FSR Brake Jack

This video illustrates the fact that FSR suspension does suffer form brake jack or squat

Category:

Sports

Tags:

• brake
• jack
• squat
• fsr
• mtb
• mountain
• bike
• bighit
• big
• hit

[spastikslingkee]

It will happen on the 05 as well, but if you actually ride the bike it brakes better than most non-fsr bikes in all conditions.

[spastikslingkee]

i think i over emphasised this. This is supposed to happen, and will happen on almost every bicycle suspension. Including Giants Maestro suspension. It is not a bad thing. It is simply the wheels momentum transferring into the suspension since the brake stopped the wheel from rotating.

[spastikslingkee]

there is nothing abnomal about the bike/shock. I just removed the coil from the rear shock.

[peanutaxis]

Correct it is merely the conservation of momentum. However you can get brake jack or squat on a horst link: The brake action transfers a torque to the seat-stays, the torque through the seat stays is transferred to the rocker. The only scenario where there is no jack/squat is when the rocker is perpendicular to the seat-stays (since the rocker moves, this is seldom the case).

[booleong]

turn on the lights dude

[peanutaxis]

This video is not of brake jack. It is merely showing the rotational energy being transferred to the bike. Think about it: if you did this same experiment with a bike with a brake isolator linkage, the same thing would happen. The suspension would still compress as the rotational energy of the wheel transferred to the bike.

[jacksona18685toot]

Sounds reasonable to me. Nothing wrong with a good deep obsession with MTB hardware.

[pjaxy]

@jacksona18685toot

after three years of obsessing with bicycle suspension, i've learned three important things

1) 90% of suspension bikes out there exhibit this "brake squat" which is usually wrongly called brake jack

2) floating disc brake system (like Kona's D.O.P.E.), eliminates brake squat

3) brake squat isn't necessarily a bad thing. in fact, Kona's D.O.P.E had two settings, one to eliminate brake squat, and one to increase squat. most people prefer increased squat

[jacksona18685toot]

@pjaxy Your FSR is not faulty. Don't worry about it. Any bike does this including a hard tail.

[jacksona18685toot]

I am pretty sure that that isn't brake jack that you are seeing there. I think you are seeing conservation of angular momentum which is a different effect. You really can't get brake jack on a Horst link setup because the brake caliper is on the seat stay. You will also see the same kick if you try this on a bike without rear suspension (although less obvious due to the greater mass of the whole bike compared to just the rear suspension swing arm).

[YourFatClownAss]

@surfersup1 Indeed, I have Trek session 77 which is fairly old now and with the bike setup for riding, this does NOT happen!

[Xantoes]

Brake jack and brake squat aren't the same thing