tetonrider

this is a fit question, but the application is for improving speed, power and, hence, racing results.

i read recently -- but regrettably cannot find the link at the moment -- that wheels contribute about 10% to rider efficiency and tires (Crr) have a similar effect, whereas resistance generated by the rider's own body (and position) is on the order of 60% of total resistance.

seeing that has made me wonder what i may be able to do to adjust my positioning on the bike.

i'm willing to be very serious about this, and i wonder if anyone knows of a leader in fit (with a specific focus on increasing power and lowering CdA) in the Wyoming (ha!)/Utah/Colorado/Idaho/Montana zone, i'd appreciate the reference.

i can play with my own position and, since i use a power meter, examine the effect on power, but it's more than a bit time consuming and also somewhat hit-or-miss.

i currently ride a 54cm frame (compact geometry; specialized roubaix) with a slightly long stem, but i've wondered if i should be on a 56cm (potentially with a shorter stem). i am able to ride up to 200 miles in relative comfort (tweaked an ankle, but that could be coincidental), but i'd like to see if i could be even more comfortable and faster from a change in position.

thanks for any advice on a facility that might be able to help in this regard. i'd like for changes to not adversely affect comfort (i accept that it might take some getting used to) while either reducing drag and/or increasing power.

i am a little worried that the result may be to put me on a larger frame; that's something i may not be able to afford.

(in case it's not obvious, i think the fit i'm looking for is beyond the scope of the local LBS, hence my willingness to travel.)

PS i'm mostly interested in the effects on mass-start races rather than time trial positioning.

spinwax

Todd Carver or Mat Steinmetz. Todd is in Denver and Mat is in Boulder. Tell them I sent you.

They have fit Garmin, Sky, Radio Shack, Chrissie Wellington, Lieto, Stadler, you name it.

umd

Why do you think you need a larger frame?

echappist

few things

1. as umd mentions, a larger frame probably won't help. it'll give you a higher headtube, thus reducing max possible saddle-to-bar drop. other thing with short stem is that the bike will get quite twitchy
2. though not diametrically opposed, the aero positions aren't the most comfortable positions. sure, you can strengthen your core & do stretches so that the positions become comfortable, but there's a reason why most beginners ride in a very upright position.
3. at a certain point, you crunch too much & limits the movement of your diaphragm, reducing your aerobic efficiency
4. a wind tunnel (or even an iBike) is probably more useful in helping you determine & lower your CdA.

one other note, your bike ain't a particularly conducive to giving you a more aero position given that for a Tarmac & Roubaix of the same top tube length, you get more potential saddle-to-bar drop on the Tarmac

badhat

theres two great fits in Fort Collins, which is probably closest for you.

Greg at ProVelo is a certified Retul fitter, and is doing a lot a fits in town for triathletes (aero-weenies) and a couple of our local road teams.

Rick at Phoenix Cyclery is also really good.

Creakyknees

flip it.

DannoXYZ 

I don't know if Chester Kyle is still at the OTC in Colorado, he was very helpful in fine-tuning my position on the bike. You most likely can do a lot without changing frame. Comfort and speed are always at odds with each other. What you can do is practice the aero position enough so that you can hold it for as long as needed in a race and be efficient, but it will never be comfortable. Some ideas:

1. flat back, as mentioned ad nauseum here. Takes a lot of training to be comfortable with your head at the same level as your hips.

2. one of the big improvements is to actually not have bars too low. That forces your forearms to aim down and block more wind. Better to have your forearms parallel to the ground and drafting behind the hands.

3. and keep your elbows in. That's one of the advantages of a larger frame, being able to tuck your elbows in without them hitting your knees. Although a longer stem is all that's needed in most cases.

agoodale

roubaix is a relaxed geometry frame that is intentionally designed to not allow a very "aero" position. if you think you've reached the limits of that frame then look into replacing it with a race geometry frame.

this is about the best i could do with my roubaix. it worked just fine for crits & road races. when i bought a new frame i also got a narrower bar which probably had a bigger impact on air resistance than the new frame:

badhat

i ride a 54 archon, and prefer a lot of drop, and i crashed out my bike on an out of town stage race this summer and had to rent a bike to finish the race. the local shop only had roubaixs for rent...

man, i'm sure its fine if youre used to it, but it was already a little tall from being a size too big for me, and even with all the spacers pulled and the stem flipped it was like sitting in a deskchair a desk for me...

tetonrider

well, i'm not certain i do, but i have wondered about this. i'm riding with a 120mm stem on the 54cm frame. i guess i was pointing out this aspect as a curiosity -- as in i'm open to considering everything.

presumably, i'm doing something right as i've been able to do rides from 5-10h in relative comfort. the fit is reasonably "tight" in that when i'm in the drops with elbows in, my knees are coming close to my elbows.

point taken. i guess if i've got a 54cm/120mm frame-stem combo now, if it went to a 56cm frame, we're not talking about needing to run a super short stem.

noted. i'm certainly less experienced than many here (hence why i'm here to learn), but i ride a fair bit (~1000 miles/month) and am rather flexible. i'm not saying i need a time trial position, but i might like to see if i can do any better (more power and/or lower CdA) given that i still want to be comfortable racing longer distances (100-200 miles).

i do recognize that changes in position affect comfort, aerodynamics, and power, and not all move in the same direction. i'd like to retain some comfort, figure out where i produce maximum power, then get as aerodynamic as possible in that position. perhaps that naive.

i could adjust position and examine it's effect on power (using my power meter), and i have done this to a small extent. it's very time-consuming and can be inaccurate (winds can change). i now there's a more systematic process that can be achieved.

noted.

thanks!

it's about 9-10h by car. something in SLC (or boise) would be a little more convenient, but i'm willing to travel for the right service.

i'm willing to put in the work. i know nothing comes for free.

thanks. i'm pretty sure my drop isn't too far now, and i do try to keep my elbows in.

thanks for your comments. i do know that the roubaix is more relaxed than, say, the tarmac. i do require a bike that makes me want to continue to ride after 50 or 100 miles or more.

folks i know that ride the tarmac tell me that the bike is more punishing for longer rides, and they tend to have multiple bikes. i don't have that luxury, and the races/events i do would be of the longer variety (playing to my strengths; i have excellent resistance to fade though am not as strong in top-end power for short bursts).

i guess i'd like to explore the limits of my current bike -- or have independent confirmation that i've reached them on my own.

i get that a larger frame would have a taller headtube, but wouldn't it also tend to stretch a person out, too?

sounds like the taller headtube would cancel out the effect of the extended reach?

THANKS!

umd

I have only a tarmac, and have had no problems riding it 100-200+ miles.

echappist

a more comfortable saddle (say the specialized avatar) could also help on a Tarmac.

vantassell

Mike Hanseen is in SLC @ Milcreek Bicycles (used to be canyon bicycles), he does really great fits. They're a little pricey (about $100 i think) but you'll be happy with the results. He's fit some pretty big names, I know DZ comes in when he's in town. He even brought his Olympic TT bike before Beijing to do a tune-up on his fit.

waterrockets 

I have an aggressive position and have been fine on 8+ hour rides, even though I only do them once/year. Never came back with any back or shoulder issues, just tired legs.

RChung

I'm not sure that most fittings can tell you about either power or CdA. Most road bike fittings are intended to help you find a position that you can ride for 100-200 miles, and you say you can do that now. Finding a position that allows you to put out sustainable power isn't usually something that a fitter can figure out in an hour -- it something you have to figure out on the road.

Racer Ex 

Most tri geeks have horrible positions, and the ones that have good ones aren't as good as TT specialists because you end up compromising for comfort over the longer distances. I've worked with several tri folks BTW, including the women who won the Cor de Lain Ironman amateur overall.

Very few fitters know much about aerodynamics or have ever been to a wind tunnel. Retul, Wobblenaught, Etc are all motion analysis fits and have zero aerodynamic components. And much of the conventional wisdom (flat back, arms flat, Etc) misses some major components to an efficient CdA position, which varies from person to person.

That not to say any of these fitters won't improve your power output, or make you faster. I've done Retul and a small shim under one cleat and a couple of hours later we figured out that I had already hit the mark. Other people have gone in there and had radical changes.

Once you do get fitted, you'll need to give yourself some time to adapt to a new position, especially if you log a lot of hours. I'd wait to compare PM numbers until at least 4-8 weeks after you've been fitted, and I would make sure that whoever fits you logs the measurements for your old position in case you run into issues.

tetonrider

thanks, umd. i didn't include you in "folks i know that have a tarmac". of the local people i know that have tarmacs, they've told me they are punishing in longer events.

i'm guessing you, umd, ride nearly year-round (forgive me if i'm mistaken); i'd wager you're pretty accustomed to what might be a more challenging ride for some others. the people around here that i know that are hard-core still generally only ride outside ~5 months of the year. for me, i'm at around 4-5 months of fairly heavy riding, but they still feel this way.

it's good to hear other opinions on this, though, so i'm not brainwashed by the small sample i know. that said, i do live in a relatively rural area, and perhaps those comments i've heard apply to long rides on our local roads (not sure what yours are like). people DO love their tarmacs.

good to know. i found their site on a web search but didn't know of anyone who had experience there.

i'd have figured olympic type of guys have access to more sophisticated systems for positioning and such (e.g., wind tunnels, computer/video analysis, etc.).

the rchung? thanks for commenting. if you are the rchung i'm thinking of, i really appreciate the work you've done for the aerolab in golden cheetah. i haven't been able to really use it effectively, yet, (some type of solver function would help me out with a starting point).

i appreciate your comments. it sounds like what you're saying is that what i'm after is not available in a fitting. perhaps i mis-used the term "fitting" -- i'm looking for something/someone to help with positioning. perhaps that requires a wind tunnel (which is beyond my means), but i'd like to at least know what it is i would have to do to accomplish the goal, and if it's out of my range, then i'd like to know what i could do that might be a next-best alternative.

umd

That's what made it so funny when he threw out the "cadence is a red herring" in the 41 and everyone jumped on him as an idiot

vantassell

I think Ex is right on this. Most fittings will help you find a balance between power output and comfort. If you're really concerned about aero drag, it seems like a wind tunnel is your best option.

You're saying that 60% of total drag is rider, but it's not like you're going to eliminate all of that 60% and make yourself 60% faster. I wonder what % improvement people can get from some tunnel time...?

tetonrider

thanks for the info. do you have any advice for how i should approach this?

you seem to say "most fitters know nothing about aerodynamics," but then you go on to say "once you do get fitted..." it seems to me like you are suggesting that most fitters cannot do what i want, so why would i go get fitted?

i've developed a comfortable position on my own and have experimented a little bit in terms of how my position affects power output (i'm sure it could be done better), but i haven't adjusted fit for CdA as well as power to find the sweet-spot.

got any advice?



i'm not naive enough to think that one can eliminate all rider drag, but if rider drag accounts for 60% of total drag and wheel drag accounts for 10%, and if we further assume that i could make a 1% gain in either area, then 1% of 60% is still more than 1% of 10%. it seems easy and possibly fun to think about wheels that are 1% more aero than what i've got now, but adjusting riding position is potentially lower cost (assuming no new parts are necessary) and can have a bigger overall impact.

of course, the best bet would be to work on all areas that affect drag, but they're not mutually exclusive (e.g., i can swap tires and reduce Crr independent of CdA or wheels). for this thread, i was hoping to balance CdA and power while not killing myself in the comfort department (recognizing that adaptation to a new position can take some time).

speaking of wind tunnels....is there anywhere with a cycling bent that i'd be able to do this? i have no clue about costs and such (presumably it would be too much), but i'd be curious to find someone with experience and see what it takes. perhaps someone who has experience with wind tunnels in a cycling context could say quite a bit to help based on that very experience, without even going into the wind tunnel. it might not be perfect, but it could be an improvement over what i'm doing now.

then again, the final conclusion may very well be that i've gone as far as i can go with my current frame (model, size). if that's the case and if i'm not in a position to get a new frame, i'd accept that. i'd prefer to know rather than not know.

Racer Ex 

A "fit" might find a position that will maximize your power output. There's also value, if the fitter knows their stuff, in correcting physical discrepancies (one leg longer then the other, Etc). I wasn't entirely clear if you were looking solely at improving power and/or integrating an aero component into the revamp.

Once you start factoring in aerodynamics into this it becomes somewhat complicated; TT nuts are constantly searching for the sweet spot where you can maintain power while reducing CdA as much as possible. There's a lot there and testing is pretty much required.

With a power meter you can do a fair amount of trial and error field testing, there are several protocols out there, some of which have been posted here or at least linked to here. The next step would be the wind tunnel; costs vary between $375-900/hr, that normally comes with a consultant. The three I have direct experience with or know a lot about are Co Springs, TX, and the A2 Tunnel in North Carolina. I've spent time in all but the TX tunnel, but Nate has spent a lot of time with John Cobb in that one so I have an idea how they run things.

I can tell you that the tunnel can produce some very big reductions in drag depending on how bad your position is it could be 15% or more at 30 MPH (the speed at which most bike oriented tunnels test).

The list of things to play with is pretty long; a quick look at the variety of positions used by world class TT guys will give you some idea.

Nate552

Ex is spot on. There is a delicate balance between aero/power. If you can find a fitter that also has an eye for aerodynamics, or is at least aware of the influence of it, you can benefit from it. But it's all experience and guesswork until you test it. When I have spent time with Cobb at the ATM tunnel he spends a fair amount of time making sure the rider can make good power in a position (on a trainer with power) before even sending them into the tunnel.

RChung

There's often a 2 hour minimum. LSWT in San Diego is also good but it's at the upper end of the cost/hr, about equivalent to TAMU. OTOH, TAMU and San Diego have rotating platforms so tests go quicker -- at A2 (which, last time I heard, is $400/hr) you can swivel the turntable but it takes longer. Some old-fashioned wind tunnels only test at zero yaw. But in any event, cyclists going into wind tunnels are generally trying to optimize their TT positions, not their mass-start road racing positions. I'm not sure how much experience the consultants will have with road positions.

None of those things are exclusive, i.e., cadence could be a red herring yet I could still be an idiot. In fact, that might've made it even funnier.

Racer Ex 

The cadence thing is interesting. Looking at the hour record there's only one guy below 100 RPM, most are in the 101-105 range. The exception is Obree who is in the low 90's. But that's another thread. I can tell you that you're an idiot for posting anything of technical substance in the 41 though (I am of course joking...sort of...and it's not like I haven't wandered down that path either).

The CO tunnel will book an hour and I believe A2 will also, though I booked a bunch so I'm not positive on that. Mike's really quick on the turntable there btw, less than 2min to make the change. If you can find someone who's going and piggyback that's always good, having an extra hand/brain is never a bad thing.

The manufacturers are definitely starting to pay attention to drag, witness the recent helmet ad. Unfortunately most people have no idea about how interrelated equipment and position is; it's looked at more like a weight equation where things are absolute.

brianappleby

Does anybody here have experience with their road positions in a wind tunnel? (as opposed to TT position)