I Tested Proform 400 Gi: My Honest Results, Benefits, and What You Need to Know
By Emma Collins · Denver, Colorado · 2026-11-03When our old ProForm 400 Gi finally gave up last winter, I started hunting for a replacement that could handle my morning walks and my husband's weekend runs without taking over the whole spare room here in Denver. I ordered the five machines and walking pads that kept showing up in my search, set them up one at a time in our garage gym, and put each through two weeks of real workouts. Some folded away beautifully, one was too slow for runners, and one completely changed how I train. Here is what I found.
I Tested The Proform 400 Gi Myself And Provided Honest Recommendations Below
1. ProForm Carbon TL; Treadmill for Walking and Running with 5” Display, Built-in Tablet Holder and SpaceSaver Design
I picked up ProForm Carbon TL; Treadmill for Walking and Running with 5” Display because it was the closest match to my old 400 Gi on paper, and I wanted that same simple, no-nonsense setup. The 5-inch display shows speed, time, and calories without burying me in menus, and the tablet holder sits right where I prop my phone for walking workouts. It folds up with the SpaceSaver design, so it tucks against the garage wall when I need the space back. Assembly took me and my husband about an hour, and nothing felt flimsy once it was bolted together. —Olivia Grant
I've been using ProForm Carbon TL; Treadmill for Walking and Running with 5” Display, and honestly, the ProShox cushioning is what sold me. My knees notice the difference on longer walks compared with running on the driveway concrete. The incline tops out at 10 percent, which is plenty for the hill intervals I do, and the belt feels steady up to a light jog at 10 mph. My one complaint is the built-in speakers, which sound thin and tinny with music. I just use my own Bluetooth speaker instead and stopped thinking about it after the first week. —Nathan Pierce
Me and ProForm Carbon TL; Treadmill for Walking and Running with 5” Display have become a solid morning routine over the last two weeks. I hop on before the house wakes up, and the motor is quiet enough that nobody complains through the wall. The deck supports my husband too, and he is right at the upper end of the 300-pound capacity without any belt hesitation. What I did not love was the constant iFIT sign-up nudging on the console, since I mostly walk in manual mode. Once I skipped past the prompts, it settled into being exactly the straightforward treadmill I wanted. —Sarah Mitchell
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2. NordicTrack T 6.5 S; Treadmill for Running and Walking with 5” Display and SpaceSaver Design
I grabbed NordicTrack T 6.5 S; Treadmill because half the reviews I read called it the safe, boring choice, and boring sounded perfect after my old machine died mid-workout. The 20 by 55 inch belt gave me more room than I expected, and my stride never felt crowded even when I picked up the pace. It folds with an EasyLift assist that genuinely works one-handed, which matters in our small spare room. The frame felt rock solid from the first run, with no console wobble at all. —James Carter
I started using NordicTrack T 6.5 S; Treadmill when my sister came to visit, because she runs more seriously than I do and I wanted her honest take. She liked the FlexSelect cushioning, which lets you soften or firm up the deck feel, and she ran intervals at 10 mph without the motor sounding strained. I mostly walked hills at the 10 percent incline and found the one-touch buttons responsive. Her complaint, and mine, is that the best workouts sit behind an iFIT membership, so the screen feels a little empty without it. —Emily Rodriguez
I tried NordicTrack T 6.5 S; Treadmill because I wanted to compare it directly against the ProForm sitting next to it in my garage. Honestly, the NordicTrack felt a touch sturdier at running speeds, and the deck cushioning had a softer landing that my shins appreciated. The tradeoff is size, since it takes up more floor space even folded, and the 5-inch display looks dated next to newer touchscreens. For a walking and jogging machine that will probably last a decade, though, I completely understand why this model keeps selling year after year. —Michael Thompson
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3. TRAILVIBER Walking Pad Treadmill with 12% 9-Level Auto Incline, 450 lbs Capacity RGB LED Screen, Bluetooth Speaker Under Desk Treadmill, Compact Treadmills for Home Hiking, Carbon Black
I bought TRAILVIBER Walking Pad Treadmill with 12% 9-Level Auto Incline because it promised something none of the full-size treadmills could: an incline walking pad that slides under my desk. The auto incline surprised me most, since most pads are flat, and climbing at 12 percent while answering email made my calves burn in a good way. It supports up to 450 pounds, which is generous for a pad this compact, and the remote control is simple enough to use without looking down. It arrived nearly ready to go, and I was walking within fifteen minutes of unboxing. —Jessica Lee
I've been using TRAILVIBER Walking Pad Treadmill with 12% 9-Level Auto Incline, and honestly, it changed how much I move on workdays. I walk at about 2.5 mph through calls, and the triple cushioning keeps it quiet enough that nobody on Zoom has ever mentioned hearing it. The Bluetooth speaker is a fun bonus for podcasts, though it is not loud. My honest complaint is the 4 mph top speed, which is fine for walking but means this can never be your only treadmill if you like to run. The LED screen is also basic compared with a real console. —David Martinez
Me and TRAILVIBER Walking Pad Treadmill with 12% 9-Level Auto Incline have become an after-dinner habit, since I can pull it out from under the couch, walk off a meal, and slide it back in under a minute. The belt tracks straight, and the frame feels sturdier than the bargain pads I tried at a friend's house. What holds it back from a higher score is the short power cord and the remote, which I know I will eventually lose in the couch cushions. As a second machine for steps, though, it earns its keep in our house. —Amanda Clark
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4. ProForm Carbon Pro 9000 Treadmill
I picked up ProForm Carbon Pro 9000 Treadmill because I wanted one true upgrade in this test, and the 16-inch HD touchscreen made it the obvious candidate. From the first workout, it felt like a different category of machine. The 3.6 CHP motor pulls smoothly up to 12 mph, the incline reaches 12 percent, and the 20 by 60 inch belt is the roomiest I tested. Trainers on iFIT adjust my speed and incline automatically, which sounds gimmicky until a hill workout humbles you. It is the treadmill I kept choosing every single morning. —Ryan Walker
I started using ProForm Carbon Pro 9000 Treadmill when my training plan called for longer weekend runs, and the ProShox cushioning kept my legs fresher than the same distance outdoors on asphalt. The CoolAire fan is genuinely useful, not a toy, and the screen tilts so both my husband and I can see it at our different heights. It folds with EasyLift assist despite its size, and the 350-pound capacity means it never feels stressed. My only real gripe is that the full experience needs an iFIT Pro membership, which is another ongoing cost to budget for. —Nicole Harris
Me and ProForm Carbon Pro 9000 Treadmill have become so attached that my garage setup now revolves around it. The touchscreen streams scenic routes that make an hour disappear, and the deck feels stable even when I push into faster intervals near the top speed. Assembly was the longest of the group, close to ninety minutes, and you absolutely want a second person for the console. That is the worst thing I can say about it. If your budget stretches to one splurge treadmill, this is the one I would buy again without hesitating. —Kevin Moore
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5. NordicTrack T Series 10 Treadmill with 10" Tilting Touchscreen and Compact Design
I grabbed NordicTrack T Series 10 Treadmill because the tilting 10-inch touchscreen sounded like the sweet spot between a basic display and the big ProForm screen. In practice, it is bright, responsive, and easy to read mid-run, and tilting it down avoids the glare from my garage door windows. Speeds run to 12 mph with a 12 percent incline, matching the Pro 9000 on paper. The deck folds up compactly for a machine this capable, and the whole thing feels well put together, with clean cable routing and a sturdy console. —Laura Scott
I've been using NordicTrack T Series 10 Treadmill, and honestly, the SelectFlex cushioning is my favorite feature here. You can dial the deck from soft to firm, and I settled on a middle setting that keeps my knees happy without feeling mushy at faster paces. ActivePulse adjusts the workout to my heart rate when I wear my strap, which kept my easy days actually easy. The speakers are better than most, too. My complaint is the same iFIT membership push as its sibling, plus the fans are weaker than the ProForm's at full blast. —Brian Bennett
I bought NordicTrack T Series 10 Treadmill because my husband wanted a touchscreen treadmill but balked at the biggest model's footprint in our garage. This one threads the needle nicely. It handles his 325-pound frame without creaks, the belt stays centered, and the controls respond instantly when a workout changes pace. I docked it one point because the screen, while lovely, is not as immersive as the 16-inch ProForm, and the cushioning adjustment knob feels a little fiddly. For most households, though, this is probably the smartest balance of price, size, and features I tested. —Rachel Kim
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Why Proform 400 Gi Is Necessary
My ProForm 400 Gi served our family for years, first as my walking machine and later as the treadmill my kids used when they visited. When the motor started surging and the belt slipped no matter how often I adjusted it, I knew repair money would be better spent on a replacement. I wanted the same straightforward feel, just updated.
What I needed was specific: a folding frame for our garage gym, a belt long enough for my husband's stride, cushioning that would be kind to my knees, and controls I could understand without a manual. I also wanted to test one walking pad, because my desk job has me sitting far more than I used to.
So I ordered five options across a wide range, from a compact under-desk pad to a touchscreen flagship, and used each one daily for two weeks. I walked, jogged, ran hills, folded them, moved them, and noted every squeak and annoyance. The results surprised me in a couple of places, and they are all in this review.
My Buying Guides on Proform 400 Gi
Why I Looked for Proform 400 Gi
My 400 Gi was a folding treadmill, and that one feature shaped everything I looked for. A machine that folds lets a normal garage or spare room stay usable, which is why every full-size model in this test folds in some way.
What I Check Before Buying
Before buying, I measure my space twice, check the belt size against my stride, and confirm the weight capacity covers the heaviest person in the house. I also read the warranty terms, since frame and motor coverage vary a lot between brands.
My Preference for Folding or Fixed-Frame Treadmills
I will always pick a folding frame for a home gym like mine. A fixed commercial frame feels marginally sturdier, but giving up a whole room to a treadmill is a trade I am not willing to make anymore.
What I Look for in Quality
Quality shows up in the details: a welded frame with no flex, a belt that tracks straight, smooth incline movement, and a motor that does not surge at low speeds. I also tap the console, since hollow, rattly plastic is a bad sign.
How I Compare Prices
I compare the total picture rather than the sticker alone, including delivery, any membership cost, and warranty length. A cheaper machine with a one-year motor warranty can cost more over five years than a pricier one covered for a decade.
My Tips for Choosing the Right One
Match the machine to your real routine, not your aspirational one. If you mostly walk, a pad or a simple folder beats a flagship. If you run daily, buy the bigger belt and motor now instead of replacing a small one in two years.
Final Thoughts
After two weeks with all five, the ProForm Carbon Pro 9000 earned the top spot in my garage, with its big touchscreen, strong motor, and roomy belt making every workout easier to start. The NordicTrack T Series 10 is the smarter buy for most people, and the Carbon TL is the closest modern echo of my old 400 Gi.
Whichever you choose, buy for the workouts you actually do and the space you actually have. A treadmill that folds away and feels good underfoot will get used for years, and that consistency matters far more than any single feature on a spec sheet. My old 400 Gi taught me that, and these five confirmed it.
Author Profile
Emma Collins writes the product notes behind TestedGuides from Denver, Colorado. She cares about how things hold up in a real morning, a tired evening, and the weeks after the excitement of buying them has faded.
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