Rubber or Urethane???????

[CRGRS 66]

I need to be ordering cab mounts and trailing arm bushings (hence this is in the suspension forum) soon.

My set up in the front will be 2.5" drop spindles and 2" drop springs (otherwise stock setup), and my rear suspension will be a porterbuilt stage one bag kit with porterbuilt adjustable trac bar. No notch in back, bags are just to adjust ride height if towing, or carrying a load. Should be running around equivalent to a 3" or 4" drop.

I am inclined to order the urethane kits, but would be interested in hear opinions from you guys who have used one, the other, or both.

[Ziegelsteinfaust]

I like urethane because of its stiffness, but I never had trailing arm suspension. I have only used them in A-arm/leaf suspension.

[SCOTI]

For the truck arm front bushings, I'd use them. For cab mounts, I'd use rubber. I don't see the need for poly as a body mount.

[69gmcc10]

From a handling stand point the urethane body mounts are supposed to tie the frame and chassis together and make it a stronger unit. It also is a more firm ride than rubber. For the trailing arms urethane stiffens up the joints and limits deflection of the joint, according to No Limit Engineering the only thing that should be rubber is the trailing arm mounts so there is less binding at that pivot point and everything else should be urethane for rigidity.

I have urethane cab mounts and didnt notice much difference in ride and I also have urethane trailing arm mounts and I think they are just fine, they certainly will last longer than the rubber will in that joint!

[SCOTI]

Originally Posted by 69gmcc10

From a handling stand point the urethane body mounts are supposed to tie the frame and chassis together and make it a stronger unit. It also is a more firm ride than rubber. For the trailing arms urethane stiffens up the joints and limits deflection of the joint, according to No Limit Engineering the only thing that should be rubber is the trailing arm mounts so there is less binding at that pivot point and everything else should be urethane for rigidity.

I have urethane cab mounts and didnt notice much difference in ride and I also have urethane trailing arm mounts and I think they are just fine, they certainly will last longer than the rubber will in that joint!

For OE truck arms, the poly bushings are fine. For solid, tubular type aftermarket arms that can't flex torsionally like the OE I-beam can, I would not do poly.

I agree the poly cab mounts will last longer. But, if you're not seeking a roller coaster type cornering experience, the rubbers will last years & are easy enough to replace should you keep your truck another 20+ years on the road. I would think the main downfall of them isn't so much a worse ride, but increased noise/vibration levels if the truck has the pre-73 type rubber-bushed metal sleeve trype a-arm bushings.

Interestingly... my buddy recently priced some Moog a-arm bushings & rubber body mounts @ the local auto parts place only to find the poly stuff available @ a pretty decent reduction in cost from Summit. If it's cheaper to do poly, they're the way to go.