Hello all!
My name is David, and I’ve been a member of the club since 2019, although I’ve been a cyclist in the region since about 2013. Unfortunately I haven’t ridden as much as I would have liked this summer - a broken collarbone back in July certainly didn’t help. I’m also an engineer who likes to tinker.
I (along with two of my brothers) have developed what I’m calling a resistive training device that, in a nutshell, makes your cycling harder at lower speeds while road cycling outdoors. You throw the device on, and rather than needing 200W to travel at 30 kph, you now need 250W. The primary use-case would be to allow for cycling with others of different abilities while still getting exactly the workout you want. The way it works is by using high-power magnets to generate eddy currents in an aluminum wheel which creates resistance on the back wheel without needing to make contact with it. For those of you who are familiar with the STAC (now 4iiii) trainer, yes, it is based on the same technology. It sits on your seat tube, and has magnet arms which reach down to the rim. There are silicone strips which protect your paint, so only silicone and rubber bands are in contact with your frame. The device is completely silent, allows for adjustable resistance on the fly, doesn’t impact the ride feel at all, and can be put on/off in seconds.
The idea for the device was sparked by trying to get my partner into cycling and then looking into ebikes for her. After seeing how expensive ebikes were and not wanting to bike at painfully low watts if we both had regular bikes, I thought that rather than speed her up, I should figure out how to slow me down. Thus this project was born.
Here’s an example of it on my bike:
I’m looking for 4-8 people to test out a prototype on a few rides before we finalize our design. There are a few requirements:
- Must have a frame that the device is compatible with. We have designed it to work with probably >95% of frames so this shouldn’t be a problem. Here’s a handy guide that shows roughly which styles it’s compatible with. If you’re not sure, and we try to see if it works and it doesn’t, that’s still helpful information for us.
- Must have aluminum wheels without a steel bead or pin in the wheels. Here’s a handy guide on how to check if you’re not sure: https://4iiii.zendesk.com/hc/en-us/articles/360027746432 The wheel can be either rim or disk brake.
- You can commit to testing it on 2-4 rides within a week or two of me getting it to you (which should be within a week or two from now).
- You’re willing to provide some brief feedback to me on what you liked or didn’t like, and what you think might make it better.
- Optional, but helpful: A power meter of some sort on your bike. And then also your willingness to share your ride data with me.
For anyone who is interested, please email me at davidjwulff@gmail.com, let me know below in the comments, or message me.
In appreciation of your contributions, if you like the device after testing and don’t want to return it, you can keep the prototype for $40 (to help cover the costs of the parts), or I can give you a discount for 50% off for the production version if/once we start producing it. We haven’t decided on pricing yet, but it will probably be in the range of $150 - 250.
This has mainly been a fun project over the summer, and I have little idea of what the demand might be for something fairly niche like this (we might only sell like 3 haha), but we’re thinking of doing a kickstarter and we would go ahead with it if we get say 50 or 100+ orders for it.
If anyone has any comments/feedback, I’m super open. Even if it’s critical!
Thanks for your time,
David
Both my son and my wife prefer to ride their own bikes rather than be tied to me. Apparently I ride more aggressively then they are comfortable with although I do try my best to be good! Also I like to ride at a higher cadence and we have to compromise on that too. Welcome to try ours too if you like.
