Technical Drawings Of The 205 Torsion Bars

[Batfink 201]

I have found a company who make torsion bars but they have asked me if I can send any technical diagrams with all the sizing and dimensions of the standard bars(splines etc). Does anyone have this information to hand as well as the antirollbar info.

 

Kev

[M@tt 77]

Paul (205Turbo) sells these in various sizes so he'd probably be able to supply one in what ever size you need or is it a case of trying to get one made cheaply yourself?

he's not been on here in ages but if you want to contact him let me know and i can give you a number for him

Edited September 2, 2008 by M@tt

[Powers 13]

Spline pattern, length, diameter and a torsional spring rate per meter.

Have you not got any you could give to them?

[benlilly 0]

I'd be happy to have a go at drawing the bars from the original parts (my beam is in bits at the mo) but getting the splines just right might be difficult.

 

Does anyone know if there are standard spline patterns?

 

Could the bars be rated by fixing one end and measuring the torque taken to twist the bar 'x' degrees....?

[pug_ham 240 3 Cars]

Splines are 30 / 32 basis giving almost infinite adjustment

 

Rate calculations can be done here

 

If you haven't got a torsion bar to measure they are 992mm long with 23mm dia at one end (30 teeth) & 25mm at the other (32 splines).

 

On the bar I measured, the splines were 25mm & 27mm wide making the effective bar length 940mm.

 

This pdf could be have some useful information when making them. ( I haven't read it yet)

 

Graham.

[benlilly 0]

If you haven't got a torsion bar to measure they are 992mm long with 23mm dia at one end (30 teeth) & 25mm at the other (32 splines).

 

I make mine 25.5mm dia (32 splines), 23.9mm dia (30 splines). This is the max diameter, measured on the splined part.

 

Older/later type or measurement error do you think?

 

Ben

[dirtdog 4]

sorry to interupt here guys, but does this company also make main tubes/rear crossmember by any chance?

[309PUG 2 1 Cars]

I have found a company who make torsion bars but they have asked me if I can send any technical diagrams with all the sizing and dimensions of the standard bars(splines etc). Does anyone have this information to hand as well as the antirollbar info.

 

Kev

 

Hi Kev,

 

I have made many TB and ARB for this forum with a group buy and supply AB Motorsport and Peugeot Sport Special Tuning, I can make your bars for you if your interested and I have a semi technical drawing of a std TB & ARB.

Let me know.

Chris

[Batfink 201]

Chris! even better. I'd rather use a fellow forum owner

[DamirGTI 323]

Hi Kev,

 

I have made many TB and ARB for this forum with a group buy and supply AB Motorsport and Peugeot Sport Special Tuning, I can make your bars for you if your interested and I have a semi technical drawing of a std TB & ARB.

Let me know.

Chris

 

How hard is to make this TB/ARB bars ? can it be done on a ordinary center lathe or it must be some special CNC machine ?!

Also what kind of material/steel is needed for making them ? (if it's not a secret !)

 

The reason why aim asking is because i can't buy uprated torsion/ARB bars here in my country , and ordering/buying a pair form EU includes a bit high cost regarding postage because of the weight + i need to pay tax when they arrive in Croatia (taxes over here are complete rip off..) , so in the end this becomes very expensive ..

 

Thanks !

Damir

[pug_ham 240 3 Cars]

I make mine 25.5mm dia (32 splines), 23.9mm dia (30 splines). This is the max diameter, measured on the splined part.

 

Older/later type or measurement error do you think?

Must be measurement error from just human eye reading. I took those measurements last night just before posting them using an engineers steel rule & (tired) Mk1 eyeball so I should've put approximately.

 

Not having seen an early set of torsion bars I don't know if the spline diameters differ just that the number of splines on each end do. (28 / 30 iirc)

 

Damir, you need a special gear cutter for making the splines in the suitable material afaik.

 

Graham.

[benlilly 0]

Must be measurement error from just human eye reading. I took those measurements last night just before posting them using an engineers steel rule & (tired) Mk1 eyeball so I should've put approximately.

 

Not having seen an early set of torsion bars I don't know if the spline diameters differ just that the number of splines on each end do. (28 / 30 iirc)

Graham.

 

Ok, thats good.

 

I'll get the drawing finished at lunch. Seems we probably don't need it but not alot left to do.

 

Ben

[benlilly 0]

If we need it, here's a drawing.

 

I'm sure the spline detail isn't 100% correct as it's almost impossible to measure.

 

Be good if people could check it.

 

STD_205_19MM_TORSION_BAR.pdf

 

Ben

[309PUG 2 1 Cars]

If we need it, here's a drawing.

 

I'm sure the spline detail isn't 100% correct as it's almost impossible to measure.

 

Be good if people could check it.

 

STD_205_19MM_TORSION_BAR.pdf

 

Ben

 

Excellent bit of work Ben, I have checked it with my drawing and all appears spot on. How about one for an ARB ??? shouldn't take too long as they a very similar to a TB.

 

Chris

Edited September 5, 2008 by 309PUG

[benlilly 0]

Excellent bit of work Ben, I have checked it with my drawing and all appears spot on. How about one for an ARB ??? shouldn't take too long as they a very similar to a TB.

 

Chris

 

Hi Chris,

 

Should have a few more done by Monday.

 

Also, as I wasn't sure about the exact specification for the splines, I spoke to a local gear cutting company who are going to try and spec them based on my approximate dimensions and a photo.

 

Ben

[cybernck 400 1 Cars]

which is the arm-end of the bar - 30 or 32 splines?

[welshpug 1,622]

Arm end is the larger of the 2

[cybernck 400 1 Cars]

ok, as i've got a brand new rear tube that's unfortunately of the very early 28/28 variery:

 

 

 

so i'll need custom 28/32 bars (for use with later/normal style arms).

 

 

Ben, could you try to do a schematic of the 28-spline design?

 

 

thanks.

[pug_ham 240 3 Cars]

Quick question for calculating the spring rates of torsion bars.

 

What measurement are you using for the arm length?

 

Stub axle centre line from torsion bar c/l in fitting or distance from c/l of radius arm shaft to c/l of torsion bar?

 

If its the first one then its different for each side so I think it must be the later.

 

Graham.

[pug_ham 240 3 Cars]

After a bit more searching through google I think I've found my answer;

LL - Lever (arm) Length

The length of the lever arm that applies a twisting force to the torsion bar (from bar end to wheel centreline)

Could this explain why they are handed because using the measurements above each side is a different length / rate.

 

http://www.ac-parts.co.uk/utilities/torsionbars.html

 

Graham.

[RossD 43]

I think with the design of the 205 rear beam, you would measure to the end of the pivot point on the lever, which would be the beam tube and not the end of the bar.

[Tom Fenton 1,525]

Graham

 

I was thinking about this a few months ago. The twisting moment applied to each bar is governed by the pivot of the trailing arm on its shaft. Therefore the torsion bar only sees the leverage of the distance from the fulcrum of the pivot shaft to the centreline of the torsion bar. This is the same even though one bar is situated in front of the cross tube and the other behind.

 

In effect can be looked at as two moments, the moment of the force acting on the end of the suspension arm, and the moment of the reaction to twist of the torsion bar.

[RossD 43]

Graham

 

I was thinking about this a few months ago. The twisting moment applied to each bar is governed by the pivot of the trailing arm on its shaft. Therefore the torsion bar only sees the leverage of the distance from the fulcrum of the pivot shaft to the centreline of the torsion bar. This is the same even though one bar is situated in front of the cross tube and the other behind.

 

In effect can be looked at as two moments, the moment of the force acting on the end of the suspension arm, and the moment of the reaction to twist of the torsion bar.

 

What I said but put much more eloquently

[Tom Fenton 1,525]

Ha ha, indeed!

[pug_ham 240 3 Cars]

Thats what I initally thougth but when I tried to work out the effective spring rate difference last night using this calculator I was getting some stupid results but it doesn't seem to far off now.

 

I was comparing 19mm bars with 23mm bars & from thie link above the 23mm bar is 114.7% stiffer than the 19mm one just now which souns rigth imo.

 

Weird.

 

Thanks for your input.

 

Graham.