CS1N 2 Speed

CS1N 2 Speed

Lenco CS1N Transmissions

For more specific information on any of these Lenco transmissions please refer to the Tabs below, or call our tech line at (909) 673-9080. Lenco Parts and Price List is available here.

The CS1N 2 Speed is the biggest and baddest of all Lenco Racing transmissions. Specifically engineered for the rigors and demands of hyper-torque applications . Uses special cut monster 2 gear sets in forward low gear case. Second gear set case, in the event of 3 or 4 speed applications, utilizes our standard sized 1” gear.

Uses special cut 2" gear sets in forward low gear case. Second gear set case, in the event of 3- or 4-speed applications it is possible to utilize standard 1" gear. CSlN is slightly larger than standard CS1 at 9" diameter and 9 1/4" length.

As with all LENCO transmissions the CS1N is based on individual 2 speed planetary units with additional speeds being achieved through utilization of multiple 2 speed units.  See How Lenco Works tab above for additional information.

Standard components.                
Low drag (angular contact and needle bearings).                
Choice of ratio.                
Air servo or max-adjust shift tower.                
Input shaft.                
Choice of output length and spline (16, 32 or 35).

CS1N Gears 2"

1.17% (1.165) - Uses 22/38 tooth planet gears, a 24 tooth sun gear and an 84 tooth ring gear. 
1.19% (1.191) - Uses 28/38 tooth planet gears, a 23 tooth sun gear and a 91 tooth ring gear.
1.22% (1.219) - Uses 30/35 tooth planet gears, a 23 tooth sun gear and a 90 tooth ring gear.
1.25% (1.252) - Uses 24/28 tooth planet gears, a 23 tooth sun gear and a 78 tooth ring gear.

In general, all LENCO transmissions are a planetary design. Planetary transmissions rely on a central sun gear to provide a 1:1 direct drive ratio once shifted from the launch ratio.

In order to achieve an underdrive first gear launch ratio the LENCO transmission relys on planet gears which rotate around the sun gear.

Each sun and planet gearset provides two speeds. Those two speeds are (1) the lower underdrive ratio and (2) the direct 1:1 final lock-up drive ratio.


Each LENCO transmission is thus a two speed and is housed in one dedicated two speed.

We acheive more than two speeds by combining multiple cases.

For example, a three speed requires two cases.
A four speed requires three cases.

A five speed requires four cases, and a six speed requires five cases.



Since each case contains one gearset and provides both underdrive and direct drive, multiple cases (gearsets) provide multiple underdrive ratios.


You must multiply each cases underdrive ratio in order to determine the first gear ratio.

In the example of a four speed, the case nearest the engine would contain a 1.37 ratio planet gear set. The middle case would also contain a 1.37 planet gear set.
The rear case a 1.31 ratio gearset.



By multiplying these three ratios you come up with a 2.46 first gear ratio. Second gear ratio is 1.80 and third gear is a 1.31 ratio. Final drive ratio is 1:1.


Multiply all three gearset ratios to determine the first gear ratio of 2.46:1. Multiply the two rear case gearset ratios to determine the second gear ratio of 1.80:1. The gearset in the third case alone, 1.31:1, determines the third gear ratio. All three units shifted equal final drive ratio of 1:1.


The internal action of a LENCO is such that when the transmission is in first gear the dedicated planet gear assembly provides the launch ratio. The planet gears are driven by an encompassing ring gear.


When the transmission is shifted a clutch pack compresses the rotating sun gear assembly to the direct drive central sun gear. Thus a 1:1 ratio is achieved.


Each case in succession, with its particular underdrive ratio, determines the immediate drive ratio.


Once all cases have been shifted the entire transmission assembly is locked in the final 1:1 direct drive ratio.


It is not necessary for the driver to disengage the clutch when shifting from ratio to ratio since all shifting is done with the engines clutch fully engaged.

(909) 673-9080

Please call for ordering or technical information.

  • Views: 26855
  • Brand: Lenco Racing
  • Product Code: CS1N-2
  • Availability: In Stock

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Tags: cs1n, transmission, racing transmission, 2 speed

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