Just seen ebay item 260019136481 short chassis.
Looks very interesting because of a strengthening "strap" running underneath the top hat chassis rails longitudinally?
I always believed that the "chassis twist" was a transverse twisting as opposed to a longitudinal bend?
I know that racers box the chassis to close the "U", which would increase the torsional stiffness of each rail, thus stiffening the whole assembly, but I didnt realise there was a longitudinal bending issue?
Any comments?

Regards

Steve

Yes it would seem that the 7 chassis frame is quite flexible in all planes. While rebuilding my first RN for the second time in forty odd years I finally found why it was difficult to fit the front axle/spring assembly-the offside longitudinal had an upward bend in it. This was of about 1/2" between the front end and the front cross member which put the nosepiece out of alignment with the radius rod ball joint. A rail bending cramp, known as a Jim Crow, and a 6' straight edge soon straigthened it up and the axle assembly now fits quite easily with no twisting of the shackles.
The rear crossmember of our second RN had a lovely bend in it- the middle of it was about 1/2" in front of the ends. Finally I've heard on more than one occasion that fitting a strengthening gusset between the front crossmemnber and the offside brake cross shaft bearing improves the brakes. Dave.

I think that Dave has the right idea about that strap on the chassis - I reckon it's there to stiffen up the cross-shaft bearing.

However, my main comment about that advert is that I have severe doubts that it is a GE Cup chassis, for several reasons: I have never heard of GE fitting straps like that, it appears to be fitted in a very amateur fashion, I don't think GE fitted labels to the chassis, and finally chassis for GE Cups did not have the outer body brackets on the cross-member.

David

David - I agree about the Cup, although most of my knowledge of them is secondhand, some of it from Tom Abernethy. Over 25 years of working in business on Austin Sevens I found very few chassis without longitudinal bends, more particularly on the long-wheelbase high frames, Ruby ones not too bad. At one stage it was so prevalent that I had my 8' straightedge checked ! Not all rails drooped the same, giving a twist to the chassis. I jest, but The classic example of drooping was when I picked up for our Club the remains of two '28 Chummies which had been destroyed in a severe bushfire. Apart from the obvious heat, they had to withstand the weight of the garage which had burnt & fallen in. The chassis were so bent that the front crossmembers touched the ground. No, we didn't bother straightening them. Re the brake brackets, if you're not fussed with originality, diagonal braces to strengthen will work wonders with your stopping efforts. Cheers, Bill

My own Cup Model chassis (No:90767), has the exact same strap on it.

I always assumed it had been added by an owner at some point, can nayone else shed light onto this??

Ruairidh

Tom Abernethy came to visit this morning by chance and I mentioned the comments on the GE Cup Chassis, he tells me that the chassis did have a plate rivited to them but he hasn't heard of the straps. Like David he agrees that the chassis shouldn't have the body mounts, but suggests it may be a stadium?? Anyone got a Stadium to check?


R

I wonder why the strap is fitted on the nearside. The only reason I can think of is to improve the efficiency of only the nearside rear brake, by improving the stiffness of the cross shaft mounting, thus acting in opposition to the usual cross shaft twist effect. Ruairidh, does your Cup pull up in a straight line without the usual fudges?

Not like GE to add weight (or expense!) unless for a very good reason.

Regards, Stuart

The only way my Cup would go in a straight line at the moment would be for you to drop it from a great height. It is in many, many pieces and likely to stay so for some time to come......

I have no way of knowing if the strap was fitted by GE or not, just surprised to see it on another chassis with the same modification.

Cheers

R

Ruairidh

It would seem the crank in the GE's engine should be safe for a while yet then, considering how they seem to have a short life in your family up there!

Mick

Safe as houses!

It may just be a Scottish Club thing, I have heard of three breaking in the last two weeks!

R