yes, it is possible to install bigger forks on mountain bikes, road bikes, gravel, and BMX but you have to face difficulty and rapid issues in the handling of your bike, depending on the trails where you are going to ride your bike, if the trails are uphills and you install big sized forks in your bike then it would be much harder to push the pedals and bigger forks will constantly increase your pedal striking, as time passes you will lose all of your stamina and body power and it would be harder to pedal further on the uphill and harsh terrains.
The distance between the front hub axle and the crown of the bike fork measures the size of the fork related to bike geometry. if the distance between the front axle and the crow of the fork is 10mm then 140mm to 145mm forks are recommended but if the distance is greater than 10mm then it is not possible to install 140mm forks and you also need bigger and larger forks based on the distance between the fork crown and hub axle. but if your bike frame is compatible with 140m forks and you are installing bigger forks than the usual, then it would be a better step because bike frames are manufactured and are compatible with properly sized forks, smaller or bigger forks would change riding, handling and gripping of the style of the rider and it feels like you are riding a different bike.
If the bike is new then the bike front hub, axle, and bike frame are also new, chances of cracking and breaking of frames would increase after installing bigger forks in your bike. the bike frame and front head tube, and seat tube angles of uphill and downhill bikes are different from each other. installing smaller or bigger forks on these bikes would also affect everything in your bike style and you are going to face much more difficulties with the bigger forks, your weight is pushed in the forward direction and you won’t be able to control your upper body smoothly above the addle and seat of your bike.
There are specific forks for uphill and climbing trails, shorter or longer mm forks are not installed on uphill bikes, but if your trails are smooth and not aggressive it would be possible to install different-sized forks in your bike. there are the following changes that you are going to face after installing bigger forks in smaller compatible bike frames.
- Greater Front End
- Much More Drag Force In the Pedals To Climb Upward
- Raise Bottom Bracket
- Change In Head Tube Angle And Seat Tube Angle
All of these things would matter and change after installing 15mm to 20mm bigger forks from the normal, and there are more chances of breaking the head tube angle with the bigger forks due to the change in the angle of the head tube, you will not notice in the beginning but after few rides, you will notice that head tube and seat tube angles re deforming and bending, and also the lower axle ends of the front wheel would also increase and affects riding especially when you are climbing uphills.
Bottom Bracket Height:
When you install a bigger fork the frame of your bike would also increase the height of the bottom bracket would also increase, and it will negatively affect pedaling of the rider affecting the center of gravity as the distance between the ground surface and the bottom bracket has changed from the usual.
Lesser Grip Of Front Tire When Rolling:
Bigger forks do not allow the treads of the front tire to roll better on the trails, and the center of gravity of the front tire is affected badly. weight of the rider is not pushed towards the front tire, as result, there are more chances of falling and coming backside down mostly when climbing on uphill trails.
Bigger Forks And Lesse Tire Pressure:
Bigger forks usually are less consistent in absorbing bumps and jumps of the trails at the recommended tire pressures usually for mountain bikes. so if you are installing bigger forks keep the tire pressure at a lower pressure to make the ride comfortable for uphills and downhills.
Rear Tire Ad Upper Body:
When you start pedaling on the uphill trails with the bigger fork, the rear tire would constantly slip and skid and you have to apply force on the pedals, you have to pull and drag your upper body in the forward direction to climb with your bike which is almost much irritating and you will also lose the gripping of the front tire, it will constantly move and come upward from the ground when you are pedaling uphills, these are the drawbacks of a mountain bike with bigger and non recommended forks.
Height Of The Saddle:
You also have to adjust the height of the saddle, so that the angle and height of the saddle and handlebar should be compatible with the hands and upper body of the rider, you have to lower the saddle position when you are going downhill trails, and when you are climbing then again you have to increases the height of the saddle with a bigger fork.
The speed of your bike increases much more with bigger forks, especially on downhill trails, even if it is hard to handle and control the speed and you have to keep the speed at a minimum level when you are riding on DH trails with the bigger forks.