VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 "31 2-bar bumper ride height

I've straightened and assembled the 2-bar front and rear bumpers for my '31 Coach. Mounted on the car, the top of the front bumper is about 18"+ from the floor. However top of the rear bumper is about 22" above floor. Car is close to fully assembled, just have the 2 doors and the rear seat to put on, about 100-150 lbs or so. and when I put my 200 lbs weight on back bumper it only goes down perhaps 1/2 inch.

It seems GM would have designed these to be close to same level when fully loaded. Is this the case? If not, what is approximate dimension for top of rear bumper above floor? My car has always looked high in the rearend to me, but not sure just what to expect. Eveerything on suspension is original as near as I can tell.

The bottom of the rear bars should be approximately level with the bottom edge of the rear fenders. The front double bars should have a upside down U shaped clamp bracket with the bolt into the frame horn above the front bumper support bracket. This U bracket / clamp bracket lowers the front bumper.

The rear bumper should be higher than the front bumper.

Thanks Jack, I have them installed correctly, and thanks JYD for the advice the rear was higher. I suppose fully loaded with 3 adult rear seat passengers and their whiskey, the rear would drop a bit. I was thinking if one had to push a Chevy with a Chevy, bumper to bumper, the fact the bumpers don't line up would be a problem. Also in a rear end accident, the front bumper would ride under the rear. Oh well, if someone can give me a measure for top of rear one that would be a good confirmation if mine is too high at 22".

The overall height of the rear bumper would also depend upon the arc of the rear springs as well.

Gunsmoke --

Not too much higher than my 31 Coupe. Mine measures 20 3/8 to top of top bar directly behind mounting bold at rear frame horn.

Front is wacked up on mine. The frame horns are same distance, but bumper brace is twisted somehow and the difference between ends at bolts is 2". Left front is 18" and right is 20", so, as an average it should possibly be 19"??

As Mr. Dog states, the cars are going to be different from each other for various reasons. Best to ya.

Jim.

Thanks jdv123, I figure fully loaded mine rear bumper will get down close to what your's is, about 20.5"-21", so guess that is normal. My front one is arrow straight and both sides measure exactly 18" from floor (about 20 lbs air in tires) so 18"+ seems about correct. On one side the back bar is 4.8" from tire, other side 5.2", about 3/8" difference which is not noticeable. I think Harry has suggested about 5" is normal.
The front bars can be straightened easily on a decent vise with some spacers etc. However straightening the back bar needs a heavy mall and anvil and some skill using them, or a heavy duty industrial vice or press.

Don' forget that a coach has 8 rear spring leaves , and a coupe only 7(unless it is a sport coupe or 5 pass coupe) , so that will make a difference also in comparing specific height from different cars.

I did not know that. Good point.

20.50"
21.00"
20.50"
My 31 Four Door. Al W

I made a mistake here. The front U bracket has the bolt under the front bumper bar support bracket, so that effectively raises the front bumper bars.

Interesting Al, suggests your front and rear bumpers are about same height. I would have thought that would be GM's intention notwithstanding that some variables such as spring curvature, load carriedetc, or sag may alter the dimensions somewhat. I have been contemplating putting a 1" or 1.5" machined spacer under the rear spring saddles which would lower car accordingly. Maybe next year.

I'd wait until the car has a few Hundred miles on it before doing anything to modify the ride Height. Let her settle in and my car had a full Tank of Gas at photo time. Al W.

Here are some dimensions for 1932 Chev Sedan. You could use these to determine the measurements that you want.



Click here for FULL SIZE

---Bill Barker

I thought only Australian 1932's used twin bumper bars. Is this an export diagram or from some where other than the USA ?? Canadian maybe?

Bill,
That is an interesting illustration. Though it is labeled as 1932, it clearly is a 1931 or earlier. I think it probably is an early engineering drawing based on a '31 (note hood, sunvisor, bumpers) with dimensions intended for a '32. It illustrates a common problem with Chevrolet documents. Many contain differences from production vehicles.

Yep.....that ain't no '32.

Thanks for posting this Bill. Appears to be a generic drawing, as indicated by other responders. I note it shows running board is not level, but slopes toward front of car, as does mine, perhaps 1/2"-3/4" slope depending on load.

From a conceptual perspective, I think the designers would have aimed to have the centerline of the bumpers on centerline with the wheels, especially in front so most forward curve of tire is on center with bumper (this is a common feature of many cars of the period). And, the designers would also want back bumper/tire relationship the same or close fully loaded. Your diagram shows this way, i.e. both bumpers are at same level and about on C/L of wheels.

Of course after the designers are finished their work, the assembly/manufacturing engineers take over, and design concepts may not always be translated perfectly.

Yep Gunsmoke. You're exactly right. This diagram may not be what it's purported to be... and again, may not be what was actually manufactured. Remember they didn't have the Internet back then to keep them honest.