Advent X setup - close, but never 100%?

Tech Tech Help
1

My oldest kid (now 14) and I built up their current MTB out of an assortment of parts we had lying around, new stuff, and new-to-us stuff. It has served them pretty well for very light riding the first year or so, but after racing cyclocross on it last fall, and a full summer practicing with the High School MTB team, they’re shifting a lot more and finding some limitations of my mechanic ability, or the equipment (or both).

We’ve been able to get the shifting consistently 80-90% reliable, very good in the workstand or soft pedaling, but there’s always at least one gear that doesn’t want to play nice once it’s being ridden with any sort of load.

The relevant bits I can think of:

  • Early 2000’s Jamis Durango frame (hardtail, 26”, 135mm QR, multi-part housing/exposed cables)
  • Samox crankset (OEM for Spawn Cycles/”Brood”)
  • SRAM Eagle 30T chainring (6mm offset)
  • Microshift Advent X cassette/shifter/derailleur (I think it’s V2)
  • SRAM PC-1071 chain
  • Shimano M629 rear hub

I’ve checked most of what I could think of - limit screws and cable tension, derailleur hanger straightness, chainline measures ~49.5mm, no misplaced spacers in the cassette.

Took it to our closest shop to see what they could do (also, take ‘Dad’ out of the equation) - with the seeming result that I wasn’t too far off. They replaced the cable and housing (with the note that a few of my housing sections had been a little short), and checked the hanger alignment too - noting that the current hanger is ‘soft’ and recommending replacement.

Unfortunately, the shifting is still a bit hit-or-miss - probably not so bad that I couldn’t ride around it, but bad enough that it’s super frustrating for a newer rider who hasn’t learned to finesse a slight over-shift or ease off the pedals just a bit.

Any advice, tips, or tricks? Definitely ordering some new derailleur hangers, changing drivetrain is a possibility (2 more kids to hand the bike down to), but concerned that if we can’t get this right, spending $200+ to do something like Deore 5100 isn’t going to change much.

2

I find that dialing the b-screw (or end-screw) out a little to allow the derailleur to swing under the cassette more sometimes pushes the shifting from ‘meh’ to ‘pretty good.’ I don’t take mfg’er pulley/cassette gaps as gospel, but merely as a good starting point. If you go too far, maybe there is too much chain slack in the small cog or the pulley starts to interfere with the large cog. This also requires the chain length to be correct. Chain too long and you won’t be able to get a good b-gap without excess slack in the small cogs.

Other than that, you could try some other chains, like Shimano HG-X (their mtb 10 speed chain available at various price points). Sometimes chain plates play well with certain cassettes and not others.

I would def. consider CUES over 10speed Deore. There is def. a weight penalty, but I find the CUES shifting much more forgiving than 10 speed Deore.

3

Follow the chain length setup exactly. It is different and slightly longer than the traditional method