300m u-joints

[mrblaine]

Bobby said no aftermarket bushing U-joint should be used on a daily drive that saw many miles. He said you'd be greasing the U-joints on a weekly basis. Jack said it would probably be fine as long as the joints didn't run dry.

I've looked at both joints and would say they are very, very similar. The bushing design doesn't hold as much grease on the trunnion as the roller bearings can.

Bobby is a really good guy and knows his stuff, unfortunately, he's wrong about the bushings in Jack's u-joints and they were tested a long time without hubs on the street before Jack ever released them.

The design between the two may be similar, but Bobby's don't have bushings unless he's changed the design recently.

Does the bushing design hold enough? Maybe, Elusive has had good results. But one manufacturer definitely doesn't recommend it.

There's far more to that equation than how much grease is in there. You could make a case easily that because needle bearings have such a small contact area, the design is poor. I know there is some merit to that because the diameter of them has changed between the 297 and 760 versions.

Also, the bushing material that Jack uses is from a category of metals known as bearing bronze. It's stuff specifically designed for use in bearing applications.

BTW- Elusive is not the only one with good results and I can attest to his good experiences 100 percent being duplicated by many others.

As far as who's 300m U-joint or support is better, I don't know I haven't been able to brake one.....yet.

It's pretty simple. If Jack's joints couldn't be street driven, he would put a big disclaimer limiting their use. Elusive's testament as to how Jack treated him for warranty is how Jack treats everyone. He wouldn't be able to keep making them if they had to be replaced or repaired everytime someone drove them on the street.

Finally, the last person you should listen to regarding a product is someone trying to sell you a competing version.

[bullysteve]

i have personally been to ctm's shop and talked with jack himself regarding using his u joints on the street , his response was they are fine for the street and he said think about the only time u joints are most stressed is when there in a bind , what would mean in off road conditions not on the street , he also said he's be using them on the street with no issues

[Double AA]

i have personally been to ctm's shop and talked with jack himself regarding using his u joints on the street , his response was they are fine for the street and he said think about the only time u joints are most stressed is when there in a bind , what would mean in off road conditions not on the street , he also said he's be using them on the street with no issues

I don't believe the strength of a 300m joint for street use is in question. It's the hour after hour of relatively high speed use that a street vehicle sees which puts the joint into a completely different environment that's in question.

When a vehicle is going straight the U-joint does nothing. It's when the vehicle is turning that the caps start to move back and forth on the trunnions. The faster the vehicle moves, the faster the U-joint has to move which leads to more heat. Heat brakes down the lubricant which leads to wear and ultimately failure. Going down the freeway at 80 mph is much easier on the joint than going 45 mph through Malibu Canyon.

[Double AA]

While I wouldn't say I know either person, I have meet and spoke to both several times. I've been to Jacks shop and have seen his work. Definitely high quality stuff and I believe he does all the machining there. I haven't been to Bobby's shop but I know outsources a lot. Not that any of it is of poor quality, but he doesn't have any control of a piece he doesn't build.

It was three years ago that I put the 300m joints in the D44. Obviously Jack's received feedback since then. At that time Jack didn't offer any actual experience of his joints in a daily driven vehicle. He also didn't have an answer for the maintenance intervals of his joints used on the street other than to keep them well greased.

From a design stand point, I believe you're correct in saying that a roller bearing isn't as strong as a bushing. But in my experience that's rarely the cause of a failure. On street driven vehicle it's typically maintenance, and on an off road vehicle it's typically a structural issue other than the roller bearings. I'm a layperson, but it seems the roller bearing has adequate strength, holds more grease and would go longer distance's between maintenance on a street driven vehicle. Of course if you're braking U-joints off road, 300m is the only alternative.

I know of four companies producing 300m U-joints. Of the four only one has "For off road use only" on the package, and it's not Longfield. I'm not so sure that the lack of that verbiage means that the others are for street use. If there's a failure on the street, chances are it's going to be that the bearing ran dry of grease. At that point it becomes a maintenance issue, and it doesn't matter if you drove 200 miles or 20k miles, it's going to be a hard sell trying to get any company to replace a fried U-joint.

If you find yourself in a situation where you have to run 300m on your daily driver, I would say grease them often. After every two or three trips to JV, I grease the joints and drive shafts. It takes about 15 minutes to jack the front end up and rotate the wheels as I lube them. My U-joints are a mess because I make sure all the old and possibly contaminated grease has been pushed out.

[Jeeperator]

I think what it comes down too is they should be lubed alot for longer life. I dont drive my jeep on a daily bases so I dont think it will be an issue as long as I lube them before or after every outing. Are ctm's still using bushings. The current trend seems to be no bushing just a chromoly cap which is most likely a softer material anyway.