BXT Gravel 135 Sizing Question and versus Velobuild GF-002?

[p4R4d0x]

Between BXT and Velobuild, is one generally considered higher quality or safer than the other?

I’m looking to built up a frame as a winter gravel/road bike to save my main bike from salty conditions and to have a spare for my wife to try out gravel if she wants. I have most components already for a build, as take-offs from upgrading the other bike; just missing frame/fork, stem and bars. Both of these frame sets seem to be available for roughly the same price right now (BXT on Ali Express, Velobuild on their site or SP Cycle, though Velobuild has shipping charges). My research has led to these two options as nice looking, well priced, and reasonable geometry frames, but is there another option or any other gotchas with these two? Leaning towards the BXT because of the threaded BB and potential protection from PayPal if something goes wrong?

Also wondering about the sizing. BXT recommends the 49cm frame for my height (167cm). My main bike is bigger than this and seems to fit well (Small Lauf Seigla - 52cm?). The geo of my bike looks closer to the 52cm BXT other than the BXT having more stack and slightly less chance of toe overlap (which I do have on the Lauf). I’m thinking of going against the recommendations and getting the 52cm - any reasons I shouldn’t?


Geo comparisons:
https://geometrygeeks.bike/compare/bxt-gravel-135-2022-52,bxt-gravel-135-2022-49,velobuild-gf-002-2021-s,lauf-seigla-2022-small/

It seems the Velobuild would be the most upright? I like how the Lauf rides, but maybe having something more relaxed would be good for winter?

[JimLee]

sze 49cm is better with 700C wheel
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Jim Lee-Lightcarbon

[Sakizashi]

The only thing with the 52 is you may struggle with standover with 700c wheels and larger tires. Also may struggle even more if you use a top tube bag.

Otherwise, I would get the 52 for the longer front center unless you really need the lower stack of the 49. I am a couple of CM taller (169cm) and run a 685mm saddle height (just measured straight from the BB, not an X, Y measurement) and I would get the 52 for myself as I care more about on the bike handling and can get on and off without stand over being an issue.

[p4R4d0x]

sze 49cm is better with 700C wheel
---------
Jim Lee-Lightcarbon

Better in what way? Better (fit?) than 52cm? Or just better than 49cm with 650b wheels?

[p4R4d0x]

The only thing with the 52 is you may struggle with standover with 700c wheels and larger tires. Also may struggle even more if you use a top tube bag.

Otherwise, I would get the 52 for the longer front center unless you really need the lower stack of the 49. I am a couple of CM taller (169cm) and run a 685mm saddle height (just measured straight from the BB, not an X, Y measurement) and I would get the 52 for myself as I care more about on the bike handling and can get on and off without stand over being an issue.

Thanks, Sakizashi!

Yeah, it looks like the 52 might be just a bit taller standover-wise than my Seigla, which with my top tube bag is just touching, and I do have to tilt the bike slightly to get over it without contorting..

https://bikeinsights.com/compare?geometries=65274e2449251b001f81c1e4,634540af519a28001cd467c9,

BikeInsights doesn't list standover, and Geometry Geeks doesn't have it calculated/listed for the BXT frame for some reason, so I'm not sure how to tell real-world how different they are, though. My saddle height (if I'm measuring correctly) straight-shot from center of BB to the top/center of the saddle looks like ~700mm, on my Seigla with 165mm cranks and Fizik shoes. So that points to the 52 being a better fit, I think? Not having toe overlap would be nice. But not needing a ladder to hop on would also be nice.

Any thoughts on the BXT overall? It sounds like the Velobuild and the Airwolf YFR0068 I was also looking at both have pretty frequent headset issues?

[jonathanf2]

There are some build videos on Youtube with the BXT 135. There doesn't seem to be any issues other than possible water leak through the top headset cabling (unless you opt for a fully integrated cockpit). Personally I'd go with 49cm. You can offset twitchiness with a longer stem and you can minimize toe overlap with slightly shorter crank arms (165mm). Plus the smaller frame should weigh slightly less and be a bit more stiffer if you care for that stuff.

[p4R4d0x]

There are some build videos on Youtube with the BXT 135. There doesn't seem to be any issues other than possible water leak through the top headset cabling (unless you opt for a fully integrated cockpit). Personally I'd go with 49cm. You can offset twitchiness with a longer stem and you can minimize toe overlap with slightly shorter crank arms (165mm). Plus the smaller frame should weigh slightly less and be a bit more stiffer if you care for that stuff.

All makes sense - except this will be getting the take-off parts from my other bike, so 170mm cranks. And the front center on the 49 is already smaller than on that bike, which still gets toe overlap on the 165s anyway.

Now I just have to wait for the price to drop back down, it looks the BXTs were on some sale when I first found them, and are over $100 more now. Oops.