Rotoflex yet again

[TomMull]

Dimensions available in the attached Dunlop brochure. GT6 has 113mm pcd ( source factory wsm) .
Brian

I can't seem to get from the Triumph part number, GCD301, or the Lotus part number C050D0034Z or A026D0034 to the numbers on the PDF.

Also note that the GT6 Donuts are quickly catching up with Lotus ones in price. These are also marked as aftermarket on Rimmer's website. With the prices roughly equal, there is little reason to try to fit the Triumph joints.

Tom

[Andy8421]

I have read that Chapman had to chose between rotoflex and inboard brakes and chose the rotoflex. The reason was presumeably handling and some subtlety with the geometry.

Given Chapman's reputation, the reason was most likely cost.

[jono]

...cut out the middle man:

https://www.robush.com/?s=rotoflex

(and get your wisbone and other bushes as well)

[69S4]

...cut out the middle man:

https://www.robush.com/?s=rotoflex

(and get your wisbone and other bushes as well)

They even do a steering column Rotoflex

It doesn't say but I presume there's a substantial minimum order to buy direct.

[rgh0]

...cut out the middle man:

https://www.robush.com/?s=rotoflex

(and get your wisbone and other bushes as well)

The use the cheap pressed metal bolt sleeves rather than the original design judging by the photos - i would look for another supplier if i was trying to continue to use rotoflex copies

cheers
Rohan

[Quart Meg Miles]

Dimensions available in the attached Dunlop brochure. GT6 has 113mm pcd ( source factory wsm) .
Brian

Thank you, Brian!

The PCD of an old set of mine is 106 mm but I will try to measure the bolts on the car in a few days. The only one anywhere near that in the Dunlop list is 113, so it looks like we may have a match with the GT6. BTW Dunlop's PCD is between opposite bolts, not adjacent ones.

The 12 segment version 21/979/1 is 40% stiffer than the 6 seg 21/932/1 and so is the torque capability but other data are the same.

[oldelanman]

According to Robinshaw and Ross the driveshaft PCD was reduced from chassis no. 26/4108 onwards and the nominal dimensions were confirmed in an earlier thread on here as 100 mm on early cars and 96 mm on later ones.

viewtopic.php?f=37&t=17430&start=

Looking at the Dunlop Rotoflex chart it seems to me that Pt No 21/1004/1 .. 100 mm PCD (without interleaves) would apply to early cars and Pt No 21/967/1 .. 96 mm PCD (with interleaves) would be for later cars.

The GT6 item at 113 mm PCD appears unsuitable for either application.....or am I missing something here ?

[oldelanman]

Out of interest I just got a quote from Robush for the Metalastik Rotoflex coupling Pt No 21/967/1 which appears to be the correct item for later Elans. They were unable to confirm if this was Original Equipment but do say it is an original part and not a copy. The good news is there is no minimum order quantity and the item is available from stock, however ....... the price quoted is ?136.49 each +VAT which is nearly double what the Lotus suppliers are charging.
So .... either the Lotus suppliers are getting a substantial trade discount which they are passing on to us or, and possibly more likely, they are selling a different aftermarket part from an alternative source.

[jono]

...another (possible) option:

https://classicalfa.com/105-coupe-parts/propshaft-axle/

I'm not sure if these have the same PCD (but I can check as I have a 105 Alfa too) and I also note they do not have the 'webs' of the Lotus type but they are cheap in comparison.

A previously mentioned these do not receive any articulation in the Alfa application so perhaps not appropriate to a driveshaft use.