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Will a Front Seat Fit on Your Bike?

By Annette 3 years ago12 Comments

Front mount seats do not fit ALL types of bikes. Work out if a front seat will fit on your bike.

Thule, Yepp & BoBike all make  Minis which are a front mount kids bike seat (meaning your child and the bike seat are between you and the handlebars).

A front bike seat is attached and mounted to your bike at the handlebar stem by one of 2 adaptors (mounting brackets).

  1. Standard Adaptor (mounting bracket) sold with every Front Seat – Thule, Yepp or BoBike
  2. A-Head Adaptor (mounting bracket) only sold with the Front Seat for Mountain Bikes Combo (Yepp Mini)


To work out which adaptor will work on your bike you need to understanding the SPACE that is available or can be made available on the handlebar stem of your bike

You also need to work out if you have room for a front seat and still be able to safely ride by understanding the SPACE between you & the handlebars


Please work through both points to understand if a Front Bike Seat is the right solution for your family.

Detailed information about BoBike attachment is still being created – the process is the same as for Thule & Yepp seats but the measurements are different.  A standard BoBike adaptor requires 35mm of space.  For a BoBike video that introduces the Mini go HERE

For details and video Thule & Yepp Front Seats…How to Attach A Front Mount Kids Seat


Not sure about working out space… choose to


 Receive goRide’s personalised kids bike seat recommendation for your family. Use our Solution Finder.  (For New Zealand residents only).

What SPACE is available on your handlebar stem?



A handlebar stem is the vertical part of your bike that is found just under your handlebars.  There are a huge variety of handlebar stems out there so you must understand what YOUR handlebar stem looks like to buy the correct type of Front Mount Kids Seat.

Front Mount Seats sit on adaptors that are attached to your handlebar stem.  The adaptors are rectangular so to identify if you have enough space you need to work out if the rectangles will fit on YOUR handlebar stem.

For the  A-Head Adaptor to fit you need an uninterrupted rectangle of 5mm (h) x 85mm (l)
For the  Standard Adaptor to fit you need an uninterrupted rectangle of  21 mm or more (h) x  70mm (l)
If the height of your rectangle is less than 5mm and you have a threadless stem (see below) the only way to gain space is to buy a stem extender or a completely new stem. Please consult a bike mechanic to see whether this is an option for your bike.
A-Head Adaptor. Yepp Mini fit. goRide

A-HEAD adaptor attached to a threadless handlebar stem (a spacer has been removed to expose 5mm of space).


STANDARD adaptor attached to a quill/threaded handlebar stem (the space available was greater than 21mm).

Diameter of the stem must be between 20 to 28mm to attach the adaptor.

Find out which stem you have – threadless or quill handlebar stem.  Then measure it!

  1. A Threadless handlebar stem – this type of stem is newer (more modern) and predominately found on ‘sport’ bikes. This stem clamps around the steerer tube. The only way to expose space on this type of handlebar stem is to remove spacers. (Spacers are generally 5mm or 10mm in height and look like rings wrapping around the stem).

Note: if you have spacers above the clamp you can re-organise the position of the clamp and spacers so that there is more exposed handlebar stem below the clamp.

For how to remove spacers: see How to attach a Front Mount Seat

Removakl spacers for A-Head Adaptor

This type of stem is commonly found on mountain bikes, sports or hybrid type bikes.


Measure the height of the rectangle that is available if you remove one or more spacers. Can you remove spacers to create a rectangle of either:

  1. 21mm (h) x 70mm (l) for the STANDARD ADAPTOR OR
  2. 5mm (h) x 85mm (l) for the A-HEAD ADAPTOR
height handlebar stem A head goRide

This photo shows a spacer can be removed to create a rectangle with a height of 5mm to allow an uninterrupted rectangle (5mm x 85mm) for attachment of the A-Head Adaptor.

This stem also has a spacer (red) above the clamp. As mentioned above – the clamp and spacers can be re-organised on the stem to allow more space below the clamp for an adaptor to be attached.

A-Head Adaptor = Front Mount Seat for Mountain Bikes = The Thule Yepp Mini
Standard Adaptor = Front Mount Kids Seat = The Thule Yepp Nexxt Mini
  1. A Quill (also known as threaded) handlebar stem – you are looking for an older style stem on an older style bike.   The stem will insert down into the steerer tube and be held in place by a nut & bolt.  These types of stems are easily raised or lowered to vary height.
Threaded handlebar stem. Yepp Mini fit. goRide

This type of stem is commonly found on town, urban, cargo bikes


Measure the height of the rectangle that is available or can be created (by loosening the nut to raise the handlebar stem). DO YOU HAVE A RECTANGLE OF 21mm (h) x 70mm (l) for the STANDARD ADAPTOR

Slimfit adaptor rectangle goRide

This photo shows that this quill stem has a rectangle with a height of 21mm to allow an uninterrupted rectangle (21mm x 70mm) for attachment of the Standard Adaptor.

As this is a quill stem, it could be lengthened to more than 21mm if there was not enough space available.

Important: Most handlebar stems have a “minimum insertion” mark that shows how high they may safely be set. If you can see this mark, the stem is too high meaning you need more of the stem down in the tube. If your stem doesn’t have such a mark, a good rule of thumb is that there should be at least 2 inches/50 mm of stem inside the tube.

Standard Adaptor = Front Mount Kids Seat = The Thule Yepp Nexxt Mini

You should now know which adaptor you need and therefore which Front Seat you will be considering buying – Thule Yepp or Thule Nexxt?

Do you have enough SPACE between you & the handlebars for a Front Mount Kids Seat? 

The space you need is different depending on the adaptor used. Did you need an A-Head or Standard Adaptor?

Using the A-Head Adaptor – Front Seat for Mountain Bikes – Yepp Mini

When the Yepp Mini is mounted on an A-Head adaptor you will need 43cm+ of space between your chest and the handlebars when seated on your bike seat/saddle.  The A-Head adaptor mounts a front seat in a more reclined position therefore you require more space.

Yepp Mini mounted onto A-HEAD adaptor

Using the Standard Adaptor – Front Mount Kids Bike Seat – Thule Mini Nexxt

When the Thule Mini Nexxt is mounted on using the standard adaptor you will need 28cm+ of space between your chest and the handlebars when seated on the seat/saddle of your bike.

Thule Mini Nexxt mounted onto STANDARD adaptor


Do you have enough SPACE? The amount of space that you will have available depends on your riding position and the size of your bike frame. Are you upright or in a lean forward riding position?

Leaning forward position

As your body position moves forward you have less space available for the Yepp Mini. Generally mountain styled bikes position the rider at a 65 to 45 degree angle to the bike seat.

How much space do you have between your chest and the handlebars? Do you have enough? (Remember the space you need will depend on the adaptor used).

Frame Size is IMPORTANT!

If this is your riding position – to have enough space you will most likely need a bike frame that is medium in size or bigger. That is a frame size of at least 42-43cm or 16 inches or more (medium frames suit a rider of 168-178cm in height).

To measure the size of your bike frame place your tape measure between the centre of the crank, up to the top of your seat tube (do not measure any of your seat post).

Measuring frame size. Kids Bike Seats. goRide

Upright rider

Generally riding town style bikes…think cruisers, retro or cargo bikes where the rider is sitting at an 85 to 90 degree angle to the bike seat.  This straight back creates lots of room between you & the handlebars.

How much space do you have between your chest and the handlebars? Do you have enough space? (Remember the space you need will depend on the adaptor used).

If you have greater than 21mm of space on your handle bar stem & have more than 28cm of space between your chest and the handlebars. 

If you have 5mm of space on your handle bar stem & have more than 43cm of space between your chest and the handlebars. 

…so you and your family can SMILE when you goRide

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  • CH says:

    thanks for all these explanations. i just bought a yepp nexxt mini with the standard adapter. I wanted to mount it on my urban arrow but it seems it won’t fit. I’m not sure even after having read the above that it will fit with a ahead adapter. I wish I had read this before buying :)! at least it will help me buying -or not- an ahead adapter :). thanks a lot

    • Jo says:

      Hi Caroline
      Thanks for getting in contact. Sorry you didn’t see this information before your purchase. I will send you an email and maybe if you send us a photo of your bike we maybe to offer some further assistance.

  • Erick says:

    This is a great post, thanks!

    Please note that your description of how to adjust stem height is not correct. Adjustment is via a bolt which is twisted from the top of the stem. See http://www.madegood.org/bikes/repair/adjust-handlebars-attached-to-a-threaded-steerer/

    Again, thanks!

    • Annette says:

      Hi Erick,
      thanks for taking the time to make a comment. We really appreciate it. We’ve adjusted our description to try and make what we are saying clearer. It’s been quite challenging conveying all this information in a simple way that everyday people can understand.

  • Mark says:

    Hi thanks for the helpful information. I can’t find much information on the difference between the Yepp mini and the Thule Yepp mini Nexxt. My Thule Yepp mini Nexxt adapter doesn’t fit on my mountain bike and I’d like to use the ahead adapter but I’m not sure if the adapter fits the Yepp mini Nexxt or Just the Yepp mini. Thanks for your help!

    • Annette says:

      Hi Mark, thanks for your comment. Sorry we haven’t made this more clear, it’s definitely something that most people interested in a front kids seat would want to know. In answer to your question about whether the A-Head adaptor is compatible with the Thule Yepp Mini Nexxt – the answer is NO even though both seats are owned by Thule – frustrating ah? This is why we continue to stock the Yepp Mini as it is the only front option that will work with the combination of an A-Head mounting adaptor and a threadless stem, commonly found on mountain and trail style bikes, which are really popular bikes in NZ.
      This is one of a couple of slight differences between the two products. The Thule Nexxt is the latest version onto the market so has the advantages of a magnetic buckle system which is really easy to use and it is made from compressed foam (stuff helmets are made from) making it the lightest front seat available.
      Hope that explains things a bit better.
      Regards Annette

  • Rc says:

    Hi, thanks for the post. Could you please advise which Of the seats and adapter I should buy To fit cannondale from the quick series (women).

    • Annette says:

      Hi, thanks for the question about your Cannondale Quick Womens bike. This hybrid sports bike has a threadless stem with rings or spacers around it, each spacer will be either 5 or 10mm wide. Depending on how many spacers there are as to whether a standard adaptor (needs 21mm or more) or an A-Head adaptor (needs 4mm) will fit. If you are confident you have a combination of spacers that gives you 21mm the Thule Front Seat will fit. If you are not sure, the Yepp, Front Seat for Mountain Bikes, comes with two adaptors – one being an A-Head needing only 5mm so this will definitely fit.
      Hope that helps and anymore questions, please just ask… Annette

  • Daniel Rooke says:

    Hi Annette,
    I’m trying to work out if i can get the Yepp Nexxt Mini will fit my headset. I have the Minimum 21mm of height clearance but my stem is 32mm thick. Is there anyway i can fit this system?
    Thanks in advance

    • Annette says:

      Hi Daniel, the standard adaptor used to mount the Yepp Mini Nexxt is compatible with stems from 20 to 28mm in diameter. Sorry, your stem is too big to safely attach the adaptor.

  • Jakub Skudlarski says:

    Do you know if there is more or less space needed with the ahead adapter and bobike compeared to Thule? Espescially the measurement where Thule needs 43cm.
    Thanks for the response in advance.

    • Annette says:

      Hi Jakub,
      Mountain or trail style bikes with threadless and angled handlebar stems create this need for space (43cm) as they recline the seat when it is mounted. As far as we are aware the BoBike is not compatible with threadless & angled stem attachment – the design of the seat puts the child footrests where your front forks are. We have tried and failed to get a BoBike Mini One onto a full suspension mountain bike which is disappointing because the BoBike A-Head adaptor only needs 4mm of space.
      Hope that answers your question.
      Regards Annette

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