Condensed Answer: A cruiser seat can be installed on a mountain bike. The procedure often requires a replacement of the entire seat post because cruiser saddles are not compatible with the seat posts of modern MTBs.
The Differences Between MTB and Cruiser Seat Posts
- Saddle Attachments
The vast majority of MTB seat posts grab the rails of the seat via a plate clamp secured by one or two bolts. To tighten or untighten the clamp, the cyclist needs a 6mm Allen key.
This mechanism allows the user to slide the saddle forward and back across the rails to adjust its position.
However, this attachment mechanism is not compatible with classic beach cruiser saddles.
Most cruiser saddles attach to the seat post via a circular clamp designed for a “naked” seat post.
For that reason, the top portion of a cruiser seat post is usually of a smaller diameter than the rest of the post. That section is designed specifically for the circular clamp found on the saddle.
The change of diameter is necessary to prevent the saddle from sliding down.
Not all cruiser saddles use the standard attachment mechanism. Some models connect to the seat post via a clamp grabbing the seat’s rails.
These saddles can be installed on an MTB without having to replace the seat post. That said, high-level cruiser saddles do not fall into that category.
Requirements to Install a Cruiser Saddle On an MTB
- The Right Size Seat Post
As already mentioned, to install a cruiser saddle on an MTB, you will need a new seat post designed for such a saddle model.
The seat post will have to meet certain criteria or else the conversion won’t work.
In the best scenario, the diameter of the new seat post will match that of the original seat post. It’s also possible to use a seat post of a smaller diameter combined with a shim.
In most cases, MTB seat posts have a 31.6mm diameter. To find out what size seat post your bike has, check the indications on the seat post or its clamp. If you can’t see anything use a caliper or a ruler to measure the diameter of the seat post.
Note: The seat post should be able to provide as much or more height than the original one. Otherwise, it may be impossible to elevate it enough for comfortable pedaling
- Proper Seat Post Installation
Once you have the right seat post, it’s time to install the saddle on it. To install the cruiser seat, slide it onto the smaller diameter section of the seat post and tighten the clamp.
Apply a thin layer of grease onto the seat post’s body to prevent corrosion. This is particularly important when the frame and the seat post are made of different materials. For more information on greasing a seat post, check out this article.
Then, insert the seat post into the seat tube, adjust the saddle’s high and tighten the seat post collar.
Note: Respect the minimum insertion length indicated on the seat post to prevent damage to the seat post and frame.
The Benefits of Installing a Cruiser Seat On an MTB
- More Comfort When Riding Upright
Cruiser saddles are more comfortable when riding a bike in an upright position. When the rider is upright (the back is vertical to the ground), there’s a weight shift towards the rear wheel. Also, the contact area between the rider’s body and the saddle increases.
Thus, in this case, a wider, springy saddle is useful because it reduces the stress and the vibrations reaching the rider’s body. For that reason, classic city bikes use cruiser style rather than competition saddles.
The Downsides Of Installing a Cruiser Seat On an MTB
Cruiser saddles offer comfort only when the rider is upright. If the geometry of the bike is more aggressive, then a wider saddle can be uncomfortable because it creates lots of friction during pedaling. This is why road racers use very narrow and firm saddles.
А cruiser seat on an MTB is more likely to turn out convenient and comfortable when the geometry of the bike is more upright.
For that reason, cruiser seats are often installed on retro MTBs that have been converted into commuters.
If you put one on a modern MTB, you’re very likely to be disappointed.
Cruiser seats are large and use a spring mechanism to soften the ride. This combination offers comfort when the rider is upright at the expense of extra weight.
Cruiser saddles are bulky and therefore have no business on bikes used for stunts due to the extra weight and the greater possibility of hitting the saddle when executing a trick.
Summary: What You Need To Know
- A cruiser saddle can be installed on an MTB, but in most cases, the procedure requires a new seat post because standard MTB seat posts are not compatible with cruiser saddles
- Ideally, the new seat post will match the size of the original one. Alternatively, the user can also get a slimmer post and use a shim to stabilize it.
- Some cruiser saddles can be mounted on seat posts clamping the rails of the saddle.
- Cruiser saddles are designed for bicycles with an upright geometry. Putting such a saddle on a race bike will result in lots of friction between the saddle and the rider’s thighs. Hence why road racers use narrower saddles.
- Cruiser saddles are notably heavier than race saddles.