Low Rider ST (FXLRST) Rear Shock: Bags First, Then Everything Else

Fairing up front, hard bags at the back, all of it resting on one shock. Work out your load before you shop.

Does this apply to your bike? FXLRST Low Rider ST, an M8 Softail with a West Coast fairing and hard bags. Not for the base FXLR or the FXLRS, whose loads are different, and not for any Dyna or pre-2018 Softail. It also is not for true Touring bikes, which have twin shocks.

DifficultyIntermediate

Time3 to 5 hours, depending on bags and access

This bike looks like a bagger, so people treat it like one and expect it to shrug off a loaded weekend. It has a Softail's single shock, not a Touring bike's pair, and those hard bags hang your whole weekend on it. A shock picked for a bare Low Rider is the common mistake. Start with the weight, not the catalogue.

Tools

Secure rear support
Soft surface for the bags
Bathroom scale for the bags and luggage
SAE and Torx sockets
Torque wrench
Tape measure and helper
Tool for your adjuster
Service manual

Weigh the weekend

Pack the bags as you normally do, then take them to a bathroom scale, full. Add yourself in riding gear and any passenger. Write the total on paper. Most riders guess this figure low, often by a surprising margin, and a shock is selected on the number you give, not the one you are actually carrying.

Then compare it to what the manual allows. Your bike's load limit is printed in the owner's documentation, and you should not exceed it, whatever shock you fit. A stronger spring does nothing to raise the rating of tyres, frame or brakes.

If you ride sometimes empty and sometimes loaded, plan for both. An adjuster that is quick to change has real value on this model, so look at what yours is and how long a change takes. With a hard-to-reach setting, you will end up riding with the wrong one.

Questions to put to a shock seller

Give them your code, your year and your written total, and ask what spring suits it. Ask if the shock was developed with bags in mind. Ask how much adjustment range it has at your load, and whether it needs a different mount or adjuster setup from your factory unit.

A polite vague reply, or a page of praise from solo riders of other Softails, tells you little. Your load case is what you are paying for.

Keep the old shock's condition in the picture as well. Oil on its shaft, or a rear that keeps moving after one dip, justifies replacing it. A sound unit that only struggles when the bags are full may just need more preload for those trips, so test that with your real packed weight on board before you spend anything on a replacement.

Skip any lowering kit unless you have thought it through. Dropping a bike that is loaded in this way reduces the travel available at exactly the time it is needed. Those kits fit only certain adjusters anyway.

Clearing a path

Empty the bags and take them off per your manual if they block access. Rest them on a soft surface, with their paint upward. Note how each one latches and where any hardware goes.

Support the rear well, then pull the seat. From here, the manual decides what else must move, often near the battery tray and side parts. Be careful with wiring in this area, and photograph as you go, since your memory will not hold it all.

Removing and reading the old shock

Note the adjuster type and setting before anything gets undone. Undo the mounts per the manual, with the rear held, and take the unit out along its proper path. Leave its spring assembled, as it remains under compression and requires the correct compressor for any further work.

Bikes that are often loaded push hard on their bushings. Inspect the eyes, bolts and mount points on both the frame and swingarm, replacing anything cracked, loose or worn out of round. If the rear has been bottoming, look for impact marks and rubbing near the tyre as well.

Fit, then set for both loads

Bring the new unit in and hand-start its bolts. Take your tightening figures from the service manual for your year and apply them with a torque wrench. Restore the components you moved, confirm the wiring, and refit the seat.

Mount the bags, empty for now. Measure sag with yourself aboard. Next, fully load the bags, add any passenger, and take a second reading. Both need to fall into the range specified by your manual or shock maker. Note what preload setting got you there, and store it with your toolkit.

Prove it loaded

Your empty test ride is only half a test. After a short, gentle run and a check of the mounts, ride it again fully loaded over a route with some bumps, keeping your speed modest. The fairing puts weight up front, and the bags put it at the back, so notice how the bike steers, and whether the front feels light.

When you return, check that the bags still latch cleanly, then look for marks on the fender and tyre. Go over the fasteners one final time, and remember to reset preload when the luggage comes off.

Mistakes that cost money

Guessing the load instead of weighing it.
Choosing a shock suited to a bare Low Rider.
Believing a stronger spring raises the bike's load rating.
Testing only empty, then setting off fully loaded.
Leaving preload at the loaded setting after the bags are emptied.

When to stop

If the bike bottoms out or the front feels light with your normal load, unload it and do not carry that weight until the spring and setup match it.

Other Harley how-to guides

Street Bob FXBB Monoshock: Replacing It on the 2018-Up Softail Fat Bob FXFB Shock Upgrade: Fitting a Monoshock for Control Low Rider FXLR Rear Shock: A Monoshock Picked for How Many Ride Rear Suspension Preload and Setting Sag

This guide covers procedure and judgement. Torque figures, fluid capacities, gaps and tension settings are specific to your model and year and must come from the factory service manual for your motorcycle — we deliberately do not print numbers we cannot stand behind for your bike. Independent aftermarket retailer, not affiliated with Harley-Davidson, Inc.