Longer linkage -> Consequences for travel,geometry,angel?

[Grogurs]

Hej guys,

I need some physics cracks. Consider this situation and the pics below:

Longer linkage (3,6cm from damper bracket to back bracket), same suspension length. What will change?


I suppose:
- higher angles for the black stay, seat stay, headtube
- higher BB
- more travel (which calls for a harder spring/more bar?)

But is this correct? Thank you very much!


Best
Tom

Bigger pics

 

[gtRTSdh]

Re: Longer linkage -> Consequences for travel,geometry,an

I suppose:
- higher angles for the black stay, seat stay, headtube - yes off the bike but importantly dependant on where you set the sag
- higher BB - as above
- more travel (which calls for a harder spring/more bar?) - yes

If you set the shock in the position further out from the frame the bike will be more akin to where it is now, but with increased travel

 

[Rampage]

If the distance between the frame pivot and the shock pivot stays they same I think you will only be changing the chain/seat stay angles and the wheelbase (slightly due to rear pivot design), BB height will very slightly increase I think.

 

[cce]

taking into account the pivot at the dropouts, it may not make that much difference to the overall geo...

 

[cce]

that isnt to say it wont make any difference, the actuation ratio at the rear will be changed meaning as well as more travel, it'll feel quite different.

 

[gtRTSdh]

If the distance between the frame pivot and the shock pivot stays they same I think you will only be changing the chain/seat stay angles and the wheelbase (slightly due to rear pivot design), BB height will very slightly increase I think.

Where the seat stays connect will travel further due to the extended radius increasing wheel travel.

 

[Rampage]

If the distance between the frame pivot and the shock pivot stays they same I think you will only be changing the chain/seat stay angles and the wheelbase (slightly due to rear pivot design), BB height will very slightly increase I think.

Where the seat stays connect will travel further due to the extended radius increasing wheel travel.

I assumed he was asking about changes when the bike was at a standstill (not under load)?

 

[Grogurs]

Thank you mates!

Okay, sounds logic. Any disadvantages? (despite the higher angles which could be too much, as the FSR is quite top-heavy?)

I assumed he was asking about changes when the bike was at a standstill (not under load)?

Hmmm, yes and no. As I want to ride this bike, the changes when driving are more interesting

 

[greenstiles]

If you end up with a lot higher bottom bracket check that your wheel base hasn't shrunk too much. If the bb comes up and the chain stays start angling downwards at the drop outs , wheel base will shrink. But sit on the bike with sag and get another to measure wheel base then with your weight on as it will flaten out or angle up chain stays then.

Just imagine a tail of an animal going too far up or too far under, when in normal riding conditions..will affect steering and handling / stability a lot.

 

[xerxes]

Looking at the two linkages, the original has the shock mount roughly half way between the two pivot points.

The new linkage has a longer space to the rear pivot point. I would have thought this would increase its leverage, resulting in softer suspension, unless you fit a stiffer spring and increase the damping.