Team Yokomo: YD2SX2 / Roundly Steering Rack Setup
In this article we will show you how to fine tune the new curved slide rack for our award winning YD-2 drift chassis series. Team YOKOMO developed a slide rack that gives optimal steering characteristics using the latest drift settings. As well as the arc movement of the rack, giving better Ackerman control and feel, it is mounted at an angle that matches the movement of the suspension, helping to almost eliminate bump steer. We have only just released it and already it has earned high praise from many drivers over a short period of time.
It will be installed as standard on the new drift chassis kit the “YD-2SX II” which will be on sale soon.
Y2-202 SRE Curve slide rack set for YD-2E series ¥ 17,600 (excluding tax)
Y2-202 SRS YD-2S Series Curved Slide Rack Set ¥ 14,200 (excluding tax)
The movement of the steering rack is adjusted by rotating the bearings on the supporting rail and the bearing posts are an eccentric cam design. Here we will inform you of some helpful tips to further improve the new steering racks accuracy. We recommend assembling the slide rack itself but leave the bearings and posts loosely to begin with. Please ensure the adjustable bearing posts are temporarily tightened in this position.
There is a mark on the head of each bearing post that are made into an eccentric cam, the side with this mark is thickest and the clearance becomes tight if you turn the mark toward the rail side. Since the clearance is fully open in the image above, first rotate the posts B and C and tighten the screws so that the mark is closest to the rail. If B and C are not symmetrical, a left and right difference will occur in the movement of the rail, so be sure they are symmetrical.
Finally post A needs to be adjusted to remove any additional play. From here, gradually rotate the A post to take up the play, but please operate the rail by hand before and after adjustment to check that the movement is still smooth on the bearings, if it’s set too tight it will damage the bearings and the rack. Although our manufacturing tolerances are the closest they can be the adjustment range may differ and it’s possible to have slight differences in the parts. Most of the time the position of the posts on the top image is the optimal position for the slide rack. After a while the clearance may change due to dust ingress and wear. Metals also expand slightly with changes in temperature, so before driving your chassis we recommend removing the servo link and confirm that it still works perfectly with no binding or excessive play. The bearings we use are of the highest quality and will work for many cycles if set correctly with no binding. Adjustment of the bearing posts can take a lot of play from the front and back of the rail but there is also a slight clearance in the vertical direction. This is there to ensure that your new steering rack operates smoothly right away and does not cause premature wear of the aluminium or carbon parts.
The image above is from the side of the slide rack, since the thickness of the aluminum rail is larger than the thickness of the bearing, there is a slight clearance above the bearing. This is there to absorb any individual differences of parts etc. but if when you assemble the steering and find there is a lot of play you can also remove any up and down play if you require. Simply add a shim between the bearings on the posts to reduce the clearance until any play has gone. Once you have done the following please check the movement is still smooth and be aware that decreasing the clearance may have a negative effect on the wear rate of parts or cause binding if it is done incorrectly.
The shim we recommend is 4.0mm ID stainless steel precision cut (ZC-S40S 450), 0.05mm, 0.1mm, 0.2mm thick shims supplied as a set. Team yokomo measured many different parts and found the thickness of the rail was about 6.0mm and the thickness of the two bearings was around 5.9 mm, so theoretically there is no clearance when using a 0.1 mm shim. We suggest to try using a 0.1 mm shim first and check if this is good with less free play.
The response of the steering will change by adjusting the slide rack to have minimal play. In some extreme cases the gyro can over compensate (malfunction) if there is excessive play in the steering affecting the stability and feel of the chassis. We believe careful assembly will lead to better chassis performance.
Please also remember the tolerances inside the bearings can change, especially with precision parts adjusted to give optimum performance this makes it difficult to keep smooth without any play at all. For future maintenance and smooth operation please check the steering regularly for any binding.