Jamis Portal C3 — GX AXS | Custom Build Review

Walk-through filmed after the bike was set back to its sale build.

This is the Portal the way Steve actually rode it. Before it sold as a more standard SRAM GX build, he ran it through the fall as his personal demo — set up the way he’d build one for himself: SRAM GX AXS shifting, his own XX crank with a power meter, and carbon Reserve wheels. This is that configuration.

Steve’s setup

This is where Steve’s version differs from the bike that eventually sold. He ran a SRAM GX AXS Eagle rear derailleur — wireless shifting — though he points out the frame doesn’t have a universal derailleur hanger yet: “I’m sure we’ll see one” on the next update. Up front was his own SRAM XX crank, the one with the power meter that he kept when the bike moved on. It’s a wider crank and chainline than the frame technically calls for, so he “cheated the shims a bit, shot a little windage on it… got it halfway and it worked fantastic.”

The wheels were carbon Reserve 28s pulled off his ZFS, with a carbon bar up top. He finished the fall on a worn set of Schwalbe Racing Rays and Racing Ralphs he was using up. Frame, fork, and shock are the stock C3 package — a 130mm Fox 34 and a Fox Performance shock set in the high position — on SRAM G2 R brakes, which he’s become a convert on.

The build

FrameJamis Portal C3, carbon
Travel130mm
ForkFox 34 Performance
ShockFox Performance (high position)
DrivetrainSRAM GX AXS Eagle
CrankSRAM XX (power meter)
BrakesSRAM G2 R
WheelsReserve 28, carbon
BarCarbon
DropperRace Face Aeffect

How it rode

This is the setup Steve put his fall miles on, and it left a real impression. It’s fast, and it’s not fragile — “you could take it off some drops and ride it through rocks.” It pedals really, really well, and it’s a pleasure to ride — enough that the shop brought in more Portals after spending time on it. The one weak point was the dropper, a Race Face Aeffect he “wasn’t very impressed with.”

“One of the better-pedaling bikes I’ve ever ridden — and probably the most surprising.”

Steve, on the Jamis Portal C3

Where it ended up

Steve kept the XX crank and the carbon Reserve wheels, and the Portal went out the door in a more standard SRAM GX build for a customer. The as-sold spec and the full story are in the Jamis Portal C3 GX Mechanical writeup.

See it on the trail

A quick clip of the Portal out on the trail — the short version for anyone who’d rather watch than read.

Builds like this, for the money

The shop puts together a lot of interesting builds for the budget. If you’ve got something specific in mind, just ask.