After a false start with an O2 VAM rim brake that I found dangerously flexible, and then a disc O2 that was good but would not hold any bottom bracket short of gluing it in permanently, I have moved on to an Ostro. Build is Dura Ace Di2 with Light Bicycle WR50. 7.01kg on lbs scale with one bottle cage, no bartape. Size is 56.
200km over the weekend. These are my initial impressions.
The standout characteristic is comfort. Considering the chunky aero seatpost and the massive front fork, I expected a very firm ride. I am aware others have been surprised by the level of comfort, including some professional reviewers, but I was skeptical. My guess is that the Ostro owes its comfort to the design of the rear triangle, and the included Black Inc. barstem. Those dropped seat stays must be relatively flexible – that’s all I can come up with. As for the barstem, I pushed down hard on the hoods while standing in front of the bike and there was significant give, enough that I checked to see if I had a soft front tire. In fact, at the beginning of the first ride, I kept checking both my tires thinking I might have a slow leak. The ride was that much softer than expected. Even with my hands on the tops beside the stem, the sensation was not in any way harsh over rough surfaces, so there is more to the front-end comfort than just the barstem. Perhaps some fork steerer flex?
Are these seat stays the source of comfort?.
One of my regular routes takes me over several wood bridges. The decking consists of horizontal boards that are badly worn at the edges producing sizeable gaps between them. These bridges form the perfect big hit comfort test as the surface just shakes the crap out of you, particularly if you hammer them. On Saturday I crossed them after about 100kms, so I was far from fresh, and my ass, hands, and feet have rarely had a smoother ride on them. Still felt like riding over cobbles, but the sharpness of the impacts was noticeably muted. On my second ride I added about 7psi to my tires to see if I was being fooled by low pressures. The comfort did not decline at all.
The rest of the performance variables easily live up to what you would expect from a state-of-the-art race bike. The Ostro feels plenty stiff out of the saddle, although it does not quite have that perfect sense of power transmission when you stomp on it as the very stiffest bikes do. There is some minor twist to the frame if you push hard at lower cadence. I think the top tube is not particularly rigid. My guess is that the top of the frame diamond has some flex, while the bottom is more robust. But this combination seems to work, particularly when you consider everything that riding involves beyond just stomping up a short incline. In terms of power transmission I would summarize the Ostro as very stiff, while not being perfectly responsive. More of a sense of inertia as opposed to tossable and snappy, pretty much what you would expect from and aero frame with relatively deep wheels and a 400+ gram fork. This impression is no doubt compounded by years spent riding a 6.3kg Parlee. It’s worth noting that I am 77kg with good short duration power. Lighter riders, or those with different power attributes might have a different sense of the responsiveness.
Handling-wise, the bike tracks very well, straight-line stability is excellent. There is an interesting sensation that the steering gets heavier at higher speeds that adds to the sense of stability. It almost feels like an overtightened headset, but of course the headset is just fine. Perhaps this is the result of the deep fork legs acting like wings. The Ostro steering is very precise in hard cornering, though I have experienced better, notably certain Colnagos. Still, it does an excellent job of keeping its composure (and line) in rougher corners. I assume a part of this is the result of the overbuilt fork. It just doesn’t budge.
A few looks at the fork and head tube
rear view
I do have some reservations regarding the barstem. The bend of the drops is too tight particularly where my hands rest when working the brakes. This results in my palms contacting the bar at each side of my hand with a void in the center of my palm. It takes a bit of wiggling to really get the hand pressed into the curve – a must for good control in aggressive cornering/descending. A more uniform radius with a deeper drop would make a better bar.
Another characteristic of the bar that doesn’t thrill me is that it is hard to achieve a flat transition from bar to hood. There is a minor dip even with the hoods located as high as practicably possible, which makes some hand positions less comfortable. On the upside, I find the tops supremely comfortable.
Stepping back and looking at the big picture, other than the superior comfort, my impressions are not gushing with superlatives. Fair to say it’s a case of the Ostro doing a very good job in all areas without excelling at any one thing. Some might find the overall feel a bit muted, but that IMO is vastly superior to abundant road surface feedback at the expense of comfort. The Ostro just handles everything without drama which could be mistaken for a dull personality in what is fundamentally a taught race bike. Not the case at all IMO. Rather, I would describe the personality as "serious" or "all business". As a package, it is certainly the best bike I have ridden. Note that I have not included speed in my assessment. It is entirely possible that the Ostro is right up there with the fastest bikes on the market. Something to keep in mind as far as "the big picture" in concerned.
From a commercial perspective the basic identity of the Ostro is “aero but also light”. If independent testing shows the bike to be very aero, and it can be built to 6.8kg without exotic parts, then my perspective is that the Ostro is a great success. I may be stingy with superlatives, but I also cannot find any fault. Throw in the comfort bonus and I think anyone who can manage the geometry would be happy with it.
the top tube has a little trough likely designed to aid stiffness, but in the rain I see it channeling water into the seat tube. Bike won’t see rain so no issue for me.
tidy rear light. No way I am strapping anything to the seatpost. The bike should come with a rear light solution.
Front mount situation, not the most compact but not bad. I won’t ride without flashing lights. Three friends hit by cars turning left into them in broad daylight in the last few months.
