The Shiny New AM831 Group Buy (A) Thread!

[FlaMtnBkr]

If you look at the current linkage, there is a cutout in the middle which won't allow a single axle, and is likely there to give the shock some clearance. With a piggyback shock I think it's likely necessary. Might not matter for a completely inline shock but I imagine most are running a piggyback.

As for the shifting, all those that say they don't have a problem, does it shift great and you're really happy with it or it's as good as similar drivetrains you've ridden? It couldn't be better? For my setup, the hanger is causing problems. I was a bike mechanic for many years and have taken it to 2 shops/guys that I trust and they couldn't get it better and probably left not quite as good as I brought it in, though that doesn't mean it was good to start.

I'm out of town so it will take a few days but I will post pics showing it's currently out of Sram's specs, and where they say that anything outside of those specs can cause shifting problems. And it might shift ok now, but what happens as things begin to wear? The hanger IS out of specs. If yours shifts ok that's awesome. But mine doesn't and it is a problem for me. And maybe anyone else once the new starts to wear off and things become less precise or maybe not. But I'm surprised no one seems to have an issue with something that Sram says is outside of what 12 speed drivetrains are designed for...

[JJJ]

I took the bike out today with the 1mm thick nylon washers on the outside of the carbon of the offending link underneath the aluminum bolt outside lip and it was very solid. There was no noticeable flex and the suspension seemed smooth and responsive. The bolts also did not come loose. There were not any clicking or creaking noises. Bike rode really well.

I think there is a chance that this may work. Bushings have long been used successfully in suspension design.

It'll work in the short term, but the bolt will inevitably come loose with the rubbing. The rubbing will increase as the press-fit mount of the bearing degrades.

Bushings are mounted such that any rubbing cannot loosen bolts. This is a traditional bushing mount - you can see that nothing will tend to turn the pink bolt. (My Altitude has this type of pivots.)

[JJJ]

If you look at the current linkage, there is a cutout in the middle which won't allow a single axle, and is likely there to give the shock some clearance. With a piggyback shock I think it's likely necessary. Might not matter for a completely inline shock but I imagine most are running a piggyback.

That cut out is the first thing that made me doubt about this frame. The stiffness is obviously impacted. There is a similar cutout in the bottom link. Very strange design, because the links are more complex to manufacture than through-axle links. There is no need for such cutouts, even for piggy-back shocks.

[JJJ]

I found someone willing to make the bolts, a friend and co-founder of Effigear (https://www.effigear.com/en/). They make gearboxes for bikes (and also some bikes), and equip among others the Cavalerie bikes (https://www.cavalerie-bikes.com/home).

The cost is approx 280 EUR for a small series (up to ~50 bolts), so the more we are, the cheaper. They will even anodize them in black. They could deliver by end January 2022.

I've set up a spreadsheet for those interested. In there, please indicate the D and L dimensions for your frame, to check if these values are consistent. If not, I have another solution.

https://docs.google.com/spreadsheets/d/1VllNnFhMycufNw3H4toELJPXWNQe-djAg7zDEYvuD0o/edit?usp=sharing

Those who are interested by the bolts should also buy the pair of 6703-2RS bearings. I've ordered my pair at AE here. They are cheap, so you can buy them straight away to help fine tune the measurements.

I've updated the spreadsheet, for those who receive their bearings, with a W measure (width of the eyelet with the new bearing installed), so that we can better define the L measure (width of the carbon shoulder in the eyelet). You can then also confirm if the inner race of the new bearing turns without rubbing on that shoulder (indicate this on the spreadsheet).

[deucelee]

I got the washer at the hardware store and got to work with some scissors to trim the outer diameter

can you get us some pics? and maybe the bolt to reference? i haven't gotten my bike yet so was just trying to prepare. thx

[Clement_m]

Dear all,
I'm also a "lucky" owner of the AM831 frame, I haven't posted yet but I'm trying to follow all the discussions since I haven't really started building the bike. Well let's say that I have now some hesitation to invest more money and time on this bike...

Anyway thank you all for the effort you put into finding a smart fix !
I will complete JJJ spreadsheet as well to participate to the bolts group buy. I just ordered the bearings.

Moreover I hope that Eddy will come back to us with a solution or at least a compensation. You can count me in if you decide to go for a group claim.
Have a nice day,

[sips56]

JJJ thank you for your work! I am on the list and will pick up the outer bearings to confirm spacing. Have you done so on your frame yet?

[deucelee]

Guys, do the L and D measurements differe from bike to bike? due to the size of the bike? j/w for my info...i haven't gotten my frame yet, it's in the mail. thx

[sips56]

Guys, do the L and D measurements differe from bike to bike? due to the size of the bike? j/w for my info...i haven't gotten my frame yet, it's in the mail. thx

No they should be the same, but JJJ is trying to account for potential tolerance differences that production may have yielded.

[Rod.GL]

I found someone willing to make the bolts, a friend and co-founder of Effigear (https://www.effigear.com/en/). They make gearboxes for bikes (and also some bikes), and equip among others the Cavalerie bikes (https://www.cavalerie-bikes.com/home).

The cost is approx 280 EUR for a small series (up to ~50 bolts), so the more we are, the cheaper. They will even anodize them in black. They could deliver by end January 2022.

I've set up a spreadsheet for those interested. In there, please indicate the D and L dimensions for your frame, to check if these values are consistent. If not, I have another solution.

https://docs.google.com/spreadsheets/d/1VllNnFhMycufNw3H4toELJPXWNQe-djAg7zDEYvuD0o/edit?usp=sharing

Thanks JJJ
I put myself on the list/spreadsheet. I will provide the measurements later.

[Maffly]

It'll work in the short term, but the bolt will inevitably come loose with the rubbing. The rubbing will increase as the press-fit mount of the bearing degrades.

Bushings are mounted such that any rubbing cannot loosen bolts. This is a traditional bushing mount - you can see that nothing will tend to turn the pink bolt. (My Altitude has this type of pivots.)
[/quote. Thanks JJJ. Aware of the loosening risk (hence the gobs of locktight). I also carried the fat Allen wrench with me on the ride. I put myself on the list for the bolts and will continue to ride this thing to see how long it works for. 

[JJJ]

I found someone willing to make the bolts.

I've set up a spreadsheet for those interested. In there, please indicate the D and L dimensions for your frame, to check if these values are consistent. If not, I have another solution.

https://docs.google.com/spreadsheets/d/1VllNnFhMycufNw3H4toELJPXWNQe-djAg7zDEYvuD0o/edit?usp=sharing

I now received a cost estimate and updated the cost in the spreadsheet. With currently 15 potentially interested members, the cost for a pair is at 25.20 EUR (plus shipping).

I see some variations for the diameter D. Slightly bigger than 23mm shouldn't be a problem, because the 6703 bearing is only intended to compensate the axial play. However, I see Rod.GL at 22.8mm - the 6703 bearing will not fit - please double-check.

Also, don't forget to update the "W" dimension, taken between the two bearings if you can. This will confirm the tolerance of the L dimension, which is important for correctly placing the shoulder in the bolt. If there is too much variation in the L dimension, I have another slightly more complex bolt design, with a grub screw in the middle.

[cybrsrce]

I now received a cost estimate and updated the cost in the spreadsheet. With currently 15 potentially interested members, the cost for a pair is at 25.20 EUR (plus shipping).

I see some variations for the diameter D. Slightly bigger than 23mm shouldn't be a problem, because the 6703 bearing is only intended to compensate the axial play. However, I see Rod.GL at 22.8mm - the 6703 bearing will not fit - please double-check.

Also, don't forget to update the "W" dimension, taken between the two bearings if you can. This will confirm the tolerance of the L dimension, which is important for correctly placing the shoulder in the bolt. If there is too much variation in the L dimension, I have another slightly more complex bolt design, with a grub screw in the middle.

https://imgur.com/a/8etfikF
Updated measurements in the doc and took a few pictures of the bearings in the frame.  Enduro bearings 6703-2RS, perfect fit.

[Maffly]

Looks good cybrsrce. JJJ I am on the list but have not measured yet as I have my nylon bushings in there and they are working great. No loosening or slop in the pivot after 40 fairly hard trail miles. Lots of jumping and drops last ride without issue. Don’t want to pull the bolts until I have to. I have ordered the bearings though and am going to go for your much more permanent solution. Thanks again!

[Gigelz]

i am in too. but i am still waiting for the frame