cybrsrce AM831 build

[Maffly]

Hope you can get the frame dialed in. Kind of a bummer with all you have put into the build. I had an Evil Following for years that started to get more and more play in the back that would not tighten. Carbon had compressed a bit around the main pivot. I rigged up a couple of washers and it tightened right up. Friend on same frame with same issues. Evil actually gave him some thicker hardware they made to solve the issue. Frame was as good as new. Very interested to see how this resolves as it has me less excited for the arrival of my frame.  Good luck and keep us posted.

[cybrsrce]

Yeah, I'm not that worried about it.  If I can get it sorted, great - if not, also good.  It is good enough to ride but I still have my eye out for a hightower or megatower frame where almost everything transfers over.  Maybe even some of the high pivot frames but I'm trying to stay focused on the better pedaling bikes.  I think a few of us should make videos of the flex just to compare.

[FlaMtnBkr]

The bolt I had to shim was one of the 8mm bolts at the upper linkage. But if I put my fingers behind the seat stay and my thumb on the linkage and pulled, it was very noticeable where it flexed over until it contacted the bolt head.

I still don't have adapters for my rotors so no brakes, but just pedaling around and shifting thru the gears grinds on my nerves, if nothing else. It's not even close to smooth. And as a person that as a teenager took apart and put back together bikes to learn how and get tuning optimized because I was tired of going to races and having my shop tuned bike not up to my "standards", there is no way I can ride it in it's current state.

Maybe I'll grab a 10 or 11 speed cassette, Shifter, and derailleur to throw on because they aren't nearly as finicky to derailleur placement and adjustment as 12 speed is. Assuming it's determined the frame is rideable and not wet noodle flexy. I don't like throwing parts at something instead of figuring out the actual problem. But from what I've found, the issue for my setup is mainly the hanger and not something I can do much about. If I had access to a CNC machine I would have already started modeling a replacement but I'm not paying what a 1 off part usually costs. On that note, I did get a reply from Eddy asking for more information so he could discuss it with his engineers, and I sent him the drawings and everything needed to make a revision if so inclined. Will see what his reply is.

I'm really trying to withhold judgement and not condemn it before doing some real riding. But excitement is dropping off pretty quick. My daughter has a softball game further away than a 6 and under game should be, so hopefully I'll get by some shops tomorrow because my parts still haven't shown up.

[cybrsrce]

I added makeshift shims made from a gallon water bottle and it seemed to stiffen up the rear a bit.  I don't know if it was that, tightening most of the drive side spokes, or a combination of both but it takes more effort to make it flex.  I forgot to measure the bolt width, I'm thinking of ordering a few different width washers and seeing if I can get a 2mm on each side to really tighten it up.

Proper shock goes a long way in making the bike feel more put together.  Steeepened the HTA to 65° but my effective (adjusted to saddle height) seat tube angle is still 75°.  Whatever though, it still climbs pretty well.  More tuning tomorrow and maybe throw the MegNeg in the mix next week.

Silly question FlaMtnBkr, is the surface under the hanger flat?  You have multiple hangers and they all have the same result?  Have you checked it out with a hanger alignment tool?

[FlaMtnBkr]

Did you feel some movement or just made the washers to see if it would help? I'm glad that it seemed to help. I'll see if it looks like a standard size and try to get something in metal. Or see if I have some hole punches the right size and get some shim stock or a beer can to see what it does. If it helps I might try making some for each pivot point as long as it doesn't bind or interfere with the bearings. It's not hard to make a hole punch if it seems like it will help. I've described it somewhere else but can do so again if anyone is interested.

The carbon should be flat under the hanger but throwing on a new one is something I should try. I have used an aligner to check it and made a slight adjustment but it came pretty straight. When reading the Sram document that describes the hanger dimensions, it said to check with aligner and as long as it's less than 5mm at the rim then it should be OK. I was pretty surprised it specified that much! I guess across the diameter of a wheel it's a pretty small angle but I always go for perfect.

I'm about to fall asleep but out of curiosity, with a Rim with 595 ERD and assuming the tool feeler touches on one side and is 5mm off at 180 degrees, that's only about 0.48 deg which isn't much and less than I thought before actually thinking about it.

Anyways, I'll check back but my body is insisting on sleep

[cybrsrce]

Did you feel some movement or just made the washers to see if it would help? I'm glad that it seemed to help. I'll see if it looks like a standard size and try to get something in metal. Or see if I have some hole punches the right size and get some shim stock or a beer can to see what it does. If it helps I might try making some for each pivot point as long as it doesn't bind or interfere with the bearings. It's not hard to make a hole punch if it seems like it will help. I've described it somewhere else but can do so again if anyone is interested.

With everything torqued correctly as labeled, I can put one hand on the saddle and one hand on the top of the wheel and watch the seatstays flex what looks like 10-20mm without a whole lot of effort.  It looks like it is a bit less with the shims which may be made better by adding washers between the seatstays and the upper linkage.  I'll throw the caliper on it to see what will fit in there from off the shelf.

The carbon should be flat under the hanger but throwing on a new one is something I should try. I have used an aligner to check it and made a slight adjustment but it came pretty straight. When reading the Sram document that describes the hanger dimensions, it said to check with aligner and as long as it's less than 5mm at the rim then it should be OK. I was pretty surprised it specified that much! I guess across the diameter of a wheel it's a pretty small angle but I always go for perfect.

I'm about to fall asleep but out of curiosity, with a Rim with 595 ERD and assuming the tool feeler touches on one side and is 5mm off at 180 degrees, that's only about 0.48 deg which isn't much and less than I thought before actually thinking about it.

Anyways, I'll check back but my body is insisting on sleep

That all checks out just due to the nature of wheels.  For hub trouble I have used the hanger alignment tool to check using the 50T cog in the cassette instead of the rim.  All roads may lead to you finding out that your rear triangle is just way out of spec.  Just in contrast I haven't even had to use the micro adjustment feature to fine tune the AXS shifting.

[Snacks]

I think I have the same flex in the rear triangle . I had my hand on the chainstay before when trying to check for any lateral movement and it wasn't bad at all but once I put my had on the saddle and tire it flexes something like 20mm very easily. I wonder if this is what caused the rubbing before  . I'm heading to the hardware store tomorrow to see if I can find a shim or washer that'll fit and tighten it up

[Maffly]

Hey cybrsrce,  do you feel like the 1mm spacers brought the stiffness to a solid level?  One on each side of seat tube main pivot?  What material are they made of and where did you get them?  Interesting that Eddy is saying they are altering the carbon layup a bit to address the issue. Unfortunately mine will probably not have these changes. Have you gotten the new rear shock in there. Been following your build and reports and am very  interested in hearing how the final product has turned out. Your posts have been very thorough and help to fill a bit of the information vacuum that exists when diving into this process. Thank you!

[cybrsrce]

Hey cybrsrce,  do you feel like the 1mm spacers brought the stiffness to a solid level?  One on each side of seat tube main pivot?  What material are they made of and where did you get them?  Interesting that Eddy is saying they are altering the carbon layup a bit to address the issue. Unfortunately mine will probably not have these changes. Have you gotten the new rear shock in there. Been following your build and reports and am very  interested in hearing how the final product has turned out. Your posts have been very thorough and help to fill a bit of the information vacuum that exists when diving into this process. Thank you!

It felt acceptable at the ~20mm flex in the video and now if feels like roughly half that.  I haven't had it out on the trail yet but I assume it will be even more predictable.     

I got these M18x27mmx1mm - https://www.amazon.com/gp/product/B07NRXPYDG but I might experiment more.  The bolts are M16 (I think) and then ~2mm x ~2mm unthreaded surface to sit on the bearing.  I might try two of the M18 washers (cut to the size of the bolt head) and one or two M16 on the surface that touches the bearing to make sure there is good contact.

I do have the new shock in, first ride with it wasn't great.  Way too harsh even after I let it sag to 35% with rebound full slow and LSC open (full soft). Fork and shock recommended PSI, rebound, LSC, and fork HSC have all been way off for me.  Removed two tokens from the fork, one token from the shock, and added the MegNeg with a single band.  That seems to be what most of my near-clyde brethren are doing so I'll check that out.  Going to borrow a ShockWiz to speed this along.

I'll add some pictures of the bolt/washer combo and maybe a new flex video with it on the turbo trainer.

[cybrsrce]

I printed up some 1.5mm thick washers with a 1.5mm width and that seems to have the best results yet.  They are solid pla prints but I'm not sure how well they will hold up.





Video of best result so far.  No clicking and minimal movement from the connection near the seatpost.

[Maffly]

Thanks for the new information and updates on progress. Keeping my fingers crossed that my frame will be tight but if not I have a great blueprint for a fix. Can get spacers 3D printed out of carbon filament. How do you think that very hard but perhaps somewhat brittle material would work for this application?

[Snacks]

I printed up some 1.5mm thick washers with a 1.5mm width and that seems to have the best results yet.  They are solid pla prints but I'm not sure how well they will hold up.

Oh wow that looks a ton better than before! Got some metal .5mm spacers coming. Hoping 3 on each side does the same for my bike . I put some 3m protection film over the spot that rubbed and now the rear triangle has rubbed right through that. I'll upload a pic when I get home from work. Afraid to ride the ride bike until I get a better fix for this so the rubbing doesn't continue to damage the seat tube 

[Gigelz]

good work so far do you have torque recommendations for the bolts ?

[cybrsrce]

good work so far do you have torque recommendations for the bolts ?

Those are printed as 17Nm max and it still feels properly torqued even with the variety of janky washers I've tried.

[cybrsrce]

The stl files for the different washers attached should anyone want them.  My old printer didn't like them all arranged in the stl so I had to add them individually for some reason.