rubber bumper weight

Hey Guys and Gals, I have a question regarding the weight of the actual rubber bumper, lie i have said before my car came without bumpers when i got it, i have installed the sebring rear valance which weighs next to nothing and installed new fuel tank, which of course is empty, whilst under the car installing the gas tank i noticed that the rebound straps to the rear axle are all the way extended, im sure it will drop some when i add fuel and a seats, carpet etc, but does teh rear bumper weight so much that it pulls it down that far ? seems like i would have next to zero movement if i ht a pot hole or something instead of a bump... any ideas, i am already going to lower the car as rb ride height looks goofy sans bumpers, but how far do i need to go???how much slack should be in the rebound straps?? thanks in advance
Darren

Landon Hunter just shipped one to me. According to the shipping invoice it weighed 48.6 pounds. I imagine at least 3.6 pounds of that was the box and packing, so the bumper itself must be about 45 pounds or so.

Which brings up another question. You always see these called "heavy rubber bumpers" in comparison to a CB. Anyone know how much a rear chrome bumper with brackets and overriders weight? I can't imaging it would be much less - if any.

You might find this thread useful....

http://www.mgexperience.net/phorum/read.php?1,456722,457737#msg-457737


As for the rebound straps, I doubt the weight would affect the arc in the straps. Mkae sure you have the right straps. They aren't the same for RB and CB. RB's straps are longer.

For what its worht if you look at the specs a rb MG weight approx 100 lbs more than a CB one.

If you have the axle on stands and the straps are stiff, that is one thing. If you have jackstands under the body and have straight straps, that's because the axle weight is pulling down on the springs and rebound straps, and they would naturally be straightened out.
I would much rather carry around a chrome bumper than a rubber bumper, but don't know the actual weights.

Simon Wrote:

Ok here is the info i have, maybe it will help someone find an answer for me.
the rear of the car is on the ground, the front is on jackstands, (dont think that will effect anything, but it may) when i purchased the car, i was told it was a chrome bumper car as there were two chrome bumpers in teh cockpit, however they werent for the car( so it is possible as peter suggested they could be the wrong straps if purchased by the PO thinking it was a chrome bumper car) There is also about 5 inches between the tire and the fender (can fit fist in) tire size is 195/65/r14. to me car sits waaaaay too high

If it is a 75, it is a RB model.

It is definitely a 75 rb model, as i had to hack at the front bumper mounts to get a grille to fit! my question isnt about what year or if it should be chrome bumpered, i am wondering if something isnt wrong as the car sits so high, or will it drop after i reassemble it, the pics of cars i see that are stripped like mine dont sit nearly as high

Something is definitely amiss if the rebound straps are stretched to the limit and rear is sitting that high - especially with the front of the car on stands. Sounds like your car is sitting a lot higher than the stock height RB cars shown in the following table...

<http://www.mgexperience.net/article/height.html>

The heaviest part of the CB setup are the spring steel backing plates that sit behind (inside) the bumper... wish I had a few laying around to weigh.
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The RB setup adds weight to be sure, and in absolutely the wrong places. Racers strive to keep all manageable weight within the wheelbase, not way out on both ends of the car where it exerts a pendulum effect.
.
The RB is aerodynamically preferable to the CB, thats why the SCCA racers use it... but they are not required to use the heavy substructure of the bumpers... just the cover.

Jack,
Actually the one I based that on was the early RB and it did not have a cat converter or cast iron manifold.

JoeReed Wrote:

Mike
I just measured the rebound straps on my 75: 11/25" top to bottom with the rear suspension hanging on the hoist.

On the ground my car is 15.5 inches chrome strip to wheel centre, both front and back.

Hope this helps.

I think I'd definitely want to get the suspension correct before lowering it....

Sitting that high, I'd guess that you DO have the RB rebound straps...I'm not sure CB straps would go that far.

From top to bottom, are your spring shackles slanted toward the front of the car, or toward the back?

Any chance the PO could have put in spring from some other kind of car?

i really wanna see a picture of a profile shot of the car!

sounds like it sits real high!

here ya go, but heres a thought that i just had, i have the jackstands up front but maybe not far enough forward to let the weight of the rear of the car drop, i will drop it from the stands and measure again

sorry about pics, cant get a profile right now as the garage is a mess!!! but if i stand in the living room with carea through door thats what i get!

Ok dropped the car off the jack stands and it was definately affecting the height i am down to 16.5 now, i feel better, i can drop it from here with blocks and reach a low enough height that wont look silly.

I would guess PO has done something to that rear end so those wheels will fit. Has he by any chance put the axle under the spring instead of on top of it?

The Wiz Wrote: