Chinertown
Chinese Carbon MTB => 29er => Topic started by: G161 on May 30, 2022, 03:22:50 AM
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Has anyone used this bike or has experience with BXT?
BXT-MTB-117 150mm AM bike.
https://www.bxtcycle.com/am-fullsuspension-carbon-frame-29er_p69.html
The geometry looks great!
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Thats the "updated" AM831: http://chinertown.com/index.php/topic,3593.0.html
Original: http://chinertown.com/index.php/topic,3172.1245.html
Some are happy some are not.
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I still have some concerns about tire clearance (2.4 feels like an ice skate to me after years on 2.6-2.8 and fat bikes) and the beefiness of the swing links/bearings, but this version seems much improved in the front triangle and more or less completely addresses the flex and play experienced with the V1 mold. I know a couple riders who own this version of the 831 and also own recent Santa Cruz models — they say the difference is negligible or even unnoticeable.
That said, nobody’s had any version of this bike long enough to explore all the issues that it can have — especially the V2 (revised rear triangle/links) and V3 (both ends revised with flat top tube, taller head tube). So be aware you’re still at least somewhat of a beta tester if you buy this frame. Expect at least some degree of fiddling, needing to replace the OEM bearings etc.
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I still have some concerns about tire clearance (2.4 feels like an ice skate to me after years on 2.6-2.8 and fat bikes) and the beefiness of the swing links/bearings, but this version seems much improved in the front triangle and more or less completely addresses the flex and play experienced with the V1 mold. I know a couple riders who own this version of the 831 and also own recent Santa Cruz models — they say the difference is negligible or even unnoticeable.
That said, nobody’s had any version of this bike long enough to explore all the issues that it can have — especially the V2 (revised rear triangle/links) and V3 (both ends revised with flat top tube, taller head tube). So be aware you’re still at least somewhat of a beta tester if you buy this frame. Expect at least some degree of fiddling, needing to replace the OEM bearings etc.
Thanks for the detailed response. Makes sense why I couldn't find much information on this frame. I was under the impression that this was a completely different bike to the AM831 and made by BXT because of the different front triangle. The BXT frame looks identical to the Santa Cruz.
Do you have any idea of BXT as a brand?
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Do you have any idea of BXT as a brand?
I have purchased several carbon hardtails and forks from BXT and I only have good things to say. Quality was great, shipping times weren't immediate but were reasonable (to the US), and their communication was prompt and helpful.
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Thats the "updated" AM831: http://chinertown.com/index.php/topic,3593.0.html
Original: http://chinertown.com/index.php/topic,3172.1245.html
Some are happy some are not.
The kinematic is similar but different bike.
Front and rear triagnle are different (straight top tube on BXT for instance)
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I ordered one on aliexpress about a month ago to build up for my girlfriend (in pink of course). I'm still waiting for it to ship. I've built up 2 BXT hardrail frames without much drama.
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I also ordered this Frame 10, May on Aliexpress. BXT did not ship out the frame yet.
I have asked about the status, their reply is always same. "This frame is currently missing some accessories. At present, the supplier of accessories has no inventory of accessories for the time being. The factory needs to wait for the frame parts from the supplier."
According to them they also don't know when they get parts to build the frame.
I am not sure how long I should wait further or better cancel this frame.
Is there anyone having same issue?
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I also ordered this Frame 10, May on Aliexpress. BXT did not ship out the frame yet.
I have asked about the status, their reply is always same. "This frame is currently missing some accessories. At present, the supplier of accessories has no inventory of accessories for the time being. The factory needs to wait for the frame parts from the supplier."
According to them they also don't know when they get parts to build the frame.
I am not sure how long I should wait further or better cancel this frame.
Is there anyone having same issue?
Some patience is required when you are your own importer.
Remember they were quite hit by harsh covid rules not so long ago.
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can anyone tell me what is nowadays's lead time of Chiner carbon MTB frame in general?
I am asking this because BXT told me before my order purchase, "Normally about 10 working days". I feel cheated and not comfortable with this situation.
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can anyone tell me what is nowadays's lead time of Chiner carbon MTB frame in general?
I am asking this because BXT told me before my order purchase, "Normally about 10 working days". I feel cheated and not comfortable with this situation.
Uh..... How so? Many of us waited a few months lead time to get our bikes produced. 10 days production and then shipping sounds like a dream!
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great to hear waiting a few months is normal here. no need to check my order status every day from now on. thanks, guys!
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In 5 days it will become 120days since I ordered this frame. Shipment extension seems not anymore possible which means my order will be automatically canceled.
Honestly said I do not really understand why BXT keeps selling this frame while they even can not deliver...
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Just info for whom may be interested in.
BXT proposed me to change from BXT-117 to BXT-087. Reason is, some parts of 117 are missing to build while 087 is available and able to ship out within 2 working days.
087 has rather older geometry compared to 117. Thus, I decided to let my order canceled automatically in a few days.
They were not able to tell me why they still keep selling 117 even they can not build it though...
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order any bxt product at your own risk. I bought a frame from them and had issues. They seemed eager to help until they realized it was a problem with the frame itself and not just hardware. Then they ghosted me and wont' respond.
For me personally, BXT will never get a dollar from me again.
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Thats the "updated" AM831: http://chinertown.com/index.php/topic,3593.0.html
Original: http://chinertown.com/index.php/topic,3172.1245.html
Some are happy some are not.
Has it been confirmed these are the same mold for the rear? The specified bushing sizes for the BXT MTB-117 (24/24mm) and the Tideace/Haideli AM831 (30/22mm) are not the same. The front triangle is obviously different which likely explains the 30mm vs 24mm bushing, but the rear is different too. Or does the actual measured come out the same?
Also, the derailleur hangers don't appear to be the same.
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I seem to be on the same track when it comes to warranty on the frame.
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It seems have some update on BXT 117 frame.
Initial version was similar to tidace AM831:
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Upgraded version use links with through axles:
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Link axle was the main issue of similar tidace am831 frame...
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Those swing links look much more solid. My first impression of the 831 — before we even knew about the flex/play issue — was that its links looked like they’d have questionable longevity.
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My 831 with the upgraded rear triangle is holding up fine with around 1300 miles of trails with jumps drops and janky rocks and roots, Turned out to be a great frame in the end, still love mine
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Those swing links look much more solid. My first impression of the 831 — before we even knew about the flex/play issue — was that its links looked like they’d have questionable longevity.
My son built up this frame (BXT MTB-117). I can confirm that all the pivots are now thru axle. I have attached a picture of the top pivot. It's massively overbuilt.
A few things to note:
1. The rear post mounts are default for 180mm rotors (not 160mm as shown on the specs.)
2. Internal routing was fiddly and in the the case of the rear hydraulic hose, a little tight at the head tube. Either the opening diameter was undersized, or there was a burr in there. We needed to open up the hole a little.
3. 24mm bushings for the shock pivots. Some places still show 22mm.
4. I do not know why some people seem to think this is some updated version of the Tideace AM831. The dropouts, bushing sizes, BB mounting standard, and general look are not the same as the latest generation of the AM831. The front triangle on the BXT is missing the dated "camel hump". This bump might have been cool in 2015, but not today...
5. My son is notoriously hard on his bikes and so far there are no issues with flex or failures (but he is under 140lbs so YMMV.)
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Well that looks way better than the AM831
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Anyone else running this frame?
Seems like the best value chinese carbon frame at the moment - $1150 AUD delivered off aliexpress.
Can a 180mm dropper be used on a large frame?
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Anyone else running this frame?
Seems like the best value chinese carbon frame at the moment - $1150 AUD delivered off aliexpress.
Can a 180mm dropper be used on a large frame?
The seat tube is interrupted by the shock. You might be able to fit a 180mm if you are long legged. My son has a 150mm on his and can probably fit a 170mm.
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I placed an order for the BXT-MTB-117 a couple weeks ago. After a few days of the typical questions (verify color, size, address my Q on weight and layup) it's gone into the production schedule with around a 10 day paint timing.
It's definitely not the AM831, I was quoted 3300g weight. The AM831 was running around 2400g. I don't love that it is this heavy, but I think this is a result of the previous stiffness issues with AM831 and the solution was to lay up a lot more carbon. The Hightower CC is 2890g with shock, so around 2500g no shock. At 800g more, the BXT is edging into the HighTower AL frames' weight, which are around 3800g.
Even with the heavier frame my build out using mostly hand-me-down parts and a X2 Pro rear looks to be around 31.5lb, so respectable. This is using i35 alloy rims.
As long as it's not rolling weight it isn't too much of a big deal, what doesn't kill us will make us stronger
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I finished my BXT-MTB-117 (v3) build. It's sweet. Only very minor issues (no directions on the washer 'direction' on the upper pivot lower bolt, one cable housing point on the HT was too tight for the brake housing).
I don't have a lot of miles, but no reason to believe any issues coming.
Mine was about 3100g (fully painted in white gloss). I weighed everything and documented the build on MTBR here:
https://www.mtbr.com/threads/hightowur-v2-open-mold-carbon-build.1222774
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My size L measures around 11.5" of seat tube depth. I did have some minor resistance to putting the seat post all the way in, but I couldn't see any flash so kept on pushing and steady pressure got past the tight spot (which was around 10" down.)
I can fit all of a 170mm PNW loam dropper in the seat tube.
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Thanks for all the info and build documentation! I'm in the market for something in the 130-150mm travel range and might go with this frame.
Grinchy, your BXT experience wasn't bad? I think that's my biggest concern right now.
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I am considering the frame to replace my AM831. My 831 creaks terribly and I can't figure out where it is coming from. It's super annoying. I messed with the headset and replaced the bottom bracket and that didn't fix it. I thought the bottom bracket fixed it at first, but it came back as annoying as ever. I bought the bearing upgrade created on here and there is a little less flex, but there is still some and the loud creaking. I can't pinpoint where it is coming from and I don't want to keep throwing money at it replacing things.
This frame looks great but I am nervous about getting burned again. Don't know if I should give this one a try or stick to alloy frames. Keep us updated on how you like it, please. Did they offer any other colors besides the one on AliExpress?
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Thanks for all the info and build documentation! I'm in the market for something in the 130-150mm travel range and might go with this frame.
Grinchy, your BXT experience wasn't bad? I think that's my biggest concern right now.
I bought from the official BXT store on Aliexpress. Make sure you have the correct model, they are still advertising the v2 that doesn't have thru pivots.
My experience was completely fine. BXT verified the color, logo/no logo, and size. I asked some Q on the weight and verified it was thru bolt version, which they answered. They suggested I tack on $45 for Fedex shipping. This I did, but it was optional. The Q/A phase took a couple days, they were responsive, but there is a time zone difference and I have a job, so often I could only respond once a day, then they'd respond. Nothing unusual about that.
The order was sent to paint, and about 10 days later shipped out. Then about five days get to my location. In total it was about four weeks from order to receipt.
I have one question open with them regarding the upper link upper washer orientation, they haven't ghosted me, but it seems to be going in circles re: getting the info back, but I've already decided which way the washers should go, so it is only for verification at this point.
I've had the bike out once so far, with another, bigger ride this weekend. It's dead silent and absolutely a pleasure to ride. You should get one.
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I am considering the frame to replace my AM831. My 831 creaks terribly and I can't figure out where it is coming from. It's super annoying. I messed with the headset and replaced the bottom bracket and that didn't fix it. I thought the bottom bracket fixed it at first, but it came back as annoying as ever. I bought the bearing upgrade created on here and there is a little less flex, but there is still some and the loud creaking. I can't pinpoint where it is coming from and I don't want to keep throwing money at it replacing things.
This frame looks great but I am nervous about getting burned again. Don't know if I should give this one a try or stick to alloy frames. Keep us updated on how you like it, please. Did they offer any other colors besides the one on AliExpress?
All good so far. Biggest issue is people on MTBR giving me grief for using SC decals. As far as my frame goes, it's beautiful. I highly recommend the white.
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On frame flex, this version appears to have none. It is rock solld. And silky smooth. I have been afraid to torque to the 20Nm. I chickened out before my wrench clicked. I may try again after my next ride, at least to 15nm.
There are only a couple of minor quibbles.
The upper link is solid aluminum. Drillium could fix this.
The bearing races ride against washers. This is normal, but it's a little bit of a pain to sandwich the washers in between the link and frame and then put the bolt thru. Grease is your friend for this.
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Thanks for posting your experience with this frame here and on the mtbr thread. I am really considering this frame or a Status frame. Your impressions of the bike really help.
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How tall are you on that large, Grinchy?
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5'11". The way I have it set up with 15mm rise bars and a 35mm stem it's 32" to the handlebar grip center from BB center. I use RAD to do the initial fit on my bikes, though for this one I sought a longer reach and a shorter stack to get to my fit. I have a Hardtail that is a shorter reach and higher stack for the same 32", as it's future is headed for a DJ, party bike kind of ride.
SC posts a chart on their site for the HT2, identical geometry so I suggest starting there, FWIW 5'11" is smack dab in the range on the L size (473 reach).
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I mounted a coil in this frame. As it's a Hightower v2 clone that was always going to be a challenge, but I thought I'd try.
My shock tunnel pass thru was around 50.5mm wide. Most 'modern' 1 3/8" springs run 52mm+ in outside diameter. So the first thing is that you won't be putting a Fox SLS, Cane creek VALT, or any other modern spring thru it. Just accept that. I looked high and low for springs that would fit, and even ordered a cane creek DB IL Coil (with 500 lb linear Valt spring). The spring is 53mm wide . . .
Luckily I'm old. Usually that's a disadvantage, but i happened to own a Specialized full suspension bike in 1997. And I swapped the spring to a lighter tension. That bike was stolen in 2002, but I somehow still had the old spring in a bag. Back in the day, springs were built on 1 1/4" inner diameter. This 400x2.0 spring measures around 48mm OD. I would've had a dance party but it'd hurt my back. It isn't the 'target' spring constant (calculators put my weight and the HT2 leverage curve for that weight at 30% sag between 500 and 525 lb/in, depending on the assumptions).
So I was excited to try it out, but not to hopeful I'd get sag on this spring. 400 to 500 is a big difference!
I tossed that spring on the shock (adapters will need to be made eventually for the shock collars, but it works ok to test), and after pull the upper link lower bolt, finagled it in there.
I"m still not sure on sag this frame is devil hard to measure coil sag on as one person, but I think it's around 15mm (33%). Which isn't ideal (I'd like 25%), but it's workable. And this is no preload, so I could dial it back a bit. I'm not sure why calculated spring vs actual spring is so different, but this isn't really a Hightower 2, so maybe the leverage ratios are different.
Some issues:
It's pretty hard to source these old springs. There are some on ebay, they aren't particularly cheap because they come with an old shock, and they're all too stiff at the moment. There's a 550lb for $130. Which is a bit steep.
the 2.0 shock is probably a bit short. at 2.25 would be ideal, a 2.5 would be better than a 2.0. The shock may bind before reaching full travel. It hasn't yet, but I haven't been out really riding yet. I go tomorrow.
It's red. I'd much much prefer an old Fox shock, they're black.
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Edit: Added answers to my own questions after messaging BXT Official Store on aliexpress.
Hanger: Where can you order or find a replacement derailleur hanger for this frame? Should I assume it's not a UDH but a proprietary hanger?
Answer: BXT sent me this link to buy an extra hanger: https://www.aliexpress.us/item/2251832586891043.html They do no list a boost 148mm option. Order the "axle thru 142 12mm" option even for boost 148 spacing. It's actually not just a derailleur hanger but a bolt on drop out that includes a hanger.
Shock hardware: I've never installed new shock hardware, and I could use a little guidance. If the bushings are 24mm, what size mounting hardware do I order? I see m8x23.88 or m8x24.89 listed here: https://thelostco.com/blogs/blog/mtb-rear-shock-mounting-hardware-explained?variant=32303772237905 (I'm assuming the bolt size is m8. Correct me if I'm wrong)
Edit: I found mounting hardware on aliexpress that is nominally m8x24mm. Seems like that's worth a try.
Headset: Does the frame ship with the headset? I assume it's integrated, so do the headset bearings come with the frame?
Answer: The headset doesn't seem to come with the frame.
Edit: I noticed that the headset BXT recommends comes with an expander nut rather than a star nut. I think expander nuts are more commonly used in carbon steerer tubes which suspension forks don't have. You may want to go with a different headset or buy a separate star nut and top cap / bolt.
BXT says you can order the headset here: https://www.aliexpress.us/item/2251832509492748.html
Order HS-001 for a tapered steerer tube fork. (HS-003 for straight fork, but I'm not sure who is using a non-tapered fork)
More information sent by BXT:
The order comes with: frame, rear thru axle, seat clamp, and derailleur hanger
Edit: The BXT rep was wrong on more than one occasion including the shock dims they quoted. Treat their advice as suspect.
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This frame is on CyberMonday sale through today. Aliexpress seems to be offering $80 off $450 (code: BFUS80) plus $4 of every $20 up to $16. I guess that means you could get $96 off the current sale price, and I think that would apply to any frame you order from Aliexpress.
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Edit: I tried a super deluxe select + on a medium frame, and it seems to fit fine. The BTX rep quoted me the wrong size shock, and tried to sell me a inferior shock. Treat their advice with some scepticism. The reps don't have much expertise and are selling lots of different models of bike frames.
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Can anyone confirm that a piggyback air shock like the Super Deluxe will fit in this frame?
In my correspondence with BXT, the rep claims that piggyback air shock won't fit in this frame. It looks like the piggyback might fit similar to the hightower as long as the air can fits in the ~50mm width of the shock tunnel. I've attached the images the BXT rep sent me.
The rep said:
The dimensions of the shock seem wrong, and maybe the rep is just trying to sell me the deluxe inline shock they carry.
My son has this frame and I do not know if a piggyback shock will fit since he does not use a piggyback shock. And Fox type air shock with a piggyback will probably fit, but a coil may not. YMMV. The shock is definitely a 210x55 standard eyelet and the bushings are 24mm as I stated in reply #21 of this thread. Do a little research on how shocks are mounted so you know what kind of hardware is needed for the shock. There is nothing propietary about the mounting on this frame.
You will need to buy a headset with cups. Nothing is "integrated".
For extra dropouts use the "142" 12mm thru axle variety. BXT has standardized this type of dropout on other frames including those with non-boost 12mm thru axle spacing, but they never bothered to update the listing.
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Thank you for the clarification, daifanshi. If I understand correctly, the frame has boost 148 spacing, but you order the dropout & hanger kit that's labeled as "142" from the link they sent. I also ordered the headset from another link they sent which is an "IS" type as expected. (My previous post has the links.)
The BXT rep did figure out the weird shock dims they quoted were wrong after I pointed it out, but they did try to sell me a 210x50 shock. I'll find and install my own 210x55mm shock. The BXT reps are probably selling lots of frames, and they might get things wrong.
It's not clear if a piggyback air shock like the super deluxe will fit in this frame. I looked through the AM831 thread since the frame is similar. At least one person seemed to have success with a super deluxe on the AM831, but the frame clearance might be different. It may even be frame size dependent. It's clear that the shock tunnel is even narrower than a hightower and a modern coil won't work, but the limiting factor for a piggyback air shock is probably the clearance to the upper linkage as the suspension cycles.
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Do you use frame without bearing spacers or you modified links before hard using?
(http://)
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Make a linkage model for S size frame. Indeed frame latched after 52mm of stroke (!) (with 210x55 shock)
I recommend using 210x50 shock.
Antisquat insesitive to cassette chainring. Sensitive to drive chainring - more tooth - less antisquat (at the same sag).
(http://)
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naeTech has posted some great information about this frame. I built up a bike using this frame, but I haven't been able to ride it much due to snow season, but here are some quirks I've noticed so far.
- The suspension gets stuck when the shock is bottomed out with a 210x55mm shock. (Edit: This may happen only on some size frames. See reply #61 for more info) The lower linkage rotates to the point where it gets cammed in the bottom out position, and the suspension won't extend. naeTech says this happened to him at 52mm, so the practical option is to use a 210x50mm shock for 136mm of travel according to his model. This bike is not a 150mm rear travel bike.
- According to naeTech's model, the leverage rate of the suspension has a 39.2% progressivity through 136mm of travel. This seems a bit extreme, and I couldn't find another example of a trail bike with similar travel and that much progression.
- I experienced excessive friction on the upper linkage / lower bolt at low torque. I tried some different washers that helped somewhat. In an mtbr thread, naeTech has found that a spacer that bridges the inner races of the bearing here on the hightower is missing from this frame. A custom spacer might help here. The linkages are not very refined. Many of the bolts experienced friction at torques much lower than SC hightower specs.
Some of the quirks might be addressed with some tinkering, but understand that you are getting 136mm travel with almost 40% progressivity with this frame. It seems like these numbers would be hard to change unless you are able to take some extreme measures like fabricating a new linkage. (Edit: Maybe not accurate for all sizes. See reply #61 for more info)[/b]
If anyone can think of a way to get closer to full 150mm travel and a less extreme leverage progressivity, I'd love to hear it!
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This frame is basically a clone of the Santa Cruz Hightower V2. Depending on which model year they copied, the shock specs are actually different depending on the frame size. I believe S and M specified a 210x52.5mm shock while L,XL,XXL are able to accept a 210x55mm shock. Travel was either 140mm or 145mm depending on the model year. So the suspension model may not apply to all sizes.
But I would think that 150mm sounds a bit out of reach for this frame even if they advertise it as such. Cascade makes a alternate lower link that claims 160mm of travel for the hightower, but who knows if that will fit in the BXT. For now I would just try it with a 55mm stroke to see if the suspension locks. And then add enough 2.5mm spacers until it doesn't.
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I use Size S frame for make measurements for linkage model. Different sizes have different lower link or differen front triangle axle positions?
If you have measurements for cascade alternate lover link (between axles) - then i make calculation for such setup :)
Upd: Usually inside the positive air shock chamber there is an oring 2..3 mm thick that holds the volume spacers. It also limits the stroke that can be squeezed with your hands.
I haven’t fully assembled the bike yet, but it seems to me that the hand-locked suspension can be unlocked simply by sitting on top of the bike...
Those. probably this is a false alarm - there is latching, but you can only encounter it by squeezing the deflated shock with your hands)
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I make spacers! Now levers works great not depend on tightening force.
Drill holes at lower link 17mm and upper link 19mm.
Spacer size for lower link 12.1x16x37.2 (+0.2 to bearing space), 12.1x16x44.2. For upper link 15.1x18.5x51.2. Why bxt not did that in stock??? (its cheap operation in industrial environment)
(http://)
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Maybe I'm not getting what this is for, but can't you just put two separate spacers on the outside of the bearings using the existing through bolt without redrilling the linkages?
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Without drilling spacers not fit :)
(bearing spacer (what i custom) - red color, outside separate spacers - yellow)
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naeTech, very impressive modification. Did you bore out the linkage to make the hole wider, and can you do this easily with a normal drill press?
I tried to free the stuck suspension at bottom out by sitting and bouncing on the bike, but it did not break free. Even if this method worked to free the stuck suspension, it would still be bad to have the linkage jam in the bottom out position on a big jump. Let me know if your experience is different.
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Maybe I'm not getting what this is for, but can't you just put two separate spacers on the outside of the bearings using the existing through bolt without redrilling the linkages?
daifanshi, naeTech is talking about a spacer between the outboard bearings that appears as a tube labeled "spacer" in the attached picture of the hightower v2 linkage. They bridge the inner races of the bearings accrding to naeTech's diagram. The hightower has them and the bxt doesn't. I experienced some binding and friction at low torques from these pivots. The spacers may help with this, but it looks like you have to modify the linkage and fabricate the spacers.
naeTech, did you add 2 spacers to the lower linkage as in the attached diagram?
While the BXT 117 may look like a hightower v2 copy, the kinematics, weird stuck suspension problem, and lack of linkage refinement like spacers suggest the copy isn't very good ;). The progression of the leverage curve is significantly greater on the BXT (some might say extreme) if naeTech's model is accurate. I don't think you could call the kinematics the same.
All sizes of the hightower 2 accept a 55mm stroke shock, but the same stroke on the BXT 117 will cause suspension to jam at bottom out. As I understand, the 2020 hightower 2 had a 52.5mm stroke shock for "140mm" travel and the next year they shipped the same frame with 55mm of stroke for "145mm" travel in all sizes. I tested and jammed it with 55mm stroke and low air pressure on a size medium. naeTech says it happened at 52mm of stroke on size small.
If you revert to a 50mm stroke shock, the actual travel on this frame seems to be about 136mm, and the progressivity may make it difficult to use full travel. The takeaway is that the suspension travel falls short on this frame not because of marketing exaggeration but a defect that prevents you from using a 55mm stroke shock as designed. (Edit: This may happen only on some size frames. See reply #61 for more info)[/b]
If you have this frame, I suggest you try for yourself because it could be dangerous on the trail (although the high progressivity might make it difficult to reach the bottom out point). I believe you will need at least a bit of air pressure in the shock to get the suspension to jam. It's the extension pressure that cams the linkage into bottom out position.
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I left about 25psi in the my son's Fox DPS 210x55mm shock and I confirmed I can't get it to "lock" or "cam" when the suspension bottoms out with the full shock stroke. It is a size Large frame. For us this appears to be a non-problem. And I do not see any issues with friction in the pivots. He purchased this frame more than a year ago. Maybe something changed over the last year.
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Can you unscrew the big axle and take a picture of the internal space between the bearings? Check if there is a spacer there?
In such manner :
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naeTech, did you add 2 spacers to the lower linkage as in the attached diagram?
Yes - in lower same situation.
Aluminum drills easily by sharp drill. The main thing is to securely fix the parts.
It seems to me that for such a progressive frame it is not particularly important whether it gives 135 or 150 strokes. This is more critical for linear frames. Branded bicycles also have bump stops and full travel can only be achieved in extreme conditions.
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Can you unscrew the big axle and take a picture of the internal space between the bearings? Check if there is a spacer there?
In such manner :
This might take a while. Don't hold your breath. Not my bike.
I just remembered I posted a picture of the top link a year ago in reply #22 of this thread. See if it shows something.
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This might take a while. Don't hold your breath. Not my bike.
I just remembered I posted a picture of the top link a year ago in reply #22 of this thread. See if it shows something.
I not see spacer tube here.
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daifanshi, seems like size Large may not get stuck at bottom out. That's good news for Large frame owners. I'd still suggest that owners test their frame just in case to prevent a potential dangerous situation on trail.
It seems to me that for such a progressive frame it is not particularly important whether it gives 135 or 150 strokes. This is more critical for linear frames. Branded bicycles also have bump stops and full travel can only be achieved in extreme conditions.
I just hope I'm able to use full travel on a bike with such a progressive leverage curve. As a light rider, I'm afraid the 135mm of travel will feel like 120mm. I will see in the springtime when I can test the bike.
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Eh, using full travel in anything short of super extreme situations is kind of a <2015 thing. Suspension has improved now to the point where impact force should be well managed even if you don’t use more than 70-80% travel on most rides even if they’re pretty intense. Only large drops and jumps should get you beyond that.
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Finished the washers. Their thickness must be adjusted to the specific frame.
The preferred additional length of the tubes is from 0 to 0.2 mm.
In the drawings, I simply subtracted the additional width of the tubes from the thickness of the original washers.
I note that it is better to make the hole for the tube at least 0.5 mm larger than the outer diameter of the tube.
I drilled BOTH holes for the axles of the lower link to 17mm. And BOTH holes of the top link are up to 19mm.
See imgs:
(http://)
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An update to the problem of stuck suspension on bottom out:
On my size Medium frame, a 210x52.5mm shock does not get stuck at bottom out while a 210mmx 55mm shock jams in the bottom out position. At least one person reported that a size Large does not get stuck at bottom out while naeTech reports size Small gets stuck at bottom out at 52mm of shock stroke. The limited sample so far suggests that the problem gets worse as frames get smaller below size Large, but that's not confirmed.
I would still suggest that anyone with the frame test their bike by bottoming out the rear suspension with at a low air pressure in the shock to make sure the suspension does not jam at bottom out. Since the suspension is so progressive, you may need to reduce the air pressure in the shock to reach full bottom but you should have at least a small amount of air pressure to see the problem.
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Just ride your bike and stop sweating the details.
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We now have meter-deep snowdrifts and a 3D printer with a lathe standing idle... ;)
New printed link for small 200x50 shock. work but leverage go to linear...
(http://)
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NaeTech, this is an inspirational level of customization. Very impressive!
A couple of questions:
- Your "washers" are similar to the part called "Pivot dust shield AL" on the Santa Cruz diagram, correct?
- Why do you want to use a 200mm shock when the frame is designed for a 210mm shock? Lower bottom bracket?
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1) Original washers have more space for lubrication and a larger diameter than the bearing. And on the original links there are grease fittings that fill this system with lubricant without the need for disassembly! It makes sense to realize this beauty if you have links with grooves for large washers. But Chinese links do not have grooves and there is no place for it either. Therefore, I decided to use simple washers with a thin dust gap filled with lubricant - it will not allow moisture to easily reach the balls.
2) I just have an extra shock absorber of this size lying around “under the sofa” for a long time.
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We now have meter-deep snowdrifts and a 3D printer with a lathe standing idle... ;)
New printed link for small 200x50 shock. work but leverage go to linear...
(http://)
What material was that printed with? Is it just a plastic stand in for static (non-riding) testing before you make a metal version, or is it something you’ll be riding on?
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This is PETG for size checking. If I decide to move forward, I will print from PA-CF20.
But what I see now makes me understand that petg does a good job - the plastic part can be made larger. For example:
(http://)
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This is PETG for size checking. If I decide to move forward, I will print from PA-CF20.
But what I see now makes me understand that petg does a good job - the plastic part can be made larger. For example:
(http://)
@naeTech If you do decide to make it will you offer some for purchase?