Electric Mountain Bike Tire Guide: Sizes, Treads and Pressure

Electric Mountain Bike Tire Guide: Sizes, Treads and Pressure

Choosing the right tires optimizes your electric mountain bike’s traction, comfort, and handling for the trails you ride.

Factors like tire diameter, tread patterns, rubber compounds and ideal pressure vary based on eMTB type and riding style.

We’ll review how tire sizes, tread designs, pressures and other aspects affect performance to help select the best electric MTB rubber.

Tire Sizing Overview

One key factor differentiating electric MTB tires is diameter:

26” – The longstanding standard size still common on some eMTBs. Quick accelerating but less stable rollover.

27.5” – The current most popular diameter. Offers a balance of agility and momentum retention.

29” – Largest size gaining widespread use on eMTBs. Excellent rollover but slower steering response.

Plus sizes – Offer extra width on any diameter for added cushion and grip.

Larger diameter tires have better roll-over-obstacles ability but menuver slower. Narrower widths are more agile while wider tires provide more traction and damping.

27.5″ Electric MTB Tires

27.5” tires represent the current sweet spot diameter for many eMTB riders, maximizing acceleration while retaining good bump absorption and angle-holding capabilities from the moderately large contact patch.

Popular 27.5” options include:

• Maxxis Minion DHF/DHR II – Legendary tread in an eMTB optimized dual compound rubber.
• Schwalbe Magic Mary – Uses Addix Soft compound for reliability and grip even in loose conditions.
• Pirelli Scorpion – Harder center knobs reduce rolling resistance while side lugs grab corners tenaciously.
• Continental Baron – Gravity-oriented open tread sheds mud extremely well.
• WTB Vigilante – Fast-rolling center tread makes for a quick-handling front tire.

For versatility across varied terrain, 27.5” eMTB tires offer a diameter balancing speed and control very effectively.

29” Tire Options for eMTBs

29” tires continue growing in popularity for electric mountain bikes, especially in cross country applications. Their oversized diameter enables:

• Improved angle holding and rollover clearance to plow through obstacles more easily.
• Greater stability at speed from the large contact patch and gyroscopic effect.
• Increased momentum retention for efficiently covering ground.

But the bigger circumference can make 29” eMTB tires handle more slowly and less instinctively if rider input lacks finesse.

Top 29” eMTB tire models include:

• Maxxis Minion DHR II – Fast-rolling center tread reduces drag for XC efficiency. Side knobs bite well for cornering.
• Schwalbe Nobby Nic – All-round evolution edition improves grip and durability for technical terrain.
• WTB Ranger – Tightly spaced center knobs flow quickly while side blocks carve aggressively.
• Pirelli Scorpion – Moderately spaced lugs provide a balanced grip to low resistance ratio.

29” tires shine for plowing through technical obstacles but suit more calculated, momentum based riding styles rather than aggressive maneuvers.

Plus Sized eMTB Tires

Plus sized tires starting at around 2.6” deliver additional volume for improved:

• Traction – The larger footprint and lower pressures increase mechanical grip.
• Puncture resistance – More rubber thickness helps prevent flats.
• Cushioning – The large air volume absorbs bumps and vibrations exceptionally well.
• Floatation – The exaggerated size allows riding over muddy and loose terrain that would swallow smaller tires.

But plus sized eMTB tires result in:

• Sluggish handling – The huge contact patch slows steering inputs and reduces cornering precision.
• Pedal strikes – Added height raises bottom bracket, requiring more pedal awareness and clearance.
• Limited frame fit – Many eMTBs lack clearance for massive 2.8-3.0” tires, especially on full suspension bikes.

While the damping and traction gains prove excellent for rough terrain, plus sized tires should be matched carefully to both the eMTB frame design and type of riding you undertake.

Tread Patterns for Electric MTB Tires

Tread design plays a significant role in optimizing electric mountain bike tire performance:

Short, tight knobs excel on hardpack surfaces, rolling quickly with minimal drag while still providing sufficient grip across dry conditions. But wet weather grip suffers. Popular as eMTB front tires.

Tall, widely spaced lugs allow mud, loose debris and water to clear easily while biting into soft terrain. But increased rolling resistance slows acceleration. Better suited to rear eMTB duties.

Ramped, directional blocks roll quickly in a straight line but still provide hooked edges for planting laterally during cornering. Versatile for rear eMTB tires if riding varied terrain.

Siped tread blocks use small cuts to provide many biting edges and flexibility for conforming and shedding material. Improves braking and turning traction.

Analyze your riding terrain most frequently encountered when choosing an ideal tread pattern. A combination of front and rear tires can balance low rolling resistance with ample traction.

Tire Rubber Compounds

Electric MTB tire rubber compounding affects grip, longevity, and terrain suitability:

Softer durometers around 50 Shore A offer the stickiest traction on rocks, roots, and hardpack but wear quicker. Best for freeride and downhill oriented eMTBs. The added grip helps handle the explosive power of stronger motors. But frequent replacements are needed.

Firmer 60-70 Shore A compounds provide better puncture resistance and extended tread life for cross country type riding while still cornering precisely. The firmer rubbers roll quicker too. But wet and loose surface traction is compromised.

Dual compound tires utilize a softer, grippier shoulder rubber extended down the side knobs while a firmer center tread compound reduces rolling resistance. A versatile blend of traction and speed.

Consider riding style, terrain, and motor torque when choosing rubber hardness. Softer grips best but wears faster. Firmer rolls quicker yet sacrifices wet weather handling.

TR Electric MTB Tire Pressure Recommendations

Finding the ideal tire pressure balances traction against puncture resistance:

Hardpack – 25-35psi lets the center tread maintain contact for speed while side knobs still grip. Allows lower pressures than rocky terrain.

Loose-over-Hard – 23-30psi allows the knobs to sink in slightly for control without excessive squirm.

Sand and Mud – 18-25psi maximizes contact patch without too much drag and tire roll under power.

Rock Gardens – 28-35psi supports sidewalls against pinch flats while keeping knobs in contact with rocks.

Downhill – 25-30psi. Enough firmness for stability under braking and cornering but compliance for bumps.

Plus Sized Tires – 10-18psi provides a large supportive footprint. The extra volume supports ultra low pressures.

Finding the ideal inflation sweet spot depends on conditions and riding style. When in doubt, start slightly higher and gradually reduce pressure until the tire squirms excessively.

Tube vs Tubeless eMTB Tires

Tubeless eMTB tires provide key benefits:

• Ability to use lower air pressure without pinch flatting.
• Reduced risk of punctures and flats since sealant plugs small holes.
• Elimination of tube pinch flats from bottoming out rim hits.
• Improved ride feel and traction without tube drag.

But tube-type tires should still be considered for:

• Easier repair if damaged since tubes can be swapped trailside.
• Ability to continue using existing standard rims. Tubeless needs sealed rims.
• Avoiding mess if sealants won’t plug a gash. Some tubeless damage is difficult to plug.

While tubeless improves traction and prevents flats, tubes provide a backup if damage occurs and allow using any existing wheels.

Front vs Rear eMTB Tire Differences

Optimize traction and speed by matching specific tires to each wheel:

Front eMTB Tires

• Shorter, tighter spaced tread for low rolling resistance
• Exceptional grip and cornering traction matters most
• Softer rubber for maximizing stick on rocks and roots

Rear eMTB Tires

• Larger, more open tread to shed debris
• Durable compound for wear resistance
• Stiffer sidewalls to support motor torque and pedal forces

The front tire greatly affects steering and cornering traction so needs grip. The rear tire experiences more forces from power delivery. Use tires optimized for each end’s demands.

Converting Rim Widths for eMTB Tires

Many eMTBs now use wider rims. When converting rim width:

• Going wider, use a tire narrower by the same increment. I.e. from a 25mm to 30mm rim, reduce tire by 5mm.
• Going narrower, increase tire volume by the same amount. This retains similar tire profile and diameter.
• Rotate existing wider tires to the rear when putting on narrower rims if they fit. Wider rear tires aid traction.
• Adjust tire pressure appropriately as widths change relative to rims. Wider rims need slightly increased inflation.

With careful matching, you can mount existing tires on new wider or narrower rims to improve performance and utilization.

Tire Inserts for eMTB Protection

Tire liners and inserts can enhance eMTB tire durability:

Foam Liners – Closed cell foam rings add cushioning to reduce pinch flats but add weight. Minimal puncture prevention.

Solid Tire Inserts – Very durable hard plastic inserts protect against flats and rim damage. But can bounce and mute ride feel. Heavier.

Flexible Inserts – Made from materials like silicone or flexible plastic, these damp vibrations while still preventing punctures. The added compliance improves feel compared to solid inserts. A favorite eMTB upgrade.

Tubeless Sealants – Liquid latex based sealants injected into tubeless tires plug small punctures and holes instantly. Lightweight protection against trailside flats.

For hardcore sharp and rocky terrain, flexible inserts combine the best flat protection with minimized ride quality sacrifice compared to solid inserts or heavy liners.

Signs Your eMTB Tires Need Replacing

Replace worn eMTB tires exhibiting:

• Visible cracks in rubber or frayed knob edges
• Numerous cuts and slices exposing cords
• Bulges or deformities in the casing
• Knobs worn down exposing minimal tread depth
• Hardening rubber compound providing decreased grip
• Frequent punctures and leaks as rubber weakens
• Visible cords or threads showing through the rubber

Retiring eMTB tires once the tread depth becomes overly worn or significant rubber damage accumulates prevents sudden blowouts and accidents.

Optimizing Cornering Grip on eMTBs

To carve corners, utilize these techniques:

• Lower tire pressures slightly to increase side knob grip when cornering hard.
• Lean bike aggressively and use your body weight to press the tires into the ground.
• Shift weight forward to increase front end bite. But avoid sliding the front wheel.
• Drag the rear brake slightly to settle the rear suspension and distribute weight evenly.
• If washout occurs, relax grip and look towards the exit. Avoid fixating on obstacles.
• Experiment with tire pressure, lean angles, and speed to understand grip limits.

Good cornering skills require practice. Let the bike roll under you, trust the tires, and maximize contact pressure.

Why Plus Sized Tires Shine for eMTB Use

While heavy, plus sized tires optimized for electric bikes provide major advantages:

• Enhanced traction to apply the copious motor torque through loose terrain
• Ability to run extremely low pressures for technical sections
• Increased bump absorption from the high volume casing
• Decreased risk of punctures thanks to more rubber thickness
• Improved stability and confidence at the higher eMTB speeds
• Floatation over mud, sand and other loose surfaces
• Cushioning to smooth rough descents and trail chatter

While sluggish steering is a tradeoff, plus sized tires allow skilled eMTB riders to rail through otherwise unrideable conditions.

Conclusion

Your tires constitute the most critical connection between an eMTB and the trail. Rubber compound, tread design, diameters, and inflation pressure must be tailored for electric riding. Prioritize grippy rubber for taming torque. Softer durometers improve rocky traction but shorten lifespan. Larger diameters excel on rough terrain given adequate pressures. Experiment to optimize tire setup for your motor output and local tracks. Grip confidently!

eMTB Tire FAQs

What’s the best tire pressure for electric mountain bikes?

25-35psi for most conditions and plus sized tires. Lower pressure maximizes grip but risks rim strikes and punctures. Start higher and gradually drop until squirming.

Do eMTBs require wider rims?

Yes, rims with internal widths of 30-40mm better support plus sized tires and prevent tire rollover under hard cornering forces.

How much tire pressure do you lose per week?

Expect to lose 1-3psi per week as sealant and rubber porosity allow slow air seepage. Check inflation at least weekly.

Should plus sized tires be used on eMTBs?

For loose, muddy terrain they excel. But sluggish steering must be considered. Weight-conscious riders may still prefer normal widths.

How do you plug a torn eMTB tire?

Tubeless plugs can temporarily fill small holes. For larger gashes, swapping the tube or tire is required. Carry plugs and tools to make trail repairs.