Hey everyone,
Continuing on the theme of suspension measurements on the rear 4-link for the 120, I was interested to know the geometry for the separation between the lower trailing arm and the axle housing.
It has been quoted in several places that the lower trailing arm will bind on the differential axle housing. This is also one of the principal sales reasons behind offset arms made by Superior Engineering and Roadsafe.
Cross-flexing on my Stanfred ramps and measuring the gaps on both sides gave me quite a large data range, giving the following relationship between shock length and rear lower trailing arm-axle housing separation;
Extrapolation of the data shows that the arm won’t bind until a shock length around 800mm.
This means those running very long rear shocks without a swaybar shouldn’t have any binding issues on the 4-link. The upper trailing arm won’t bind on the fuel tank until around 740mm, and the lower trailing arm won’t bind on the axle housing until around 800mm.
The longest shock I’ve heard of in the back of a 120 is 700mm being run by member 8608.
Based on the extrapolation of my upper and lower trailing arm measurements, we are never in danger of binding anything, so I’m very curious to know the source of the fuel tank and axle housing binding claims.
Even so, the after market trailing arms are much stronger than the OEM arms, and on this basis alone I will eventually replace my OEM trailing arms. The upper arms are particularly weak, and it is clear that a significant proportion of anti-squat is running through them and breaking them in very remote locations.
Anyone know where the claims of trailing arm binding on the 120 originate from?
Best
Mark
Continuing on the theme of suspension measurements on the rear 4-link for the 120, I was interested to know the geometry for the separation between the lower trailing arm and the axle housing.
It has been quoted in several places that the lower trailing arm will bind on the differential axle housing. This is also one of the principal sales reasons behind offset arms made by Superior Engineering and Roadsafe.
Cross-flexing on my Stanfred ramps and measuring the gaps on both sides gave me quite a large data range, giving the following relationship between shock length and rear lower trailing arm-axle housing separation;
Extrapolation of the data shows that the arm won’t bind until a shock length around 800mm.
This means those running very long rear shocks without a swaybar shouldn’t have any binding issues on the 4-link. The upper trailing arm won’t bind on the fuel tank until around 740mm, and the lower trailing arm won’t bind on the axle housing until around 800mm.
The longest shock I’ve heard of in the back of a 120 is 700mm being run by member 8608.
Based on the extrapolation of my upper and lower trailing arm measurements, we are never in danger of binding anything, so I’m very curious to know the source of the fuel tank and axle housing binding claims.
Even so, the after market trailing arms are much stronger than the OEM arms, and on this basis alone I will eventually replace my OEM trailing arms. The upper arms are particularly weak, and it is clear that a significant proportion of anti-squat is running through them and breaking them in very remote locations.
Anyone know where the claims of trailing arm binding on the 120 originate from?
Best
Mark
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