Carbonda fm936 Thoughts

[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?

[Pharaohollie]

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?

I had the same discussion with Adam @ Carbonda when I was talking about my linkage problem with him. He said the frame is designed for 165x40. I told him on full compression there is more than enough clearance and he said "If you tried it and there is clearance then no problem".

On full compression, there is a good 4mm of clearance of the upper seatstay brace. I took a few medium-sized drops (not the most graceful landings, either) and there's been no issues at all. I am about 76kg geared up. For the frame's intended purpose and riding style, 42.5mm stroke works absolutely fine!

Would there be an issue for heavier riders? I don't know.

Here is a picture with the shock depressurized and suspension at full compression.

[Colt__Seavers]

Thanks @Pharaohollie
4mm is not much. When you land on the saddle with your ass the seat tube flexes back and also the rear end has some flex to it. So these 4mm are gone in no time.
Does a shock really fully compresses with the right PSI setting. And because I won't do any big drops (lower spine disfunction) I don't think I'll have a problem here.

[Pharaohollie]

Thanks @Pharaohollie
4mm is not much. When you land on the saddle with your ass the seat tube flexes back and also the rear end has some flex to it. So these 4mm are gone in no time.
Does a shock really fully compresses with the right PSI setting. And because I won't do any big drops (lower spine disfunction) I don't think I'll have a problem here.

At my weight and how I ride, this amount of clearance seems to be fine. That's why I left the caveat about heavier riders above. Also, from my understanding, the rear triangle isn't designed to flex much in this area. Most of the flex is in the seatstay/chainstay junction (speaking of this area: if you have a creak you cannot trace, check your rear brake bolts are tight!)

Also, I don't know how you ride but I never take jumps or drops and land on the saddle with my ass. In these cases, thank goodness for dropper posts

I am running 230psi in the shock for approximately 11mm of sag. I only bottomed out once so far and that was on a high-speed descent with a drop to flat.

That being said, I also have a 165x37.5 shock on the way to test a more XC-oriented set-up for marathon rides. It's a really fun and versatile frame.

[wfl3]

Same with cable noise. Similar solution to yours as well as some small wedges in the cable ports on the rear triangle took care of the cable rattle.

I rode some pretty rough trails this weekend and also noticed some cable noise.  I'm worried about being able to retrieve the pool noodle after installation so I'll be trying to install the slim, self adhesive plumbing insulation with the cables in the frame.

The piece I put in is the full length of the downtube to cable port and is compressed a bit (18" I think), it will be easy to grab and pull back out thru the headtube.

On a fresh cable install I'd use the neoprene jackets (like adroitrider linked) over the individual cables instead of the pool noodle hack.

[theirishrider]

Thanks for all the shock info. Does anyone know if it's possible to reduce the stroke on either the:
Fox Float DPS https://www.ebay.co.uk/itm/Fox-Performance-Float-DPS-42-5mm-x-165mm-Shock-Trunnion-3-Pos-Adjust/143042612579?epid=7026833371&hash=item214e010d63:g:rLEAAOSwRDJcCemV
or the 2018 RockShox Super Deluxe RCT https://www.ebay.co.uk/itm/2018-RockShox-Super-Deluxe-RCT-Black-Trunnion-Rear-Air-Shock-165-x-45mm/383382375030?hash=item59435eca76:g:w~8AAOSw2FJc3xyT

I've had a look but it all seem in conclusive.

[theirishrider]

So I've been doing some digging.
If we look up the tune code of this: https://www.ebay.co.uk/itm/Fox-Performance-Float-DPS-42-5mm-x-165mm-Shock-Trunnion-3-Pos-Adjust/143042612579?epid=7026833371&hash=item214e010d63:g:rLEAAOSwRDJcCemV

Tune code: DDC9, we yeild thse details:

Code Select Expand

2018 Performance Series FLOAT TRUNNION, 2018, FLOAT DPS, P-S, A, 3pos, Trunnion Evol LV, Giant, Anthem 27.5 2, 165, 42.5, 0.8 Spacer, DCM, DRM, CML, YS 2272/YS 2272 Logo

Lets go to the manual page:
https://www.ridefox.com/fox17/help.php?m=bike&id=861

Here we can see there's 3 similar shocks all with the same main parts:

Code Select Expand

Shock Size Metering Rod Shaft Compression Rod Ano Body Kashima Body
165 x 40 mm 210-84-011 229-72-011 210-24-201 204-54-231 207-50-031
165 x 42.5 mm 210-84-011 229-72-011 210-24-201 204-54-231 207-50-031
165 x 45 mm 210-84-011 229-72-011 210-24-201 204-54-231 207-50-031

So I think, the 45mm stroke has 0 travel spacers, the 42.5mm has 2.5mm spacer and the 40mm a 5mm spacer.  This is then confirmed by the parts list:

Code Select Expand

Part Description
233-00-261 Spacer: Metric Travel [.360 ID X .550 OD X 5.0mm TLG] 6061, Black Ano
233-00-260 Spacer: Metric Travel [.360 ID X .550 OD X 2.5mm TLG] 6061, Black Ano
2.5 mm https://www.bike24.com/p2331384.html
5 mm https://www.bike24.com/p2331384.html

Now the big question: can one easily access this?? I believe we need this drawing

Code Select Expand

Assembly Drawing: 2018 FLOAT DPS P-S from the above fox website. I know it has eyelet mounts but the mount is modular so uses the same rod, damer, canister I think. Drawing: https://www.ridefox.com/fox17/img/help/page861-YJLQ/Assembly-Drawing-2018-FLOAT-DPS-P-S.jpg

You can see the spacer location better on Bike24 https://cdn.bike24.net/i/mb/03/4d/bc/331447-01-d-696101.jpg . It's located at the end of 'shaft'.

Tearing down the shock https://www.ridefox.com/fox17/help.php?m=bike&id=549
I don't know if this spacer can be added without sliding it over the shaft. It's plausible that it could be modified to be a c-clip style spacer - but I don't know. If you have to remove the shaft you'll need nitrogen to reassamble (I think).

[theirishrider]

I think considering it would seem that the travel spacers are aluminium '6061, Black Ano'. I think it's fair to use some plastic, ideally with a decent elastic modulus maybe nylon (tough) that can be cut with a very sharp knife, heated until they are a little more flexible and the slipped over the shaft. This will mean you only have to do a very trivial air can service.

This one will have to be turned down but if you don't have lathe, use a M8 bolt with 2 nuts and mount the washer between the nuts. Then put it in a drill and split it on some sand paper. Don't let it over heat.

https://ie.rs-online.com/web/p/tap-washers/0280521

https://www.mcmaster.com/90295A460-90295A160/

Alternative: https://ie.rs-online.com/web/p/collars/4490665/ Slight too large OD, Too small ID. Better because its not split but the risk is the screws come out and you've got steel screws about.

Another option is to use a 5mm spacer and score the edge to make a groove. then use a o-ring streched over from the top (narrow) end of the shock to keep the cut gap in the nylon together. You could also try thermally bonding the nylon.

Unknows: Does the temp in the aircan get above the temp limit at which nylon deforms very easily plastically? Will it get smashed up very quickly? I think it should be ok since the washer fox sells is aluminum...

[Pharaohollie]

I think considering it would seem that the travel spacers are aluminium '6061, Black Ano'. I think it's fair to use some plastic, ideally with a decent elastic modulus maybe nylon (tough) that can be cut with a very sharp knife, heated until they are a little more flexible and the slipped over the shaft. This will mean you only have to do a very trivial air can service.

This one will have to be turned down but if you don't have lathe, use a M8 bolt with 2 nuts and mount the washer between the nuts. Then put it in a drill and split it on some sand paper. Don't let it over heat.

https://ie.rs-online.com/web/p/tap-washers/0280521

https://www.mcmaster.com/90295A460-90295A160/


Unknows: Does the temp in the aircan get above the temp limit at which nylon deforms very easily plastically? Will it get smashed up very quickly? I think it should be ok since the washer fox sells is aluminum...

Or 3D Print in ABS? ABS has a glass transition temperature well above nylon (105 C vs 70 C) if you're worried about heat.

[theirishrider]

Or 3D Print in ABS? ABS has a glass transition temperature well above nylon (105 C vs 70 C) if you're worried about heat.

Interesting thanks for the suggestion. Is the abs elastic enough to deform over the shaft diameter with a 1mm slice?

If anyone need these I'm happy to manufacture them.

I made some edits to the post above too sorry.

[Pharaohollie]

Or 3D Print in ABS? ABS has a glass transition temperature well above nylon (105 C vs 70 C) if you're worried about heat.

Interesting thanks for the suggestion. Is the abs elastic enough to deform over the shaft diameter with a 1mm slice?

If anyone need these I'm happy to manufacture them.

I made some edits to the post above too sorry.

ABS is more durable and flexible than PLA. Should be fine for this application. Try it and let us know!

[Colt__Seavers]

Would be cool if my DPS 42.5mm can be transformed to a 40mm which is more save to use.

[adroitrider]

Would be cool if my DPS 42.5mm can be transformed to a 40mm which is more save to use.

There have been no reports of damaged frames with the 42.5mm. But, if you are 100kgs then you probably already know that not all bikes can handle the power/watts being dished out. Of note, Carbonda does not list a max weight but the Scott Spark lists 110kgs as the max...

[Colt__Seavers]

Yeah I'm 115kg and Carbonda Frames are save up to 125kg they say. I took the standard version to be on the safe side. Again, only using it for Gravel and easy forest paths. Need a fully for my spine issues

[casual_build]

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.