Ohlins TTX22m.2

Mixed Feelings

I have very mixed feelings about the Dragonfly's rear suspension.  On the one hand, I have always regarded Ohlins products as second to none.  The fact that the Dragonfly uses a shock designed for mountain bikes makes access to service and obtaining different springs easy.  

On the other hand, the shock was designed for a mountain bike, not a motorcycle.  Ohlins provides the following warning right in the owner's manual, This product was developed and designed for the bike industry and shall only be installed on to related vehicles, including pedal-assisted motorized cycles that produces a maximum of 250 watts of power.  DO NOT use any Öhlins bicycle suspension product on any throttle-equipped motorized cycle or any vehicle carrying more than one operator or rider, such as a tandem bicycle or heavy utility bicycle.  Any use outside of these terms must be approved by Öhlins on a case-by-case basis. Any such unauthorized misuse may result in failure of the suspension, which may cause a crash and result in property damage, SERIOUS INJURY OR DEATH, and void warranty.

Presumably, Mecatecno has gotten Ohlins's blessing for this application.

TTX Technology

Note that the terms low-speed and high-speed refer to the rate at which the shock shaft is moving, not the vehicle's speed. 

The lockout feature only applies to a mountain bike.  It is used to eliminate wasted suspension damping while climbing. 

Ohlins mentions that it's possible to adjust the shock's stroke length simply with the three included 2.5 mm spacers.  This seems more applicable to a mountain bike.  The Dragonfly shock does not have any spacers installed and thus travel is already configured for the maximum possible.

Shock Service Interval

The recommended fluid change interval is every 100 hours or annually.  Ohlins specifies their shock absorber fluid, part number 01304-01 which has a viscosity of 11 cSt @ 40° C.  MSRP is $33 / liter.

There are 51 Ohlins MTB dealers in the USA.  There is an authorized service center in Kansas.  Ohlins USA is located in North Carolina.  Full factory service is available in the USA for $220.

If you want to do the work yourself, the adjacent video shows the 200-hour rebuild procedure (although I feel the demonstrator could use a bit more finesse in places).

Ohlins Springs

Having the correct spring is going to be critical to properly setting sag and achieving desirable steering geometry.  Ohlins says that using more than 2 turns of preload indicates the need for a different spring rate.  Fortunately, springs are easy to change and no special tools are required.

As mentioned previously, springs are available in 4 N/mm (23 lbf/mm) increments.  They cost about $100 each. 

Ohlins spring part numbers are of the form XXXXX-YY.   XXXXX indicates the spring series number and -YY is a code for the spring's rate.  

Three different series of springs are manufactured that fit the TTX22m.2 body: 18073, 18075, and 18077.  All spring series begin with 180.  73, 75, and 77 indicate the maximum permissible shock travel in millimeters to ensure coil-bind does not occur.

The standard Dragonfly spring is Ohlins part number 18075-16.  Ohlins currently offers 15 springs that permit a 75mm maximum travel.  Realistically, I see only a few spring rates on either side of standard covering a wide range of rider weights and abilities.

Standard Dragonfly spring is Ohlins P/N 18075-16             106 N/mm (605 pounds per inch)

Bottom-Out Bumper

Bottom-Out Bumper

The shock's bottom-out bumper (black item with upsidedown part number) is visible in the adjacent photo.   As far as I know, their use is universal on monoshock suspension systems. 

The bumper is an elastomer like rubber or urethane that cushions the shock at maximum compression travel.

It acts as an additional spring in parallel with the main spring.  Springs in parallel add together thus increasing the total spring rate.

This can make the spring's overall rate very high in the final part of the travel to prevent hard bottoming.

Aftermarket Springs

Springs are also available in the aftermarket - some are even progressively wound.  Aftermarket springs use a different identification scheme.  Typically, one number indicates the spring rate in pounds-force per inch.  Another number is the “free stroke” (spring travel before coil-bind occurs) which may be measured in inches or millimeters.  The order varies by manufacturer.