Rear axle Torsion bars dimension changes

[DavidHill]

Morning,

I have my rear axle apart (as a consequence of the major battle I had to take part the rear wheel bearing)...I am now putting it all back together, and in the process have noticed that the torsion bars are different diameters.  One is 17.5mm diameter, the other is 19.5mm diameter.  Does anyone know why they are different...and if it is an issue having two differing thicknesses?

cheers
David.

[Jay]

Interesting, I can measure mine over the weekend, do you know which side each one came off?   

[simonandjuliet]

Is this an S1 vs S2 thing - ie do you have one of each ?

The later cars had larger outer wheel bearings (and therefore stub-axles) and different dampers, so was this also part of the change ? I would need to check the parts books to see if the torsion bars have different references

Don't Lambdas have different driver/passenger side springs ? Theoretically the cars were driven more often just by the driver(no passengers) so it was set up with stiffer springs on the driver's side

Fact or fable ?

[DavidHill]

well the thicker torsion bar did come out of the drivers side, so maybe that is a theory...I have now refitted both of them, so will see how it rides...but before I do that I need to position the handbrake cable arms the correct side of the spring...which will mean either dropping the spring again (which I am loath to do) or stripping the brakes and taking the back plates off...which I think is the less stressful method!  Oh the joys of Aprilia ownership !

[Dikappa]

Simon,

I haven no information that there would be different springs left or right on the Lambda, and also the factory drawings do not show this.  Just for your info!

Koen

[Jay]

Both of my series 1 car are 17.5mm od, looks like you have an odd pair