I'm interested in finding out what bike you've owned that you thought descended well. I also inspired to bring this after reading a post on Red Kite Prayer (an great website https://redkiteprayer.com) reviewing the descending characteristics of a Tarmac and a Roubaix.

I'd especially like to hear from people who consider themselves competent or good descenders and who have also own multiple frames and compare those....i.e your CAAD9 vs Orca etc.

Any stiff frame will descend well.

You can't really post this question without providing the size, frame angles, fork rake, and wheelbase of your bike.

Any of the Colnagos (C50, EP, EPS) that I have had descend very well. Classic stage racing geometry works well for those applications.

I've owned three Tarmacs as well, both S-works and regular variety. The Tarmacs had a shorter wheelbase and steeper head tube angles.... they didn't descent as well as the Colnagos. However, they never exhibited any speed wobble or excessive twitchiness.

Now I'm going to have an EPS and and S-works SL3... best of both worlds

Wobbles at the wheels at high speed could be due to unbalanced wheels, make sure to check those out.

the question isn't about my bike....i re-edited the original post to remove that part

The question I'm interested in is comparing the bikes you've owned and how you liked descending on them.

I've got to test a Colnago C-40, a LOOK KG381, K461, two 585s a Fondriest MDC, and a Cervelo R3 on Colorado mountain descents. I liked the R3 the least because the wheelbase was too short and the steering trail too small.

It rare for a frame to really be bad at descending, unless it's a large frame the lack rigidity. In the 51cm size that I ride, they are all stiff.

Colnago uses more steering trail than most other brands. That's neither good or bad, it just requires getting used to. It requires a little more constant countersteering to keep the bike turning, since more trail increases the tendency of the front wheel to self-center. I prefer a little less trail, as used on the LOOK frames. All four of mine had the same 72 degree STA with 43mm of fork offset.

I've had my CAAD9 regularly over 45 a few times coming down some twisties. I would say that I was more worried about my Ultegra brakes being insufficient more than my frame being unstable. As stated, rake and wheelbase has a lot to do with it because those two factors have more to do with turn-in and radius than anything.

Anything super-stiff with a fairly standard "race" geometry with a solid fork and brakes will descend well. It's more you than the bike at that point.

SystemSix is fantastic (52 cm), by far the best descending bike I've had in a while. I'm still out on the Tsunami (identical geometry with two 1 1/8" headset bearings and a tried-and-true Reynolds fork) - I think my wheel and tire choices are compromising its cornering at the limit.

Fastest ever was my Specialized M2 S-Works frame, but I never did many switchbacks with it.

Based on other bikes, I think that a stiff fork, solid head tube placement (i.e. not much flex), and a nice forward position (longer, lower stem) really makes for a nicely descending bike. For me it's been about weight up front - if I don't have enough weight up front, I don't feel secure, esp in turns.

After stability in a straight line, the most important part with a descent is turns - if the bike doesn't turn well at 50 mph, it's not going to be very confidence inspiring.

cdr

I have my saddle a long way back (6-7cm behind the BB with a 73cm saddle height), but still get 45% of the weight on the front with only a 110mm stem and short reach (75mm) bars. An 11cm drop lowers the torso and weights the front.

My Time VXS descends better than I do.

Bastid.

Ummmm, not really. You can still give a 'general' idea for how a bike handles based on the design of the fork and frame itself. One of the best descending bikes I've ever ridden was a Pinarello Prince; that was due mostly to the Onda fork design, awesome fork and coupled with a fat ass front end and rear end designed like the fork, man that bike was fast. By the way, its not mine.

Mine

My favorite descending bike was a pre-trek Lemond Ti frame. I've had that bike over 50-60 MPH many times. My Scott Cr1 is potentially a great descender, managed about 35 and is rock steady. it has possibilities but I'm older, wiser (maybe), worried about self-preservation and will never hit those speeds again on a bicycle.

I love descending on my 07 Tarmac. However, the bladed spokes make it miserable with a crosswind.
I am not a heavy rider but one of the better descenders in my bike club. I suck at climbing this year so I have to excel at something.

My battleship steel Bianchi cross / touring bike descends better than my race bike (even with the same wheels). I suspect that most of that has to do with longer trail.

The two best descending bikes I have owned were an early 1990s Bottecchia, and a mid-90s GT. Funny thing is, other than both being steel, they really had nothing in common. The Bot had a more compact frame, heavy, and little to no noticeable flex; the GT was a larger frame, substantially lighter, and probably not as stiff, but it could rail the turns which gave me a lot of confidence. Never been a great descender, but the few times I topped 50 mph were on the GT.

I'm guessing these are going to be older frames than you're interested in, but in order, my favorite descenders for 40-50 mph action:

1. Univega Super Special - slightly longer wheelbase made it feel a little more stable than...
2. Pinarello Record
3. Nishiki ?
4. Trek 400T

The top 3 were great. The Trek was only OK. It was a bit of a spongy, floppy frame - especially bad on mild downhills where you really had to spin to keep the speed above 40.