BXT-MTB-117 150mm AM bike

[naeTech]

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:

[veeTee1Pah]

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.

[daifanshi]

Just ride your bike and stop sweating the details.

[naeTech]

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...

[veeTee1Pah]

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?

[naeTech]

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.

[FullCarbonAlchemist]

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...

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?

[naeTech]

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:

[japjoe7]

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:

@naeTech If you do decide to make it will you offer some for purchase?

[japjoe7]

Nice pic from the ride today.

[Tom.Stevens.ADL]

Has anyone had any issues with this frame so far other than the mentioned problem with certain sizes and the shock sticking?

Also, anyone mulleted it yet? I really like a 460-465 reach, if I get the large and mullet it, it'll come out at 460ish pretty nicely

[veeTee1Pah]

Has anyone had any issues with this frame so far other than the mentioned problem with certain sizes and the shock sticking?

Also, anyone mulleted it yet? I really like a 460-465 reach, if I get the large and mullet it, it'll come out at 460ish pretty nicely

I've mulleted mine, and the bottom bracket is a bit low even with a specialized 2.6 rear tire and 165mm cranks, and a 160mm fork but it's rideable. I haven't tried offset bushings or even shorter cranks, and that might help pedal strikes.

I know people will disagree with me, but I think the sum of the big and little issues with this frame make it a flawed product that's rideable if you spend time and energy troubleshooting.

The glaring issues are the suspension getting stuck when compressed (small and medium frames?) and the weird overly progressive leverage curve. With the shock spacer to prevent the stuck suspension and the overly progressive suspension, the bike feels like it has less travel than advertised. There are also smaller issues like less than ideal friction on a linkage,or under bb cable routing rubbing a groove in the carbon as suspension cycles. These are examples of the little issues you will have to deal with. I still have fun on mine. I've realized I'm not discerning or skilled enough for it to bother me too much. Still, given the price it takes to build up even an inexpensive frame and the depressed prices on new and used brand name bikes at the moment, I'd probably go a different route if I did it over again.

[uberamd]

Still, given the price it takes to build up even an inexpensive frame and the depressed prices on new and used brand name bikes at the moment, I'd probably go a different route if I did it over again.

I'm with you. Frame is alright, rides great, but it was a hassle and a half to get going.

Ex: I was never provided the linkage spacers with my frame, and obviously those are required. By the time I got them from the seller (6+ weeks after frame delivery) they sent me the wrong ones (they were sized incorrectly). So I 3d printed my own in ABS after figuring out what the dimensions should be. Those 3d printed spacers are working fantasticly but still, that shouldn't be required to make this frame work.

Totally agree on the cable routing, being under the BB is odd. The dropper post routing is equally strange, so I'm using an AXS dropper to avoid needing a cable in that weird location.

The link design makes removing and installing the shock a pain in the ass because you can't access the rear shock bolt. Again, not a huge deal but still annoying.

The spacers provided that attach the top tube link to the top of the rear triangle are oversized, so getting them in the frame is difficult. Huge deal? Nah, but it probably is putting excessive load on those bearings.

The derailleur hanger is weird -- its got a threaded insert for the axle that is kinda just free floating, and the hanger itself is held together by 2 screws, one of which backed itself off during a ride and interfered with my cassette by wedging itself against the cassette lockring. Looks like the frame now uses UDH which is nice.

The holes for routing the brake/shift housing were a hair undersized, I had to use a drill to round them out a bit more so the housing/hose would fit.

Luckily I have no issue with the shock sticking on my size L frame paired with a 210x55 shock.

Overall, pretty good frame but when you factor in the price (especially now with tariffs) there are used name brand options that are competitively priced and don't have these annoyances.

[veeTee1Pah]

I'm with you. Frame is alright, rides great, but it was a hassle and a half to get going.

Ex: I was never provided the linkage spacers with my frame, and obviously those are required. By the time I got them from the seller (6+ weeks after frame delivery) they sent me the wrong ones (they were sized incorrectly). So I 3d printed my own in ABS after figuring out what the dimensions should be. Those 3d printed spacers are working fantasticly but still, that shouldn't be required to make this frame work.
...
Overall, pretty good frame but when you factor in the price (especially now with tariffs) there are used name brand options that are competitively priced and don't have these annoyances.

Ubermd, I agree 100%. A lot of people on these forums are really asking the same question: "Can I get a bike that works like a name brand frame for a fraction of the price?" For full suspension bikes at the moment, I think the answer is "Probably not!" Let's put it this way: A mainstream publication would probably give a bike like this a poor review. There's a big gap between the refinement of this open mold frame and name brand bikes.

My guess is that there isn't a big mountain bike culture in China yet. Companies with a lot of manufacturing experience are designing and building mountain bikes from a CAD file without a lot of practical experience, testing, and feedback. That's how you get bikes with suspension that gets stuck a full compression and downtubes that won't clear fork crowns (not this bike but another on this forum).

My issues weren't exactly the same as yours, and I probably don't remember every quirk I dealt with, but I certainly spent hours dealing with weird flaws over many weeks. For example, I replaced a couple of plastic linkage spacers because the shape of the original ones caused friction. Santa Cruz VPP linkages don't have plastic spacers, and they have other design differences like a grease ports, dust covers, and between bearing spacers to mitigate lateral loads. My point is that most people aren't aware of details like this when considering an open mold frame purchase.

I also agree that you can have fun riding this bike! The geometry is decent, and that goes a long way to making the bike handle well enough for me despite the "unorthodox" leverage curve.

However, I wouldn't recommend a purchase like this for someone who just wants to buy a bike and ride it asap without faff. However, if you're a tinkerer who loves the challenge of a product with potential but flaws, this frame could be for you!