Rotoflex or CV Conversion ?

[JamesM]

Have standard spec sprint, with new set of rotoflex. Car used for mostly for road but will be off to various track days. Question is shall i change them ?
Any thoughts ?

[john.p.clegg]

I got fed up renewing the expensive rotoflexes,and Kangarooing in reverse,fitted u/j's with a sliding spline shaft and have never looked back
Go for it!
John

[gjz30075]

I wouldn't change them if you have brand new donuts fitted, unless you don't like the kangarooing around, as John put it. Start gathering the parts for your conversion now and be ready when its time to renew the donuts. I went for the inner and outer CV joints.

Greg Z
'72 Sprint

[theelanman]

I shall be collecting my mick miller drive shafts from the NAC show next month!!!.......new donuts are to coin a phrase 'cr@p'
due to the OEM compounds being completely toxic and deadly and the new manufacturing rules that say blah blah blah 'biodegradable' and 'envonmentaly friendly' the stuff they put in the new ones just aint the same and you'll find they dont last very long at all!!!
Ive had a pair of new inners on mine and theyre worse than the original (old type) ones that are on there
Ive chosen MM drive shafts ad they get rid of the 'nutz' completely rather than the like of the spyder ones which still retain one each side and other makes that have other (in my eyes) draw backs.....the TTR ones can lock on full droop.....erm cant remember the rest of my research but these were the 3 main ones.....
hope this helps
cheers
Gareth

[type26owner]

Ironic but the donuts don't have any bad handling habits when used at speed and at WOT on the track. It's just when doing gentle accelerations and when lifting off the throttle aburptly that the driveline windup is annoying.

[blueseamonkey]

If you've got the cash to spare, and nothing else that needs doing first I'd go for the changeover now. Failed rotoflexes can cause an expensive lot of damage, as I learnt from experience But my new Miller driveshafts make a great difference, especially for road use. I definitely recommend them.
Rick

[Dag-Henning]

Get rid of the rubber! They are no "design-advantage". Guess Hickman/Chapman chose them for cost-reasons.....
Dag

[marcfuller]

<i>"Guess Hickman/Chapman chose them for cost-reasons.."</i>

Did Eric Broadly at Lola have the same rationale for using them in the GT-40?

[nebogipfel]

Order a set of Mick Miller shafts without hesitation.

The only difference I have noticed is that there is no wind-up while driving

and ....... I do not have to drive the car with a worried expression!

[elansprint]

I suspect as well as being cheap to design they could charge an exorbitant price to change them on a regular basis

regards

Ian

[elansprint71]

"Did Eric Broadly at Lola have the same rationale for using them in the GT-40?"

Ah but GT40 drive couplings are much larger and were changed after each drive! I understand that their couplings are also now made to a crap spec- flailing drive-shaft at 180 mph anybody?

Don't foget these were originally just general engineering couplings, not specifically designed for cars.

Cheers,
Pete.

[marcfuller]

"Don't foget these were originally just general engineering couplings, not specifically designed for cars. "

Your statement is just as true for sliding spline, Hardy-Spicer and CV joint couplings. Although CV joints were designed in the late 1920s they were not used successfully in cars until the late 1950's and then only in relatively low horse power, light weight, front wheel drive cars. The point I was trying to make was that for the early 60's rotoflexes were not a poor or simply budget driven choice. It was one of the only choices available. That is why Lola also choose to incorporate them, and as you point out they are larger ... probably because the GT40 weighed 500 lbs more and had almost 300 more horsepower than an Elan. Together with the rotoflexes, a lot of parts on the GT40 were changed after every race.

When the set of rotoflexes I am using wear out I will likely switch to a CV conversion as well. Although by then, I hope that the Elan Factory or someone will come up with a conversion using the newer Australian based Thompson Couplings, and they can be evaluated for an Elan. Thompson Couplings appear to be about the same size as CVs and unlike CVs have no load bearing sliding surfaces. So they are more efficent and have supposedly no wear, binding on full drop, vibration, lubrication or other similar concerns.

[M100]

>Thompson Couplings appear to be about the same size as CVs and unlike CVs have no load bearing sliding surfaces. So they are more efficent and have supposedly no wear, binding on full drop, vibration, lubrication or other similar concerns.

If anyone wants a pdf copy (2.7MB) of the patent application for the Thompson Coupling just drop me a line at lotusdriver at hotmail dot com

[was]

The one thing I never liked about my Elan was the bungee-cord axles. Keith is right on about them being well behaved under load. But a lot of my driving was and will be easy puttering about, and then the kangaroos come out in force. I'll be going to the double CV axles when I get that far in the upgrade.

BTW, I have written to the Elan Factory twice with no reply. Are they on vacation? Else, maybe I am just persona non grata to them.

[rgh0]

Was

Dont know why Elan Facory has not replied. I was talking to Steve Taylor a couple of weeks ago and should see him at the Sandown Historic races this weekend. I will ask him if he is behind in his mail

Rohan