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CV joints vs Donuts

PostPosted: Wed Nov 22, 2006 6:44 pm
by jmesh
First, I finally pulled the trigger and bought an Elan. A green 1967 S3 DHC. Thank you to the many on this list who helped in my 10-month search!

Of course, now the hard part begins. Turns out, the rotoflexes have some minor cracking and I want to replace them. I think I may bite the bullet and buy the cv joints from Bean ($1500!) but think I should still consider the rotoflexes and save some money, at least for now. I like the safety aspect of the cv joints vs the rotoflexes but is this something I should really be concerned about?



Re: CV joints vs Donuts

PostPosted: Wed Nov 22, 2006 9:35 pm
by bcmc33
The Bean shafts look expensive at first glance, but they do include diff output shafts. Below are some recent posts that should be read to give you a good account of the ?if?s & but?s? and ?do?s & dont?s? of solid driveshafts.
It should be worth asking Bean what material the diff output shafts are made from. Rohan in Australia gives a good account of the potential weakness of the pre-Sprint output shafts. I feel sure that Bean has addressed this issue ? but it is still worth asking.

I am in the process of installing a pair of Mick Miller shafts to my Sprint.

I hope this helps

Brian Clarke

Re: CV joints vs Donuts

PostPosted: Wed Nov 22, 2006 9:58 pm
by ppnelan
I only replace my rotoflexes when I can see them start to come apart i.e. when the rubber begins to tear away from the steel plates. This is most obvious when the car is jacked up with the suspension at full droop, e.g. on the (UK) MoT test inspection !

They often develop surface cracks after a short while, but this does not necessarily mean they are at the end of their life.

Anyway, if you don't drive hard, they can still stay in one piece even when some of the plates have separated - I speak from experience :!: :shock:
(One year, the MoT man said he couldn't fail it as it is not part of the test, but he suggested it was driven home v-e-r-y s-l-o-w-l-y.... When I dismantled it to replace them, they literally fell apart when the tension was removed...)

They are not all bad, but I suppose that if you've had a particularly bad experience with them, it's enough to put you off them for good. It also seems that some people get used to abusing their modern cars with 'violent' gear changes & clutch engagements, and are then surprised when their 30+ year old Lotus can't take the same sort of punishment.

I would definitely recommend regular checks...!

:arrow: Matthew

Re: CV joints vs Donuts

PostPosted: Thu Nov 23, 2006 4:39 am
by jmesh
Great. I knew this had been covered recently but I didn't realize how recent and how in depth!
I've spoken to Bean and, while I don't know what material they use, the output shafts are uprated to handle high performance applications. They are SCCA approved. My car was autocrossed for years and was restored back to original when it's competition life ended but I don't know the condition of the output shafts. I believe they are fine as the rest of the restoration was to good quality by someone with a solid reputation in Lotusland.

I guess it won't be an easy decision either way. I'd probably rather have the cv's but they are pricey.


Re: CV joints vs Donuts

PostPosted: Mon Nov 27, 2006 11:12 pm
by RobCapper
not to hijack your thread, but simply as the topic is being raised.. what is the apporx price of the Mick Miller CV joints? I'm near to a donut replacement and am considering the change - I've not heard a bad word about the Miller unit...

..other units of course considered - price is very much a factor!


Re: CV joints vs Donuts

PostPosted: Mon Nov 27, 2006 11:18 pm
by bcmc33
The price I paid was 385 GBP + VAT = 452.38 GBP.
I collected them from Stoneleigh, so there was no P&P cost.

Susan Miller is on 01728 603307

Brian Clarke

Bean CV Joint Conversion

PostPosted: Tue Nov 28, 2006 1:34 pm
by CBUEB1771
I installed the Bean CV conversion in my +2S many, many years ago and have probably 50,000 miles on the set by now. I have had no failures but I can't say that I beat the car very hard. The improvement in driving smoothness on a +2 is quite dramatic. Even brand new Rotoflexes wind up significantly. One word of caution however. If you get the Bean kit, inspect everything very carefully. I had one diff output shaft with the bearing seat and drive spline centerlines offset significantly, meaning the two centerlines were in separate but parallel lines. I don't recall the dimension of the offset but it would have been enough to damage the spline or bearing fairly quickly. Dave Bean was gracious and replaced the one shaft without any debate. I don't mean to single Dave Bean out, limited production of anything implies some degree of caveat emptor. I am restoring my S2 Elite now and thank heavens I have free access to the machine shop and inspection room at work. Nothing ever just goes together first time with the older Lotuses.