Friday, February 21, 2025

Gravel bike conversion to electric

We have enjoyed multiple bike trips to Italy riding the dedicated separated bike trails of the Veneto region. While there, we were introduced to the Refugios that are perched high in the mountains. They are mountain huts but that name does not do justice. A refugio will have simple dorm accommodations and a nice bar and restaurant with simple but satisfying meals. Usually they have a nice deck to enjoy sunrise and sunset from a spectacular view high in the mountains. Many people take advantage of being able to hike from refugio to refugio with minimal equipment and mountaineering experience. 

These refugios are often maintained via gravel roads that wind from the lowlands up to the high reaches. What a great idea to cycle from refugio to refugio. Many refugios also embrace ebikes by providing charging stations.

So I decided to try and convert our gravel bikes to bikes that could handle the rough gravel access roads that sometimes border on mountain bike single track. Many of the roads have quite a climb and I decided we needed a little help to get to the peaks.

There are multiple ways to create an electric bike from a standard bike. I wanted a stealth approach because of my own bike aesthetic. The rear hub motor method can employ a hub motor that requires the replacement of the rear wheel but otherwise no further modifications are needed. Some of the rear hub motors are so small in diameter that it is hard to tell they are a motor.

  I ran into a stumbling block with the first conversion because even tho' the bike was a carbon cyclo-cross bike it was old enough not to have the required 135mm rear axle spacing required of the available hub motors. So I found a frame at a surplus supplier randombikeparts.com, in Minnesota. It cost $199 and was a quality aluminum frame that would fit the bill. I ordered a Sutto 250w 36v rear hub motor kit for $380 which included everything I needed. There are many misconceptions in DIY ebike conversions and a lot of people who want powerful electric motorcycles for road riding. Which is fine but that is not what I wanted.  The 250 watt motor is more than enough power to assist in climbing the Italian Dolomites. It is very compact and relatively light (for ebike motors). 


The kit included a complete rear wheel with the motor, controller, display, cables, headlight and special brake levers that cut the motor off when you are braking. The motor controller manages the motor. I already had the battery from a previous project.


I put the bottle battery in the trunk bag. The frame bag has two zippered compartments and I put the motor controller in the bottom and used it as a cable hub to route cables around. 


From the cable hub I ran the single multi-purpose cable up to a stem bag (below) that I used as a forward cable hub. The single cable then branches to plug in the display, the brakes, the headlight and a sensor that stops the motor when shifting the derailleur.


I put on a Rockshox Paragon fork to help absorb the bumps on the gravel roads and added a dropper post primarily to make it easier to get on and off the loaded bike. The tires are 700x40 wide gravel tires.

It was a nice option to add the rear taillight and the lights are controlled right from the display. They are not the extremely bright lights commuters use but for the times when you are late in getting to your destination before dusk they will work very well and they are powered by the ebike battery.

The bikes perform better than I expected and have about a 40-mile range with the small bottle battery.  Like our eMTBs, these electric-assist gravel bikes will give us access to rides we normally would not be able to do. They make riding more fun. In our first outings riding against a strong headwind was not an issue; it neutralized the headwind.

The bikes won't go anywhere unless you pedal and you can control the level of assistance.

There is a "dark" side to this project. No airline will transport a used ebike, period.

You can't ship them via courier either. Renting an ebike in Europe is an expensive proposition at around 100 euros a day. That is not practical for us. When we go to Europe we stay for as long as we can to make the trip worthwhile. But I think I have figured out a legal and safe way to transport the batteries for this eGravel bike project. 

I will describe my transportable battery solution in the next article.

 

Sunday, January 19, 2025

Thursday, January 16, 2025

Wild Lobsters spotted in the Sonoran Desert

Sweetwater Preserve, Tucson Arizona

 








Saturday, January 4, 2025

Tortolita Preserve West

 The Tortolita Preserve, in Marana Arizona, trail system wanders up and down arroyos making an interesting and fun ride.