Solid driveshafts - do they improve the driving experience?

[crannyr]

I have run cv joints in street and race cars for 20 years. The only time I had a boot failure was when we did not secure the small end of boot with a clamp or cable tie. Boot repalcement is not as difficult as donut change. Make the change.

[cabc26b]

if you make the change as suggested - inspect all the bits that hold the diff in place - solid drive shafts will pound these components -

[rgh0]

Is it possible that Lotus fitted doughnuts because they were cheap, light, cheap, worked (after a fashion) and didn't cost much?

When the Elan was designed Cv's did not exist and Chapman was concerned about sliding splined shafts binding and affecting the Elans handling hence the decision to use donuts which was a common race car solution of the time. They were also cheaper than the alternatives as well which always helped

cheers
Rohan

[hatman]

Is it possible that Lotus fitted doughnuts because they were cheap, light, cheap, worked (after a fashion) and didn't cost much?

When the Elan was designed Cv's did not exist

I'd always sort of assumed that the mini CV set up, introduced c1958, might well have been adaptable for Elan driveshafts but, as my engineering training comprised playing with Meccano, followed by trying to cajole a knackered old Excelsior Talisman Twin into starting each day and then continuing to run, I don't really claim any insightful expertise in such matters. Perhaps I have been a bit unfair to Lotus with my curmudgeonly view - sorry.

[types26/36]

I'd always sort of assumed that the mini CV set up, introduced c1958, might well have been adaptable for Elan driveshafts but, as my engineering training comprised playing with Meccano, followed by trying to cajole a knackered old Excelsior Talisman Twin into starting each day and then continuing to run, insightful .

When the Mini was introduced the inside coupleings were a bonded rubber crosspiece and gave endless problems as they disintergrated from the oil leaks, the outer had CV's but not suitable for an Elan, it was only much later that they got inside CV's but I doubt they would have been suitable for the Elan either.
P.S. I remember the Talisman Twin, a friend had one and wanted to sell it to me, I bought Ariel Arrow instead (also a two stroke twin)

[Frank Howard]

I'd always sort of assumed that the mini CV set up, introduced c1958, might well have been adaptable for Elan driveshafts but, as my engineering training comprised playing with Meccano, followed by trying to cajole a knackered old Excelsior Talisman Twin into starting each day and then continuing to run, insightful .

When the Mini was introduced the inside coupleings were a bonded rubber crosspiece and gave endless problems as they disintergrated from the oil leaks, the outer had CV's but not suitable for an Elan

Gentlemen,

I believe the original Mini used universal joints, not constant velocity joints.

[AHM]

Some Background:

CV joint history

The Fixed CV joint was patented in 1933
The plunging CV joint was patented in 1960
The VL joint used in the Elan aftermarket shafts was developed in 1962

In the context of the time I suspect most cars had a beam axle and those that did have IRS would be using Hooke's joints or Doughnuts as the plunging CV joint was only just being invented.

[AHM]

Repeat post removed

[types26/36]

[,I believe the original Mini used universal joints, not constant velocity joints.

No, the outer was a CV joint but not the plunging type as now used in the Elan conversion as the Mini has to both steer and transmit the drive through the CV joint.

[Lincoln62]

As no one has voted to stay with the Rotoflexes it looks like it is up to me.

I like them, they give the car a unique feel.

I have replaced one donut in 20 years (and 25000 miles). I visually check them every 12 months or so.

If the new donuts are poor quality and more likely to fail I would consider changing to solids though. Don't like the thought of one failing and punching a hole in the boot floor.

Peter
66S2

[spanner]

I'm with you Peter,

The doughnuts are alive... I like that! The old sheet metal, glass fiber, wood, aluminum, and wire all flex together, sort of. It's this quirky marriage of materials that gives the Elan character.

Took the old stock '65 Elan for our 39th "first spring drive" last week. Felt like I was 19 again... all flexible and alive. I like that!

[jono]

In fact all of the Mini Cooper S models used an inner Hardy Spicer cruciform joint on a sliding spline in place of the rubber type so the technology was there from very early on. The rubber type were used on the std mini to take up driveline shunt and make for a more comfortable drive

The later Mini used a conventional internal CV joint.

Jono

[elansprint71]

if you make the change as suggested - inspect all the bits that hold the diff in place - solid drive shafts will pound these components -

Absolutely correct. I fitted new top diff mounts when I put the Mick Miller shafts in- they lasted less than a year. this is due to the modern "rubber" being crap, same problem as the modern doughnuts.

The solution is to fit Tony Thompson heavy duty top diff mounts. These are the absolute business and it is what all the serious racers in the UK use. I've had them in for about 3 years now.

btw, the joints in the shafts of my FIAT 126 appeared to be made from cloth and cardboard- never gave me any trouble.

Cheers,
Pete.

[AHM]

Yes the technology was there but was not practical.

A HS cruciform joint does not give constant velocity.
If lotus had used a sliding spline they may as well have used the double hookes joint.
The Elan has a few more horsepower than the Mini.

The Fiat 126 finished life with a CV outer joint and a bipode inner joint - The 126 was also not known for its horsepower!

[elansprint71]

snip - The 126 was also not known for its horsepower!

True, but my wife still managed to spin ours through 360 when entering a motorway; she drives with a bit less verve these days!

Cheers,
Pete.