The Donnelly EMP 700×38 tire is a purpose-built option designed to handle demanding off-road terrain while maintaining the performance characteristics necessary for long gravel rides and mixed-surface racing. Named after Emporia, Kansas — home of the legendary Unbound Gravel race — this tire is engineered for durability, grip, and speed across unpredictable conditions. This article dives deep into the standout features of the EMP 700×38, offering guidance on installation, adjustment, and long-term performance.

Tools Required

• Tire levers
• Floor pump or tubeless inflator
• Sealant (for tubeless setup)
• Valve core remover
• Pressure gauge
• Clean rags and isopropyl alcohol (for prepping rim)

Installation Guide for Donnelly EMP 700×38 Tires

Installing the EMP 700×38 tires involves either a tubed or tubeless setup. These tires are tubeless-ready, and most riders will benefit from setting them up without tubes for lower rolling resistance and better puncture protection.

Prepping the Rim and Tire Bead

Before installation, ensure the rim bed is clean and free from old sealant or adhesive. Use a clean rag and isopropyl alcohol to wipe the rim. For tubeless setups, confirm the tape is secure and the tubeless valve is properly installed.

Mounting the Tire

Begin by seating one side of the tire bead onto the rim. Add the appropriate amount of sealant if setting up tubeless. Seat the second bead, using tire levers carefully if necessary. Inflate the tire using a floor pump or compressor to achieve an airtight seal. Check for even bead placement all around.

Inflation Pressure and Sealant Distribution

Inflate the tire to the manufacturer-recommended pressure range, typically between 40-60 psi for gravel use, depending on rider weight and terrain. Spin and shake the wheel to distribute sealant evenly. Recheck pressure after 24 hours to ensure a secure seal.

Adjustment for Optimal Ride Quality

The performance of the EMP 700×38 depends heavily on correct pressure and rim pairing. Riders should fine-tune pressure based on terrain: lower pressures offer more traction and comfort on rough surfaces, while higher pressures improve rolling resistance on pavement.

For best results, pair the tire with an inner rim width between 21–25mm. This ensures optimal tire profile and tread engagement. Periodically check for proper seating and adjust pressure as temperatures change or riding conditions vary.

Maintenance Guidelines

Routine checks are essential to ensure long-lasting performance. For tubeless setups, refresh sealant every 2–3 months to maintain puncture resistance. Inspect the tread regularly for embedded debris or excessive wear, particularly on the aggressive shoulder knobs.

If storing your bike long-term, deflate the tires to reduce stress on the sidewalls. Clean the tires after muddy rides to prevent rubber degradation and maintain traction.

Troubleshooting Common Issues

Bead Won’t Seat Properly

If the bead fails to seat during inflation, ensure the tire and rim bed are free from obstruction. Apply a soapy water solution around the bead to help it slide into place. Use a compressor if a floor pump isn’t achieving sufficient pressure.

Loss of Air Overnight

Slow leaks often result from improperly sealed valve stems or inadequate sealant. Tighten the valve core and re-inject sealant if needed. Examine the sidewalls and bead area for visible punctures or sealant weeping.

Tread Wear on Center Line

Excessive wear on the center tread could indicate over-inflation, especially on hardpack or paved surfaces. Reduce tire pressure incrementally and test the ride feel over several outings.

Customization and Performance Optimization

The EMP 700×38 is designed with a tread pattern that includes tightly packed center knobs for speed and tall, widely spaced side knobs for aggressive cornering. Riders can optimize performance by adjusting their pressure and wheel choice based on use:

• For Racing: Use carbon rims with a 23–25mm inner width and lower tire pressure for improved grip and reduced rolling resistance.
• For Adventure Touring: Pair with alloy wheels and slightly higher pressure for durability and puncture protection over long distances.

The tire compound is formulated to balance rolling efficiency with rubber flexibility, allowing riders to push confidently through varied terrain without sacrificing speed.

Comparison with Similar Models

Compared to the Donnelly X’Plor MSO or Clement LAS, the EMP 700×38 offers a more aggressive tread layout tailored for rugged gravel. The LAS excels on smoother gravel and hardpack, while the MSO sits in the middle, offering all-around performance.

Riders prioritizing grip in loose or muddy conditions will prefer the EMP. Those seeking speed on dry, compact roads may opt for the MSO or LAS models.

Compatibility with Drivetrain and Wheel Systems

The EMP 700×38 is compatible with both tubeless and clincher wheel systems and fits most gravel frames designed for up to 40mm tire clearance. However, always verify actual tire width on your specific rim, as it may exceed the nominal 38mm depending on rim profile.

This tire is best suited for gravel-specific or endurance bikes with wide clearance forks and stays. Avoid pairing it with road race frames, where tire rub could become an issue.

Frequently Asked Questions

Can I run EMP 700×38 tires with inner tubes?
Yes, although they are designed for tubeless use, you can install standard 700c inner tubes.

What rim width is best for these tires?
Inner rim widths between 21mm and 25mm provide the best tire profile and performance.

Are these tires suitable for pavement riding?
While they can be used on pavement, the aggressive tread is better suited for off-road and loose gravel terrain.

Do I need special sealant for these tires?
No, standard tubeless sealants like Stan’s or Orange Seal work well with the EMP 700×38.

How do these tires perform in wet conditions?
The side knobs provide excellent cornering traction, and the tread pattern clears mud effectively, making them reliable in wet conditions.

What is the weight of the EMP 700×38?
Approximately 460 grams per tire, making it lightweight for its size and intended use.

Conclusion

The Donnelly EMP 700×38 tire is a top-tier option for riders tackling aggressive gravel and mixed terrain. Its robust tread design, tubeless-ready construction, and fine-tuned rubber compound make it a standout for endurance and gravel racers alike. With proper installation, pressure adjustment, and regular maintenance, this tire delivers reliable performance and confidence over the most demanding terrain.