far as durability is concerned you can take the wheels apart yourself and replace a damaged rim or repair a leaky gasket. The original wheel builder must supply the needed halves, so you are beholding to them. I haven't had any problems in the 5 years I've been running them on the street.

Generally, 3 piece wheels tend to be the flagship models of a wheel manufacturers' range so they tend to be forged and therefore very light (Kinesis, Fikse etc). However, a forged one piece wheel will be lighter because it has less bits on them. Independent tests have verified that one piece BBS wheels tend to be among the lightest available, lighter even than the factory fuchs. The top end Japanese forged wheels are lighter still. Formula cars all use one piece wheels because they are the lightest, weight is less important than flexibility to endurance cars hence the use of 3 piece on those type of cars. I think Jim T has pointed out the potential pitfalls with 3 piece wheels on road cars. But a set of BBS LM's would look dead sexy on my 930 though...

Try this thread for a previous discussion: http://www.pelicanparts.com/ultimate/Forum3/HTML/006782.html