Spare Tire Delete Train Horn — Frame-Mount Kit Install Guide
Spare tire delete kit for train horn — mount tank + compressor in spare-tire well. Bracket options, truck-by-truck capacity, install tradeoffs.
A “spare tire delete” install puts your train horn for truck air tank and compressor in the spare-tire well under the bed instead of the typical frame-rail or behind-cab mount. The spare tire comes out (relocated to bed, trailer, or skipped entirely on daily drivers who never use it). The result: hidden install, no bed-floor space lost, factory bracketry leveraged.
Most truck owners on a daily driver don’t carry a full-size spare — they have AAA or run-flats. Removing the unused spare creates a clean rectangular mounting cavity that’s perfectly sized for a 1.5-3 gallon tank + compressor combo. This guide covers the bracket options, truck-by-truck spare-well capacity, and install tradeoffs.
For the bolt-on bracket adapter category overview see /vehicle/train-horn-spare-tire-mount/.
Photo · Prometheus · Wheel close-up (spare tire well becomes air system home)
Why spare tire delete is the cleanest pickup install
Three reasons this approach beats frame-rail or behind-cab mounting on modern pickups:
- Hidden install — air tank and compressor live under the bed completely out of sight. No visible aftermarket hardware. Looks factory-stock from any angle.
- No bed-floor space lost — frame-rail tanks bolt to the side of the frame and steal vertical clearance from under the bed. Spare-tire well uses the existing factory cavity that’s already there but unused.
- Factory bracketry available — HornBlasters Goliath and similar bolt-on adapters use the factory spare-tire crossmember mount points. No drilling required.
Trade-off: you don’t have a spare tire anymore. For daily-driver pickups this is usually acceptable (most drivers haven’t used a spare in 5+ years). For long-distance / overland / off-road trucks, plan for AAA membership, run-flat tires, or relocating spare to a bed-mount bracket.
Bracket options
| Bracket | Fit | Tank capacity | Price | Best for |
|---|---|---|---|---|
| HornBlasters Goliath (2014-2018 Tacoma) | Tacoma frame-rails in spare position | 2-3 gal + Viair 280C | $120-150 | Mid-size pickup, most-tested option |
| Universal spare-tire bracket (generic) | Adjustable to most pickup spare wells | 1.5-2 gal + compressor | $80-120 | DIY-friendly fit on multiple chassis |
| Custom fab plate | Welded angle iron + factory mount points | 5 gal possible on full-size | $20-50 in materials | Larger tank capacity, custom fit |
| HornBlasters bed-toolbox kit | Inside locking bed toolbox | 5 gal + 1NM compressor | $400-600 (full kit class) | Owners keeping the spare tire |
For deeper bracket category coverage see /vehicle/train-horn-spare-tire-mount/.
Truck-by-truck spare well capacity
Approximate dimensions of factory spare-tire wells on common pickups (measure your specific truck before ordering — these are nominal):
| Truck | Spare well dimensions (approx) | Realistic tank capacity |
|---|---|---|
| Toyota Tacoma N300/N400 | 28” × 20” × 8” | 2-2.5 gal |
| Ford F-150 (12th-14th gen) | 32” × 28” × 10” | 3-5 gal |
| Chevy Silverado 1500 (T1XX) | 32” × 26” × 10” | 3-5 gal |
| RAM 1500 DT | 32” × 28” × 10” | 3-5 gal |
| Toyota Tundra (XK50/XK70) | 32” × 28” × 10” | 3-5 gal |
| F-250 / Cummins 2500 / Silverado HD | 36” × 30” × 12” | 5-8 gal |
| Toyota 4Runner / SUV | 24” × 22” × 8” | 1.5-2 gal |
Compressor mounts inside the same well or adjacent on the frame — verify clearance before plumbing.
Install procedure
Standard spare-tire delete install workflow on a Tacoma N300 (extends to other pickups):
- Remove spare tire from factory winch mechanism (release winch cable per OEM procedure)
- Bolt bracket to frame using factory threaded holes (Goliath bracket uses the existing spare-tire crossmember anchor points)
- Mount tank to bracket with clamp-style retainers
- Mount compressor on adjacent inboard bracket extension
- Run air lines — 1/4-inch SAE J844 nylon from compressor to tank, 3/8-inch from tank to solenoid (or 1/2-inch for K5LA-class)
- Run power feed along factory harness path through firewall to battery+ (use 30 A relay + inline fuse within 18 inches of battery)
- Mount trumpets behind bumper or above radiator support (per chassis-specific section)
- Pressure test at 150 PSI with soap-water on every fitting
- Test fire with hearing protection, trumpets pointed away
Total DIY time: 4-5 hours on a Tacoma, 5-6 hours on a full-size pickup (more frame real estate to navigate).
For full install procedure on the kit-side see /guides/how-to-install-train-horn-on-truck/.
Recommended kit by truck class
| Truck class | Recommended kit | Spare-well fit |
|---|---|---|
| Tacoma N300/N400 | HornBlasters Conductor’s Special 232 ($799.99 sale) | Yes via Goliath bracket |
| F-150 / Silverado 1500 / RAM 1500 / Tundra | Conductor’s Special 232 or 540 ($799.99-899) | Yes, 3-5 gal capacity |
| F-250 / Cummins 2500 / Silverado HD | Conductor’s Special 544 Nightmare ($1,049.98) | Yes, full 5-gal kit fits |
| Compact pickup (Maverick, Frontier, Ranger) | Stebel Nautilus or Kleinn Direct Drive 6126 ($55-339) | Optional — small kit fits engine bay too |
For chassis-specific install details see /vehicle/ — F-150 / F-250 / Chevy / Silverado / RAM / Tundra / Tacoma / semi all have dedicated playbooks.
Common spare-tire-delete pitfalls
- No-spare paranoia: people overestimate spare tire usage. Average US driver hasn’t used a spare in 5+ years per AAA data. AAA roadside membership ($60-90/yr) covers the rare flat-tire scenario.
- Compressor mounted above exhaust — heat soak triggers thermal cutoff. Mount compressor on the cold side of the spare well, away from exhaust routing.
- Air-line routing through frame — never run lines through chassis drain holes (water seeps in through fittings). Run inside frame rails along factory harness paths.
- Forgetting clearance for spare-tire winch hardware — even with spare removed, the winch mechanism stays attached to frame. Plan tank position around it.
- Not pressure-testing before final assembly — leak detection is much harder once everything is bolted in. Test at 150 PSI with soap-water on every fitting before closing up.
When to skip spare-tire delete
- Long-distance / overland / off-road truck — keep the spare; frame-rail mount is more accessible for service
- Trailer-tow truck where flat tire on trailer requires same-size spare — keep the spare for cross-axle compatibility
- Lifted truck on 35”+ tires — spare doesn’t fit anyway, but the larger tire makes frame-rail mount space tighter; bed toolbox install is the typical alternative
For broader install-decision context see /guides/train-horn-buying-guide/.
Sources
- HornBlasters Goliath Tacoma bracket: hornblasters.com/products/goliath-train-horn-mount-2014-2018-toyota-tacoma
- HornBlasters spare-tire mount category: hornblasters.com/collections/train-horn-mounts
- HornBlasters Conductor’s Special 232: hornblasters.com/products/hk-s4-232
- Tacoma World 130 amp alternator thread: tacomaworld.com/threads/130-amp-alternator-upgrade.302907
- HornBlasters Jeremy’s 2016 Tacoma install case study: hornblasters.com/pages/jeremys-2016-toyota-tacoma
Frequently asked.
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