new spax dampers

[Ray Hill]

I've given in to all the advertising for new tele dampers (I've still to fabricate the brackets), aluminium steering rack blocks, replacement nylon bushes for rear suspension, and so on. I then notice the dampers have old rubber bushes. Would anyone agree that seems a bit inconsistent?

[BrianC]

I'm not an engineer, but I would assume that these bushes are required to absorb shock and therefore a greater amount of compressibility is required than would be provided by harder nylon or poly bushes which are probably better suited to rotational locations. I await a real engineer's comments/correction

[Ray Hill]

I'm not an engineer, but I would assume that these bushes are required to absorb shock and therefore a greater amount of compressibility is required than would be provided by harder nylon or poly bushes which are probably better suited to rotational locations. I await a real engineer's comments/correction

 

Thanks Brian, but isn't absorbing the shock the function of the shock absorbers?

ray

[Alec Pringle]

Hi Ray,

 

the primary function of the shock absorbers, or dampers, is controlling the rebound of the spring.

 

Rubber isn't a totally outmoded commodity by any means, the more difficult aspect these days is obtaining an adequate quality of rubber for the particular application. Rubber, poly and nylon bushes offer different characteristics and differing strengths and weaknesses. Ride comfort against speed and accuracy of response, for example, is one trade off.

 

It's a big subject, I'd guess there is a heck of a lot of discussion about it available on the 'net.

 

Revington TR are probably the best source of information in this field - Neil has done a great deal of research on TR suspension over 30+ years, aided by some high-powered specialist engineers, and the guys at Super Pro know their stuff. I say that having had the benefit of some lengthy expositions from Neil and his colleagues in years gone by.

 

Cheers,

 

Alec

[RogerH]

Hi Ray,

the shock absorber actually controls the return of the spring (expanding). The spring actually absorbs the shock (in compression).

Without the spring the ride would be unbearably hard/rough. Without the shock absorber (damper) you would be bouncing along the road.

The rubber bushes possibly protect the shock absorber internals - or maybe not.

 

Roger

[BrianC]

The rubber bushes possibly protect the shock absorber internals - or maybe not.

I was thinking rubber would protect the actual mounting points a little more than nylon or poly and provide a marginally less harsh ride (but only guessing - it would be interesting to hear from an expert like Neil).

[littlejim]

It's fairly stiff rubber, and as said already it's only for the mountings, it's not going to do any shock absorbing work. Bit like not wanting nylatron seat bottoms or a nylatron mattress on your bed I guess. Sometimes a bit of softness is good; put the hard stuff where you don't want any movement.

 

Bit like the choices with springs and anti-roll bars. If you want it really stiff, solid springs with no coils and massive roll bars. Going to extremes doesn't actually improve the grip at the contact patch but you feel better because you haven't tilted outwards on the bend. Does work OK on gokarts.