How Tire Width Affects E-Bike Performance
Although technically developed by Frenchman Jean Naud in the '80s to cross the Sahara, fat-tire bikes first became commercially available in 2004 with the launch of the Surly Pugsley, and allowed riders an easier way to tackle extreme terrain and winter riding. Nowadays with the surge in popularity of electric bikes, fat tires are more widespread than ever. While electric bikes have made it possible for almost everyone to enjoy riding a bike without straining or sweating - fat tire bikes have made it possible for someone to ride on almost any surface or terrain.
With the wide variety of e-bikes available, choosing the right e-bike for your needs is critical. One of the most important factors in e-bike selection is the tire size. It’s crucial to understand that manufacturers design different bike models with distinct components to serve particular needs, and use specific parts that they view as the best for optimal performance. That is to say - the tire width will dictate the geometry of the rest of the bike and its intended purpose. With that in mind, let's walk through the pros and cons of fat tires on electric bikes, in order to determine what tire size is right for you. By the end of this article, we’ll drop some knowledge on how to find the sweet spot in e-bike tire sizing.
Fat Tire Benefits
“Fat tires'' are typically defined as bicycle tires at least 3.7” wide - and can even exceed 5” width. Riders are often drawn to fat tires because of their rugged appearance and general badassery. Aesthetics aside, fat tires are ideal for those looking to ride over gnarly terrain like snow, sand, and mud - as they provide more stability and traction over these types of surfaces and prevent the bike from sinking. Fat-tire bike riders often mention a sense of “floating” over the ground, as the relatively lower tire pressure allows the fat tires to absorb the unevenness and bumps, and act as a suspension system.
Fat tires provide better grip because their large surface area distributes weight more evenly. Although, when it comes to road grip, the tire’s air pressure (measured in PSI: pounds/square inch) makes a significant difference, arguably more than anything else. While narrow road bike tires usually run between 90-120 PSI, hybrid/commuter tires run around 60 PSI, and mountain bike tires run between 25-50 PSI - fat bike tires should usually be between 5-20 PSI.
Even though all fat tires will run at a lower PSI than their skinnier counterparts, fat tire riders will want to experiment with PSI to determine what works best given their preferences and terrain. While the higher side of the fat tire PSI range will result in more shock absorption and a smoother ride, erring on the lower side of the recommended fat tire PSI range will result in more traction. Usually a very low PSI (below 5!) is recommended for riding over fresh fluffy/loose snowfall, a PSI around 10 is ideal for dirt paths, and between 15-20 PSI is better for those stretches when you’re taking a fat bike on pavement.
Lastly, due to their lower pressure and higher tire “deformity”, fat tires are less likely to result in both pinch flats and puncture flats. Think of two balloons, one inflated to the max, and another just partially inflated. The balloon with less air is more malleable and less likely to go flat when poked than the one inflated to the max.
Bottom line: fat tires look rad (dare we say “phat”?), provide excellent traction, offer more shock absorption than narrower tires, are less susceptible to flats, and open up a world of exploration with the variety of landscapes they can cover.
Fat Tire Drawbacks
Although fat-tire bikes work just fine on paved surfaces, it’s akin to driving an off-road Jeep in a neighborhood cul-de-sac. While fat tires will allow your electric bike to traverse more easily across exotic surfaces like snow, sand, or mud - they are not without their drawbacks. More traction means more friction, which translates to more rolling resistance and a much slower travelling speed over paved surfaces common to most city-dwellers.
Let's consider the weight. Fat tires weigh much more than normal tires. Moreover, they need heavier rims and a much heavier frame, which usually makes the overall weight 10-20 lbs heavier than e-bikes with regular frames and tires. The increased weight leads to additional problems, including difficulty in accelerating, gently applying the brakes, and making smooth turns. As the increased surface area and weight causes more friction, the extra load goes directly to the battery, draining power faster than usual, and thus decreasing expected miles per charge. Another thing to consider is the ease of storage and portability. Electric bikes with fat tires weigh more, take up more space, and are tougher to load into vehicles or car racks.
Compared to “regular” hybrid tires (ranging from 1.25”-2.5”) or road bike tires (0.9”-1.25”), fat tires are harder to steer. While narrow-tired racing bikes are extremely nimble and even “squirrelly” with their ease of turning, fat tire bikes require a bit more effort to turn, and perhaps a bit more braking if turning at speed. Because of their increased weight, fatter tires also result in bikes that are slower to accelerate and stop.
Although increasingly less of a factor due to the ever-growing popularity of fat tires, fat tires and their compatible inner tubes are a bit tougher to find at some bike shops compared to more standard width road or mountain bike tires. Lastly, although it will occur less often, changing a fat-tire can be particularly challenging, particularly if you are out on the road.
Bottom line: Fat tires are slower on pavement, more taxing on your e-bike battery, less nimble at handling tight turns, and tougher at uphill climbs. They result in bikes that are heavier, harder to transport, store and swap out tubes.
Finding the Sweet Spot - What tire is best for you?
Each style of tire has benefits and drawbacks. You will only be satisfied with the tires that best fit your needs, so there are a few things to consider when choosing tire size on your electric bike.
- What type of terrain will you be riding most often: sand, snow, paved roads, or gravel?
- How will you be transporting or storing your e-bike?
- Do you prefer to go as fast as possible or instead value a diversity in terrain?
- Does the size and weight of the e-bike make a difference to you?
Here at MOD BIKES, we have tested out nearly every tire size conceivable on electric bikes, and have found that “plus-sized” tires strike the perfect balance between fat tires and traditional commuter tires. Typically defined as tires of 2.8” - 3.0” width, plus-sized tires are ideal for riders who value comfort across pavement, gravel and trail riding.
While you will definitely want true fat tires for crossing the Sahara desert or the Siberian tundra, we’ve found plus-sized tires to be the perfect “happy medium” sweet spot for 99% of riding situations. Both our MOD Easy and MOD City + feature 3” plus sized tires ideal for urban riding and perfectly capable of handling virtually any terrain mere mortals are bound to come across. If square footage is a concern - the MOD City + is foldable for easy storage and trunk transportation.
If you’re looking to traverse a bit more rugged terrain, the MOD Black also features plus-size 3” tires with knobby tread and dual suspension for a luxuriously smooth ride across dirt, gravel and trails. For those who mostly stick to urban environs and value going a bit faster, the MOD Berlin features tires of 38 mm (~1.5”) width.
Each of our bikes was carefully crafted for optimal performance, and we can’t wait to chat with you to find out which is most suitable for your riding needs! Give us a call at (512) 518-3445 or send us an email to schedule a free online bike fitting with our professional consulting team today, and we will be happy to help you find the best electric bike to suit your needs.
Bottom line: if you have epic snow drifts or gnarly terrain to explore in your area and you don’t mind going slow, consider fat tires. If you’d rather go extra fast and have mostly paved streets to ride on nearby, you’ll likely enjoy narrower tires. If you value comfort and easy handling over speed, plus-sized tires are perfect for you.