uo5nVEtj9 wrote:
Anachronism wrote:
davidalone wrote:
+1. you make no effort to normalise the power at which everyone was riding. Roadies attack on hills to drop people, not riding steady state. in fact even if you're riding normally it's quite common to have power go up when riding uphill.
This is exactly my point, on a group ride/race it is easy to keep up on the flats when riding in a pack with or without the added advantage of an aero bike. On the hills where the pace is pushed the advantage goes to the lighter bike.
What races are you doing?
Ever been attacked (or have you ever attacked) at 50 km/h in a crosswind? That aero bike will make a difference. When you're biting your stem in a gutter you'll know just how much power gets pushed on the flats.
Ever been attacked (or have you ever attacked) at 75 km/h on a downhill? That aero bike makes a difference.
And at 20 km/h uphill the aero might make a difference too, but significantly less. However, even if you only save 5 watts, you're now saving 5 watts for 20 minutes.
davidalone wrote:
sigh. no no no no no.
If someone rides 400 watts on the flats or the hill, its going to be tough for you to keep up either way. you made no mention of what power people were putting out on the flat or the hill. if in your group ride people were ambling along at 200 watts and then suddenly went off at 400 watts of course you'd be dropped on the hill and find it harder- in fact it's very common! the aero bike or the light bike is not going to help you with 200 watts either way! get a powermeter and ride in your next group ride. I guarunteee you the power ramps up once you hit any hill.
seems you don't exactly how aero works, so this is a VERY SIMPLIFIED analogy
an aero bike might save you somewhere around 10 watts ( comparing best and worst) at say 40kph. drag squares with speed, so a doubling in speed gives 4 times more drag. at 20kph you would be saving somewhere around 3-4 watts ( comparing best to worst). maybe. aero is always 'on', even if you're drafting. the wats savings are slightly less, but it's there.
so say you have an identical twin riding with you in a race. you're on the light but absolutely un-aero bike. he's on the aero bike. you're both in the same race.
Now let's say the race is 'on' with lots of attacking going on around 40-45kph. you see this at critical points in races- just before a decisive corner, hill, the finish line etc. suppose 20% of race time is spent when the race is 'on' . in a 3 hour race thats about ten minutes your twin is pushing ten watts less than what you need to keep up to the peloton's speed. 10 minutes at 10 watts above your FTP could be enough to cook you, while ten minutes at FTP is pretty much sustainable if you have the fitness.
An aero bike won't automatically make you a winner but it can make those 'hard' moments just abit easier, and saves you energy so that you're fresher at the critical moments.
I probably should have mentioned I am not a top 1%er like most of the posters here seem to be (ambling along at 200 watts?). I don't have a power meter and it's not in the budget anytime soon but I am definitely not sustaining anything near 400 watts - probably more like 200-250.
I do almost exclusively triathlons and my local club time trial. I usually average 22-23mph on a sprint tri and 20-21 at a Half distance on my cervelo P2 and I don't worry that much about weight. At one local sprint tri my bike split was 30th out of 500 with some decent competition.
I do have a pretty good understanding of aerodynamics, I can see the case of a strong crosswind negating much of the advantage of drafting but in most cases, in my experience and from what I have read, the benefit of drafting is huge. Obviously if someone is massively stronger than you they will get away but I have had no problem sticking with riders who are a little stronger than me on the flats on the group rides I have done.
I will have to take the word of more experienced riders that an aero frame helps in group ride/ draft legal races but I am curious how this transfers over to riders of lower ability. If the weight difference is less than a pound I can easily see the balance being tipped for the aero bike assuming other factors where also close. That three pound figure was put out by someone other than me.
As far as descending I am always one of the fastest guys on my tri bike or non aero road bike. I often pick up a few spots on long descents at hilly tris and I have a few KOMs on descents including a segment into Keene at IMLP.