Servicing question: Front fork, mid suspension, and SRAM brake

[andylo]

Hey folks,

In short, it's been about 2 years since I last rode my MTB, a 2014 Giant Trance. During that time, it's been upgraded with Rockshox front fork and rear suspension, a SRAM brake, and one of those battery-electrified seat posts. Before I parked it, I had it fully serviced.

Now, I'm looking to get it back in action, mainly for my 16-year-old to use. I know that the SRAM brake requires annual brake oil changes, which I haven't done. My question is this: if I break it out during Easter, do I need to service all of the above components to keep everything running smoothly, or can I get away with it for now?

I'm leaning towards saving some cash, but I also understand that skimping on maintenance might end up costing more in the long run, especially with broken components.

Appreciate any experienced input and opinions you folks can offer. Thanks in advance.

[Duck!]

SRAM brakes are generally not an upgrade. Some models have known problems of poor master cylinder bore tolerance, which causes the piston seal to stick and prevent the brake lever from returning & releasing the brake, so look at them first. Give the levers a squeeze; if they do not return, they are stuffed and will need replacing; given it's a manufacturing flaw, they're not serviceable. Fortunately SRAM will replace them under warranty, even if they're outside the standard term, because it is a flaw they know about.

The other potential thing to look for while checking the brakes it to see if there is any lever travel at all. The DOT 5.1 fluid that SRAM use has a voracious appetite for water absorption, which pulls in around the caliper seals and causes the fluid volume to increase and push the pistons out & onto the rotors, locking the brakes on. Fortunately this can be rectified by a full system bleed with fresh fluid.

The fork & shock should generally be OK, but it will depend a bit on how hard the bike was ridden when it was previously being used. They will need the air spring pressures topped up. Give both the front and rear a few bounces, twiddling all adjustment knobs to ensure they do their proper things; if they're working properly there will be a considerable difference in both compression and rebound speeds as the dials are tweaked. If there isn't, some seals will have perished & blown, allowing the damper oil to drain to somewhere it shouldn't be. Most RS forks are very simple to service (the "Charger" cartridge dampers are a bit more complex, however less likely to fail from disuse & dried seals). Rear shocks are more difficult to service,so need specialist attention.

If the shocks are hunky-dory, it's worth flipping the bike upside down and leaving it that way overnight to allow the lubricating oil, which will have all pooled in the bottom of the lowers over the two years of disuse, to run back up into the bushings and inside the dust wipers, which will minimise stanchion wear. Switch the fork lockout to the ON position when flipping the bike over to reduce damper oil migration; it depends a lot on the damper type, but some RockShox ones go funny when the bike is flipped or laid over for an extended period; the oil migrates and the lockout doesn't work until the oil has drained back into its normal bath. It does fix itself in fairly short order, but it is a bit alarming to find the lockout has stopped working, when it was fine yesterday, and all you did was flip the bike over for a few hours!

[andylo]

Very insightful, thank you heaps