School me on the affect of minor geometry tweaks

[robertbb]

Thanks all.

Unfortunately neither F-C or BB drop are given for the frames. I've contacted manufacturers (both large multinationals) and the "support" people were not able to give me specifics.

My take-away is that the two are really very similar, and that as mentioned the one to the right (shorter H-T) will be slightly less twitchy.

Is anyone aware of a good, up-to-date, thorough book on this stuff?

[Dave]

I use the STA, in addition to the reach and stack, only as a reference for seat post setback. The small frames that I ride usually have 74-74.5 STA and that works fine for me with a 25mm setback post.

[dddd]

Once we started getting sloping-toptube frames, this "Stack" dimension became the way to know if a new frame would need a pile of spacers underneath a cool-looking negative-rise stem.
Also better for the headset function if a ton of spacers aren't there.

All this somewhat reminds me of how one "improvement" begets new issues within the overall big picture.

So sloping toptubes remind me of carbon rims. We get lighter weight for any given width and aero depth, but then find ourselves "needing" disc brake frame structures to deal with the reduced braking performance, leading to the "need" for ever-wider tires to provide compliance, and now have to go tubeless to seal up all of the added thorn punctures that a thinner-walled and wider tire mops up. And on top of that, the new sub-2-pound frames seem to be extremely fragile in the context of minor tip-overs, but are again "needed" to counter the added weight of going disc.

In the end, it's nothing that money can't fix, though I dislike the prospect of any unexpected latex sealant shower from the lead rider's punctured tubeless tire.

[robertbb]

Higher modulus carbon in general seems to be more prone to cracks and brakes with "tip-over".

Sure it's stiffer but also far more brittle.

One of the experts, Raoul Leuscher (see his vids on Youtube) has stated that T700 is pretty much the best blend of stiffness, weight and impact resistance.

T700 is also used on pretty much all the mid-level frames as far as I can tell. It's the "high end" that get into T800 and T1000 carbon.