It is quite common among the scaler/crawler enthusiasts to tilt the shocks to increase the suspension travel.
In this talk we provide a graphical simulation and a practical example to show how relevant the effect is, but also explain what to check before acting on the rig to make this change.
Foreplay checks before tilting the shock absorbers
The first check is that all parts work properly with the desired travel and articulation. This requires disconnecting the shock absorbers and checking that there are no restrictions on the free movement of the axles in all directions.
Free damper positions on the shock tower
Check the availability of free attachment points on the shock tower that allow the upper front shock to be moved rearward and the rear shock forward. You also need to check that moving the damper position the ground clearance of the model does not change. When there is no such possibility, all that remains is to buy or make a plate to connect to the existing shock towers to fix the damper where you need it.
There is a wide availability of optional or adaptable parts for various models on the market, but there are also those who enjoy making special and customized parts for their cars as in the pictures below.
Simulation parameters
We performed a CAD simulation considering fairly standard equipment among the stock models: 130 mm rear link and 90-67 mm shock absorber (extended and compressed). To simplify the graphics, we considered the end of the link and shock absorber connected at the center of the wheel, but the results are still valid.
Setup configurations
We analyzed 4 setup configurations that differ only in the position of the upper shock mount.
The starting condition is with horizontal link and fully compressed shock absorber, which in the 4 configurations assumes an angle of 90°, 65°, 45° and 35° from the link, respectively.
The image shows the CAD simulation of the compressed and extended condition for each configuration and the travels obtained.
Results in suspension travel
The summary of the results with a 130mm link and 90-67mm shock absorber is quite clear and shows significant effects when going from a vertical shock to one inclined at 35°, with an increase in travel of as much as 14 millimeters.
Conclusions
Simulation has shown us that higher angles match with higher suspension travel . This method can also be useful for recovering or taking advantage of shorter shocks, which in a vertical configuration would limit the performance of the model.
Finally, it is important to consider that wheel travel has a direct influence on twisting, so we can conclude that tilting the shocks to increase suspension travel also has the additional effect of increasing crawler twisting which is far from minor effect for a scaler/crawler.