CV Joint Conversion





After several years driving around in a Herald at top speed, the prospect of having a rear suspension set-up that didn’t try to kill you if you got your cornering wrong was quite attractive.


However, the Rotoflex set-up does have some drawbacks:

It is complicated and expensive to overhaul

It is rather heavy (but that’s another story)

The rotoflexes themselves can be rather short-lived especially some of the pattern ones.


I have had quite a bit of trouble with the rotoflex couplings themselves over the years – initially I think because a lack of bump stops meant excessive suspension travel and thus excessive drive shaft length-change, but also using ‘cheap’ pattern parts has proved to be an expensive mistake.


So, when they once again needed replacement, I pulled the whole lot apart and tried to get real Metallastic (now Trelleborg) replacements.  This proved extremely difficult.  Reluctant to condemn myself to repeating the job in a couple of years I decided to consider alternatives:




  1. Convert back to swing axle using the long drive shafts and a swing spring as Triumph themselves did with the late GT6. 

Pros: Pretty reasonable handling, simplicity, light-weight.

Cons: Relatively expensive due to the parts required.  UJ life not great.  Shafts can break.  Tricky to get a swing spring able to take the weight of a well-laden Vitesse.  Seems like a backward step.

  1. Found a website (see link) showing a conversion using a Lobro joint in place of the rotoflex.  This involves cutting down the outer shaft, welding a suitable flange to it and manufacturing a suitable inner shaft using the standard UJ on the inner end and having a spline to suit the lobro on the other.

            Pros: Gets rid of the rotoflex

Cons: Questionable practice using a UJ and CV joint on the same shaft.  Means sacrificing hard-to-get outer driveshafts, making it irreversible.  Complex, expensive work to make inner shaft.

  1. There have been various one off conversions done using T2000 parts.  These are strong but a lot of work and the end result still suffers from the notorious ‘spline lock’ when pushed hard.
  2. There have been various one-off conversions done using BMW or Ford parts, often using the differential as well.  Probably the ultimate technical solution but way beyond my intentions.
  3. The Kiwis seem to use RWD Datsun/Subaru parts with great success. Again, a lot of work plus the parts are much less common in the UK.  See Link.
  4. Canley Classics are in the process of developing a CV joint shaft.  They are understandably coy about their methods, but I understand it uses Triumph joints and will be a direct bolt-on replacement.  It is not yet available (in testing at the time of writing - late 2005).
  5. Looking at the partly dismantled assemblies it occurred to me that the uprights looked as though they had been designed to take a CV joint.  Being a firm believer in ‘parts bin engineering’ but more in hope than expectation, I set off to my local scrapyard with the upright and hub to see if anything would fit.