Condensed Answer: A full-suspension bike is not an optimal machine for jumping because it takes more effort to control the bike and get the rear end high in the air.
For that reason, most jump bikes are either fully rigid or have only a suspension fork. That said, a full-suspension bike can still be used for jumping with decent results if one practices sufficiently.
The Downsides of Using a Full-suspension Bike For Jumps
- Flexible Rear
The rear-shock of full-suspension bikes makes the rear of the bike “independent”. As a result, it takes more effort to control it before and during a jump.
If the lip of the jump is close to vertical, the rear shock will compress right before the jump, decompress afterward and send the rider in an unpredictable direction.
Full-suspension bikes are heavier than both dirt jumpers and regular hardtails. The heavier the bike, the more difficult it becomes to jump with it and control it.
Below is a table comparing the weight of dirt jumpers and full-suspension bikes:
|DMR Sect||11.5kg||Mondraker Summum||16.8kg|
|Scott Voltage YZ 0.1||12.8kg||YT Industries Tues 29||15.4kg|
|Marin Alcatraz||9.8kg||Commencal Supreme DH||17.1kg|
|Commencal Absolut Dirt||11kg||Canyon Sender CFR||15.8kg|
|NS Bikes Metropolis 3||13.9kg||Scott Gambler 900 Tuned||15.6kg|
|Canyon Stitched 720 Pro||12.05kg||Yeti – SB 165||14.67kg|
Conclusion: On average, full-suspension bikes are 4.1kg/9lbs heavier than dedicated dirt jump bikes. In the world of cycling, this is a substantial difference.
The extra weight of full-suspension bikes comes from the rear shock, the suspension, the front brake, the larger frame, the derailleur and the cassette.
Full-suspension bikes accelerate slowly and are difficult to “pump”. Thus, one is very likely to lose speed in-between jumps. The lack of acceleration makes it close to impossible to ride on diverse tracks.
- Large Tires
Modern full-suspension bikes come with either 27.5″ or 29″ wheels whereas dedicated dirt jumpers have 24″ or 26″ wheels.
The bigger wheels on full-suspension bikes reduce the bike maneuverability and make it more difficult to accelerate (get the bike up to speed).
- Overly squishy suspension
The suspension of full-suspension bikes is designed to be more responsive in order to handle small obstacles and irregularities on the road. However, the extra squishiness makes the bike less responsive, slow and needlessly bouncy. This issue can be mitigated to a degree by making the suspension firmer via its settings.
- Super Slack HeadTube Angle
The head tube angle is the angle formed between the head tube of the bike and the ground.
Modern mountain bikes have a slacker headtube angle which makes the bike more stable at speed but hurts its maneuverability.
For that reason, dedicated dirt jumpers have a steeper headtube angle.
The next table compares the headtube angles of dirt jumpers and downhill bikes:
|Dirt Jumpers||HTA||Downhill Bikes||HTA|
|DMR Sect||69°||Mondraker Summum||63.5°|
|Scott Voltage YZ 0.1||68.5°||YT Industries Tues 29||63.5°|
|Marin Alcatraz||69°||Commencal Supreme DH||63.5°|
|Commencal Absolut Dirt||69°||Canyon Sender CFR||63°|
|Santa Cruz Jackal||68.7°||Scott Gambler 900 Tuned||62°|
|Canyon Stitched 720 Pro||69°||Yeti – SB 165||63.5°|
Conclusion: Full-suspension bikes have a notably slacker head tube angle than a dedicated dirt jump bike. This makes the performance of technical tricks more difficult.
- Longer Chainstays
Another difference between dirt jumpers and full-suspension bikes is the length of the chainstays. The chainstays of dirt jumpers are notably shorter than those of regular MTBs. This makes it easier to lift the front and rear wheel.
The next table compares the chainstay length of dirt jumpers and full-suspension bikes:
|Dirt Jumpers||Chainstay Length||Downhill bike||Chainstay Length|
|DMR Sect||390mm||Mondraker Summum||445-460mm|
|Scott Voltage YZ 0.1||380mm||YT Industries Tues 29||440mm|
|Marin Alcatraz||395mm||Commencal Supreme DH||439mm|
|Commencal Absolut Dirt||390mm||Canyon Sender CFR||435-445mm|
|Santa Cruz Jackal||387.4mm||Scott Gambler 900 Tuned||435-450mm|
|Canyon Stitched 720 Pro||397mm||Yeti – SB 165||433mm|
Conclusion: The chainstays of full-suspension bikes are notably longer than those of dedicated dirt jumpers. As a result, it’s more difficult to lift the front and rear wheel of full-suspension bikes during jumps.
The Benefits of Using a Full-suspension Bike For Jumps
- More Forgiving Landings
The main benefit of full-suspension bikes is that they’re more forgiving when riding on diverse terrain and landing.
The rear shock compresses upon meeting an irregularity and keeps the rear wheel planted. Conversely, the rear ends of rigid bikes bounce around since there’s nothing beside the tire to absorb a hit.
Having said that, this benefit of full-suspension bikes isn’t enough to negate all the negatives.
Hence why dedicated jump bikes will continue to come in a hardtail format.
Summary: What You Need To Know
Full-suspension MTBs are not optimal for jumps because:
- The rear suspension could push the bike in an unpredictable direction when jumping.
- Full-suspension bikes are notably heavier than hardtails and dirt jumpers.
- Full-suspension bikes have longer chainstays which make it more difficult to lift the front and rear wheel.
- The head tube angle of full-suspension bikes is slack and hurts maneuverability.
- Full-suspension bikes accelerate slowly and make it more difficult to hit a series of jumps with sufficient speed.
- The wheels of full suspension bikes are larger than the 26″ models that we find on dirt jumpers. This hurts the bike’s acceleration and maneuverability.
A full-suspension bike may be imperfect for jumps, but it can still be used for that task if one is sensible and aware of the bike’s limitations. That said, nothing beats a dirt jumper for jumping.