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Re: Ican S3 XC Frame For the linkage nerds among you (who haven't done it themselves yet), I've done some analyzing of the S3 diagram using Linkage X3.

Firstly, two purely subjective design aspects I don't like about the S3 when compared to the FM936:
- They had to redesign the rocker arm, due to the horst link rear giving more travel. To counter that, they moved the top shock mount further away from the seatstay, lowering the leverage ratio. The new rocker arm looks a bit dull to me.
- The angle of the seatstays does not allign with the angle of the top tube. That's something I love about the FM936 design. The S3 looks a bit more old school there in my opinion.

Now, moving on to the objektive stuff:
- The leverage ratio looks good, fairly progressive for an XC frame (around 11% from SAG). Also, the software confirms what has been said before: 40mm shock = 100mm of travel, 45mm shock = 112mm of travel.
- Anti squat is relatively high, so a bigger chainring is recommended to not increase it any further. A 34t should be okay, while a 32t will already give way too high anti squat at SAG, which may result in a lot of pedal bob. Pedaling technique also plays a role of course. But generally, 100% anti squat at SAG is preferable.

And here some screenshots. Enjoy :)
May 18, 2021, 02:17:05 AM 		1
Re: Ican S3 XC Frame
Quote from: Ben78 on May 27, 2021, 08:09:46 PM
Awesome! Did you end up getting a 165x45 shock? No dramas at all?
165x45 works great
June 03, 2021, 03:14:39 AM 		1
Re: Ican S3 XC Frame Seems like the S3 has a much better suspension design than the FM936.

Attached is the leverage curve sent by Adam at Carbonda and the S3 (thanks Julian)

As you can see the S3 is progressive to linear, similar to most modern XC bikes designed for an air shock

The FM936 has a really pronounced falling rate in the end of travel, this would mean it has very little bottom out resistance. Almost no bikes are designed like this today. We want a rising rate.

I have been looking at these bikes for my next downcountry bike but seems the S3 is a better choice for anyone who will bottom it out. Too bad its heavier than the FM936 by more than 400grs (comparing the SL version)
June 10, 2021, 10:02:28 PM 		1
Re: Ican S3 XC Frame
Quote from: jetpilot on June 10, 2021, 10:02:28 PM
Seems like the S3 has a much better suspension design than the FM936.

Attached is the leverage curve sent by Adam at Carbonda and the S3 (thanks Julian)

As you can see the S3 is progressive to linear, similar to most modern XC bikes designed for an air shock

The FM936 has a really pronounced falling rate in the end of travel, this would mean it has very little bottom out resistance. Almost no bikes are designed like this today. We want a rising rate.

I have been looking at these bikes for my next downcountry bike but seems the S3 is a better choice for anyone who will bottom it out. Too bad its heavier than the FM936 by more than 400grs (comparing the SL version)

You're welcome :)

Your analysis is correct, but I'm not sure if you can trust Adam's material. It seems like he's also using X3 to calculate the leverage ratio, but with that software it's absolutely impossible to calculate the actual leverage ratio of the FM936, because it does not have any means to factor in the flexing seat stays. If you only put in the actual existing links, the software will have a calculation error. I'm no engineer, but I'm pretty sure a flexing part does not have one fixed pivot point, but one that moves throughout the bend (similar to a VPP). That's why I have refrained from posting any leverage ratio stuff on the FM936. I've tried to get close to the actual leverage ratio by using a classic swingarm 4-bar design (so one additional pivot point in the seat stays) and placing the rear link pivot in the middle of the seat stay, where it's the most bendy. But placing it there will cause the seatstay to shorten a lot more than the actual bending does. So neither leverage ratio nor actual travel can be properly calculated.

I've tried out various different positions for that rear pivot point and the leverage ratio was always fairly progressive. That is also supported by what NS Bikes claim for the not-so-different Synonym and by what FM936 riders have reported so far. So I believe that the actual leverage ratio is absolutely fine for a down country bike.

I've attached some examples for different pivot placements in the middle and further back as well as one where it pivots around the rear axle. The "truth" could be somewhere between those estimates.


June 11, 2021, 01:30:36 AM 		1
Re: Ican S3 XC Frame
Quote from: jetpilot on June 11, 2021, 11:06:02 PM
Awesome Julian!! I was hoping you would do that  ;)
Yes seems they are both good bikes then, the leverage ratio from Carbonda did seem a bit odd but I found it plausible given what I have seen been done in China ("designers" that dont even know how to use the thing they are making, happens in many products).
I actually prefer the FM936 as its lighter and that's kind of the whole point of this bike (I already have a 160mm bruiser), plus flex stays is the new thing right  :P
Can you post the antisquat curve at least for one of the flex points? ("further back" seems like a good middle ground) THANKS!

Sure thing :)

Absolutely true about the chinese frames sometimes having weird linkages... but yeah, the FM936 seems pretty fine.

The anti squat is actually not affected by the placement of that rear pivot point, but very much so by the center of gravity, and I honestly have no idea how to correctly estimate that. I've just kept it where the software suggested it to be.

Anyway, it's probably very similar - if not identical - to the NS Synonym, and the magazine reviews haven't reported any terrible ride characteristics.

So, here you go, anti suqat for 32t and 34t (the highest line is with 50t, the lowest with 10t).
June 12, 2021, 05:05:46 AM 		1
Re: Ican S3 XC Frame Great thanks!

It has good pedaling characteristics from what I can see. I usually like to see ~120% on 50T so it stiffens up a bit especially if its a XC bike. This will also try to keep it above or close to 100% when on an uphill (CG moves forwards).
From my anectodal experience, 100% usually means it will bob slightly when mashing but it will stay fairly calm if you spin seated. A pedal switch is still going to be useful for sprinting and making the bike "feel" more efficient without perfect technique.


What software is this btw?
June 12, 2021, 09:05:44 AM 		1
Re: Ican S3 XC Frame
Quote from: marcocpl on June 16, 2021, 10:07:18 AM
Damn, I just found some quality issues with my frame while I was wrapping protective films on it.
The carbon finishing near the CS Axle pivots looks pretty bad. I'm not sure if I should continue building with this CS.
You can see the CS Axle Pivot Right Side - Low is perfect but others aren't.

I've sent ICAN an email. Let's see how it goes..

Looks like normal unfinished carbon. Frame would cost a whole lot more if you wanted it to be finished perfect.

I'd send it.
June 16, 2021, 03:02:54 PM 		1
Re: Carbonda FM 1003 / Flybike FM 1266 180mm "Super Enduro"
Quote from: chetosmachine on October 31, 2022, 03:05:55 AM
Could you please tell me which big brands offer alu frames at this price? i have a friend looking for something like this and all he finds is considerably higher cost :(

I think the closest option is probably the propain spindrift AL? https://www.propain-bikes.com/en/product/framesets/frameset-spindrift-al-29/ At least if you're in Europe, it's more expensive in NA.

It's mentioned earlier in this thread, but the Bird Aeris 9 is an interesting option, however with the 180mm link it ends up at just under1600usd https://www.bird.bike/product/aeris-9-frameset/#configuration

I've been considering the 1003 for a while now, but the lack of a bottle cage is holding me back. It'd just be a park/lift day bike, and in that case a full dh bike might just make more sense.
October 31, 2022, 01:25:29 PM 		1
Re: Carbonda FM909 I'm planning a new XC/DC build but really want room for two bottles without some odd mounting option, and I'm not sold on the LC 918. After seeing the update to the FM936 for 120mm of travel I thought I would ask about the FM909 just to see. Here's the reply from Adam:
"Yes,we have updated 120mm travel linkage for FM936.
And we are also on developing the 120mm travel for FM909,this project should be done in 3 months.
The best regards!
Adam"

So realistically 4 months out? Glad that I asked and didn't move on something else.
March 07, 2023, 08:39:36 AM 		1
Re: Spcycle 2023 New Travel 120mm Super Light 29er full suspension frame
it looks promising, but :

1-put the cables out of the headset;
2-put the cables out of the headset;
3-put the cables out of the headset;
4-put the cables out of the headset;
5-put the cables out of the headset;
 ;D
6-build a reinforcing arch thru the seat stays;
7-66°HA, 75,5°STA;
8-high quality bearings, bolt, axles.
May 03, 2023, 10:57:13 AM 		1