Carbonda fm936 Thoughts

[casual_build]

Hi guys, I have to raise the rear shock questions l again.
I'm in touch with Wing from Carbonda and she said "don't use a 165x42.5 shock! The FM936 was designed for 40mm". And she had a client who jumped into a deep hole and had the rear end touching the frame, resulting in harm of the frame.
What I'm asking you guys with a 165x42.5 shock is, how much clearance do you have when there is no air in the rear shock and you use all travel? If it's just a few Millimeter, then I'm very sure that this distance might be null or even less when the flex of the frame during a jump gets added.

Maybe would be also great to know how much clearance is present when using a 165x40. Does someone have these numbers?

Did wing say that the rear shock was 165x42.5 on the bike that was damaged? Sounds like she was just to use factory spec, which is the safe side of things. I think 4mm space is enough, but I bet it varies frame to frame.

[Colt__Seavers]

Hi guys, I have to raise the rear shock questions l again.
I'm in touch with Wing from Carbonda and she said "don't use a 165x42.5 shock! The FM936 was designed for 40mm". And she had a client who jumped into a deep hole and had the rear end touching the frame, resulting in harm of the frame.
What I'm asking you guys with a 165x42.5 shock is, how much clearance do you have when there is no air in the rear shock and you use all travel? If it's just a few Millimeter, then I'm very sure that this distance might be null or even less when the flex of the frame during a jump gets added.

Maybe would be also great to know how much clearance is present when using a 165x40. Does someone have these numbers?

Did wing say that the rear shock was 165x42.5 on the bike that was damaged? Sounds like she was just to use factory spec, which is the safe side of things. I think 4mm space is enough, but I bet it varies frame to frame.

Yes she did mention it was 165x42.5mm

[Colt__Seavers]

Sharing build progress, right now its more like buying progress.

This is my first build, total noob with no gear. Going for a trial bike over XC, trying to be a weight weenie but on the cheaper side.

Here is an indepth look at parts I bought for the frame. Including money spent, dont know if thats taboo, just want to be transparent.

I want to share for others to use, but also I want someone to tell me if i made a mistake! Like do I need an adapter for 180mm rotors on the rear?

Before this I had alan keys and a pump. So I dont have/ordered tools to cut the headtube or work with the BB, or grease. Could use some recommendations.

Hope you appreciate some of the detail I put into to this.

Really nice work man! I also did such a list and will share it ones I have all my parts. I also included a column "where bought", so people from the same country might benefit from it.

Go for a bike tool box for starters. Something like this:
https://a.aliexpress.com/_dXbpm2n
You can also find something like that in a local online shop. Starting from that you need a handful of other things like a steerer cutter (15€ tube cutter from your local hardware store for tubes up to 30mm, if you have aluminum steerer), bleeding kit (10€), pressfit tool (20€) and maybe a few other things

[casual_build]

Yes she did mention it was 165x42.5mm

Maybe buying that shock was a mistake... lol, although I could really see how landing in a ditch would squeeze the bike lengthwise

Really nice work man! I also did such a list and will share it ones I have all my parts. I also included a column "where bought", so people from the same country might benefit from it.

Go for a bike tool box for starters. Something like this:
https://a.aliexpress.com/_dXbpm2n
You can also find something like that in a local online shop. Starting from that you need a handful of other things like a steerer cutter (15€ tube cutter from your local hardware store for tubes up to 30mm, if you have aluminum steerer), bleeding kit (10€), pressfit tool (20€) and maybe a few other things

Thanks and thank you for the advice! I will look out for your list, I still dont have all my parts but they are all on the way.

[adroitrider]

Oh yeah, I was just riding along (trying to race an E-bike) and the frame failed (after riding straight into a tree at 20mph) because the shock stroke was too long.

Classic, JRA...

 

[Colt__Seavers]

Oh yeah, I was just riding along (trying to race an E-bike) and the frame failed (after riding straight into a tree at 20mph) because the shock stroke was too long.

Classic, JRA...

 

Really? Or ?

If the rear end really touches your seat tube, then it's maximum a crack, but won't fail immediately I think.

[carbonazza]

Not really what I wanted to read, with my 42.5mm shock waiting for the frame 
But being at around 67kg, and not particularly a jumper I guess it will be ok.
I'll put a gummy tape on the seat tube in any case, to soften any impact from the seatstays bridge.

NS Bike designed a rear triangle maybe just to offer a 120mm version.

[adroitrider]

Oh yeah, I was just riding along (trying to race an E-bike) and the frame failed (after riding straight into a tree at 20mph) because the shock stroke was too long.

Classic, JRA...

 

Really? Or ?


If the rear end really touches your seat tube, then it's maximum a crack, but won't fail immediately I think.

I was just kidding around. The only post in this thread with frame damage is with the 45mm stroke...and that was minimal.

[theirishrider]

Not really what I wanted to read, with my 42.5mm shock waiting for the frame 
But being at around 67kg, and not particularly a jumper I guess it will be ok.
I'll put a gummy tape on the seat tube in any case, to soften any impact from the seatstays bridge.

If you're worried I'll send you a spacer to insert into the shock, free. only need to unscrew the aircan its a 15 min job...

[Colt__Seavers]

Not really what I wanted to read, with my 42.5mm shock waiting for the frame 
But being at around 67kg, and not particularly a jumper I guess it will be ok.
I'll put a gummy tape on the seat tube in any case, to soften any impact from the seatstays bridge.

If you're worried I'll send you a spacer to insert into the shock, free. only need to unscrew the aircan its a 15 min job...

Ist it that simple? Is there a tutorial on YT?

[casual_build]

Not really what I wanted to read, with my 42.5mm shock waiting for the frame 
But being at around 67kg, and not particularly a jumper I guess it will be ok.
I'll put a gummy tape on the seat tube in any case, to soften any impact from the seatstays bridge.

If you're worried I'll send you a spacer to insert into the shock, free. only need to unscrew the aircan its a 15 min job...

I would love to take you up on that, what size spacer? Maybe its possible to have just a 1mm spacer so travel is still a little higher than 100mm?

[theirishrider]

Not really what I wanted to read, with my 42.5mm shock waiting for the frame 
But being at around 67kg, and not particularly a jumper I guess it will be ok.
I'll put a gummy tape on the seat tube in any case, to soften any impact from the seatstays bridge.

If you're worried I'll send you a spacer to insert into the shock, free. only need to unscrew the aircan its a 15 min job...

Ist it that simple? Is there a tutorial on YT?

You only need to do up to the 1:35 mark, insert the spacer and screw the can back on.

[theirishrider]

Not really what I wanted to read, with my 42.5mm shock waiting for the frame 
But being at around 67kg, and not particularly a jumper I guess it will be ok.
I'll put a gummy tape on the seat tube in any case, to soften any impact from the seatstays bridge.

If you're worried I'll send you a spacer to insert into the shock, free. only need to unscrew the aircan its a 15 min job...

I would love to take you up on that, what size spacer? Maybe its possible to have just a 1mm spacer so travel is still a little higher than 100mm?

Potentially, I still need to work out how a 1mm nylon washer will behave in the shock. Probaly will make it 1.50-2.00 mm to account for the 'squish' factor of nylon when a full bottom out occurs. I've not actually got my shock yet so this is all a bit theoretical. If you want me to tell you what parts you'd need then I can try.

Edit:
This could be easily solved with that 3euro https://www.bike24.com/p2331384.html part but you've got to disassemble the entire damned shock and put back in the pressurised nitrogen... Hence, the spacer has be something that can be slipped over. Not to mention, being able to change the shock by 2.5 mm is super useful for racing or riding difference conditions.

[Colt__Seavers]

Not really what I wanted to read, with my 42.5mm shock waiting for the frame 
But being at around 67kg, and not particularly a jumper I guess it will be ok.
I'll put a gummy tape on the seat tube in any case, to soften any impact from the seatstays bridge.

If you're worried I'll send you a spacer to insert into the shock, free. only need to unscrew the aircan its a 15 min job...

I would love to take you up on that, what size spacer? Maybe its possible to have just a 1mm spacer so travel is still a little higher than 100mm?

Potentially, I still need to work out how a 1mm nylon washer will behave in the shock. Probaly will make it 1.50-2.00 mm to account for the 'squish' factor of nylon when a full bottom out occurs. I've not actually got my shock yet so this is all a bit theoretical. If you want me to tell you what parts you'd need then I can try.

Edit:
This could be easily solved with that 3euro https://www.bike24.com/p2331384.html part but you've got to disassemble the entire damned shock and put back in the pressurised nitrogen... Hence, the spacer has be something that can be slipped over. Not to mention, being able to change the shock by 2.5 mm is super useful for racing or riding difference conditions.

So it's not that easy like in the video?
Then I have to live with it for now and see where I end up with 42.5
I keep my eyes open for a 165x40 and might sell the other one. But not for now. Now I'll wait for the frame and will test it first.
A side question. I never had a fully nor a rear shock. Is it normal that I can't compress the shock with my weight, pushing it to the floor and bending over it with my torso? Unbelievable stiff. If that's normal, the forces which the frame must withstand are enormous.

[theirishrider]

So it's not that easy like in the video?
Then I have to live with it for now and see where I end up with 42.5

If I can get a nylon washer to work, the only steps needed would be as the video describes up to 1:3, the slip the washer on, and screw it back up.