Maybe a daft question - replace rear shock with solid piece

Avi

A friend has a stumpjumper and has asked me .. Would it be possible to replace a fox rear shock with a solid piece of aluminium (he works in a machine shop) whilst funds are found for a new shock ?

I know it is physically possible .. but what are the consequences?

Dirtrider

thats a bit of a ridiculous idea, you could try it, steel is possibly better because it has some give in it compared to alu being very brittle, having said that, i lump of steel is going to help on the weight saving front.

i wouldnt do it, i cant think of any specific reasons, i just wouldnt.

Andy B

The frame is designed to have a shock in it, running with a solid bar would increase the frame stresses which the frame isn't designed for.

nicklouse

there used to be a solid bar that had a few small elastomers in it to take the sting out. But i have not seen one for over 5 years.... i wonder why. Not the best idea.

Marjory Stewart BAxtor

bad idea. like andy b saiid, the frame is designed for all of the unbalanced force to be translated into a single linear shock, taking that away chanells the shock wave back into the frame. Hard tails get away with that by canti-levering two triangle structures about the seat post but sus frames simply don't have that superstructure.

Therefore all the energy goes into the weak spots in your frame which firstly is your pivot bolts, and depending on the structure of your frame and also mess up your hubs or welds or worse, your knees depending on where the frame is designed to focus the energy.

nicklouse

Marjory Stewart BAxtor wrote:

bad idea. like andy b saiid, the frame is designed for all of the unbalanced force to be translated into a single linear shock, taking that away chanells the shock wave back into the frame. Hard tails get away with that by canti-levering two triangle structures about the seat post but sus frames simply don't have that superstructure.

Therefore all the energy goes into the weak spots in your frame which firstly is your pivot bolts, and depending on the structure of your frame and also mess up your hubs or welds or worse, your knees depending on where the frame is designed to focus the energy.

sorry wrong. the same force get transmitted through the bolts if the shock is there or a bar is there. so your ideas have just gone up in smoke.

Marjory Stewart BAxtor

no no no no no.

is about energy not force.

shock absorbers dissipate enrgy by "wave damping" converting kinetic energy to compressive heat, taking away the means to transpose that energy manifestation leaves that kinetic shock in the frame, so without welding up those pivots, it's those weak spots that have the only means of damning (as there needs to be movement).

(this is teh second time in a week my physics undergraduacy has come in handy - who knew)

scotttomo

Ok then would a wham bar suffice as a shock then?

Marjory Stewart BAxtor

newton never excluded it.... try it!

scotttomo

Lol, newton was fond of them as i seem to remember from school science classes . I asked a similar question bout replacing the shock with sommat solid a while back. Only to be shot down in flames by nick l