wens

You're scared to learn to glue tubulars?

jsutkeepspining

wookie does that **** for me

burnsce

Okay, so I'll trust your math, but 10mph in 1 sec?! That doesn't seem reasonable. Unless you're Robbie McEwen, I'd be surprised if you've ever gone from 30mph to 40mph in one second. (is this even possible?) Can you recalculate for 2, 3 or 4X longer?

Two things to think about. 1.Many 'sprints' don't require you to accelerate at all. False flats and small hills often only require you to keep the same speed as your lead out man in order to finish ahead of your competition. Now this doesn't address accelerating out of corners. True.

2. But, while you have the additional weight to accelerate, which costs watts, you make those watts back in spades from losing additional grams of drag. Grams of drag cost you watts. I'd rather burn 2 more watts in corners in order to lose an average of 15+ watts on the whole course (crosswind especially).

jsutkeepspining

i acclerate when i start sprinting.....i dont think u have raced very much. if i kep tthe same speed i would get beat majorly. i jumped from 29 to 36 mph in my last sprint, and it was a flat to slight uphill

carpediemracing 

I understand the math about accelerating. I spent a lot of time on the analytic cycling site putting numbers into different boxes, both before and after buying the Jet wheels. One thing that no one understands is how badly I wanted the Jets to work.

However the big weakness is that the site doesn't take into account the need to respond to other riders' actions.

So... in a TT will weight make a big difference? No, not really. In fact early disk wheels had spots for weights to increase moment of inertia. If I could time trial I'd be thinking about Jets for that.

In a mass start race, where drafting is exponentially more significant than weight, it makes a huge, huge difference. If you're trying to accelerating 3-4x every 60-90 seconds to stay within a very specific area behind other riders it's harder with an extra kilo of weight on your rims/tires. It's the whole "you can save energy by accelerating much less out of a corner but then you'll use all that energy and more time trialing behind the field" thing.

If you solo off the front then the weight effect is kind of gone again because you're simply doing a steady state time trial type effort. However that's not normally in my realm. I tried a few times last year, a couple times actually thinking about it beforehand, and I'll say that weight didn't matter and aero was all important.

One thing to consider is that I have no room for waste. I'm trying to average in the 155-195 watt range for a crit, meaning that's about all I can do. I'm trying to average 155-195, not limit myself to 155-195 watts. Right now I can't go beyond that; in races where my average was close to 195 I was struggling to stay in touch (and that power number I think is too high - I haven't calibrated my second SRM spider yet). In one race this year I placed at 153 watts (same course, basically same competitors). I was shelled in another race after holding 275 watts for a bit... no way I could do that for an hour.

I no longer have the headroom to do a bunch of 1000-1200 watt spikes to stay on wheels. In fact, in my earlier post where I mention hitting 1250 watts in a corner, I actually hit the number with 3 turns to go in a (p123) crit and I was drifting back a bit in that turn. I blew myself up accelerating out of the turn and couldn't sprint in that race. I didn't even make it to the next turn without blowing up.

I'm not good at math/physics so I won't try to figure out an equation that takes into account drafting but that's what's necessary to illustrate this. If someone jumps hard (like if they're attacking or it's a hard turn) then how hard do you have to jump to stay in the draft. Your power requirements would go up as you drop out of the sheltered spot, and the faster you go the worse the effect would be.

Other factors include rider type (I am more fast twitch than not, I have no aerobic capacity) and things like amount of wind, size of rider in front (too tall is just as bad as too short, at least for me), how close one can ride to the next rider (I am good at riding pretty closely), etc.

carpediemracing 

I think it's important that this all involves more peak type power levels. It's not a time trial. It's a vicious acceleration where you're trying to keep in touch with a rider that is doing a lot of work to get rid of you. It's 800-1000-1200 watt stuff (for me), not 150-200-250 watt stuff. At 600-1000 watts 100-200 watts is sort of insignificant, I can easily spike an extra 100 watts without thinking about it. I'll do a "small" jump and only after the download I'll realize it was the peak for the ride/race at 1200 watts or whatever.

At 1000 watts a 2% margin of error (SRM's margin I think) is 20 watts. It's not even worth talking about numbers until you're outside that realm, so +/- 20 watts is simply "the same". It's +/- 50 watts, +/- 100 watts, that's where things start to add up.

Finally as far as shelter goes I usually apply zero power for about 30 seconds a lap at Bethel. Once I'm in shelter I'm good. If I'm not in shelter I'm burning 250-500 watts in the wind. That's a huge difference for someone that hasn't broken 200w average in a race for 3+ years (and when I broke it I did 202w and I couldn't sprint), especially if there's a hard crosswind or it's totally strung out. It's critical to be in shelter immediately and never to lose it.

Fat Boy

Almost every time I get pitched, it's from repeated accelerations over a long time frame, not due to a single long sustained effort. Honestly, that's what I've been training more to be able to absorb lately. So I really do understand your point, and I think it's a valid one. It's kind of a 'death of a thousand cuts' issue more than getting stabbed through the heart.

carpediemracing 

Exactly. Well maybe 15-20 cuts, not 1000

burnsce

I'm a lowly Cat 3. Perhaps my experience is not quite so extensive as yours. I did win on saturday though. My acceleration according to my Garmin file was actually 'negative' for the win. Yes, with the hill, I lost speed. I went from around 36mph in the pack (a bit downhill), to hitting the wind for the sprint uphill and crossing the line a hair under 34mph. Another instance on the podium we hit the last corner at 27mph (it's really tight), hit a hill and I crossed the line at 30mph. Positive acceleration! Three miles per hour! How about another example? Giro d'Grafton. Dead-flat. Bunch is doing 36mph when the guys who are going for the win are accelerating to (my teammate at least) 39.6mph.

Look for Cavendish's comments on Renshaw. Keeping speed is a common theme. Everyone else is dead at that point.

Perhaps my take-away is that I should move to OH?

Regardless, how much energy do you think is required to accelerate the additional wheel weight, minus the grams of drag saved?

carpediemracing 

I honestly don't know. I think it's in the 100-200 watt range (so 10-20%, sort of), maybe a bit more. That number is purely a guess though. The critical part is that it pushed me up to, and over, my cusp where I blow up or not. So 600 watts to 800 watts is one thing, 1000 watts to 1200 watts is something else.

It's also effort over time. I remember at Tour of Michigan I had a bunch of fast race wheels with me, TriSpokes (aka HED3), Zipp 440s, GEL280s, and some clinchers for any training we might do. In one race with basically a 180 (Munroe? race was at night) I chose to use the lightest wheels I had, the GEL280s, instead of more aero ones, because I figured the hairpin would really fatigue me if I used heavier/aero wheels. I could get up to speed in about 5-6 pedal strokes. I'd ease and soft pedal while other guys were struggling to get up to speed for another 2-3 pedal strokes. This was the case even for riders in front of me, allegedly able to go faster through the turn.

I want to try to do some experiments to check out my theory. I believe in science/math/etc after all, not in hocus pocus. Heck I even spent a lot of money to buy wheels based on science/math/etc (and also wanting to be "CSC-like" and do aero road stuff) - my whole second bike was based on having big aero wheels, even a disk in the rear, sort of an aero wheeled version of the 2003 Cervelo that Hamilton rode in LBL (it's a favorite race of mine, regardless of the background/history). I even invested in Camelbaks to avoid using bottles (to naught... bottles work better/easier).

The problem is I don't know how to set up the experiment. I asked someone that offers me advice, a former Cat 1 racer engineer type. He is or was heavily involved in aero testing out west and has a lot of unpublished ideas, thoughts, and experiences. He pointed out to me that the most aero road frame would get me, at best, about 1 kph in a sprint. After some thought I realized that I'd get even less of a benefit, with such a short frame (9.5 cm head tube).

Interstingly he did an experiment with weighted wheels and found them faster than unweighted ones (not sure on details of courses etc but it was for a while).

He suggested getting a pair of identical wheels and weighting one of them. I'd need to put weight in a water bottle (I'd need two identical bottles too) to balance out the light wheel (so if I used 1 kg of weight in the wheel then I need to put 1 kg of weight in the "light wheel" water bottle. That would allow me to keep the bike weight the same while altering the rotating weight, and if someone else put the wheel/bottle on then I wouldn't know which wheel was on (blind test). I could do this experiment with a teammate or something so it would be quick, easy, I could trust the person to put the skewer on, etc.

I thought a good test would be to have a standing start acceleration to catch a vehicle that drove by at a certain (faster) speed. So maybe a car goes by at 28-30 mph and the rider jumps as the car goes by. This would require intense acceleration to get to the draft and then drafting the car (and coasting/recovering while doing that - it's quite easy to sit on a wheel once you're there). The would end at a further end point to further separate sitting in from drafting (so it would be beneficial to get into the draft as quick as possible). In other words if the rider doesn't get the draft there'll be a huge penalty because the rider will need to go 300 meters in the wind (or whatever). I could check the power graph for the efforts (#1-6 or whatever) and my helper would note which wheel was on for which effort. Hopefully I'd see some correlation.

The other thing is I could simply race the Jet 9 rear and then use the Stinger 9 + a weighted bottle. Aerodynamically they're similar (the Jet 9 is a bit better, at least the shape I have, I think.... not sure), and I could see how things go. With a Tuesday Night Worlds race I could even stop, change wheels + add/subtract bottle, and jump back into the race. It's not blind but the power meter wouldn't lie.

Unfortunately I don't have power data from most of the 2010 season. My battery died and since I only use the numbers for post-race analysis I wasn't super concerned. I was so busy racing and training I just let it go for almost a year. After that I lost tons of fitness and gained a lot of weight so the numbers don't relate.

shovelhd

I am an engineer but I'm not going to throw down here, just talk about reality. I race 1250g 404's in criteriums. In a pan flat race, I don't think two pounds makes a lot of difference. Maybe as much as one of those new aero helmets. But most of the big time criteriums around here have elevation in them. Thater. Boston. Even 30 feet of elevation makes a difference when you do 45 laps at 28+ mph. It wears you down. It takes the sting out of your sprint. An extra two pounds is significant to me.

Racer Ex 

When people start talking about how "little" something might be better or worse, I always reflect on this picture:



Somebody figure out how many watts, grams, or whatever made the difference between winning and not for me here. Then explain why we shouldn't sweat the small stuff.

The rub here is that mechanical watts are seldom considered in the equation, nor is stiffness. But can create a benefit or loss of net forward motion.

Pretty easy to drive yourself a bit bat**** crazy over this stuff but it can often be worth making your best educated guess on the best performing wheel for a particular course.

Racer Ex 

Racer Ex would appreciate at least a nod in his general direction

echappist

wait, did you create the video? also, you are/were on slowtwitch?

shovelhd

fify

Fat Boy

Well, here's the deal. Everything is a compromise. A Flo60 wheel may weigh more than a XXX, but it's more aero. A YYY wheel might be lighter and just as aero, but more expensive. We can continue down this road and, as you say, drive yourself bat$&!%. At the end of the day, you just have to make your choice and take the best shot you can with the best information you can come up with.

Racer Ex 

If wadding up a $4000 wheel set bothers you, then stay a Cat 5.

Money should never be a consideration. If little Billy or whatever your sad offspring is named needs corrective surgery, they can sell organs or blood like the kid who provides me with my pre race transfusion. You need the handmade in Bavarian custom integrated seatpost/seat/chamois combo.

Yes and on rare occasions, yes.

Hida Yanra

he doesn't always ST, but when he does it's pretty funny.
However, most of the snark seems to stay on this side of the forum lines... (my observations, could be totally off - I don't stalk the man, just his aerobars

Hida Yanra

nicer gear is nicer. FACT

I've raced on jet6s, 808s, 50mm tubular (Gigantex) wheels, clinchers of all sorts, box section tubulars, hed3s...

OP - you'll be fine on the Flo wheels, they are heavy but it isn't the end of the world.
I've been REALLY enjoying racing on a set of Psimet 20/24 clinchers as well as a set of 3x 32h tubulars recently. I just put in for my 2014 racing wheels, and they'll be a new set of box section tubulars, but with high end hubs and rims.
At the moment I can't realistically afford the replacement cost of a carbon wheel, so I don't go buying them.

MDcatV

of course. apologies.

shovelhd

Agreed. Heavy isn't the end of the world. You'll be fine.

I haven't raced on my Psimet 50mm 24/28 clinchers yet, but I train on them every training day. Very pleased. A bargain.

echappist

i recall seeing the Lance & Oprah spoof on slowtwitch (https://forum.slowtwitch.com/cgi-bin/...374455#4374455), but i don't know how that poster first got a hold of the link

Fat Boy

Prudent advice. This should be on a sticky somewhere.

zigmeister

1956gms is relatively heavy? They are ridiculously heavy. Wouldn't put any wheel on my bike that heavy.

Why don't you wait for Vision to release their Metron 40s/55s and even the clincher weighs 1295gms in the 55 depth. Claimed 30gms heavier than the tubular. 40s are 100gms lighter.

Cannondale is on these exclusively this year. I think if Basso and the likes can use the 40s for climbing and Sagan the 40-55s for sprinting and wheeling...I think they are good enough for any rider on the planet IMO.