Aluminum, Steel or 'Glass?

What do you think makes the best material for off-road bodies? Aluminum, Steel or Fiberglass?  

I think 'glass, 'cause it's relatively cheap, and if you have a white vehicle to begin with, you don't even have to paint it if it has a white gelcoat. Aluminum is cool 'cause it's light, but it's expensive and a pain to fix.  

Fiberglass. For exactly the reasons you stated, its relativly cheap to fix, and its flexable. If you get hit by a rock or tree branch the fiberglass will be more willing to give than to dent or crack from the hit.  

I'll give this thread a bump.

For me it's steel.  Aluminum is lighter but to get the same strength out of it as with steel, it needs to be thicker.  It also gouges easier then steel.  I don't like fiberglass unless on a race or superlight build.  Yes, it flexes a bit more then steel but when it cracks it makes a mess.  Fiberglass does not like stuff sliding across it either.  Age can also be an issue.  UV damages the gel coating and can spider over time.

For me the easy answer is steel.  It's cheap, and it can be trail fixed.

I think Petersons 4Wheel & Off-Road has done a comparison in the past and they went with steel as well.  

None of the above. It's polyurethane!

I'll have to back up a bit and say that polyurethane isn't stiff enough to craft a whole body out of, but I recently got to see some polyurethane prerunner fenders made for a Ford Ranger. The fenders are paintable as long as a flex agent is added to the mix. The fenders themselves can be bent, folded in half, stepped on, and twisted. After all that abuse they'll morph themselves back into their original shape.

If there's a downside, it's that not very many applications exist. Kartek Off-Road, who makes the Ranger fenders, tells us that it takes about three months to get a mold made in order to start producing the urethane body parts.

So for the ultimate off-road body, I'd go with a body tub from steel, aluminum, or fiberglass (they're all good, but for different reasons) and urethane front fenders and urethane rear flares.

Check out www.kartek.com and navigate to the Ranger fenders. There's a video that shows the fenders getting stepped on and springing back. I saw this happen with my own two eyes. It's 100% real.  

Would be interesting to see a reinforced poly with maybe a harder plastic skeleton.

Jeeps already use poly flares and the front grill is plastic.  Years ago, Saturn touted plastic panels but if you gouged them, you're sort of SOL trying to fix it.

If you bend them enough they will crease.  The other downside is having a body part match up with steel parts or even other poly parts isn't that precise.  Then again most of us here aren't worrying about looks so much as the utility.

You would probably have to hand fit the parts before sending the parts out to be painted.  Although they could be dyed to match somewhat as well.  Still, I think weight would be a consideration as poly would have to be thick for a large piece like a a front clip to stay in shape.  Storing parts might also cause issues of their own, as poly is soft enough to flex under it's own weight.  If the piece isn't stored properly, it could deform and have to be forced a bit to fit. But that's more of a mfg. issue and reseller problem.