Driveshaft Using Giubo / Flex Disc

[Carott]

I was wondering if anyone had some experience using a pair of Giubos (flex discs) to couple a solid mount transmission output to a solid mounted IRS differential?



I plan to connect the output from a 70's BMW motorcycle transmission to the IRS differential from a BMW car. I want to keep the driveshaft as short as possible and will adjust the axle lengths to align the transmission output with the differential input.

The Giubo is plenty strong for the job as BMW uses it to connect the car's transmission to the driveshaft.

I was wondering how much alignment error they will tolerate and whether a sliding spline to compensate for changes in length would still be needed.

I suspect I may be over thinking this but I know that the experiences of other members can save me a lot of grief.

Any thoughts would be greatly appreciated.

Brett

 

[stacebg]

I was wondering if anyone had some experience using a pair of Giubos (flex discs) to couple a solid mount transmission output to a solid mounted IRS differential?

I plan to connect the output from a 70's BMW motorcycle transmission to the IRS differential from a BMW car. I want to keep the driveshaft as short as possible and will adjust the axle lengths to align the transmission output with the differential input.

The Giubo is plenty strong for the job as BMW uses it to connect the car's transmission to the driveshaft.

I was wondering how much alignment error they will tolerate and whether a sliding spline to compensate for changes in length would still be needed.

I suspect I may be over thinking this but I know that the experiences of other members can save me a lot of grief.

Any thoughts would be greatly appreciated.

Brett

View attachment 68138

welcome to our crazy world lol have not used one before didnt know there was such a thing for a car but if it works in a car certainly hold up to a bike engine... if it were me i would make two exact duplicates out of steel bolt the trans coupling and engine together and be very careful about putting in the trans mounts in... u have solid mounts i see no reason it wouldnt work

 

[Fowler]

on my first trike (link below) I used something like this for a while then switch to a u joint.

it connected straight from the trany to the rear end.

It was a long time ago so I do not remember all the details

http://3fowlers.com/firsttrike.html

 

[LarryA]

with careful alignment, both angular and up/dn/ and side to side, those couplings should work just fine....if you measure distance accurately or have some means to move the rear end components fore and aft it should be good. I did align a chriscraft transmission and prop shaft yrs ago...forgot how now, but there should be a lot of info on coupling alignment on u-tube. good luck, sounds like a great project, post some pics when you can.

 

[Carott]

with careful alignment, both angular and up/dn/ and side to side, those couplings should work just fine....if you measure distance accurately or have some means to move the rear end components fore and aft it should be good. I did align a chriscraft transmission and prop shaft yrs ago...forgot how now, but there should be a lot of info on coupling alignment on u-tube. good luck, sounds like a great project, post some pics when you can.

Larry,

Thanks for the reply. I hope to get going on this project by late spring (If it ever comes). I will keep some info posted when I can.

Brett

 

[stacebg]

with careful alignment, both angular and up/dn/ and side to side, those couplings should work just fine....if you measure distance accurately or have some means to move the rear end components fore and aft it should be good. I did align a chriscraft transmission and prop shaft yrs ago...forgot how now, but there should be a lot of info on coupling alignment on u-tube. good luck, sounds like a great project, post some pics when you can.

that is what i was suggesting with the steel spacer probably should have explained more

with the engine and trans bolted in place i think i would get a rough measure within a 1/4 or so, have the driveshaft made bolt the drive shaft to the trans... then set the rear in place i think i would try to suspend it from the ceiling as near in line as you can... and bolt the drive shaft to the rear perhaps with a pc of manila folder in between. the trans an the driveshaft .. with it suspended hopefully there wont be any stress on the shaft... rather than have the trans "hanging" on the shaft... then make all the mounts just tack them in place..

next i would take out the steel spacer..and the manila folder spacer.. the slide the spacer back in and see if the gap is the same all the way around... the folder should give you space enough to slid the spacer back in..and it wont be enough to affect the couplings. hope that makes a little sense at least