Shortening LWB arms to SWB car

[mepstein]

Is there anyone set up to shorten LWB trailing arms to fit on a SWB car. I can take them to my metal guy but if someone already has a jig to make the adjustment, it might save a lot of work. Thanks

[1QuickS]

I modified my SWB bearing hubs to use LWB banana arms after re-locating inner pickup points. Lots of work. I aligned rear wheels and then "Floated" the LWB banana arms to fit between SWB bearing housings and the inner pickup point.

LWB banana arms will require cutting near the hub to allow the shortened banana to mate up with inner pivot. I suggest you make left & right jigs using SWB arms as masters. Be wary of lower shock mount location, if LWB shock location is fundamentally different from SWB location then you may have a shock tube clearance issue with the pocket in the cross member.

[ibmiked]

If you're going to all that trouble, best to use a set of aluminum arms from a '74+ car.

[mepstein]

I modified my SWB bearing hubs to use LWB banana arms after re-locating inner pickup points. Lots of work. I aligned rear wheels and then "Floated" the LWB banana arms to fit between SWB bearing housings and the inner pickup point.

LWB banana arms will require cutting near the hub to allow the shortened banana to mate up with inner pivot. I suggest you make left & right jigs using SWB arms as masters. Be wary of lower shock mount location, if LWB shock location is fundamentally different from SWB location then you may have a shock tube clearance issue with the pocket in the cross member.

Paul - Thanks for your input. Left and right jigs are going to be the starting point. I want the hub and caliper mounting of the lwb but the length of the swb. I'll keep an eye on the shock location. The chassis is bare and up on a rotisserie so pretty easy to test fit to make sure we are on the right track.

ibmiked - I've seen aluminum trailing arms used on early lwb cars. It's not a big deal to make it work. I want to keep swb length trailing arms on my swb car so the amount of fab and welding to an aluminum trailing arm is more than I'm ready to take on.

[1QuickS]

From a structural point of view: The connection of the banana tube on a SWB is MUCH more robust than for the LWB. When racing the RSRs, the hub to banana arm connection required reinforcement due to the extreme loading. LWB hubs allow larger calipers but most of braking force is at front so big calipers on a SWB are not so important. LWB bearings are easy to get compared to those in SWB hubs. Also, LWB hubs allow for larger CV joints.

I like having SWB hubs on my car due to the original design of the bearings that support the hub spreads the loading nicely within the hub and due to the robust connection to the banana is possible as a result of the bearing separation within the hub. The LWB hubs provide extra length for the CV axles which needed as much length as possible to accommodate the permanent angularity of the axles due to increasing the wheelbase length by 2.25 inches. By selecting a duplex bearing set the CV axles could be longer but this led to a weak banana to hub connection. The original design is the cleanest design.

[mepstein]

From a structural point of view: The connection of the banana tube on a SWB is MUCH more robust than for the LWB. When racing the RSRs, the hub to banana arm connection required reinforcement due to the extreme loading. LWB hubs allow larger calipers but most of braking force is at front so big calipers on a SWB are not so important. LWB bearings are easy to get compared to those in SWB hubs. Also, LWB hubs allow for larger CV joints.

I like having SWB hubs on my car due to the original design of the bearings that support the hub spreads the loading nicely within the hub and due to the robust connection to the banana is possible as a result of the bearing separation within the hub. The LWB hubs provide extra length for the CV axles which needed as much length as possible to accommodate the permanent angularity of the axles due to increasing the wheelbase length by 2.25 inches. By selecting a duplex bearing set the CV axles could be longer but this led to a weak banana to hub connection. The original design is the cleanest design.

The car is getting a 3.2 so using the later cv's is a bonus.