Tom Woods Super Flex U-Joint -- Review
Elegant innovation for a common problem

By Lou Dawson

Super Flex™

With three customized 4x4s in the family, if there is anything I've learned it's that building a trail ready 4x4 is a lesson in consequence. You change one thing, and it ALWAYS affects something else. And those somethings get expensive when the consequence is breakage or premature wear.

Witness drive shafts. You lift your Jeep, fit nice monster tires, and now your drive shafts are working at angles that resemble the pitch of a cathedral roof. Consequence: your U-joints bind -- and break.

You can solve this problem with a number of expensive solutions. But how about something simple, economical, and strong?

Enter the Tom Wood Super-FlexTM Universal joint. Simply a u-joint with with an off-set, the Super-Flex sets the drive shaft mating yokes farther apart than a regular U-joint, thus allowing more room for the joint assembly to flex without binding.

Our binding U-joint before Super-Flex.

After CODE 4x4 did an excellent spring-over lift on our Jeep, our front drive shaft bound up at full droop. I clearanced the yokes aggressively and gained a few degrees of angle, but had to quit peeling metal off the things before they exploded the next time I pulled out of the garage.

We needed about 2 more degrees of flex, so I started looking at solutions such as CV joints that flexed more than we needed (and cost way more than our budget allowed).

After Super-Flex, major gain in joint clearance.

Then Woods came out with the Super-Flex U-joint. Problem solved. After installation our max driveshaft angle went from 30 degrees to a good 40, with axle droop increasing 2 1/2 inches. That's WAY more than enough for our suspension travel.

Downside? The Super-Flex will lengthen your drive shaft a bit. If your slip joint has marginal travel (ours does), you might need to have your drive shaft shortened. More, in our case we do get moderate vibration when we drive over about 15mph with our front hubs engaged, but it's more of a hum than a shudder and doesn't feel particularly destructive (though it wouldn't do for highway driving).

Conclusion: The Tom Woods Super-Flex is an incredibly easy and cost-effective way to add MAJOR flex to drive shaft U-joints, especially a front drive shaft that is only engaged for lower speed trail use.

(Author Lou Dawson is our CODE4x4 webmaster and a well known Colorado outdoor writer who's first drive was his dad's flatfender Jeep. Article copyright Louis Dawson, WildSnow.com )