A spec sheet comparison of the BC ER coilovers and the TEIN Mono Sport coilovers. To come to a winner I scored the different features of each coilover.
The scoring of these coilovers comes from the perspective of someone that regularly uses their car on track days (2+ times a month), will drive the car to and from the track day and does not use the car as a daily driver.
1. Top Mounts
Both coilovers have adjustable top mounts so both get 5 points. Adjustable top mounts allows the user to easily adjust the camber and/or caster of the suspension while the suspension is mounted on the car.
BC 5 – Tein 5
2.Top Spring Seats
Both have independent springs seats ie the springs seats do not rest against the the top mount. This gives more consistent spring and dampers performance because the springs are compressed parallel to the damper. Both get 10 points.
BC 15 – Tein 15
Both kits use linear springs. This means the dampers compress with equal force throughout their travel. Not ideal for the road but essential for the track. Both get 5 points
BC 20 – Tein 20
Both kits use the bottom bracket for height adjustment. This means the height of the suspension can be adjusted a lot without effecting the travel of the damper unit. The downside to this is the extra weight. 5 points each
BC 25 – Tein 25
The TEIN Mono Sport uses a mono tube damper which has a bigger fluid capacity then a twin tube damper. This gives better performance under extreme conditions because the temperature of the oil in the dampers stays more consistent. A mono tube damper also tends to be stiffer than a twin tube design again improving performance in extreme conditions. The BC uses a twin tube damper. Tein scores 5 points, BC scores 0 points.
BC 25 – Tein 30
Tein adjusts bump and rebound together. BC has independent bump and rebound adjustment give the user many more set up options. The BC also uses external reservoirs for increased oil capacity. Tein scores 0 points, BC scores 10 points for the bump and rebound adjustment plus 5 points for the external resevoirs.
BC 40 – Tein 30
I think without a doubt Tein is more respected than BC although BC also had a good reputation. Tein scores 10 points, BC 5 points
BC 45 – Tein 40
Both coilover kits use standard internal diameter springs so it is easy to change the spring rate if and when you need and it is easy to get hold of the springs, you do not need to get the springs from the manufacturer. Both score 10 points
BC 55 – Tein 50
BC ER vs Tein Mono Flex Summary
The BC wins this comparison because there are more adjustment options in the damper and the dampers have external reservoirs. In the other aspects the two coilovers were evenly matched.