Rivian's TM-B electric bike
129 comments
·October 22, 2025jakedata
trvz
My local bicycle dealer has models in the window up to 15k$. There’s a market for such priced products.
jakedata
Oh, clearly. But for that money I'd buy a really nice BMW i3 REX. Obviously not an option for everyone.
wigglewoggle
What kind of capacity from your LFP battery? Is it diy built? I did one in the spring 16S with 25Ah cells and it's been amazing since. Only problem is it's a bit too big to fit anywhere I'd like it to. I have to mount it on a rear rack
jakedata
I am using 3x 12v 185wh batteries in series. Realistically I can count on around 500wh. They are only 3 lbs each and fit neatly within the frame of the mtb. I don't like having them up on the rear rack, they tend to make the tail of the bike wag a bit compared to low and centered.
https://old.reddit.com/r/ebikes/comments/1o0qthk/dynagirl_ri...
I just 3d printed protective covers for them last week when marketing turned their back on the new Bambu printer.
wigglewoggle
Nice
I have a big commute and in the (Canadian) winter my old 750Wh was sometimes not up to the task. So I went wildly over the top and built a huge cap battery. I never need to worry now
legitster
So the interesting thing about this is the ... peddle-by-wire drivetrain? So unlike a normal e-bike, when its battery dies it turns into a stationary bike.
I love ebikes and generally like what Rivian does, but in a very competitive market it's hard to see the appeal of this.
hbarka
If I may also peddle my opinion, this e-bike is a fresh innovation and it's easy to see how revolutionary it is. What very competitive market has regen, 180 newton-meter of torque, programmable power curve, shape-shifting? This e-bike is incredible. These days, who lets their iphone battery die?
kridsdale1
> a pun
Eyyyyyyy
null
dreamcompiler
808Wh battery and 100 miles of range. These two numbers track with each other and are roughly believable.
OTOH, with a battery this big, a generator powered by the pedals, and regen braking this thing has to be heavy. I'd expect it to weigh at least 80 lbs. More likely 100. The fact that their "specs" say nothing about weight suggests they're embarrassed about the weight.
dylan604
My eBike is close to 90lbs, but it is a large cargo bike touted as a "small car replacement". It is close to a tandem bike in size with a steel frame. I'm so used to it now, but I live in a house and never need to carry it up stairs. It does mean that I need an expensive bike rack to support that weight.
CorrectHorseBat
My Stromer ST3 weights about 30kg, has an 1kWh battery but doesn't come anywhere close to even 100km range at full speed.
I suspect pedal-by-wire will only be slightly heavier since it doesn't need gears, but the range will probably be even worse.
jeffbee
Regen braking is how you can tell this was designed by a moron. The energy balance simply does not favor regenerative braking on a bicycle, especially a bicycle that flippantly ignores aerodynamics like this one does. A bicyclist loses roughly all of their energy to air resistance. It's not a truck. There is not substantial potential energy to be recaptured going down hills.
big_toast
Not a big cyclist but is that still true for lower speed city riding (typical to flat european cycling prone countries), hillier SF, or mountain biking?
It seems obviously true to typical racing or distance scenarios. And i notice the wind even at lower speeds on e-bikes in SF.
But between their quad scenario and what I imagine as the urban car replacement scenario it doesn't seem as obvious.
jeffbee
Yes, it is true at all speed and under all conditions. The system simply does not have the mass that would give it a great deal of gravitational potential energy, and it reaches a power equilibrium with the air at low speeds. Example:
100kg rider at 15 kph = .24W-h kinetic energy. At this speed there is probably roughly 11N of air and rolling resistance, so the steady state power is about 3W-h per km. If you go 1km between stops, or more, the amount you can expect to gain by regeneration is extremely small. It could perhaps extend your range by 5%, generously.
CorrectHorseBat
My e-bike has regen braking and it's definitely noticable, but I don't know how much it helps
edaemon
What do you mean? The regenerative braking only kicks in when you engage the brake lever. It's not going to add much range but it's free, I don't see any downside to including regenerative braking.
jeffbee
It isn't free. How could it be free? It requires at least an electronic control system and a pressure sensor.
Erikun
It has a bit of a “The Homer” feel to it, but maybe the designs grows on you.
bigwheels
https://static.wikia.nocookie.net/simpsons/images/0/05/TheHo...
(https://simpsons.fandom.com/wiki/The_Homer)
A classic Simpsons episode!
PaulDavisThe1st
What I want ... not an E-bike, but an E-version of the BMW C1
Critical features: 1. moderate weather protection 2. vastly improved crash protection 3. top speed above 50mph 4. luggage capacity of a small flatbed trailer
I acknowledge the utility of e-bikes for many; for me, I prefer my non-e bike when I want to ride my bike, but would love an e-motorycle as an alternative to 80% of my car trips.
https://www.theautopian.com/bmws-first-scooter-had-a-ridicul...
a_ba
You‘re in luck BMW recently presented their vision CE.
https://www.bmwmotorcycles.com/en/experience/stories/urban-m...
PaulDavisThe1st
Sadly, no weather protection and apparently almost zero luggage capacity. But it's a very tiny step in roughly the right direction ...
dylan604
oh, those concept shots are hysterical. the one with the pink bike and the woman with 3 dogs kills, but the dj setup is where I said "too far" and closed the tab
eecc
Christ what an ugly kludge. Just spend a weekend in Amsterdam and check out the Tenways and the Vanmoof roaming the streets for an idea how to do it, if not right, at least decently
barbazoo
Not affiliated but I'm looking into converting my commuter bike with a kit from https://ebikes.ca. Seems to make more sense to turn any of the million bikes out there into an electric one using a reusable kit than buying a single purpose electric bike that will end up on the landfill once the company goes bust because no one wants to push around a bike that heavy.
oulipo2
Self-plug: you can take a look at our repairable and sustainable battery at https://gouach.com. If it gets depleted, it's super easy to replace cells, getting you a whole new battery for $50 (price of cells) instead of buying a new $200 - $500 battery
jlhawn
a full suspension e-bike, 500+Wh battery, with a belt drive for $4,500 is honestly a really good deal. There is a shortage of options when it comes to full-suspension bikes that are good for commutes. Compare this to any e-bike with the Bosch e-bike system. The big risk here for consumers if whether they can match the service, support, and reliability that Bosch has. There appears to be a class-2 e-bike option which is something that significantly differentiates it from bikes with the Bosch system.
qwytw
I really don't get what the point of the pedals on a thing like this, though. I guess mainly to satisfy some sort of regulations which separate bikes and motorcycle like vehicles? Considering that they aren't even connected to the drivetrain...
jlhawn
In the U.S., there are 3 classes of e-bike: Class 1: pedal-assist only up to 20mph (helmets optional for adults) Class 2: same as Class 1 but with optional throttle to 20mph Class 3: pedal-assist only up to 28mph (helmets required, adults only)
There's also a maximum power rating of 750 watts for all of these. I'm not sure where the "pedal by wire" feature is from a regulatory perspective, but to me this fits into either class 2 or 3 depending on what option you get.
SoftTalker
My state doesn't even require helmets for motorcyclists. I am guessing any regulations on e-bikes date back to the days when 2-stroke "moped" bikes were briefly popular.
sgarman
Based on the video and rivian history I think they wanted to redesign from the ground up a bike to match the packaging success they had at rivian and companies like lucid vs how legacy automakers approached it. The problem is the current laws about bikes and ebikes limited them and they had to make many tradeoffs which is what we are looking at. I guess we will find it if it was worth it to go ground up vs more off the shelf. As a rivian owner I'm concerned about repair-ability and maintenance.
hoherd
Some people actually do like to double up a bit of exercise with their commute.
kibwen
I was in the market for a commuter recently and my runner-up was this bike from Bulls (German brand trying to break into the US market) with full suspension, a Bosch motor, and coming in at a staggeringly light 58 lbs (battery included) for $3300. Extremely tempting, if I hadn't managed to snag a heavily-discounted Aventon Level 2 instead. https://bullsbikesusa.com/products/iconic-evo-tr-1-750
hnav
120mm seems like an absurd amount of travel for ostensibly what is a city bike
jlhawn
that's a nice bike! bummer that the rear rack isn't co-sprung.
antinomicus
The article clearly states it’s class 3.
jlhawn
From the article:
> It also features a throttle good for 20mph where regulations allow.
That must mean they have a class 2 option.
bb88
You can usually limit the bike to go less than 20mph in those cases.
It would be nice to have the GPS automatically set the pedal assist max speed when riding on shared paths with pedestrians and people.
I have also seen road bikers on those same shared paths pedal faster than 20mph.
thrill
The way I read it is if you use throttle-only you can reach 20 mph, but then if adding pedal-power you reach 28 mph. The pedal is probably not generating sufficient force to add 8 mph, but it’s telling the control system to do that.
givemeethekeys
"Honestly" does not make it a "really good" deal.
It's an e-bike. The competition is stiff, better looking, and better priced.
If they're lucky, this will appeal to university professors and over achieving parents of unsuspecting kids who want a cool bike but got an expensive dorky one instead.
jlhawn
The e-bike market has multiple tiers/segments. This is not priced to compete with brands like Rad Power Bikes, Lectric, or Aventon. It's likely going to compete with brands like Tern, Benno, Gazelle, Trek, etc.
edit: ask yourself why the median new car in the US sells for over $50k when you can easily find cars for less than half that price.
qwytw
I find it hard to imagine what the overlap between this and e.g. ebikes from Trek, though. Besides the price of course... It's an entirely different product.
Tiktaalik
> Also also unveiled its Alpha Wave helmet.... It also features integrated lights and a four-speaker, wind-shielded internal audio system with two noise-canceling mics. The helmet integrates with the TM-B’s console, where music, calls, and podcasts can be controlled on the bike.
In an ideal world these would be great features to have, but in the real world, where so many places have a near complete absence of safe cycling infrastructure and bicycles are casually mixed in with giant trucks it's a bit of a scary notion to reduce your situational awareness with a great sound system and the distraction of doing your morning zoom standup while cycling to work (I've done this before lol, tho most of my commute is in separated bike lanes...).
This points to the headwinds to adoption and success of the Also, which is that so many cities are ambivalent and uninterested if not outright ideologically opposed to building safe all ages and abilities bike lanes. That sort of safe infrastructure is critical to the success of a product like this. It's really unfortunate.
bb88
I've seen a lot of people use noise cancelling ear buds on roads using pedal bikes, so I don't see how this is any different really.
jakedata
I just added strips of fake fur to the straps my boring old helmet to diffuse the wind noise the same way a "dead cat" cover on a microphone does. They look a bit like muttonchops which is a bonus as far as I am concerned. I use wraparound bone conduction headphones that don't block my ears. I would be afraid of losing an expensive earbud.
ourguile
Very interesting, really liking the swappable components in the quad. I'm a big cyclist but have been looking for something new to take around for commuting that isn't a scooter.
Great to see more manufacturers getting in on micromobility options.
yodon
I have a 750W e-bike (which actually means 750W peak, 500W sustained).
There are hills near my house that my bike can not make it up without significant pedal assist.
If the motor and power electronics on this e-bike can only handle 750W peak, 500W sustained, as is common and I think is possibly even legislated in parts of the U.S., this bike will not be able to make it up serious hills.
With a normal e-bike, your pedaling is additive to the motor. That is not the case with this design.
derekp7
If the motor is geared it could make a difference. For comparison, most people put out about 100 watts with their legs, but need to downshift to go up hills. This looks like a mid drive unit, which should be capable of varied gearing.
bb88
I was looking for where the gearing was and it doesn't appear to be in the wheels. It looks like it's in the hub.
I have a bike with an automatic transmission and it handles steep hills just fine.
But generally speaking, I would expect the bike at this price point to have an automatic transmission.
masterj
Given it can output 180Nm I expect this thing can get up whatever hill you point it at
bb88
Despite the complaints in this thread there is already a market for $4k ebikes. And people are buying them. The bike competes with a bunch of e-bikes in that price range, Evelo Omega, Bosch, etc. So they're hardly a first mover. They are optimizing that market.
hnav
yeah but what's the point? At this price point alibaba monsters are far more powerful and real bicycles far more bicycle-like. These will sell a 10-20k units and fade into obscurity like Van Moofs and other disruptive bicycles before them.
bb88
People typically don't buy big ticket goods from a company named "YACCEEZY" like you might see on Amazon or Aliexpress these days.
It's worth noting that Hyundai had a similar issue when it entered the US market. It was an uphill battle to market itself to convince people to spend thousands of dollars of money on a no-name car brand.
$4500 is ten or more of my homebrew 750 watt electric mountain bike originally built in 2004. I just repowered with LiFePO4 after 10 years in storage and the new batteries really pull. It has a front hub motor with a throttle control limited to 20 mph. My commute is 10 miles, 6 on a dedicated bike path. Life is good.