fynnbar
Automotive
- Feb 8, 2011
- 3
Hi
I have a classic Mini with a B16 Honda VTEC engine fitted. Needless to say, this has altered the weight distribution, from an approx. 58:42 to 62.5:37.5 front to rear. I have, after much trial and error, got the front suspension to behave acceptably using coilover units, but the rear has me a bit baffled. I am using standard Moulton rubber cones, and with a 360lb cornerweight (gross), the rear suspension is extremely stiff.
Problem 1 is that I cannot find any information on the spring rate for the rubber cones. Added to the problem is that they're progressive not linear.
Problem 2 is that the suspension leverage figure is huge (if my understanding is correct). The rubber cone is compressed via a knuckle and solid bar from a lug underneath the radius arm, 40mm below the radius arm pivot point. The radius arm stub axle / pivot point centre-to-centre is 300mm - see attached image. To me, this gives a very large leverage (SL) figure of 7.5, which squared gives 56.25. Is this understanding correct ?
Using damper travel of 5" - this is also the wheel travel figure if the full range is used - the cone gets compressed 3/4".
Problem 3 is; how can I determine the spring rate of the rubber cone? Could I compress it using a hydraulic press fitted with a force/pressure gauge, measuring force every 5mm perhaps. I would like to know the spring rate in order that I can work out how to make the rear less stiff.
I have a classic Mini with a B16 Honda VTEC engine fitted. Needless to say, this has altered the weight distribution, from an approx. 58:42 to 62.5:37.5 front to rear. I have, after much trial and error, got the front suspension to behave acceptably using coilover units, but the rear has me a bit baffled. I am using standard Moulton rubber cones, and with a 360lb cornerweight (gross), the rear suspension is extremely stiff.
Problem 1 is that I cannot find any information on the spring rate for the rubber cones. Added to the problem is that they're progressive not linear.
Problem 2 is that the suspension leverage figure is huge (if my understanding is correct). The rubber cone is compressed via a knuckle and solid bar from a lug underneath the radius arm, 40mm below the radius arm pivot point. The radius arm stub axle / pivot point centre-to-centre is 300mm - see attached image. To me, this gives a very large leverage (SL) figure of 7.5, which squared gives 56.25. Is this understanding correct ?
Using damper travel of 5" - this is also the wheel travel figure if the full range is used - the cone gets compressed 3/4".
Problem 3 is; how can I determine the spring rate of the rubber cone? Could I compress it using a hydraulic press fitted with a force/pressure gauge, measuring force every 5mm perhaps. I would like to know the spring rate in order that I can work out how to make the rear less stiff.