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  1. Bike Accessories
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  6. 9 Months to 6 Years
Thule Yepp Maxi Child Bike Seat - Rear - Seat Post Mount - Black

Thule Yepp Maxi Child Bike Seat - Rear - Seat Post Mount - Black

Item # TH12020231
Our Price: $182.88
Bike Accessories
Shipping Weight: 14 lbs
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The Thule Yepp Maxi bike seat allows your child to ride behind you on a bike. This comfortable seat adjusts as your child grows and is easy to attach and remove from your bike's rear frame with included bracket. 1-800-940-8924 to order Thule bike accessories part number TH12020231 or order online at Free expert support on all Thule products. Great prices and Fastest Shipping for Thule Yepp Maxi Child Bike Seat - Rear - Seat Post Mount - Black. Bike Accessories reviews from real customers.
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Thule Bike Accessories - TH12020231

  • Child Seat
  • Seat Post Mount
  • Thule
  • Rear Mount
  • 9 Months to 6 Years
  • Black
  • 48-1/2 lbs

The Thule Yepp Maxi bike seat allows your child to ride behind you on a bike. This comfortable seat adjusts as your child grows and is easy to attach and remove from your bike's rear frame with included bracket.


  • For children ages: 9 months to 6 years
    • Note: Consult pediatrician for child under 1 year old
  • Weight capacity: 48.5 lbs
  • Seat weight: 10.1 lbs
  • 5-Year warranty


  • Child bicycle seat is designed for everyday rides
  • Carrier easily attaches to bike with included frame adapter
  • Safety features
    • Childproof safety buckle and sturdy foot straps
    • Leg shields prevent contact with spokes
    • Built-in reflector for added visibility
    • Steel frame with EVA seating and polypropylene parts
  • Comfortable design
    • Padded, adjustable 5-point shoulder harness
    • Durable, shock-absorbing seat
    • Adjustable harness straps, footrests, and foot straps allow bike seat to grow with your child
  • Convenient extras for parents
    • Easy-to-clean, water-repellent material
    • Integrated barrel lock secures child bike seat to your bicycle

Bike Fits:

  • Compatible with round seat tubes 1.10" to 1.57" in diameter and elliptical seat tubes with a max diameter of 1.57"

Yepp Maxi Seat Post Fit

Easy Installation and Removal for Stress-Free Biking

The included Yepp Maxi frame adapter secures onto your bike's seat post with included hardware and hex key. The bike seat snaps into adapter and features a green and red safety indicator so you can be assured the bike seat is properly secured.

Thule Yepp Maxi Secure Frame Adapter

The seat can then be adjusted closer to the rider or further back by using the grey slide and red button simultaneously. Once in place, the seat can be secured to the bike utilizing the integrated barrel key lock.

Thule Yepp Maxi Rear Adjuster and Key

To remove the child seat from the bike, press the blue button on the bottom of the seat and lift it off the quick-release bracket. Leave the quick-release bracket on your bike so you can easily attach the child seat the next time you take your toddler for a ride.

Thule Yepp Maxi Seat Post Adapter

An additional Thule Yepp Maxi Frame Adapter (sold separately) can be installed on a second bike to make it easier for 2 people to share carrying duties.

Thule Yepp Maxi Bike Seat Grows with Your Child

The adjustable seat harness straps allow you to customize the bike seat's fit for your child. The harness straps can be lengthened easily to fit over a bike helmet and raised as your child grows taller.

Thule Yepp Maxi Child Bike Seat

The footrests raise or lower depending on the height of the passenger, and the foot straps adjust to fit growing feet. This flexibility means that the seat will work for more than one biking season.

Thule Yepp Maxi Adjustable Footrests

Safe Child Bike Seat Gives You Peace of Mind

The Yepp Maxi bike seat is designed with your child's safety in mind. The seat's 5-point harness has a childproof buckle, so your child can't accidentally undo the harness.

Thule Yepp Maxi Childproof Safety Buckle

The foot straps secure your child's feet so they stay protected, and shielding around the legs keeps little feet and legs away from your bike's wheel spokes.

Thule Yepp Maxi Spoke Guards

Comfortable Child Bike Seat Keeps Your Toddler Happy

Go for longer, more enjoyable rides thanks to the comfortable features of the Thule Yepp Maxi. The shoulder harness is padded to prevent the straps from cutting into your child's neck and shoulders.

Thule Yepp Maxi Padded Harness

The seat is constructed of sturdy, shock-absorbing EPA material to make the ride more comfortable for your child.

Thule Yepp Maxi Rider Comfort

Practical drain holes remove rainwater or any other liquid spilled in the seat. This lets the seat dry out faster for a more comfortable ride for your child and promotes additional air flow during warmer rides.

Thule Yepp Maxi Rider Comfort

12020231 Thule Yepp Maxi Child Bike Seat - Seat Post Mount - Black

Installation Details TH12020231 Installation instructions

Video of Thule Yepp Maxi Child Bike Seat - Rear - Seat Post Mount - Black

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.

Video Transcript for Thule Yepp Maxi Child Bike Seat Review

Evangeline: Hi, it's Evangeline from, and today we are looking at Thule's Yepp Maxi, child bike seat here at etrailer. Now, this bike seat is designed to sit behind, on the rear of your bikes so that you can bring your child along on your biking adventures. This seat is designed to accommodate children from nine months to six years old. So there's different adjustment points for the different ages and height of your child.Now, this is also made of EPA material, which means it's soft, but very sturdy. Like when I press it here, it's cushiony, which means it will cushion that shock, which is great, especially on bumpy rides. And it also comes in different colors.

This is orange, and there's also black, ocean and blue.This material is water resistant, and it also is designed with these holes in the back just to make it easy for rain, water, and other liquid messes to just drain through. It's also very easy to clean.Now, for safety, this has a five point harness, and you can just buckle your child in. To release, you just press the sides and the top, then you can release on each side. And to buckle it in, just pop them back in like that. There we go.

Then tighten it down and you can adjust the straps as well, for it grows with your child. When your child gets taller, you can adjust it to have more space, or less space.The seat is attached to the bike by this steel frame. And I'm actually a big fan of this frame. If you notice how it has this flat, yet very sturdy design. I have installed other rear bike seats that have maybe a thinner and round tube that I was not as confident of its sturdiness as this is.

It looks, and it feels very strong. It is attached to the bike by this mount over here. And if you tighten it down properly and install it properly, this grips to the back. They have rubber grips to protect your frame. And it prevents side to side motion, as well as it clamps it down.These have adjustable foot rest for your child, as well as these shields to protect your bike seat, as well as your child's feet from your bike.

And these can adjust up and down. So you might start off with the foot rest up here on top, and then as your child grows, then bring it down. So it grows with the child.A lot of the sturdiness comes from this metal frame that runs around the seat and really keeps it sturdy and durable. There's also adjustment points here in the back, and it's super easy to adjust because you can just turn it, push it through, put it back on the top and release. This also has these nice plastic reflectors at three points. So that's really good because it helps protect you as you drive and keep you safe.Now I'm going down here to the foot rest. These adjusts, and they also have some numbers maybe to help you out, where if your child is one, two, three, four, five. You can have them at different points, slide them up and down and just snap it into place.Ideally, the seat should sit right over your rear axle, but if you do need some extra space, you can adjust it back and forth by loosening the bottom screws and just pulling and pushing on it. And when you're ready to go on a solo adventure, it's really easy to take it out. To release it you just press the red button and pull this lever. Then the entire seat can come out, leaving this here. If you just want to have that ease of installing and uninstalling the seat.Carrying the seat itself is not a burden. It's about 10 pounds, the weight of the seat itself. So it's really easy to take out and store and to install into place again. So to install, just get it into position. Then you engage this lever at the back and it clicks into place. From there, you can then lock the seat into place and protect it from theft.So now that we've showed you how we put the seat in and out of this quick release mount, let's show you how we installed the entire thing.So we're going to start our installation with the base. So if you have a top tube that goes down, you would need to take off the seat first. But if you have it in this style with the top tube attached to your seat like that, then you don't need to take off the seat because you would just start off with placing it into position like that. And find a good spot up and down your seat tube for it to stand for a bit. So that looks good. With this space in place we then start with, I like to start with the screws. We have four long screws here and I just put them through the holes to get them ready for our next step.So those go in, and if you do order it, they might arrive with the screws already in place. So you would have to detach them anyways.With the screws ready, you're then ready to attach the back plate and make sure that the rubber side is facing the frame like that. That rubber side is there to protect your frame from any possible damage or scratches. So you have to hold this in place while you screw the screw into the metal frame.So I like to hand tighten the screws first, just to get them in contact with the metal plate in the back before I go in and tighten it down with my included tool.So once you have them tightened down about 75%, I think that's a good place to stop because you still need to have it maneuverable with the seat on and after that, you can really tighten them down. With the frame of our mouth installed, we can then install this end piece. Now, there are two holes on the outside of the frame and four holes on the inside. So, the reason for that is so that it can be adjustable up and down according to maybe the angle of your bike, or if there's obstacles it needs to maneuver around.So for here, you just need to find, we're using the middle hole in towards the front, because I like how it angles straight there, perpendicular to our bike. You then use the large bolt and just insert that into the hole. Get that in. Then, use your Allen key to tighten that down.You then insert these two small bolts into the insides, the wall on the inside. So make sure it's on each side. And this side. That will just tighten it down. The nice thing about the included tool is it has this tapered end, which is really good for getting the bolts in at an angle.So you have to make sure that these are tightened down because they need to be flush against the wall so that you can start installing the seat.So start with the seat upside down and remember the bolts might come installed with the parts already. So you just have to make sure you take the bolts out so you start out fresh. So you need to make sure that the click part with the sticker is facing the seat. Press over and push.With the bar pushed all the way to the end, you can then install your metal screws into the sides. One on each side. Okay, with those screws tightened in, you can then flip your seat over and you're ready to install it into the mount. So get that in place. Here we go. Then you have to activate the lever and then push it in, right there. So, you know you've got it seated when the indicator shows green.Ideally this should be centered with your rear axle for the best support. So, you can push your feet back and forth to get the nice spot. That looks really good. And from here, you lock it into place with the screws that go underneath. So one over here. And one here in the back. And then, just tighten it down with the tool.So the reason I asked you just to partially tighten the front base is to make this back part install a lot easier. So what I do is I just tilt it to this side. That way I have more space to tighten down my bolt here. And with that tightened down, I can then push it back centered and tighten the front mount.Now you have to make super duper sure that you've tightened down this front mount, because if it's installed correctly and it's really tightened down, it will take out the side to side shake of your seat. So, with this tightened down, you're done and you're ready to go.Final thoughts about this is that my favorite part about the seat is the soft cushioning material it's made out of. I feel like it absorbs the shock as I ride along with this child. And that the five point strap harness here really keeps the child in and protected on our bike ride.So we'll show a little conversation I had with my coworkers and the questions they had about the seat.Okay. So, today you're looking at the Yepp Maxi of your bike seat and the Ride Along Lite. Both are by Thule here at etrailer. And so they're both rear bike seats and they attach with their own style of a quick release mount. So you put the mount in and then, you put the bike seat into the mount. So if we want to uninstall it, you just take it out of the mount and you can leave the mount on the bikes.So if you have any questions so far about the seats Matt: With the quality, does one of them feel more sturdy than the other Speaker 3: Yeah. Evangeline: Yes. They are made of different material for the actual seat. So, this is a hard plastic, and the way it's mounted to the bike is by this round frame here. So it's a lot different from this, the Yepp Maxi, which has this EPA expo material. So it's soft, and shock absorbent. And the way it's mounted is by this larger and flatter, and what feels to me, more sturdy frame. So in terms of quality, there is a difference because they're made of different material. But they both fit children from six months, no, nine months to six years old. But personally, for me, I would think a smaller child would be better in this because it has these larger winged arms, as compared to this. And this is also built to be taller. So a larger child would fit better on this, or it would grow better with a larger child. Speaker 4: Do you think there'd be any. I mean, we're not small kids, so we can't climb in there. I'm just curious if you think there'd be any difference in comfort for the child, looking at the sides that look like you can almost use those as an armrest on the gray one. Whereas, I guess- Evangeline: There's no armrest on the- Speaker 4: Yeah. Evangeline: Yes. So that's why I think for a smaller child, they would fit into this better because they're also more enclosed. But for a larger child, they wouldn't like to be enclosed into this, as compared to this, they would feel like they'd have more freedom. But in terms of comfort as well, this feels a lot more comfortable because of the foamy material, as compared to the plastic. So, actually sitting in this, I mean, I can't, but I can imagine. Speaker 3: Yeah, it'll actually move. Unlike this, it's like hard plastic. It's not going to use that much around. Plus, let's say you run into stuff. This isn't going to be as jaggedy and bouncy as this thing is. Evangeline: Yeah, this is a bit more shock absorbent. Speaker 4: You have the holes in there too. So you're vented. I bet that's a lot more comfortable. Evangeline: Yes, definitely. Speaker 4: On a hot day. Evangeline: Right. So yeah, this does have holes, and the description for it is, like for a hot day, there's air events. But as well as if we do have a mess or sweat or liquids, it drains out a lot easier too, through the holes. So for comfort, this feels a lot more comfortable. Speaker 4: Cool. Evangeline: Yep. What else They also have different harnesses here. So this is a three point harness, and this is a five point harness. So they just pop in. So if you can compare both, this feels a bit more. You have, it feels more strapped in with this, while here you just have the shoulder harness, but these also have leg, since it's five points. It's strapped in by the legs. So that means this has the wing sides, just to keep those legs in, while this is open, which is why they needed five points for this. Speaker 4: Yeah, that's what I was thinking. Evangeline: Yeah. Speaker 4: And both of them, the shoulder harnesses, it looks like they can be adjusted up at least, into the next holes Evangeline: Yes. So actually, this is really good. This is maybe better for smaller children, because this has three points of it, three levels for the shoulder harnesses. And to do so, you would just pop it out. It's a little bit harder to pop these out than the other ones. So, that might be something to consider. But I mean, if you're using it, you kind of just need to pop it out once. You don't have to constantly be adjusting it. So it's good because they're tight in here. But yeah, you can get them to a smaller size, while this just has two levels. It's really easy to adjust though because it just slides in through. Like that. Then, you can get higher or lower, but this would be great for a larger child. So there's less space down. You can have it shorter down here, while here, this is the limit just up and down. Just two points- Speaker 4: Cool. Evangeline: . for the shoulder harness. Let's see, what else Speaker 4: How heavy are they I mean, not just sitting on your bike, but also to remove the seats and are they cumbersome Speaker 3: Pretty light. Evangeline: They're pretty light. This one is lighter. The Ride Along is lighter than the Yepp Maxi, technically only by about a pound. Yeah, one pound. But what I did like about the Ride Along is that when you detach it, this is the only thing that stays on the bike, it's just this mount inaudible 00:17:04 it. As compared to the Yepp Maxi, this entire frame is what stays on the bike. Yeah, on the bike, attached to the bike. So when you remove it, you still have this whole thing attached to the bike as compared to the small box from the Ride Along. Speaker 4: So are there other accessories that'll work with that frame then Or if you want to use, I'm thinking of like the Thule bags. If you wanted to mount them on the back of your bike, I guess technically you could do that with the other one. Just if crosstalk 00:17:44- Evangeline: Exactly. Yeah. That's exactly it. But the Yep Maxi has a version where it attaches to a luggage rack. Speaker 4: Oh. Evangeline: So this is a version which is kind of standalone, but if you do have a luggage rack you would get the version that attaches to a luggage rack. That was kind of their solution for it. But as it is now, it would kind of cut down on the space you can use if you want to keep your mount attached. Speaker 3: Another thing with the weight that kind of fits in with it is just how durable it is. Not just when you're riding, but just by themselves. While this is pretty durable by itself, like if I dropped it, if I was carrying it and dropped it or something like that, I wouldn't be as. I wouldn't expect it to hold up as well as the foam one because overall, there was actual metal in- Evangeline: Mm-hmm (affirmative), there is a steel frame in there. Speaker 3: Like right in there. Evangeline: So there's that field frame, that metal frame, that goes around the seat in this one. So you have that good durability, as compared to this, which is one whole piece of hard plastic. Speaker 3: Yeah. So there's a lot more either hard or something that can hold up to things on this Yepp one, than compared to this one, just because this is probably, I would say, 90% plastic on everything. And this thing only has a little bit of plastic here and there. So if you drop it, I definitely wouldn't be worried about that one, but this one, depending on where you drop it, it could break something off. Evangeline: Yeah. Speaker 4: Does it feel brittle at all Or. Speaker 3: I wouldn't say brittle, but there's definitely points in it that don't feel the most can stand up to hard trauma or anything like that. Speaker 4: Like if your bike falls over, hopefully not with the kid in it, but if the bike falls over, it might crack along the side Speaker 3: I don't think it would crack along the side. The one part that I'd be worried about is maybe the top. The top is pretty. Because you can even see, it's really thin comparatively, but then when you get down farther, it's going to be thicker overall. Evangeline: What I do like about it though, is if you do fall over is these armrests here. So, especially with a smaller child, if it falls over, they would fit inside the armrests. So it would, I think, it would protect the child a bit more, as compared to here where their arms are out. That's just something I think about. If they're able to keep themselves inside it when it falls down. Speaker 3: So for protection, definitely for that one for younger kids, because if a five-year-old, there is a small accident, they're going to be able to handle it way better than a much younger kid. Speaker 4: Right. And they should be wearing helmets. Speaker 3: Always, always wearing helmets. Evangeline: In the description that your child should be able to keep their head up right, because it's technically allowed from nine months. But if they're under a year old, it's recommended to get the pediatrician's approval, just so that they're able to handle wearing a helmet in here. Speaker 3: Also, never go up or down very steep hills if you can't help it. Definitely down is much more of a problem because even on all. We we're reading through all the actual instructions and that's the one thing that we saw on all of them was just don't go down the hill. Evangeline: I did ride around with them a bit and I did notice it's definitely ideal to ride with just the seat because it's a change in balance for sure. So, before you put your kid in there, you need to ride around and get a hang of that extra weight in the back. Speaker 4: Yeah. That's good advice. Did you notice a difference when you we're riding around with the two of them Did either of them feel more fluid or they both just kind of felt different Evangeline: Well, we do have them on different bikes as well. I should try them on the same bike, but it's definitely weight in the back. That's just something I have to get used to. With your own bike it would be different as well because they are the same weight and they're both set over the rear axle. So it's just extra weight in the back that you have to think about it. I didn't really feel a big difference between the two. Speaker 4: It didn't feel like there was more pull to one side versus another, or anything like that Just weight on the back Evangeline: Yeah. You just have. Yeah. The instructions say it's best to have it over the rear axle, just to avoid any off-balance issues. Speaker 3: Yeah. The worst I would worry about is maybe the movement because this one's a lot sturdier at the actual base of it, all the way up to the side. While this one, it's still sturdy and it'll hold up. But you can see it's super, super thin and it's connected to that instead of how it is on that one, where it's connected higher up. Evangeline: Like on the Maxi. Speaker 3: So this one could, if your kid weighs a little bit more, you're obviously going to have more movement up and down, and side to side. Nothing that's going to throw you off, but just comparatively, that's going to be built more in than this one. Evangeline: So yeah, this is also adjustable up and down. There's a way to, when you screw it in, if your bike is a little bit different angle, you can adjust it here at the base. And it can also lock. So that's what's cool about the Maxi that the Ride Along didn't have, is that you can lock the seat into the. At the back, sorry. The lock for the Ride Along is over by the mount, while the lock for the Maxi is over by the back, which makes it easier to just take it out because this is where you unlock it and take it out. Speaker 4: Got you. Evangeline: So, that's one of the main differences. Well, that's one of the differences they have as well. So they both lock, which is great. Speaker 4: It's just a little bit easier with the Yepp. Evangeline: Yes. It's just one move, you're not going around your bike, while your kid is. Well, your kid shouldn't be on the seat anyways, while you're unlocking it. Speaker 4: Right. Evangeline: inaudible 00:24:27. Speaker 4: You got back from that long ride, it's a little bit easier to just pull off the Yepp, instead of messing around with the other one. Evangeline: Yeah. So this also has a hand grip here at the top. So, it's like your nice car seats where it's easier to just carry around. While this one has a smaller hand grip at the back, which isn't as sturdy and it's kind of small. That's another functional, ease of function difference. Yeah. But they're both pretty good. They're both really stable, sturdy. They both will get your. You'll have a great adventure with your child. If you like riding, and you want your child to experience that too, these both will work very well for that. Speaker 4: Cool. I'm guessing, if I'm looking for something now and I have a year old kid, I'm thinking I'd probably go with the Thule because it's still going to grow with him, but it's probably going to be better for him right now. Whereas, maybe if I have like a three-year-old or a four-year-old maybe go ahead and go with the Yepp because it does look nicer. The ventilation looks really nice. The construction looks great. The fact that it's easier on and off. Evangeline: Yeah, exactly. I agree with that too. Yes. Maybe another thing I would just like to make sure is that you really have to tighten down the bolts on the front mounts, because well, for this one, you just need to focus on the mounts for the bolts because that's what really takes the shake out. While for the Yepp Maxi I had to really tighten these down and the sides and underneath the seats. I just had to super make sure those we're tighten in to take out the shake. So if anyone using them might have difficulties, or might be unsure about the shakiness, just super make sure to tighten everything down. Speaker 4: Sounds good. Evangeline: Yeah. Other than that, does anyone have any questions about those too or. Pretty good Speaker 4: No, Matt you're good Matt: I'm good. Evangeline: Awesome. All right. Speaker 4: Cool. Thanks guys. Speaker 3: Thank you. Evangeline: Thank you!That was a conversation my coworkers and I had about this seat. If you had any questions about it, I hope that video helped with that. And that was a look at the Thule Yepp Maxi rear bike seat here at etrailer. Bye.

Customer Reviews

Thule Yepp Maxi Child Bike Seat - Rear - Seat Post Mount - Black - TH12020231

Average Customer Rating:  5.0 out of 5 stars   (4 Customer Reviews)

The Thule Yepp Maxi bike seat allows your child to ride behind you on a bike. This comfortable seat adjusts as your child grows and is easy to attach and remove from your bike's rear frame with included bracket.


Assembling it was a little time consuming but I appreciated watching the video by Evangeline she described every step which made assembly easier. My bike has one minor issue which it’s a hybrid cruiser bike which after mounting the adapter to the highest position and most comfortable for me was at the base of the seat adjustment part. So now if I wanted to adjust my bike seat I would have to loosen the adapter and lower it to re-adjust my seat preference. Other than that, it feels sturdy, light as I ride with my daughter and durable. I would point out obviously for safety reasons when placing child on or off of the seat that their be another adult holding the bike because depending the child’s age and weight the bike even on the peg stand cannot withstand the child as is and can fall down. I have only ridden a few times. My daughter loves it, as do I and can’t wait for more Yepp maxi adventures!


Easy to install and fits a wide range of bikes. My son loves riding in this seat much more than being in a trailer. It does change the handling of the bike, but it still prefer the seat when compared to having a trailer attached to the bike.


Daughter is 16 months old and loves it. Went for an hour bike ride the first day it arrrived and she loved it. East to assemble. And when riding you don't feel the extra weight. Would highly recommend.


An excellent product. Designed for safe carry of a small child with attention to detail.


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Used Items Available
Used Picture for Thule Yepp Maxi Child Bike Seat - Rear - Seat Post Mount - Black

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Notes: May have damaged packaging or minor cosmetic blemishes.

Our Price: $159.95
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Info for this part was:

Employee Jacob T
Video Edited:
Jacob T
Employee Kathleen M
Video Edited:
Kathleen M
Employee Amy B
Written by:
Amy B
Employee Matthew S
Updated by:
Matthew S
Employee Michael B
Updated by:
Michael B
Employee John S
Video by:
John S
Employee Evangeline M
Installed by:
Evangeline M

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