Chinertown
Chinese Carbon MTB => 29er => Topic started by: StefanB on March 23, 2022, 03:03:44 AM
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Received the new bolts yesterday, wery well made. I am still waiting for the bearings I ordered. I haven't read everything regarding the flex problem so I could use some help. Is this where the new bearing and bolt should be used?
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Yes, the new bolt goes on the upper mount on the rear triangle as marked in your picture.
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Received the new bolts yesterday, wery well made. I am still waiting for the bearings I ordered. I haven't read everything regarding the flex problem so I could use some help. Is this where the new bearing and bolt should be used?
Good move to start a dedicated thread ;-)
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I have received my enduro bearings. The fit perfectly on the new bolts but the holes in the frame are to small. I will have to find out a good way to make them bigger.
By the way. What is the screw inside the new bolts for? The original does not have this.
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I got my 6703 bearings from Fast Eddy on ebay (seem fine at this point). Fit the frame great (I'm sure the tolerances here vary with paint, etc with one requiring a tiny press in and the other side dropping in just right. I followed JJJ's advice and tapped the bolts in until I could tighten them down around hand tight and then tightened the grub screw down to hold everything tight. Seems good so far and definitely less flex back there wobbling it side to side (haven't ridden it yet to test)
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I have received my enduro bearings. The fit perfectly on the new bolts but the holes in the frame are to small. I will have to find out a good way to make them bigger.
By the way. What is the screw inside the new bolts for? The original does not have this.
You need to scrape away the paint and excess resin inside the recess to find the original 23 mm diameter.
If you don't know what the grub screw is for, BEWARE, your bearings are at risk! I explained that on the mailing list:
Important reminder: only tighten the bolt "finger tight", the purpose being only to compensate the axial clearance. The "finger tight" sensation is a little difficult to feel with the tight fit of the bolt. Tighten while turning the link; when you feel a crunching sensation in the link, stop and back-off a little until the turning becomes smooth again.
It's the role of the M8 grub screw to hold the bolt in place, tighten that one sufficiently when you've finger-tightened the bolt. Beforehand, insert the grub screw through the tip of the bolt. You can then use a 4 mm Allen wrench to tighten it through the bolt head.
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You need to scrape away the paint and excess resin inside the recess to find the original 23 mm diameter.
If you don't know what the grub screw is for, BEWARE, your bearings are at risk! I explained that on the mailing list:
Important reminder: only tighten the bolt "finger tight", the purpose being only to compensate the axial clearance. The "finger tight" sensation is a little difficult to feel with the tight fit of the bolt. Tighten while turning the link; when you feel a crunching sensation in the link, stop and back-off a little until the turning becomes smooth again.
It's the role of the M8 grub screw to hold the bolt in place, tighten that one sufficiently when you've finger-tightened the bolt. Beforehand, insert the grub screw through the tip of the bolt. You can then use a 4 mm Allen wrench to tighten it through the bolt head.
Cudos to you JJJ.
You have put some effort and thought into solving this when the when manufacturer is nowhere to be seen.
Well done.
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Crap. I must have missed the install instructions. I just put the bearings on and tightened to 17nm. I rode it once like that already.
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Crap. I must have missed the install instructions. I just put the bearings on and tightened to 17nm. I rode it once like that already.
:o You probably busted all four bearings! Didn't you feel them crunching?
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Not at all
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Well, I took the bolts off and it feels like three of the four bearings are not smooth anymore. Luckily I have three replacement bearings ready. The two new ones popped off easy. How do I get the one bearing off that was already in the rear triangle?
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any way we can edit the top post with JJJ's instructions? Might be helpful!
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How do I get the one bearing off that was already in the rear triangle?
Like you do other frame bearings, hammering it out from the other side with a bearing extractor or just a tube. Here you only have access to the inner race, so the bearing will most likely be damaged in the extraction operation. To do only if the bearing is already damaged...
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Thought I'd post JJJ's email here with the original instructions:
"The bolt diameter is somewhat close to its upper tolerance limit (at least for the ones I mounted), so it doesn't go smoothly through the 6802 bearing. It doesn't require too much hassle though (gentle tapping until you reach the threads in the link). The advantage is that it fits snugly in the bearing.
The edge of the bolt head is somewhat sharp, so you will probably need to sandpaper it a little.
Important reminder: only tighten the bolt "finger tight", the purpose being only to compensate the axial clearance. The "finger tight" sensation is a little difficult to feel with the tight fit of the bolt. Tighten while turning the link; when you feel a crunching sensation in the link, stop and back-off a little until the turning becomes smooth again.
It's the role of the M8 grub screw to hold the bolt in place, tighten that one sufficiently when you've finger-tightened the bolt. Beforehand, insert the grub screw through the tip of the bolt. You can then use a 4 mm Allen wrench to tighten it through the bolt head.
DO NOT use the bolt to squeeze the 6703 bearing into its recess. The 6703 bearing should be in its final position before you insert the bolt. If necessary, use a bearing press to fit the 6703 bearing in its recess.
Since the recess for the 6703 is not so "clean", depending on the paint and resin jobs, there may be a break-in period after which you may need to tighten the bolts a little more."
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Replaced the bolts with new bearings today. I'm glad you posted the instructions again so that I only fastened it "finger tight".
No i can finish my built of the bike and see how it rides. :-)
Thanks JJJ for the fix.
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I recommend that you are careful when tightening the grub screw. While tightening the grub, I could feel the aluminum in the link stretching. I could also see the aluminum distorting on the backside of the link. I was using a small Allen key and did not think I was torqueing it down very much. However, it appears to be an excellent fix and I look forward to testing out on the trail. Thanks JJJ and good luck to all
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No i can finish my built of the bike and see how it rides. :-)
Jeez I guess I should start eh? :I
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I have both the JJJ fix and the new modified rear triangle, Having ridden the JJJ fix for a good few trail miles and then fitted the new triangle I would say if you have the JJJ fix there is no benefit to fitting the modified rear triangle, It is no stiffer than the standard triangle with the JJJ bolts and bearing fitted.
The bearings that are fitted to the frame are low quality so if your fitting JJJ bolt fix while you have it all apart it would pay to replace all the bearings with good quality ones then the bike is as good as it can be which is pretty impressive in my opinion
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I have both the JJJ fix and the new modified rear triangle, Having ridden the JJJ fix for a good few trail miles and then fitted the new triangle I would say if you have the JJJ fix there is no benefit to fitting the modified rear triangle, It is no stiffer than the standard triangle with the JJJ bolts and bearing fitted.
The bearings that are fitted to the frame are low quality so if your fitting JJJ bolt fix while you have it all apart it would pay to replace all the bearings with good quality ones then the bike is as good as it can be which is pretty impressive in my opinion
Thanks for investing in the new triangle for the comparison!
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I just want to confirm, its a pair (2) 6703-2RS bearings that we need in addition to the bolts, correct? No other parts?
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I just want to confirm, its a pair (2) 6703-2RS bearings that we need in addition to the bolts, correct? No other parts?
That's right.
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I'm posting here the production diagram of the bolt, in case others want to have it made.
You further need a pair of 10xM8 grub screws and a pair of 6703-2RS bearings.
The hex print is not mandatory, since the bolt should only be tightened "finger tight". So with a cylindrical bore instead, the bolt should be cheaper to manufacture.
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if anyone is looking for an already fixed frame with some nice acessories, feel free to PM me https://chinertown.com/index.php/topic,3639.0.html :)
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Information for those who are interested:
According to my scale the original triangle weighs 692 gr and the new one 853 gr, 161 gr difference (without bearings or screws, only the raw carbon and unpainted), to which we must add 28 grams of difference between the original hardware and the new one (two extra bearings with two shims and the thru-axle instead of the two screws). 189 gr the total difference... quite a lot, isn't it? I honestly expected less...
Maybe I'm a weight weenie... ;D but if, as promoto says, there is no noticeable improvement in stiffness and benefit when riding the bike, I think I'll keep the original triangle with the JJJ bolts (and the 6703 2rs bearings), which only add 15 grams to the original weight, because I plan to climb a lot with it. Will see...
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All the new order would be shipped out with the new triangle FS-AM831.
Thanks
Any need feel free to contact us.
Eddy@haidelibicycle.com
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Finished my AM831 last week and took it for a first ride yesterday. There is some fixing left to do, some squeaking sounds to identify. But the bikes feels very, very nice to ride on technical trails.
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Finished my AM831 last week and took it for a first ride yesterday. There is some fixing left to do, some squeaking sounds to identify. But the bikes feels very, very nice to ride on technical trails.
On the FS830 Frames was the solution to eliminate the squeaking sound, to implement a screwable bottom braked BB86-92 eg. from Ztto and remove the bearings into Enduro bearings.
Best regards
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Finished my AM831 last week and took it for a first ride yesterday. There is some fixing left to do, some squeaking sounds to identify. But the bikes feels very, very nice to ride on technical trails.
There’s always the option to swap out better bearings into the ZTTO shell, but that costs basically the same as just buying a Wheels Manufacturing thread-together pressfit BB. When well greased these usually eliminate that classic pressfit creaking, if that’s really your issue so soon after install (it definitely could be if you didn’t slather everything in grease).
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I have built 9 bikes with frames from Light Carbon and everything has been flawless. This is the first bike I build with a frame from another manufacturer and I am disappointed.
The flex issue may not have been a problem for me and the way I ride, but it does make me feel less happy with frame anyway. Now I have finally put the bike together and yes, it rides nice but makes o lots of squeaking noise. I think it come from the suspension so yesterday I took the top-link of to put more grease. I was surprised to se how bad the bearings are fitted and on one side there is a sealing, on the other side no sealing but a old washer :-o
I think I will take the frame apart totally, and replace all bearing with good bearing with sealing, and a lot of grease. And hopefully I will end up with a nice working and quiet bike.
My next build will be from a frame manufacturer I trust, Light Carbon. I have ordered the new LCFS918.
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I have built 9 bikes with frames from Light Carbon and everything has been flawless. This is the first bike I build with a frame from another manufacturer and I am disappointed.
The flex issue may not have been a problem for me and the way I ride, but it does make me feel less happy with frame anyway. Now I have finally put the bike together and yes, it rides nice but makes o lots of squeaking noise. I think it come from the suspension so yesterday I took the top-link of to put more grease. I was surprised to se how bad the bearings are fitted and on one side there is a sealing, on the other side no sealing but a old washer :-o
I think I will take the frame apart totally, and replace all bearing with good bearing with sealing, and a lot of grease. And hopefully I will end up with a nice working and quiet bike.
My next build will be from a frame manufacturer I trust, Light Carbon. I have ordered the new LCFS918.
Please do share the sizes of bearing you used and where you installed them, mine doesn't have any issues yet, but I want to be proactive about it.
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I replaced all the bearings on mine when I fitted the new rear triangle and its been fine , The original bearings are low quality and some of them were already feeling notchy after only a few rides. I've now covered almost 300 miles of local trails and bike park trails without any issues.
I have converted to a mullet set up which i really like
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I have now been riding the AM831 4-5 times on trails and it fells nice. I haven't jumped or pushed it hard downhills though. This weekend i rode with my son and we pedaled uphill on a road and he said, "Dad, it looks like you have a tail, its wiggling, I think you back wheel is loose".
I stopped and checked the wheel, everything was tightened but when I took the wheel in my hand I could flex the rear triangle a lot. I felt his rear triangle and it was stiff (LCFS911) and my wife's rear triangle was also stiff (LCFS713).
I haven't felt this when riding but it made me feel insecure, can I trust the bike if things go rough. I have done the "flexfix" but I can not imagine that it was even flexier before that. Could i have "flexfixed" it wrong or is the result not better than this.
Made a video of the flex.
https://youtu.be/d-aWmCOIXKE (https://youtu.be/d-aWmCOIXKE)
Hoping for helpfull feedback
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Stefan, the video isn't showing up in your post.
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Stefan, the video isn't showing up in your post.
I can see it? Anyone else?
Heres the Youtube link
https://youtu.be/d-aWmCOIXKE
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I don’t see an embed and I don’t see any link to YouTube. I seem to recall this having been an issue in the past for others on this forum.
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Can’t see it in your post on the other 831 thread either.
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Really wierd, I can see booth.
Here they are again
https://youtu.be/d-aWmCOIXKE (https://youtu.be/d-aWmCOIXKE)
https://youtu.be/d-aWmCOIXKE
If you search on Youtube you must find it. Search for: tideace am831 flex
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I can see the vids on mobile, but not on desktop.
Thats a lot of flex. Hope you can get it sorted without having to buy a new rear triangle.
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Im not ready to spend 300 USB + shipping for a new rear triangle on this frame that I don´t really trust, will it be 100% good or just quite alright... . I would rather move everything over to a frame I trust. (LCFS947...) All you that have bought this frame and the the flexfix, does your frames flex this much? Is there a danger of riding with a frame this flexy?
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I'm on a PC and can't see any videos nor links, just big blank spaces
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I'm on a PC and can't see any videos nor links, just big blank spaces
same for me on mobile
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I'm on a PC and can't see any videos nor links, just big blank spaces
On a Mac with Firefox all 3! 8) videos are visible
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Went through a a period of financial hardship- I bought this frame in the first group buy, just now getting around to building it. Is this still a viable solution? If so, can anyone point me to the most current resources? Or should I just get a better frame?
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I have the new rear triangle and seems to be holding up ok, fixed the flex issue for me.
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I have the new rear triangle and seems to be holding up ok, fixed the flex issue for me.
Do you think its worth the money at this point though? I've been reading a lot of people saying they aren't too happy with it, and I don't want to put more money into it if Id be better served with another frame or even a whole bike. I don't have any parts aside from some brakes. If I spend another 2k on parts and stuff, would i be better served just buying a Vitus, or something used or something?