Watts vs. Mumford

it's just way too quiet... is everyone on siesta?

Ok the topic of the day is rear axle location and which is better from a Cost / Performance / Fabrication perspective.

I came across the Mumford link in my quest for knowledge

http://not2fast.wryday.com/chassis/mumford.shtml

And found this Mumford system for A types at Frontline

http://www.mgcars.org.uk/frontline/rearsus.htm

Does anyone have experience with the Mumford concept or the Frontline installation?

Steve

Good system, more weight than a Watts and way more than a Panhard.

Results porobably not worth the trouble unless you enjoy playing with such stuff.

Lighter unsprung than a watts, about the same total as a watts, no transverse movement like a panhard, puts the roll center beneath the ground so a car is less likely to 'nose over' in a turn giving the outside wheel less positive camber. Kept Mallocks competitive with a stick axle years after everyone else was independent.

Now to you're question. Cost/Fab/Performance.

First, if you're not buildng it youself, it will be a fight. Most Fab shops are SOOOO much smarter than we are, if this idea was any good, THEY'D KNOW about it, and since they don't, obviously not a good idea, right?

So assume that shop fabbing will be a bunch more expensive and a fight all the way. This means that cost is going to be greater than a watts or panhard. If you build yourself, since the rockers are on the chassis/body, there are some simplifications from a watts. Self fab will be a little more expensive than a watts, and a little more than that from a Panhard. Total self fab cost isn't going to be that much greater, not a factor in the decision process, just another couple linkages with rod ends.

The fact that there are a few competitive Mallock Formula Fords (front engine- yeah, I know most of you have never heard of or seen them- well, I have) with the system speaks to it's efficacy.

I've probably spread a little more confusion, rather than clarity.

Performance wise, if the geometry/swaybar rate is right, they work and work well

I driven cars with most set ups, never heard of the Mumford though. The Huffaker Bugeye had a a horizontal watts link, it took alot of sub structure to mount it and is too complicated in my opinion. Most cars I driven have had panhard bars, some better mounted than other, when they are mounted on sheetmetal they tend to over time rip the sheetmetal no matter how well they are supported, so in my opinion you should build sub structure for panhard bar mounting as well. The third type I driven, I heard it called a few different terms, like "wishbone" or "A-arm" it is a trianglated bar which picks up on the chassis near where the spring mounts with two pick points and then a single pick up point on the rear end , normally located where the drain plug on the rear end housing is. This set up take the less sub structure and keeps the weight down, but as it spans from the rear shelf to the rear end it takes a fair amount of real estate up making it hard to snake exhaust etc through, also the same arc as the springs ( or trailing arms if a coil over car) is often hard to imatate so it may be that the two set ups arc in a slightly different arc, as long as this is within the suspension travel, no harm, no foul, but if the arc exceeds suspension travel then the system can bind and cause suspesnion failure.


When I start on my own vintage car this winter, I will probably go with a traditional panhard bar with anti tramp bars and totally float the leaf springs and use a upper thrid link to keep the pinion angle where I want it.

Speedracer Wrote:

Thanks for the input. I must say I really like sitting here in the last row at the University of Go Fast and hearing what people are thinking. Thanks for the opinions.

Steve

I've saw the Huffaker midget that Joe raced in FP a few years ago race in Phoenix, it was a rocket ship!

My understanding of the Mumford is that it allows more control of the location of the rear roll center. A panhard bar establishes rollcenter where it crosses the centerline of the differential. A Watts, where it attaches to the axle housing (I think that's why Huffaker attached his Watts link to the bottom of the differential... lower roll center). The Mumford roll center is at a virtual point in space where a line drawn from the two attachment arms cross below the differential. Change the angle of the arms... change the roll center.

Steve64B Wrote:

Here's a look at the Huffaker Bugeye