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Props, Wide angle or Double Cardan and Cranked Radius Arms


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Ok, I wan to try and finally make my decision on witch way to go;

I had made my mind up at one point to use double cardan on the front and wide angle on the rear but after speaking to a guy from Bailey Morris Ltd who had some very nice looking props on show, when I asked about the double cardan IIRC he said you only need to use a DC if either face of the output or input flange is not level and by this I mean vertically or horizontally level, it does not matter if the route is offset either left or right or up and down, So basically if the T-box output flange is level both ways and the same for the input flange on the diff, I will just need a wide angle unit.

Anyhow, today I fitted my X-brake and thought I would grease the props up, the front prop was shot so I got my spare and had a look at what I had been told, now due to the lift my front axle tilts slightly forward and thus the input flange is not sitting vertically level, so if you view it from the side it points between 12 and 1 O'clock position, so if I am thinking correctly I would need a DC prop, BUT sticking in the back of my mind is the point if the axle is slightly angled forward this opens the angle from the prop up so there would be less tension on the prop, so why do I need a DC prop??

Do I go for cranked radius arms and wide angle prop or just go for a DC prop?

Sorry for the poor diagram, but it may help understand my thinking

prop.jpg

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He is right in a way, but his logic is wrong. It's due to the operating angle being too large between the two ends of the prop. This causes the vibrations.

So the two ends of the propshaft could be parallel, but if the angle in between lower and upper ends was too large, for example you put a really big lift on, you would still have vibrations. Putting on cranked radius arms will bring your diff nose down increasing the angle causing more vibrations. So typically putting on cranked arms requires a DC prop, whereas otherwise you may get away with it.

As you have the vibrations already then yes you'll need to fit a DC prop. Some of the more heavy duty wide angle props have a bigger working angle tolerance so these can work too and is why you get confusion with some people claiming that wide angle props fix this problem. In fact all wide angle props do is give a wider operating angle for the UJ's to work before they bind. It just so happens that some of the larger heavy duty props used for wide angle applications also have a bigger tolerance for working angles.

Steve

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I had the dreaded vibration issue

I tried a Wide angle(Large UJ prop) this did not cure the issue

a D2 prop cured it but lasted onlt a short while

Propshaft clinc made a bespoke one with 8 or 10 grease nipples

it has been on since the day it arrived and is fairing very well.

pics etc:

http://forums.lr4x4.com/index.php?showtopic=77

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Thanks Guy's, I dont really get much vibrations just a little when coming to a stop but I want to remove any future issues I could face, plus I think my front prop is a little short so want to change that. So it looks like back to plan A with DC on the front and Wide Angle on the rear.

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Ive had this problem, 1) i lifted my truck 2". 2) then got vibration. ( 1st transfer box died).3) i was advised by several people that a wide yoke prop was the answer. WRONG!.(2nd transfer box died). 4) Fitted castor corrected cranked front arms and still no joy. 5) d/cardon front prop from devon 4x4. All good!!!

it was a very exspensive lurning curve, but even now people tell me that its wrong (but it works fine). everyone has a different opinion. you just have to take all the advise and do your best with it.

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Thanks Guy's, I dont really get much vibrations just a little when coming to a stop but I want to remove any future issues I could face, plus I think my front prop is a little short so want to change that. So it looks like back to plan A with DC on the front and Wide Angle on the rear.

You are right to do this. Even with a small vibration it will still knacker the UJ's and it also causes diff pinion seals to go too.

it was a very exspensive lurning curve, but even now people tell me that its wrong (but it works fine). everyone has a different opinion. you just have to take all the advise and do your best with it.

Ask them to explain why you are wrong. ;)

It's fairly straight forward, and hopefully pics below will explain this better than my text in post above..

post-18-1235468493_thumb.jpg

The lift has increased the working angle at both ends

post-18-1235468510_thumb.jpg

Pic 2 shows zulublue's situation where fitting a lift with a standard radius arms will tilt the nose of the diff up and the flange is now at an angle. The diff nose being up slightly and the angle of the flange both combine to reduce the working angle of the joints. Slightly at the transfer box end, more so at the diff end.

So adding kinked radius arms would lower the diff nose, but now create greater working angles at both ends. Back to pic 1.

So adding adjusted radius arms are likely to introduce more vibration.

post-18-1235468493_thumb.jpg

Quite a few wide angle props are made with Toyota, Nissan or just bigger Heavy Duty UJ's and yokes like the GKN ones from Gwyn Lewis. By the nature of their design, these props are more tolerant to greater working angles. But if the working angle of your lifted Defender exceeds the max working angle of the wide angle prop you will still get vibrations after fitting these. That's why they fix the vibration in some cases and don't in others.

So the only guaranteed way to stop the vibrations caused by greater working angles is to fit a Double Cardan jointed prop. Even these have their limits though.

Hope this helps.

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I had a similar problem and like Scatt I went through the same costly trial and error exercise having spoken to all the propshaft people claiming to have the solution.

Wider yoke propshafts are only useful for extreme articulation where prop bind is a problem.

I eventually got an answer from the main man at QT which made sense for Land Rover.

Two seemingly identical vehicles both having the same 2” lift one will be fine while the other one can experience all sorts of problems.

This has been the way things have worked out with me. One defender and two range rovers all lifted by 2” only one gave me a problem.

I fitted caster correction radius arms and double carden to the front of my Range Rover however to my frustration it also seems to of effected the rear prop as well.

I have changed nose bearings in the transfer box and even replaced the transfer box to cure the problem.

Rear prop is being modified with a double carden as well.. Hopefully this will finally cure the problem.

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Nice picture.

It’s all to do with the speed in which the ends of the UJ travel in when at an angle. (On end of the cross will travel faster than the other in the same way the outside wheel will travel faster then the inside wheel when turning a corner) UJ have a tolerance at which they will work. The more you life the vehicle the greater the angle the two UJs have to work towards each other and a drumming effect starts which causes vibration. Double Cardon joints work like a CV and turn at a constant speed independent of the angle they are working at.

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