drive shaft coupling ID

[dgym]

Hi gents,
just quickly wondering if anyone might have any ideas about the quality of the donuts pictured. Apparently purchased from JAE approx five years ago... would these be in the era of bad couplings? I cant see any metal re-enforcement.

any ideas appreciated,
cheers,
-Jim

[rgh0]

They are not the correct donuts and look to be to flexible to work in an Elan even if the width and bolt size and bolt pitch circle fits. They may be prop shaft couplings of some other car or a standard industrial coupling that someone experimented with for an Elan.

I doubt they were sold by JAE but you could always contact them and ask if they recoginse them.

cheers
Rohan

[dgym]

Thanks Rohan,
that's enough info for me to leave it.

[mazlot]

They were sold by JAE, here is the receipt !!.

[StressCraxx]

Well, probably for the first time ever, may I respectfully disagree with Rohan?

The couplings sold by JAE are made by Giubo, SPA (pronounced "jewbo") of Italy. They are used as driveshaft couplings on BMW and other European rear drive cars. They can easily withstand the torque of the M3 and M5 motors. Their allowable angular misalignment is similar to the ratings provided by Metalastik (the original Elan donuts). Of course, Chunky ignored the Metalastik specified allowable angular misalignment and used them anyway.

I'm an industrial reliability engineer and work hard to make my decisions based on data. I used to select several types of drive couplings to convert from hard gear couplings on rotating machinery in an oil refinery.

I believe Giubo couplings if properly selected and installed should work just fine. They offer many types, dating back to the driveshaft couplings for the 50's era Alfa Romeos.

At least the JAE offerings have solid steel inserts instead of the cheap folded sheet metal on the Metalastiks that collapse when you torque the bolts to the stub axles. Perhaps Jeff Robinson could chime in on their selection process?

Giubo - translated from German
http://www.gromex.de/produkte/goetze/giubo/?language=en

Metalastik
http://www.missionsupplyonline.com/pdf/rotoflex.pdf

Best regards to you all,
Dan

[Gordon Sauer]

Interesting if they are poly as well. Somebody just about a month or two ago on here was talking about experimenting with a poly duplicate of the Roto flex couplings. Gordon Sauer

[Chancer]

In the link given by StressCraxx there is a list of couplings which give full dimensional d?tails like this

http://www.gromex.de/produkte/goetze/giubo/giubo_88551/

As well as the table showing the permitted operating angles, I dont have anything around to measure but it would be really usefull if someone could try and find the guido part number that equates to the hole diameter, PCD etc of the Metalistik coupling.

I thought that the coupling that fits the ?lans (with minor modifications) was a propshaft coupling for a BMW and not a driveshaft coupling? that would indicate a lower torque loading and lower angular deflection but higher rotation speed.

My gut feeling tells me they are more than up to the job and it seems people are using them, it would just be nice to know definitively what dimensional diff?rences there are and if on paper at least any of the design paramaters are exceeded by being used in place of a Metalistik coupling.

And as has been pointed out the Metalistik ones were used outside of their parameters, as for the modern replacements made out of cheese............................

[billwill]

I thought that the coupling that fits the ?lans (with minor modifications) was a propshaft coupling for a BMW and not a driveshaft coupling? that would indicate a lower torque loading and lower angular deflection but higher rotation speed.

The torque on a longitudinal drive shaft would be reduced numerically by the ratio of the diff wouldn't it ? But then there may be a factor of 2 coming in for the fact that there are two rear wheels and add on a bit for diff power loss.

[rgh0]

Well, probably for the first time ever, may I respectfully disagree with Rohan?


Best regards to you all,
Dan

I dont think your disagreeing with me. I thought they looked like a prop shaft coupling. I am just surprised that if JAE sold them why they had not become a more common replacement for the traditional rotoflex if they performed satisfactorily given their cost

cheers
Rohan

[CBUEB1771]

I thought that the coupling that fits the ?lans (with minor modifications) was a propshaft coupling for a BMW and not a driveshaft coupling?

I suspect we have an American English / mother tongue issue here. Dan is probably referring to what you would call the prop shaft. We in the US refer to the shaft between the gearbox and differential in a front-engine / rear drive automobile as the drive shaft. As long as these joints are safe for 300 ft-lb and have adequate angular flexure they might work.