F10 Portal Knuckle Weights: Low Offset Setup Explained
By Vanquish Products - Premium RC Crawler Kits & Accessories | Published: 2026-10-15
Category: How-to Guides
A step-by-step guide to installing low offset F10 portal knuckle weights, choosing between heavy alloy and brass, and tuning your crawler's center of gravity.
Quick Answer
A low offset F10 portal knuckle weight replaces the stock F10 portal knuckle cover and adds mass directly over the axle for a lower center of gravity. Choose heavy alloy if you want modest weight and maximum wheel clearance, or brass if you want maximum down-low mass and can accept a wider track. Both are direct replacements for the F10 portal knuckle covers and fit the plastic VPS08607 or machined aluminum VPS8640 / VPS8641 knuckles.
Why Weight Down Low Changes Crawler Performance
Adding mass at the knuckle lowers your crawler's center of gravity without raising unsprung weight high on the chassis. That helps the tires stay planted on off-camber lines and reduces the tendency to tip when you transition from a sidehill to a climb. Because the weight sits at the axle end, it also keeps the front end from lifting under torque.
The tradeoff is steering effort and suspension response. More unsprung mass at the knuckles can make the front end feel slower to settle after a drop, and it puts extra load on servo and linkage. That is why low offset versions exist: they keep the added mass close to the knuckle so you can run common wheel widths without pushing the track out farther than necessary.
Heavy Alloy vs Brass: Pick the Right Mass
Heavy Alloy F10 Portal Knuckle Weights are a low offset design that allows the use of most wheels while adding weight down low. Brass F10 Portal Knuckle Weights are also low offset, but they allow the use of a 225 SLW hub and clear 0.8 or 1.0 wide Vanquish Products wheels. Brass is denser, so it adds more mass in the same footprint; heavy alloy is lighter and can suit builds where you want a CG change without a big jump in total weight.
If you are already running a heavy chassis or a lot of brass elsewhere, heavy alloy may be the better tuning tool because it lets you add mass in smaller increments. If you need maximum down-low weight and your wheel setup has the clearance, brass is the more direct path.
Check Your Knuckle and Wheel Clearance First
Before you order, confirm which F10 portal knuckles you have. Both weights are compatible with the plastic VPS08607 or the machined aluminum VPS8640 / VPS8641 F10 portal knuckles. If you are unsure, pull a wheel and look at the knuckle cover; the part number is often molded or etched on the inside.
Wheel choice matters more with brass. The Brass F10 Portal Knuckle Weight is a low offset version allowing the use of a 225 SLW hub and will clear 0.8 or 1.0 wide Vanquish Products Wheels. If you run a different hub or a wider wheel, measure the gap between the knuckle weight and the wheel barrel before you commit. The Heavy Alloy version is described as allowing the use of most wheels, so it is the safer starting point if your wheel inventory is mixed.
Install the Weights Without Stripping Hardware
These weights are direct replacements for the F10 Portal knuckle covers, so the process is the same as removing and refitting a cover. Work on one side at a time so you can reference the opposite side if you forget hardware orientation. Clean the knuckle mating surface, then seat the weight fully before you tighten any screw.
Use a quality hex driver that fits the screw head snugly. Stainless screws into aluminum or plastic knuckles are easy to over-torque; snug them in a cross pattern and stop when the weight is flush. If you are adding the Incision 12mm Brass Hex Hub at the same time, note that it uses set screw style retention onto the stub shaft, so you will want to align the set screw with the flat on the stub shaft before final tightening.
Tune After the First Run, Not Before
Run a familiar line and note whether the front end pushes, tips, or settles differently. Adding knuckle weight often reduces tipping but can make the steering feel heavier; if the servo is straining or the front end feels vague, you may have gone too far for your servo and linkage setup. Adjust one variable at a time: tire, shock position, or weight, but not all three.
If you want to fine-tune the mass at the axle without changing the knuckle weight, the Incision 12mm Brass Hex Hub for F10 Portal Axles adds mass at the hex and is compatible with VRD Carbon Phoenix Portal F10 Portal Axles, Vanquish Products SCX10ii Currie Portals, and VS4-10 Ultra with Origin Half Cab. It includes two hex hubs and two M3 set screws, so it is a small, reversible change you can test on its own.
Step-by-Step: Low Offset F10 Portal Knuckle Weight Install
- Confirm your knuckle part number: Remove a front wheel and check whether you have the plastic VPS08607 or the machined aluminum VPS8640 / VPS8641 F10 portal knuckle. Both low offset weights are compatible with either, but confirming avoids ordering for the wrong axle. Checkpoint: if the knuckle cover is not one of these, stop and verify fitment before buying.
- Test wheel clearance with the weight mocked up: Hold the weight against the knuckle and spin the wheel by hand. Brass is the tighter fit; it is designed around a 225 SLW hub and 0.8 or 1.0 wide Vanquish Products wheels. Heavy alloy is described as allowing most wheels. Checkpoint: if the wheel barrel contacts the weight, switch to heavy alloy or change hub width.
- Remove the stock knuckle cover and clean the mating face: Work one side at a time. Wipe away dirt or threadlocker residue so the weight seats flush. A burr or grit on the face will make the weight sit crooked and can stress the screws. Checkpoint: the weight should sit flat with no rocking before you install hardware.
- Install the weight and snug the screws in a cross pattern: Use a snug-fitting hex driver. Tighten gradually in a cross pattern until the weight is flush. These are direct replacements for the F10 Portal knuckle covers, so reuse the factory screw locations and do not over-torque into aluminum or plastic. Checkpoint: stop when the weight is flush; if a screw feels soft, back it out and inspect the threads.
- If adding the Incision 12mm Brass Hex Hub, align the set screw to the stub shaft flat: The hex hub uses set screw style retention onto the stub shaft. Slide it on, find the flat, and tighten the M3 set screw against it. The package includes two hex hubs and two M3 set screws. Checkpoint: the hex should not spin on the stub shaft after tightening.
- Run a familiar line and adjust one variable at a time: Note tipping, steering effort, and how the front end settles after drops. If the servo strains or the front feels vague, you may have added too much mass for your servo and linkage. Change only tire, shock position, or weight before your next run. Next step: if you need more tuning range, test the brass hex hub alone before adding more knuckle weight.
F10 Portal Weight Options at a Glance
- Heavy Alloy F10 Portal Knuckle Weight - Low Offset: Heavy Alloy F10 Portal Knuckle Weight - Low Offset is a direct replacement for the F10 Portal knuckle covers and is compatible with the plastic VPS08607 or the machined aluminum VPS8640 / VPS8641 F10 portal knuckles. It lets you add down-low mass without changing knuckles, and the low offset design allows the use of most wheels.
- Brass F10 Portal Knuckle Weight - Low Offset: Brass F10 Portal Knuckle Weight - Low Offset is a direct replacement for the F10 Portal knuckle covers and is compatible with the plastic VPS08607 or the machined aluminum VPS8640 / VPS8641 F10 portal knuckles. It maximizes down-low weight, but the low offset design specifically allows a 225 SLW hub and clears 0.8 or 1.0 wide Vanquish Products wheels, so wheel choice is more restrictive than with heavy alloy.
- Brass F10 Portal 12mm Hex: Incision 12mm Brass Hex Hub for F10 Portal Axles is made from brass for extra mass, uses set screw style retention onto the stub shaft, and is compatible with VRD Carbon Phoenix Portal F10 Portal Axles, Vanquish Products SCX10ii Currie Portals, and VS4-10 Ultra with Origin Half Cab. It adds a small amount of mass at the hex and is a reversible way to test weight tuning before committing to full knuckle weights.
