A rant

[Northy]

Jim (Dixon) says:

A Mc phearson strut is the same way up as our toy cars.

On a WRC they are also the the same way as our toy cars because the remote reservoir can be mounted at the body/chassis end.

But he does say some damper designs should be run the other way up, dependant on the damping type and dependant on where the valving is located.

So some run one way, and some the other.

G

[DCM]

Originally Posted by mattym0310

im confused about all this meat and upside down forks. mind you i do get confused quite easily sometimes .
i just realised, if i know what your talking about, mountain bike forks are upside down compared to our buggy shocks.

so anyone want to explain the whole meat business?

original the stanchions were in the tree's, as it was easier to make fork tree's to carry the stanchions. Then someone realised, that if they turned the forks the other way up, the front end remained more rigid, and called them upside-down forks, it gave the front end tighter handling due to less flex.

[super__dan]

Regarding the meat, if it feels good, do it!

[bigred5765]

I'm not sure, but don't oil filled shocks have to be the way up we use em, because of the air inside them, it would be in the piston part of the shock if run upside down.

[Lee Martin]

cheers dan,

yeh my situation is strange at the moment....

people can say as they wish. it only really matters on the track....lol

but yeh some people need to chill out. on one of my real car forums a few years someone scratch their car, when asking how to mend this problem some complete tool said that they should use W40 sand paper...to which the idiot did and it left a nasty mess....

now this was an extreme measure, but it comes to show that stupid advice can often be taken and become regretable.......

keep that in mind when saying something stupid or something you dont fully understand.

i do not know everything and the only 2 people i would really trust with setups on this forum are rich barton and rich cree.

lee

[shinytopman]

Originally Posted by BenG

I dont get the meat thing, you guys are toooooooooooo deep

Can i be the MEAT !........Hubba..Hubba!!!!!

[ashleyb4]

I think everyone has a few select people they trust. I trust Phil Sleigh, Phil Channon and Stu evans. There people you can rely that what they tell you is good advice.

A

[b4rs]

you know its serious when jimmy intervenes! and whatever has been said it werent me ....... lol

[b4rs]

its better to aks questions, i am one for that, but if you dont ask you dont get to know, u gotto ask someone you trust. but then agian theres the point at which your answerer gets pissed off with you for asking os many q's lol, thts generally my case.

[MK999]

Strange someone should mention upside down shocks, as I actually came across this today doing some background reading, and in the damper section it mentioned them as being fitted 'upside down' compared to R/C stuff, took me 2-3 times reading it to realise I was reading it correctly after all as for performance reasons, I'm not entirely sure, it could be that it's easier to direct airflow onto them for heat dissipation when they're 'upside down' in saloon and open wheel cars, but that's the only reason I can think of

edit: as to what northy said, i think that's a design point for the progressive damping, as in if you had the exact same damper, reversed the valving on it, and put it on the other way up it would work in the same way... but not sure on that, that's just how i understand what i've read

[shinytopman]

Originally Posted by bigred5765

I'm not sure, but don't oil filled shocks have to be the way up we use em, because of the air inside them, it would be in the piston part of the shock if run upside down.

Correct me if im wrong.......( I've asked for it there !)

But in a perfect world there should be no air in the oil section of the shock and there for would make no difference what so ever to the performance, as you are solely relying on the resistance caused by the oil flowing throw a restrictor i.e. the piston.
If you have a bladder in the shock which uses the trapped air as an overall buffer (as the sealed in air will compress but not escape) all that means is, it will be more progressive towards the end of the shock travel as it will get stiffer as the air is compressed !

This is how i see shocks working. Remember the primary function of a shock is the reduce the bounce of the spring!

So to me the shock will work either way up, just doesnt look conventional thats all

Im no vastly experienced racer but i am an engineer and deal with a lot of hydraulics in my work.

Now can i be the meat......

Laid myself wide open here and ive got broad shoulders and an open mind, so feel free to correct me. Its never to late to teach an old dog new tricks.

[jimmy]

It matters which way it is up because of the unspring weight.

wikipedia refering to bike forks :
"Upside-down" (USD) forks are installed inverted compared to typical forks, with the tubes at the bottom and the bodies at the top. This decreases the unsprung weight of the motorcycle and improves its handling. USD forks are usually found on sportbikes, though Honda's large power-cruiser, the Valkyrie, sported USD forks.


like I said tho, any shocks mounted the other way seems to be because of access, design or other matters, airflow, but not all out shock absorbing performance... Should I put the oven on?

[rich_cree]

If you ran our shocks upside down you would have air not oil next to the seals, this means there would be no pressure on the seals and they would take in air when extending and piss oil out when compressing so they woldn't stay fresh as long

[Jimbo]

Interesting discussion.

Unsprung weight meaning the weight of the suspension arm, wheels etc from the hingepin and top of the shock spring outwards eh? I get confused a bit with that.

But I did wonder about the advantages of lower CG, as the shocks are mounted quite high up, and reasonably heavy (considering the weight of the car). Could be interesting to test anyway (Clearance around the shock body cap if mounted upside down the trickiest part methinks.)

[terry.sc]

Originally Posted by jimmy

I will eat my own hat if someone can prove a performance reason that shocks would be 'upside down' , at least in off road.

In the early days we ran the shocks upside down so our Scorcher or Scorpion shocks still had oil in them at the end of the race. Those single O ring seals never worked even when new

[shinytopman]

Originally Posted by jimmy

It matters which way it is up because of the unspring weight.

wikipedia refering to bike forks :
"Upside-down" (USD) forks are installed inverted compared to typical forks, with the tubes at the bottom and the bodies at the top. This decreases the unsprung weight of the motorcycle and improves its handling. USD forks are usually found on sportbikes, though Honda's large power-cruiser, the Valkyrie, sported USD forks.


like I said tho, any shocks mounted the other way seems to be because of access, design or other matters, airflow, but not all out shock absorbing performance... Should I put the oven on?

Doh!

Unspung weight, yes i'll give you that. That will teach me to have a few to many glasses of wine before opening my mouth/keyboard.....

[shinytopman]

Originally Posted by rich_cree

If you ran our shocks upside down you would have air not oil next to the seals, this means there would be no pressure on the seals and they would take in air when extending and piss oil out when compressing so they woldn't stay fresh as long

But in practice you should have no air in the shock chamber mixed with the oil so there for the pressure would be on the seal.

granted if you had air in the shock then it would create a vac behind the seal as the shock extends poss alowing air in.

[Lee Martin]

so a rant thread has quickly turned into shock thread........

[telboy]

Originally Posted by Northy

I am the meat.

G
I'm sorry G, you are wholly incorrect.

I am the meat.

Someone listened to radio one the other morning!

How funny was that!?

[jimmy]

Meat!? mad