I will make full build post. hopefully within a week. 

I ran the 4 cables via the large opening of bars.  I figured there would be less tight bends. Plus I wanted fully internal.

Fork
I ran two housings left and two right of fork. One housing on right going into the fork. If you run housings same direction around fork it wants to pull and or pinch.  I ran cables into housings before fully compressing everything.

I slammed the stem no spacers needed and I used jagwire keb-sl and lex cables.

The fully internal route on these bars is a nice option.

Yeah, +1 for making sure the cables and hoses to/from the right and left shifters are routed down the headtube and around the steerer accordingly. Also, taking a look a kbike's photo, I'd highly recommend running the cables and hoses parallel to each other through the handlebars and down the head tube without crossing over, especially if you are using spacers. Looking at that space right before the cables and hoses take the 90 degree turn down, there is actually enough room to run them all parallel to each other all the way through the bars, through the bend, and down into the headtube.

I found that if I crossed them over anywhere along that length, the pinch point eventually caused the housings to buckle making for stiff shifting and squishy braking. It's a tight fit to get them all parallel, but I used dental tools and a small flathead screw driver to get them all into correct orientation. I believe I had the brake hoses sandwiched between the shifter cables all the way through the bars, stem, headset, and headtube. Worked great even after I cut the stem down further and removed some spacers.

Hi All,

I rode my TT-X21 for about 8 months and put around 2000 miles on it. It's a 56cm frameset and the final build was all Shimano Ultegra r8070 with a Quarg PM and DUB Crankset. I run a set of Scribe Aero Wide + 60D wheels tubeless with Conti 5000s. I ran a 52/36 with an 11/28 cassette initially, then switched the cassette out for an 11/30 to do more climbing over the summer.

The TT-X21 is fast. If Strava results hold any weight for you, the bike got me enough KOMs, top 5s, and top 10s, over mostly short sprints, sprint climbs, shorter time trial segments, and a couple of descents, to confirm for me that the set up I had around a 56cm TT-X21 frame was fast. Compared to a mainstream Aero specific frame that retails for 3 times as much? Yeah, the TanTan TT-X21 is still a fast bike. That's the good news, and if you're perfectly happy with Chinese made carbon frames, you can stop reading here. Happy riding! =)

The Propel with same set-up, though, is quantitatively faster...so far. I'm way off my summer fitness peak and I haven't dialed the bike in yet, but for short sprints at top speed, yeah, markedly faster, anywhere from 1 to 3 mph faster. All in all, speed is up and wattage to achieve that same speed is down.

The direct qualitative comparison? The TT-X21 is fast, but it's a stiff and harsh ride. It's stiff, but not strategically so. That translates to good power transfer, but you really take a beating in exchange for speed. The bike doesn't exactly lumber, it gets to top end but it takes a lot of effort to hold speed.  At all out effort, on the other hand, the fork flexes and the rotors will grind. It's not a lot of flex, but the grinding is consistent when you're out of the saddle and putting the power down. It handles well enough though. Descending is rewarding. I'm not a very confident descender, but it's not because the TT-X-21 doesn't inspire. I have no complaints about the handling at speed.

The Propel accelerates really quickly in comparison. The speed comes easy, 0 flex anywhere that it matters, but it's not nearly as harsh a ride. Once it's going, it just keeps going and the handling is noticeably better. No drama, you can feel it lurch forward with every pedal stroke and you don't pay for it in ride quality. I'm not sure about the relationship between frame stiffness and power measurements at the spider, but my power readings are more consistent overall, not necessarily higher, just more consistent over the course of a ride. I wouldn't call these marginal gains. They smacked me in the ass the first time I really rode the Propel. That being said, I wouldn't call it a surprise for a frame that retails for 3 times as much.

In retrospect, would I still be happy riding the TT-X21? Absolutely! The bang for your buck is phenomenal compared to the Propel. The main reason I switched was because I felt like a 56 cm frame was a bit big for me, after all. I would have been fine trying out a 54cm TT-X21. On the other hand, I have no regrets after plopping down my hard earned cash for a mainstream frame either. As an older rider, I can appreciate the difference in ride quality without having to sacrifice the aero geometry.

Question for all,

my ltk-268 frame from longteng requires a bb86 bottom bracket.

I purchased a cheap bb86 from sigiyi/zrace with my crankset.

Is it worth paying 30-50$ to upgrade to a Shimano BB86 Bottom Bracket or something similar?

like this : https://www.aliexpress.com/item/32854261988.html?spm=a2g0o.productlist.0.0.4a44240d42JNmt&algo_pvid=4535202d-97f2-4eba-915e-fca837c24ed6&algo_exp_id=4535202d-97f2-4eba-915e-fca837c24ed6-0&pdp_ext_f=%7B%22sku_id%22%3A%2210000013315405293%22%7D


BB72-41 or RS500-PB

Just a head's up, I believe that Zrace spindle requires a DUB 29mm bearing set for the bottom bracket, so a straight swap with a Shimano bottom bracket with a 24mm bearing won't work. I'm not sure how many Chinese options there are for a DUB in the same spec, but other options are extremely limited and pretty pricey.

Is any BB upgrade worth it? Depends on what you are hoping to achieve. From what I understand, for press fit bottom brackets, creaking would bet he biggest issue.

I ordered the sigeyi power meter with cranks  + the entire  sensah empire 2x11 Groupset including the rotors, for 500usd on eBay. Thank you everyone

Wow, that's a great deal. Grats!

This is a tough one if you are looking, specifically, for a left side crank PM to fit a Zrace. I think you may have more luck with a spider based PM, with the added benefit of a better estimated dual sided measurement.

Here's the Sigeyi spider for Zrace, but I don't know if it's sold separately. It's a heck of a deal if you plan to use Zrace anyway. You may be able to pick up this crank then source the rest of the components for cheaper?

https://www.sigeyishop.com/product/zracesigeyi-rx-power-meter-crankset/

Not much to see to be honest.

Really clean! Well done!

Also this is for safety.  Re: aero and tyre profile you're undoubtedly better going with something 20-21mm ID and ~28mm OD on their Pro Ones for 25-27mm.

/shrug

I basically agree with you as far as aero gains go. I roll on 26mm Conti TLs/ 21mm ID x 30mm OD, 60mm deep rims, purely for the aero gains. On 21mm ID rims, the 26mm Conti TLs pump up to 28mm at around 90psi. That still meets the Rule of 105 on my new wheels. It didn't when I rolled on 21ID x 28OD 46mm deep rims. It's not really comparing apples to apples given the different rim profiles and depths, but the gains on the new wheels are significant.

That being said, I had no problem riding my endurance bike with the stock 32mm tires on 17mm ID rims out of the box. Really comfy.