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what handles the load more, front spring or the forks?


KER

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what takes the brunt of the load on the steering, is it the front spring or the forks? I have always assumed the spring takes the main load and the fork are just for dampening......

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russell_bynum
what takes the brunt of the load on the steering, is it the front spring or the forks? I have always assumed the spring takes the main load and the fork are just for dampening......

 

On a Telelever BMW, the forks don't do anything except connect the front wheel to the handlebars.

 

The spring/shock handles all of the suspension and damping duties.

 

(Note: There is some oil in the forks and the air space at the top of that oil acts as somewhat of an air spring that gives you some compression damping, but the vast majority of the suspension action comes from the spring/shock)

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what takes the brunt of the load on the steering, is it the front spring or the forks? I have always assumed the spring takes the main load and the fork are just for dampening......

 

Kyle, seeing as you list two BMW R bikes we’ll assume you are referring to the later style BMW R bike? Not all motorcycle front ends are the same.. BMW is different than most..

 

I don’t know if you know this or not but on the (2 BMW’s you own) there are NO springs inside the forks.. They have a single spring coiled around the shock absorber & that is mounted on top of the front control arm behind the front forks.. SO, your forks neither do the ACTUAL dampening or the load control..

 

It’s difficult to just say the forks do this & the control arm does that & the spring does this as they are all inter-related as a functioning unit..

 

For just a simple explanation (remember they all work together though) the SPRING mounted behind the forks holds the front end up & handles load control & mechanical rate.. The shock absorber (mounted inside the spring behind the forks ) does jounce & rebound control,, limits suspension travel,, & handles hydraulic rate.. The forks themselves obviously tie the shock & spring to the front wheel but do take most of the twisting load of steering & also tie the fore/aft braking loads into the control arm & upper triple tree..

 

The angle of the control arm & it’s attachment points in relation to the forks & engine mounting handle the anti dive so the front end doesn’t dive severely on hard braking (very similar to how your car anti dive works)..

 

There is lots more like rake & trail of the forks & front tire size but we’ll keep it simple here..

 

Twisty

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LanceJFerraro

DOn't forget about side loads on the forks. When you're leaned over the forks and spring is taking compression loads due to the cornering force, but also vertical loads trying to bend the forks. Which takes more load, neither. It's dynamically shared, second by second, by both.

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Joe Frickin' Friday
what takes the brunt of the load on the steering, is it the front spring or the forks? I have always assumed the spring takes the main load and the fork are just for dampening......

 

The short version: the fork slider, stanchion, and swingarm all work together to constrain the motion to a certain path; the large spring and shock work together to bear the weight of the vehicle and damp out oscillations.

 

Take away just the shock (but leave the spring), and you'd ride down the road like Uncle Buck. Take away the spring, and the slider/stanchion/swingarm mechanism would be unable to bear any weight: it would collapse until it hit a hard mechanical limit.

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