Page 1 of 2

Telescopic damper mounting angle

Posted: Sun Aug 23, 2009 9:07 pm
by linearaudio
I've been casting ideas for telescopic dampers around in my head, now I've sorted most of my other projects out (the overdrive box is tantalisingly close!), and recall all and sundry stating that the dampers must be fitted as near vertical as possible.
Now.... at a slight tangent, I fitted a full exhaust to a friends Saxo 2 months back and hey presto, another bit of modern rubbish, the flange broke off the back box today :( . SO WHAT??

Well, on crawling under, I observed the rear dampers on said car- laid at an angle of aout 35 degrees from the horizontal!

So.... how do Citroen get away with it when we can't?

Posted: Sun Aug 23, 2009 9:10 pm
by charlie_morris_minor
the later MO had telescopic dampers fitted at a simular angle.

Posted: Sun Aug 23, 2009 10:05 pm
by PSL184
No problem fitting dampers at an angle. Most important factor is that full travel of the suspension can be obtained without the dampers bottoming out or over extending.....

Posted: Sun Aug 23, 2009 11:33 pm
by linearaudio
Oh no, I feel another controversial subject looming :)

Posted: Mon Aug 24, 2009 8:07 am
by jonathon
On a solid rear axle the most effective position for a damper is as near to the end as possible and as vertical as possible.
There is no problem with angled dampers so long as they are designed specifically for that application. This being the main issue with the controversial angled Minor rear damper kit available at the moment, still not resolved after over 20 years.

Posted: Mon Aug 24, 2009 9:18 am
by dunketh
So.... how do Citroen get away with it when we can't?
1. You're talking about a small cheap french car.
(I really need not elaborate :lol:)

2. We can get away with it.
'Get Away' being the operative words. :lol: I'd say suck it and see. If you fit them and the car handles like garbage - take them off.

Just out of interest. Would gas dampers be better than oil filled ones?
Based on the fact gas cant slosh around like oil can?

Posted: Mon Aug 24, 2009 9:35 am
by Peetee
My experiences of replacement 'standard fit' gas dampers on a variety of vehicles is that they provide a similar damping effect but with less 'crash' on harsh bumps than the equivilent oil units. That's not to say all conversion kits would be like that however, as they are produced to satisfy a need to upgrade to varying degrees rather than to recreate the standard ride quality.

Posted: Mon Aug 24, 2009 10:56 pm
by bmcecosse
ALL tele dampers have OIL in them - that's how they work - by squirting the oil through small holes and controlling the pressure with safety release valves. In extremis - the valve opens and allows free passage - possibly through a slightly larger hole (in practice this will be several stages) so all damping effect is not lost when the first valve opens. Gas dampers - simply have an over pressure of inert gas applied - to prevent the oil from frothing so much. Frothy oil is useless!
The dampers work best when they have maximum travel for every movement of the suspension - they can only 'work' when the suspension moves. If mounted at an angle - the damper internals doesn't move as much as the suspension moves, and so it really can't work as well as it would if mounted so that it moved full travel with the suspension. So - if possible - mount the damper vertically (since on the whole - most suspensions move vertically - notable exception is Hillman Imp front wishbones which swing in a very definite arc with fantastic wheel camber variation!) to get the best from it. If this not possible - then the damper must be designed to be much 'stiffer' - so that it can do the same work with less movement - and in general this doesn't give as good control of the damping. It can also introduce high transient forces to the mounting arrangements - and may be the reason for the renowned 'cracking' of the attachment frames sold with some Minor rear damper kits - where the dampers are mounted at strange inward leaning angles !! In 'racing cars' - the dampers and springs are generally now mounted inboard out of the air flow - and operated through linkage systems (some 'pull rod' some 'push rod') - but where possible the wheel movement will actually be multiplied by the linkage before it reaches the spring/damper unit - to allow the maximum movement there to give very best control over the very minimal wheel movement most 'racing cars' require!
There is absolutely nothing wrong with 'lever arm' dampers - in effect - they are exactly what's used in the 'racing cars'. The Minor front damper is mounted inboard, and connected to the suspension by a link - which also cleverly (well done Issigonis!) serves as the upper suspension arm. Internally - it is a double cylinder teledamper contained in the single body casting, and it has the major advantage that it can be fine tuned by changing the valve settings and by using varying viscosity oils within the damper!

Posted: Mon Aug 24, 2009 11:00 pm
by PSL184
Glad thats got that question sorted out then :-)

Posted: Tue Aug 25, 2009 9:36 am
by Kevin
There is absolutely nothing wrong with 'lever arm' dampers
Likewise tele dampers its just some of the mounting kits that give cause for concern.

And are not the LCV standard tele dampers mounted at an angle ?

Posted: Tue Aug 25, 2009 9:42 am
by dunketh
Standard lever rear dampers are fitted at an odd angle anyway.
Just out of pure curiosity does this make them any less effective?

Not questioning their usefulness, just something I've often wandered when tinkering at the back.

Posted: Tue Aug 25, 2009 10:46 am
by Peetee
I can't see an issue with tele damper angle if the damping rate and stroke are designed accordingly. Mercedes Sprinter vans have them this way and cope with a substantial load variation. I've driven these vehicles and not found them to be lacking. In fact, looking around, they are invariably driven by maniacs as a matter of course!

Posted: Tue Aug 25, 2009 2:07 pm
by bmcecosse
Lever arm rears are only 'canted' to suit the mounting bracket - not really mounted at a 'an angle' as far as the leverage rate from the suspension is concerned - it's direct from the push-rod. What would be useful is if someone can come up with a larger rear damper unit that is easily fitted in place of the rather small standard rear damper . Anyone found something suitable ? I wonder what's fitted at the rear of a Wolseley 1500 ?
And I agree with Kevin - there's nothing 'wrong' with teledampers - but there is certainly no need to go rushing to spend a fortune on them either! The lever arms will work very well if set up properly.

Posted: Tue Aug 25, 2009 6:59 pm
by linearaudio
[quote="bmcecosse"] ......There is absolutely nothing wrong with 'lever arm' dampers - in effect - they are exactly what's used in the 'racing cars'. The Minor front damper is mounted inboard, and connected to the suspension by a link..... quote]

So I've got an F1 Moggy! Love it!! There's nothing new under the sun!

Posted: Tue Aug 25, 2009 7:29 pm
by MarkyB
Just substitute carbon fibre for cast iron and you're good to go :) .

Posted: Tue Aug 25, 2009 8:29 pm
by bmcecosse
I would say F1 etc copied the Minor - it had inboard dampers first! AND it has torsion bar springs - also used extensively now in F1 etc!

Posted: Wed Aug 26, 2009 9:38 am
by dunketh
But they probably don't replace their damping fluid with engine oil to stop them bottoming out on bumpy country roads. :lol:
Also, F1 is a strictly 'beard' and 'ale' free environment afaik, so it's not entirely allied with the average Minor owner.

I believe a lot of 'modern' French cars still use torsion bars.

Posted: Wed Aug 26, 2009 10:31 am
by Peetee
Not strictly modern but the Peugeot 205 had torsion bars. I've never driven a sporting version but have driven a bog-standard GL and that was insanely chuckable and entertaining. :lol:

Posted: Wed Aug 26, 2009 10:32 am
by jonathon
Brawn, Button ,Barrichello (BBB AKA Beardy beardy brigade) have beards, they must be Minor infiltrators into F1, no wonder they are leading the Championship, must be using BM's damper 'bodge' too. :D

Posted: Wed Aug 26, 2009 2:50 pm
by bmcecosse
Unlike me - I think they can probably afford to have custom made dampers - no need to use thick oil!