Hello. I’m a beginner student of bike suspension and user of Linkage X3 program. I’m making my first desing of a trail bike for my final engineering academic project. I have a lot of doubts and I wish to know your opinion about it. I´m going to show its features and results below. Please, help me with it.

(Sorry for my poor English)


The objectives:

- High pedal efficience 100-120% Anti-squat at SAG, in all gears
- Low Pedal-kickback
- Medium anti-rise effect
- Leverage ratio? Uhm… I don´t want a lineal or regressive LR.

And in this first desing I have also looked for a rearward axle path, so in order to get a good %Anti-squat and low pedal-kickback I’ve attached an idler pulley on the main frame. The bad thing is I get a very changing %anti-squat out of SAG (due the strong slope graphic obtained). I have another design with a much more constant %AS around SAG, without idler pulley but with a more normal path. I thinking about pros and cons of both options.

- More features:

Trail suspension bike
Rear travel: 156mm (I want to adjust it to 150mm)
Front Travel: 150mm
1x12 speed (32/10-50t)
27.5” wheels

- Results:

SAG: 25% rear wheel travel (39mm)
(This point of the rear travel means 22% of the stroke shock (200x57mm -> 12.5m). In the future, I wish to adjust the system for the 25% of the shock stroke. See this topic on the forum for more information: )

I have a lot of doubts about how to model an air shock on the program. For the moment, I use a coil shock.

I also have doubts about the Horizontal mode and which are the right results to analyze.

ANTI-SQUAT: The %AS has very good numbers in all gears, but due the strong slope it can change a lot. I don´t know if this effect is too much. What do you think?


(practically, the same Anti-squat performance in Horizontal mode ON and OFF)

Gear: 32/10-12-14-16-18-21-24-28-32-36-42-50
%AS: 101, 105, 108, 110, 112, 114, 115.4, 116.8, 117.9, 118.7, 119.6, 120.5


Gear 32/10: 101%AS




Gear 32/28: 116.8%AS




Gear 32/50: 120%AS




PEDAL-KICKBACK AND CHAIN GROWTH

- Horizontal mode ON:

Gear 32/10:




Gear 32/28




Gear 32/50





- Horizontal mode OFF:

Gear 32/10:





Gear 32/28




Gear 32/50





ANGLE AND REAR AXLE WHEEL PATH




ANTI-RISE

- Horizontal mode ON: 63.8%AR




- Horizontal mode OFF: 64.1%AR





LEVERAGE RATIO AND FORCES





Thank you very much for your comments and suggestions.

Regards

I can't make the images appears directly in the post, sorry. Please, press on the links to see them.

And if someone wants the model I can send the Linkage .LTX file. I'm not sure if it is deserving to be at the Linkage Bike Library.

Hi Donato, thanks for sharing all this!

Just quickly reading, it looks like a good bike. Of course it takes a lot of work to really build a bike, make it strong and work everything OK.

With 1x11 / 12 gears now it's not really a pain to use an idler, some people don't like the looks of it, but it can certainly work well.

Please feel free to upload any files to web library, it's much welcome. Maybe just write something in the Comment field, maybe your website url too if you have one.

Thanks, good job, if I may say!