Condensed Answer: A hardtail frame would require serious modifications to the rear triangle to become a viable full-suspension model.
In most cases, buying a dedicated full-suspension frame is a safer, cheaper, and faster method to acquire the benefits of dual suspension.
The Differences Between Hardtail and Full-suspension Bikes
- Rigid vs. Suspended Rear Triangle
The rear triangle of a bike frame is formed by the seat stays, chainstays, and the seat tube.
The rear triangle of hardtails is rigid (immobile). The tubes are welded or brazed to one another and do not move.
In different, the rear triangle of a full-suspension bike is suspended and connects to the main triangle via pivot points.
When the rear wheel meets an obstacle, the shock compresses, and the rear triangle moves upward. After overcoming the obstacle/irregularity, the rear triangle returns to its original position.
For a hardtail to perform the same task, it will need a complete rebuild of the rear triangle. The procedure is very complex and requires in-depth knowledge of frame engineering and manufacturing.
The total expenses will include the following parts and services:
- Re-engineering of the frame
- Replacement of the rear triangle tubes with new ones
- Rear shock
- Modification of the downtube and or top tube to attach the rear shock
The number of tasks required to perform the conversion and the inherent risk behind it make the idea unreasonable. In most scenarios, it will be cheaper to acquire a regular full-suspension frame.
Also, the geometries of some hardtail models make the conversion non-viable right from the start.
FAQ: How Can I Make My Hardtail Perform Like a Full-Suspension Model?
A hardtail cannot replace a full-suspension bike, but it can be made a bit more comfortable with the following changes:
- Wider Tires
Wider tires can operate at lower air pressure. As a result, they offer a greater degree of suspension.
- Tubeless Tires
If the air pressure of a tire with an inner tube drops below the “healthy” limits, the risk of a pinch flat increases greatly.
However, tubeless tires circumvent that issue and allow the rider to drop the air pressure significantly without risking a flat. Hence why tubeless tires are so popular in the world of mountain biking.
The ultra-low air pressure of tubeless tires results in more suspension and comfort.
- Bigger Wheels
One of the main reasons why 29″ wheels are liked is their roll-over-ability. The larger the diameter of a wheel, the easier it is to overcome road irregularities.
Thus, if you want to cover extreme terrain on a hardtail, a frame and fork designed for wide 29″ wheels will help.
There’s a tradeoff, however. Larger wheels are not as maneuverable as smaller ones.
- A Suspension Seat Post
Another way to soften a hardtail is to get a suspension seat post. Obviously, a suspension seat post cannot replace a rear shock, but it does soften the ride and can be installed on any bike without modifications.
FAQ: Can I Put My Hardtail Components On a Full-suspension Frame Right Away?
It’s not possible to answer this question accurately without knowing the new frame and the donor hardtail. Some components might be transferable while others may be incompatible.
Below are some guidelines that will clarify what’s possible and what isn’t:
Full-suspension frames are designed for forks with lots of travel. If you have an older XC fork, chances are that it won’t provide a sufficient amount of travel. The result will be an altered bike geometry and subpar performance.
Also, the fork may be designed for a different type of head tube (e.g., non-tapered head tube) than what the new frame comes with. In that case, you will need an adapter.
- Headset and Head Tube Cups
The cups inserted into the head tube may not fit the new frame at all. A new headset could also be required.
- Bottom Bracket
If one of the frames is designed for a threadless bottom bracket while the other uses a threaded model, then it won’t be possible to transfer the old bottom bracket to the new frame.
The new frame should be designed for the same wheel size as the old one.
The dropouts of the new frame should be compatible with the wheels. For example, if the wheels are designed for thru-axles, the frame should be made for thru-axles as well.
To minimize the chances of incompatibility, it is recommended to systematize the parameters of the current bike components and compare them to those of the potential frames.
The fork and the wheels are of the highest priority because they cost the most to replace.
HardTail To Full-suspension Conversion Kit
The company BikeControl is known for a product called the Shockster which adds rear suspension to a hardtail. The Shockster provides extra travel and thus absorption, but it also has many downsides that riders would often criticize. Those would be:
- Increased wheelbase (the distance between the front and rear axle). The longer wheelbase makes it more difficult to lift the front wheel and reduces the nimbleness of the bike.
- Extra weight
- Suspension effect that can’t match the quality of modern shocks
As full suspension bikes developed, a product like the Shockster became obsolete which is why it’s currently difficult to find.
Given the downsides of the product, it’s wiser to buy a legit, modern full-suspension frame.
What Are The Advantages of Full-suspension Bikes Over Hardtails?
The suspension of a bicycle increases traction. When the rear wheel meets an irregularity, the shock compresses, and the wheel remains on the ground. The increased traction allows the rider to reach greater speeds when going downhill.
Conversely, the rear wheel of a hardtail bounces around all the time because there is nothing beside the tire to absorb the impact.
The rear suspension greatly reduces the vibrations reaching the rider and thus increases comfort.
The Downsides Of Full Suspension Frames
- Extra Weight
Full-suspension frames have more components and are therefore heavier than hardtail models. In some cases, the difference reaches 5kg/11lbs. If you want your bike to be as light as possible, a full-suspension model wouldn’t complement that goal.
Full-suspension frames are more complicated to produce and cost more.
- Non-compatible with Many Commuting Accessories
Since the rear triangle of a full-suspension bike is constantly moving, the frames aren’t compatible with standard full fenders and rear racks. To install such accessories on a full-suspension bike, you will need specialized models. Another option would be to modify an existing product in a creative but also safe and functional manner to make it compatible with a full suspension bike.