Speedline Slashers Carbon Rims
Wheel Building & Tension Guide

Official installation, lacing, and tensioning reference for all Slashers models — produced by Supercross BMX / Speedline Parts

Overview

The Speedline Parts Slashers line is built from T700S Nano Alloy Pre Preg Carbon Fiber — a high-modulus material that combines the strength and stiffness of T700S carbon with a nano-alloy resin system for superior impact resistance and fatigue life. This is not standard carbon — it is a step above what most manufacturers use, chosen specifically for the demands of BMX racing. These rims are light, stiff, and fully tubeless-compatible across all sizes.

Building a carbon rim wheel correctly is different from building with aluminum. Carbon does not flex or forgive the way aluminum does. If you follow this guide — and respect the tension limits — your Slashers wheels will outlast everything else on the track.

Slashers Rim Specs — All Models

All models: T700S Nano Alloy Pre Preg Carbon Fiber. 4mm rim offset on 406 and OS/20 models. All models are tubeless-compatible.

Available Colors

Slashers rims are available in the following colors — availability varies by model and size:

Tools You Will Need

• Spoke tension meter — This is not optional on carbon rims. The Park Tool TM-1 is the standard. The Wheel Fanatyk Co. tension meter is more precise. You cannot build a carbon rim correctly by feel alone.
• Truing stand — A quality truing stand with both lateral and radial indicator arms (Park Tool TS-2.2 or equivalent)
• Spoke wrench — Matched to your nipple size. Most Slashers builds use 3.2mm or 3.3mm nipples (brass or alloy). Confirm before starting.
• Nipple driver — A screw-type nipple driver speeds up the initial lacing significantly and reduces the chance of cross-threading
• Nipple washers — Recommended for all Slashers builds. Washers spread the load at the nipple-to-rim interface, reduce stress on the carbon at each spoke hole, and help maintain tension over time. Use washers sized to match your nipple head diameter.
• Spoke Prep (required for alloy nipples) — Wheelsmith Spoke Prep or equivalent. If you are using alloy nipples, Spoke Prep is not optional — it is required. Without it, alloy nipples can seize on stainless steel threads due to galling, making future truing or spoke replacement very difficult. Brass nipples can use Spoke Prep or linseed oil.
• Nipple grease — A tiny amount of grease on the nipple-to-rim contact point reduces windup and makes future truing easier
• Spoke length calculator — Use bmxspokecalc.com or spokecalc.io with the ERD values above and your specific hub measurements
• Ruler / digital calipers — For verifying spoke lengths before you lace

Choosing Your Spokes

Gauge

Use 14-gauge (2.0mm) stainless steel spokes or double-butted 14/15/14g (2.0/1.8/2.0mm) spokes. Double-butted spokes store more elastic energy, which helps maintain tension longer and reduces stress at the elbow. They are the better choice for racing. Avoid triple-butted or aero-bladed spokes unless you have advanced building experience and a compatible hub.

Length

Spoke length depends on three things: the ERD of the rim (listed in the specs table above), the hub flange diameter, and the lacing pattern. Use the ERD values from this guide along with your hub's actual flange measurements in a spoke calculator. Do not guess. A spoke that is 1mm too long will strip the nipple; 1mm too short will not allow full thread engagement.

Most rear hubs have asymmetric flanges — the drive side flange sits closer to the center than the non-drive side. This means you will typically need two different spoke lengths for a rear wheel. Calculate each side independently.

Material

Stainless steel spokes are the right choice for all Slashers builds. Do not use carbon fiber spokes or aluminum spokes on these rims without consulting a professional builder first — the interaction between materials affects tension behavior and long-term durability.

Lacing Guide by Model

Slashers 406 (36h) and OS/20 (36h) — 3-Cross Lacing

The standard for all 36-hole Slashers builds is 3-cross lacing (also written 3x). Each spoke crosses three other spokes on the same side before reaching the rim. This distributes load across more spokes and is more forgiving of impact forces than radial lacing — which is critical for BMX racing where the wheel takes repeated hard landings.

Slashers 451 (28h) and Slashers 520 (28h) — 2-Cross Lacing

28-hole wheels use 2-cross lacing. The reduced spoke count means each spoke carries more load, so even tension becomes even more critical. The lacing process is the same as 3-cross above, but each spoke only crosses two others before reaching the rim. Follow the same head-in / head-out pattern and the same "over, under" crossing rule.

Slashers 559 (32h) — 2-Cross or 3-Cross Lacing

The 559 is available in both 32h and 36h drilling. 32h builds use 2-cross lacing. 36h builds use standard 3-cross. The 559 is a wider, deeper rim — confirm your spoke lengths are calculated correctly as the wider ERD (531mm) will require longer spokes than any other Slashers model.

Nipple Preparation

This step is often skipped and often the reason wheels lose tension after a few rides. Do not skip it.

• Install nipple washers first: Before threading any nipples, seat a nipple washer into each spoke hole in the rim. Washers distribute the load across a larger area of the carbon and protect the rim at each hole over the long term. This is especially important on high-tension BMX builds. Make sure each washer sits flat and centered before proceeding.
• Thread lube on the spoke threads: Apply a small amount of Wheelsmith Spoke Prep or linseed oil to the threaded end of every spoke before threading the nipple. Linseed oil is what Industry Nine uses in their professional wheel building operation — when it dries, it acts like a mild thread-locker and keeps nipples from backing off. Do not use standard Loctite or thread-locker compounds — they make future adjustments nearly impossible and can damage the nipple seat in the rim.
  
  If using alloy nipples, Spoke Prep is required — not optional. Alloy nipples will gall (seize) onto stainless steel spoke threads without it. Brass nipples are more forgiving but still benefit from lubrication.
• Grease on the nipple-to-rim contact surface: Put a tiny smear of grease on the rounded underside of each nipple — the part that contacts the washer or rim bed. This reduces spoke windup during tensioning and makes future truing much easier. Spin the wheel slowly after initial lacing to work the grease into the contact area.

Tensioning & Truing

Target Tension

The maximum spoke tension for all Slashers models is 130 kgf. Build to a working tension of 110–125 kgf on the high-tension side. This gives you headroom below the structural limit while keeping the wheel stiff and responsive.

As a reference point: Zipp specifies 115 kgf for their 3ZERO MOTO carbon wheels. Industry Nine's target for their builds is 120 kgf. The Slashers 130 kgf maximum is consistent with what top-tier carbon rim manufacturers publish — do not exceed it.

Tension Evenness

This matters as much as the absolute tension value. All spokes on the same side of the wheel must be within ±10% of each other, and ideally within ±5%. A wheel with perfectly even 115 kgf tension is stronger and more stable than one with spokes varying between 100 and 130 kgf, even if the average is higher. Use your tension meter on every single spoke — do not assume.

Rear Wheel Tension Asymmetry

On a rear wheel with a cassette or freewheel, the drive side spokes will always be tighter than the non-drive side. This is normal. The drive-side spokes pull the rim off-center, and the non-drive spokes compensate. Build the drive side to your target tension first, then bring the non-drive side up to whatever tension achieves lateral true. The non-drive tension will typically be 40–60% of the drive-side tension on a typical BMX rear hub.

Tensioning Sequence

Stress Relieving

Stress relieving is the step that separates a wheel that stays true from one that goes out of true after two rides. Do not skip it.

Once the wheel is at final tension, place it flat on the ground or lay it across two supports. Grip pairs of opposing spokes firmly and squeeze — hard. Work your way around the wheel on both sides. You will often hear clicks or creaks — this is the nipples and spoke heads seating fully. After each round of stress relieving, re-check tension and true, and make corrections. Repeat this process a minimum of three times until the wheel stops going out of true after each stress-relief pass.

The wheel is not finished until it holds true through a full stress-relief cycle without needing correction. On a properly built set of Slashers, this will typically take 3–5 cycles.

Final Checks Before Riding

• Lateral runout: 0.5mm or better
• Radial runout: 1.0mm or better
• All spokes within ±10% tension side-to-side (tighter is better)
• Wheel dish / centering: confirmed with a dishing tool or known symmetry check
• No nipples protruding into the rim bed where they could puncture a tube — file or grind flush if needed, then re-apply rim tape
• Rim tape fully sealed over all nipple holes before installing a tube or going tubeless
• Re-check tension again after the first ride. New builds almost always require minor corrections after the first hard use.

What Not to Do

Spoke Length Calculator Resources

Use any of the following calculators with the ERD values listed in the specs table above. You will also need your hub's flange diameter and center-to-flange measurements, which are available from your hub manufacturer.

• bmxspokecalc.com — BMX-specific calculator, cleanest interface for these builds
• spokecalc.io — Detailed calculator with support for 2:1 lacing and asymmetric rims
• prowheelbuilder.com — Professional-grade calculator with hub database

Guide produced by Supercross BMX / Speedline Parts. Specifications are subject to change — always confirm current specs at supercrossbmx.com. Last updated April 2026.