Author Topic: Carbonda FM909  (Read 162454 times)

lukwy

Re: Carbonda FM909
« Reply #195 on: December 11, 2021, 02:56:05 PM »
As requested by PM, here some linkage analysis.

If anyone has a vector diagram of this frame, I can provide more accurate results :)

Hi Julian, take a look at attached vector PDF. Is it enough? I can export it to CAD format (DXF or DWG) if needed.

EDIT: According to my "CAD analyze" 165x45 damper leaves about 1mm clearance between seat stays and seat tube, but I didn't take into account the flexibility of rear triangle, so 45mm travel is very risky. Besides it is only the drawing.
« Last Edit: December 11, 2021, 05:05:40 PM by lukwy »
FS: Carbonda FM936, XT/SLX 1x12, 2.4
Gravel: TanTan GR045, GRX820/105 2x12, 700x35c

Sdp74

Re: Carbonda FM909
« Reply #196 on: December 12, 2021, 01:46:21 AM »
It seems that a 165x42'5 damper will do well. In this way you could have about 110mm of travel. I would like to confirm this point. Does anyone plan to put a 165x42'5 shock absorber?

FullCarbonAlchemist

Re: Carbonda FM909
« Reply #197 on: December 12, 2021, 01:53:04 AM »
;) Christmas came early this year.

I think I have everything, but 2cm more spacer. Already ordered.
The color is amazing. When you are very close you the blue and carbon are visible.  In the Light it's then really blue. Otherwise it appears very dark. So it's a effect for the rider  ;D.  For chameleon effects I always think it's an effect only others see, but the rider always sees one color.
I already attached frame protectors.. will then start with the routing of hoses tonight. 8)

That color looks AMAZING. Which one is it? I’d be pretty tempted to get my FM1002 frame painted with that when I order it.

Pedaldancer

Re: Carbonda FM909
« Reply #198 on: December 12, 2021, 10:30:13 AM »
It's blue raw carbon.. i don't have a color code or something like that

I'm screwed...
There is a photo..guess what's wrong here.. :'(
I already wrote an email, that I need the correct dust cap.
Let's see what Katie replies.  :( :(
I am really .. sad now.

federic000

Re: Carbonda FM909
« Reply #199 on: December 12, 2021, 02:31:33 PM »
I already wrote an email, that I need the correct dust cap.
Let's see what Katie replies.  :( :(
I am really .. sad now.

Cmon buddy, did you bought the headset from carbonda? I don’t believe cable shall be routed in that way! Anyhow don’t be sad, shit happens  >:(

Pedaldancer

Re: Carbonda FM909
« Reply #200 on: December 12, 2021, 06:36:37 PM »
Cmon buddy, did you bought the headset from carbonda? I don’t believe cable shall be routed in that way! Anyhow don’t be sad, shit happens  >:(

Well federic believe it or not, that's the way internal routing works. You may Google that...fsa ACR for example.

That's simply the wrong dustcap, that's why it looks wrong and yes it is wrong. the one I received is for the classic routing. The ACR type is larger and has an extra channel for the hoses.
« Last Edit: December 12, 2021, 06:40:29 PM by Pedaldancer »

St0mpB0x

Re: Carbonda FM909
« Reply #201 on: December 12, 2021, 06:51:16 PM »
I was under the impression defualt routing was external. I'm not expecting mine to turn up with a headset suitable for internal routing.

Julian

Re: Carbonda FM909
« Reply #202 on: December 13, 2021, 01:01:59 AM »
What do you mean by a "modern" leverage ratio.
How the suspension of this one will work compared to the FM936 if they're buillt with the same shock?

I mean it's not as progressive as one might want. Doesn't mean that it's bad of course.

My take: The biggest difference to the FM936 is not the overall progressiveness, but the way the progression changes throughout the travel. The FM936 is more progressive in the midstroke and basically linear at the end of the stroke. The FM909 is linear at SAG point, then becomes slightly progressive in the mid stroke and more progressive at the end of the stroke. Now air shocks generally lack progressivity in the mid stroke and are very progressive at the end of the stroke. Also, with volume spacers you can even increase the progressivity at the end of the stroke. But you can't really change the mid stroke. And so with the FM909, those similar characteristics enhance each other, making it more likely to fly through its travel and offering less mid stroke support. With the FM936, the opposing curves add up to a more linear overall lev ratio, giving more mid stroke support. The lack of bottom out resistance can be countered with volume spacers.

But please take this with a pinch of salt. I could be wrong :)

Julian

Re: Carbonda FM909
« Reply #203 on: December 13, 2021, 01:08:13 AM »
Hi Julian, take a look at attached vector PDF. Is it enough? I can export it to CAD format (DXF or DWG) if needed.

EDIT: According to my "CAD analyze" 165x45 damper leaves about 1mm clearance between seat stays and seat tube, but I didn't take into account the flexibility of rear triangle, so 45mm travel is very risky. Besides it is only the drawing.

Thanks! I used your vector PDF and got pretty much the same numbers. 45mm stroke is definitely too much.

If my model is correct, it has less travel than claimed though:

40.0mm stroke = 96mm of travel
42.5mm stroke = 101mm of travel
45.0mm stroke = 107mm of travel and a broken frame :)

Julian

Re: Carbonda FM909
« Reply #204 on: December 13, 2021, 04:51:26 AM »
This should visualize the different progression characteristics of the FM936 and FM909.

The blue line is the overall force needed to go from 0 to full travel.
The red line is the force needed to get the next 1mm of travel at any given point.

Both shocks are the same except for a slightly bigger volume spacer in the FM936 to match the overall bottom out resistances.

As you can see, the FM909 has a more pronounced "dip" in the late mid stroke whereas the FM936 is more evenly progressive. So with the same SAG and bottom out force, the FM936 will offer a better mid stroke platform and sit higher in its travel. Maybe the soft mid stroke of the FM909 has its advantages for an XC bike, but for down country, the FM936 should be better suited - also because of the 10-15mm extra travel.
« Last Edit: December 13, 2021, 04:54:26 AM by Julian »

Pedaldancer

Re: Carbonda FM909
« Reply #205 on: December 13, 2021, 10:13:42 AM »
I was under the impression defualt routing was external. I'm not expecting mine to turn up with a headset suitable for internal routing.

Maybe. You should make that clear.
I asked for the internal routing. And update: I will get the correct dust cap, the warehouse made a mistake.
So it's just waiting then.
Meanwhile I just fixed the fork a bit to try the feeling.
I know it looks funny and a bit weird with all the hoses escaping the handlebar vertically.. but here the first impression of the complete bike in frame size S.

And then a daylight photo of the colour. Artificial light makes it appear almost black.
Those theoretical graphs look interesting.. but tell me, can you feel this differences during the ride?
« Last Edit: December 13, 2021, 10:16:59 AM by Pedaldancer »

d3xophen

Re: Carbonda FM909
« Reply #206 on: December 13, 2021, 12:24:42 PM »
Maybe. You should make that clear.
I asked for the internal routing. And update: I will get the correct dust cap, the warehouse made a mistake.
So it's just waiting then.
Meanwhile I just fixed the fork a bit to try the feeling.
I know it looks funny and a bit weird with all the hoses escaping the handlebar vertically.. but here the first impression of the complete bike in frame size S.

And then a daylight photo of the colour. Artificial light makes it appear almost black.
Those theoretical graphs look interesting.. but tell me, can you feel this differences during the ride?

How's the internel routing with XT brake through handlebar?

Pedaldancer

Re: Carbonda FM909
« Reply #207 on: December 13, 2021, 01:41:01 PM »
How's the internel routing with XT brake through handlebar?

I didn't do the routing in the handlebar yet. I started at the rear since I have a prefilled XT. But I prepared the routing with the liner pieces. Look on the photo then you can see how the bending of the hoses will roughly look. Compared to the very strong S shapes and the small bending radius the brake hoses have to follow in a fully integrated road bike handlebar,  I guess that will work. Smaller angle will have a cleaner look though cause you will see less hoses.

« Last Edit: December 13, 2021, 02:59:59 PM by Pedaldancer »

carbonazza

Re: Carbonda FM909
« Reply #208 on: December 14, 2021, 03:29:12 AM »
And then a daylight photo of the colour. Artificial light makes it appear almost black.

I'm jealous, this is exactly the blue I wanted ( like TREK bikes ) and got a purple one instead  ;D

Pedaldancer

Re: Carbonda FM909
« Reply #209 on: December 14, 2021, 05:59:06 AM »
I'm jealous, this is exactly the blue I wanted ( like TREK bikes ) and got a purple one instead  ;D
Oh that's sad. If you feel better, my first chinese frame was supposed to be purple gold. Well yes ... it has a purple gold shimmer in the sun. Basically it's black, cause the amount of pigments is not high enough.
Would you show your purple color? I am curious
« Last Edit: December 14, 2021, 06:00:44 AM by Pedaldancer »