09/01/2026
“Just another thing that can break.”
I get it, I own gyms. The #1 thing that breaks on our selectorized equipment is the cable on the weight stack. EStack replaces that cable with rope that lasts longer than the nylon-coated 49-strand stainless cable we’ve used for years. And even then, we designed it to have what is probably the easiest rope replacement in exercise equipment.
The rest of the system is a lot less scary than people imagine. When was the last time you heard about a Tesla needing a motor replaced? You hear about batteries. EStack doesn’t have a battery.
The components inside the EStack box itself are meant to live for a very, very long time. The stuff that actually gets old in consumer electronics, screens, wireless hardware, sensors, compute, etc., lives in the dial. If we make a much better dial five years from now, unplug the USB-C cable and replace it. You don’t replace the weight system.
“I don’t want my weight stack to need a software update.”
Also fair. We’ve been selling Tether for 7 years. The only updates we’ve ever shipped have made the product better. We’ve never forced a mandatory update and don’t plan on starting. If your EStack works exactly how you want it to work, you can leave it alone. You don’t even need to get the app, or put it on wifi.
“It doesn’t do anything a normal weight stack can’t do.”
1 lb increments. Eccentric overload. Spotter modes. Isokinetic training. Variable resistance. Velocity-based resistance. Different resistance profiles through different parts of the movement. Automatic unloading when something goes wrong.
And there are things that are less exciting to put in an IG video but probably matter even more in the real world. Rack-tip prevention. Fast-retraction prevention. No heavy stack of plates moving up and down next to your fingers. Way less noise, which matters a lot for apartment gyms, and garage gyms with nosy neighbors.
The part I’m most excited about is sneaking real exercise science into normal gym equipment. Most people are never going to read a paper on eccentric training, accommodate resistance, velocity loss or isokinetics. They shouldn’t have to. The equipment should just make those tools easy enough that a normal person can walk up, understand them, and use them.
A weight stack is an incredibly good invention. We’re not replacing it because it’s bad. We’re replacing it because there’s a lot more we can make it do.
