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Re: Rotoflex Couplings

PostPosted: Sat Feb 26, 2005 8:49 am
by rgh0

CV's reaching the end of their angular travel is more of a problem on the elan than the plus 2 but possible on both depending on the exact details of the CV joints used and their angular travel limit and the amount of droop allowed by the shock absorbers which varies from brand to brand. In the end if you have a problem at full droop you can limit the droop travel of the suspension a little with a restraining cable or strap.

I dont think either donuts or Cv's consume significant power. They dont get hot compared to the diff or gearbox.


Re: Rotoflex Couplings

PostPosted: Sat Feb 26, 2005 9:02 am
by steveww
TTR does droop limited dampers to go with their UJ/Spline halfshafts.

Do you take your Elan flying often ;)

Re: Rotoflex Couplings

PostPosted: Sat Feb 26, 2005 9:35 am
by nebogipfel
Berni, As Rohan says the problem is probably far less pronounced the +2 simply because the shafts are longer.

On my S4 I commented on it because the angle looks very steep.

Everything on my car is standard and the rear shocks are genuine Lotus Koni replacements.

I'm probably worrying for no good reason beacause there must be hundreds of CV equiped Elans around now. (I think something like 250 sets of Mick Miller shafts)

Re: Rotoflex Couplings

PostPosted: Sat Feb 26, 2005 9:08 pm
by berni29

I guess that it is easy enough to test by jacking the car up untill at full droop and then feeling for any resistance as you turn the wheel (by hand).


Re: Rotoflex Couplings

PostPosted: Sat Feb 26, 2005 10:25 pm
by garyeanderson
Hi Berni

Thats how I tore the boot on my CV, by turning the wheel at full droop.


Re: Rotoflex Couplings

PostPosted: Sun Feb 27, 2005 9:59 am
by nebogipfel

There is resistance on full droop and with a bodyless chassis as my car is at the moment the suspension is on full droop.

It appears to me (by loading weight onto the chassis) that the angle will still be very steep.

As I said previously, it is difficult to see how I can change anything unless I move away from the standard parts on the rear of my car.

Shorter rear springs are one obvious solution but don't want to mess around too much with the Chapman design. I would still be using Rotoflex couplings if I had confidence in them.

I have seen period publicity shots of Elan Chassis on which the drive shafts appear to be virtually straight. I can only assume Lotus doctored the springs to make it look good in the picture? If not, with full weight on, the shafts would actually have been running uphill to the wheels!

Re: Rotoflex Couplings

PostPosted: Mon Feb 28, 2005 10:40 pm
by hatman
When I bought my driveshafts from Mick Miller he said that, to avoid the possibility of problems on full droop, I should ensure that the diff was mounted at its lowest setting to minimise tha droop angle. Wasn't too sure what he meant (I didn't know that there was any adjustment in the diff mounting) but I just fitted 'em and they perform well and all seems OK (they've been on the car for just over a year now).

Re: Rotoflex Couplings

PostPosted: Tue Mar 01, 2005 9:48 am
by tdafforn
Hi all,
Had the same problem with the Tony Thompson sliding spline drive shafts I fitted last year. At full droop on a +2 the Inner UJ's bind. Chatted to TT about it and he commented that it was fine unless you jumped the car. Wasn't convinced. In the case of the Uj's however there is the option of grinding out pockets so they don't bind. However I went for the third option (which is also applicable to CV conversions) and bought a set of droop limited shocks from TT. I needed a new set anyway, and these are top adjustable, which is a bonus!
Whole setup works well apart from a very slight knock on full accelleration from V. tight corners.

Re: Rotoflex Couplings

PostPosted: Tue Mar 01, 2005 1:04 pm
by nebogipfel
Hi All,

Hatman, the diff is adjusted by adding or removing the thick washers above the mounting lugs. I adjusted mine so the diff just clears the bottom plate of the chassis

To be honest if you left all the spacer washers out it would not change the droop on the driveshafts very much.

I am heartened by the fact that although it looks like a problem it doesn't seem to be one :)

Re: Rotoflex Couplings

PostPosted: Tue Mar 01, 2005 4:17 pm
by lotus026
Way to go on converting to the CV joints - I did it on my Elan S2 after owning the car for 8 years, had never gotten used to the Rotoflex windup/down when driving it; took me all of one drive to get used to the CV joints - it's a way nicer car to drive hard now! Best $1,000 I ever spent, wish I'd done it sooner. Though my Rotoflexes hadn't competely died yet when I replaced them, it was obvious that they had for an earlier owner; flailing damage to the chassis & bodywork was visible once I was in there replacing them.
Dave B.