New bike coming?!?
I’m making a free ride bike and I would like any suggestions for my design idea’s.
The linkage 3x looks like this:
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Hi Cal, Welcome!
Cool design. I think posting images of your leverage ratio, pedal kickback, and anti squat graphs from Linkage would be very helpful.
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The only really worrisome thing I see is the Leverage Ratio. 54.4% progressive is kind of a lot. Most production DH/Freeride bikes are closer to 20-30%.
I’d love to see how you plan on packaging all of the shock and linkages into that area by the bottom bracket though. That’s gonna be difficult.
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Yeah the progressivity is a bit much in my opinion. Also, I don’t get how linkage calculates progressivity, it seems off to me. I popped it in my calculator and it came out at just under 120%.
The way I calculate it is this: ((A/B)-1)*100
where A = leverage ratio and 0mm and B = leverage ratio at bottom out. It seems to be in line with what companies are advertising. Here’s a excerpt of my spreadsheet of a few random bikes that I found published information on:
| Year | Make | Model | Travel | Lev @0mm | Lev @end | Progression %age |
|---|---|---|---|---|---|---|
| 2023 | Forbidden | Druid v2 | 130 | 2.92 | 2.3 | 27.0 |
| 2021 | Forbidden | Druid v1 | 130 | 2.7 | 2 | 35.0 |
| 2021 | Forbidden | Dreadnaught | 152 | 2.65 | 1.84 | 44.0 |
| 2020 | Rocky mountain | Slayer | 165 | 3.07 | 1.86 | 65.1 |
| 2021 | Salsa | Cassidy | 163 | 2.96 | 2.4 | 23.3 |
| 2020 | Cube | Sterio | 170 | 2.9 | 2.52 | 15.1 |
| 2022 | Transition | Spire | 170 | 3.01 | 2.37 | 27.0 |
| 2023 | Pi Bikes | HP | 170 | 2.82 | 2.54 | 11.0 |
| 2023 | Deviate | Highlander 2 | 145 | 2.88 | 2.43 | 18.5 |
| 2014 | Blackmarket | Roam | 160 | 4.2 | 1.6 | 162.5 |
| 2023 | Orange | stage 7 | 165 | 3.04 | 2.32 | 31.0 |
| 2023 | Coal bikes | TLFS | 158 | 3.42 | 1.87 | 82.9 |
| 2023 | Santa Cruz | 5010 | 130 | 2.7 | 2.4 | 12.5 |
Sorry if a bit off topic but its been on my mind for a bit. Any correction/input as to what linkage is doing would be appreciated
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Interesting design. I think going above 40% progression is risky. I’d recommend around 30-35%.
Also, careful going below 2:1 at end stroke on the leverage ratio because you might create a deep stroke rebound hang up. Also 3.65 starting will be extremely active and it would be hard to get any support from the damper.
18.5% of pedal kick is too much in my opinion.
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Thanks for the input. It is a high pivot the pedal kick back is high in the bigger gears I wanted a sort of 50/50 climb / descend gear (the picture was taken in a high gear). Can you tell me a little more about the deep stroke rebound hang up?
If you go below 2:1 at the end stroke then it will take a lot longer to recover and might create a packing situation. Most shocks are shimmed to work at or above a 2:1 ratio at end stroke. I would recommend to stay at or above 2:1 at the end or else you will have to get creative with the rebound shim stack.
I would try and have your starting leverage ratio around 3.2 to 3.4 and ending around 2:1. If you want extreme progression then I wouldn’t go above 3.5:1 and finish at 2:1. Do you have a shock you want to use in mind?
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I think I will be using a rockshox Super deluxe coil or a vivid
What is a good progression %. I am going to make a modification to the design to make two modes changed by switching linkages but what should they be?
Most modern coil shocks play nicely with 20-30% progression ratio as long as you are not far from the 3:1 starting point and and 2:1 end point. As I understand it, most modern air shocks play well in that same range. I’ve only built one full suspension bike though so I’m not an expert. My bike seems to play well with coil and air though and I followed these guidelines.
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Lots of DH bikes are between 25% to 35% with starting ratios around 3.4.
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That anti-rise number is gonna make the suspension pull together under braking, raising the bottom bracket and steepening the head tube. You might dig that but I think it would be really weird to ride, seems like it would be trying to pitch you out the front under braking and compression. I was really surprised how much anti-rise influenced how a bike rides, my dh bike is the opposite, it’s got like 200% anti-rise because YOLO, right? nope, it’s bad. It requires some interesting braking input to not load up and be really uinpleasant.
Try for around 100% if you can, moving the main pivot toward the back of the bike usually helps, seems like the farther behind the bb the, the higher the anti rise.
Good luck, give it hell.
I am using a floating brake design which lets me tune that very easily, thanks for the tip.
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Do you have any photos of previous suspension platforms you’ve worked on? There is a lot of fine details to execute o. Complicated suspension platforms. There may be value In working on a less complicated design first. You can accomplish similar numbers with a standard 4 bar design, without the need for the floater brake.
I made a 170 travel high pivot 4 bar that absolutely hammered.
Just my two cents.
I might end up doing that my current design pushes the shock up where the dropper should be. My design is a linkage driven single pivot so I might change the way it is laid out to make it simpler.
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