Upgrading Your XB1 or XB-F1
There are three separate upgrades, they're independent of each other, and you can do them in any order or stop after one. If you do all three options, it will be cheaper to get the entire kit, see more below.
1. The Simple Front — one part number
The easiest upgrade on the list. One kit, and it fits both cars.
XB-157 Simple Front Conversion Kit for XBOne & XB-F1 — $89.99
You get the O-ring damped knuckles, camber by interchangeable king pins, caster by carbon plate, and front ride height set with stainless shims. If you've been putting off learning the double A-arm front, this is the shortcut — it's easier to build correctly and lower maintenance once it's together.
One build note: The SF kit uses the original rear shelf if you are swapping FROM a -1 based DAA swap the rear shelf back to the original!
Camber and caster are set by swapping parts rather than turning a screw, so order a spread of options along with the kit. The kit ships with the 0° caster plate.
King pin sets (camber) — $14.99 each: XB-135 (0°) · XB-134 (1°) · XB-133 (1.5°) · XB-132 (2°)
Carbon caster plates — $19.99 each: XB-141 (0°) · XB-138 (1.5°) · XB-140 (3°)
Springs are simpler than you'd expect: the front uses the same V2 springs as the sides — XB-S-SF V2 Side and Front Spring Set (10pcs), $11.99. One set covers both ends, so there's no separate front spring to chase.
2. The V2 motor mount — also one part number
The rear pod update, and again it fits both cars.
XB-163 V2 Motor Mount Upgrade Kit (3pcs) — $69.99
Three pieces in the box: the carbon rear plate, the V2 aluminium motor mount and the V2 brass motor mount. Lower centre of gravity at the back of the car, and the brass counterweight is part of how the SF gets its weight distribution.
While you have the back of the car apart, think about the diff. You'll never have easier access to it than during a pod rebuild, and it's the single part most people leave too long. A fresh ball diff, the parts to rebuild the one you have, or a move to the slipper spool are all far less work now than they will be in three months.
XB1 / XBOne: XB1-090 Ball Differential, $59.99 · XB1-110 Slipper Conversion Kit, $24.99
XB-F1: F1-050 Ball Differential, $59.99 · F1-074 Slipper Conversion Kit, $24.99
Which one you want depends on your track. The slipper spool is a real advantage when the bite is up; at low or medium grip a well-adjusted ball diff gives more rotation and better consistency.
The rear spring sits right there too, and it's one of the more sensitive parts of the car — worth having the range on hand rather than the one that came on it.
Rear springs — $2.49 each (1pc): Extra Soft · Soft · Medium · Hard · Extra Hard — or the XB1-041-R multi-pack, $4.99
3. The carbon chassis — six parts, XB1 only
This is the one that isn't a single SKU, because the new chassis changes the side link geometry and the servo mounting along with the plate itself. This path is for XB1 owners. The XB-F1 runs its own chassis and isn't part of this upgrade — F1 drivers, take the two above.
Carbon Chassis for XB-SF (1pc) — XB-112 — $69.99
Side Link Tower Kit (2pcs) — XB-117 — $14.99
Carbon Side Link Plate Kit (2pcs) — XB-119 — $14.99
Alu Servo Mount — XB-121 — $13.99
Plastic Center Pivot Kit v2 — XB-122 — $9.99
Carbon Damper Plate v2 — XB-150 — $6.99
Total $130.94
What you're actually buying here is the flex. The carbon chassis is meant to twist, and the brass weight screws at the rear are how you control how much — fully screwed down is the stiff, predictable baseline, and backing screws out frees it up dramatically. It's the thing a steel chassis can't do, and it becomes one of the biggest tuning levers on the car.
The servo mount matters more than it looks: it floats, so the servo stops fighting the chassis twist. That's why it's on the list rather than optional.
The new side link geometry is the other half of what you're buying, and the side springs are what you tune on top of it — the most sensitive adjustment on the car and the fastest thing to change. These are the same V2 springs the front uses, so a single spread covers both ends.
V2 side & front springs — $2.49 each (2pcs): Extra Soft · Soft · Medium · Hard · Extra Hard — or the XB-S-SF set of 10, $11.99
Set them with no preload — the springs should just touch the plate — and tune on rate from there.
Doing all three? Read this first.
The three upgrades come to $290.92 — the optional camber, caster and diff parts above aren't in that figure. A complete XB-SF chassis kit is $299.99.
So if you're planning to do the whole car, buy the kit instead. You'll pay about nine dollars more, you'll get wheels and discs in the box, and you'll still have a complete running XB1 as a second car or a spare rather than a pile of parts on the bench.
The upgrade path makes sense when you want one of these things, or want to spread it out over a few orders. It stops making sense the moment you want all three at once.
Where to start
If you're not sure, start with the front. It's the cheapest of the three, it's the biggest change in how the car feels day to day, and it fits whichever car you own.
Once it's on, the SF Testing Team Notes covers the setup — discs, dual rate, caster, camber, the O-rings and flex.
Prices current as of September 2026.