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Old 06-28-10, 01:56 PM   #126
bcellis
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I've been trying to read as much as possible about aerodynamic field testing (with a powermeter) to determine optimum position, equipment, etc. It sounds like it's definitely feasible and sounds like a few people here have had good success with it. There's talk of roll-down tests, "half-pipe" courses, etc. I'm just wondering if there's any reason NOT to do this type of testing at a high school track. I've heard mention of going to a track, but I assume that's a velodrome and not a running track. It seems like a running track would be an ideal location since it's flat and wind effects should be negated due to the setup.

Is it too simple to assume that I could just go to a (running) track, do a few laps at a constant speed (or power) and then start comparing setups that way? For instance, say I go to the high school, cruise around for a few laps at a consistent speed (or power) with one setup, then do a few more laps with a different setup. It seems like I should get some comparable data for both setups to determine which is faster (ie, setup 1 needed 215 watts to go 20 mph and setup 2 needed 205 watts to go 20 mph). I feel like that should work but I may also be oversimplifying the whole thing.
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Old 07-01-10, 01:43 PM   #127
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That's a good simple solution. However, to get consistent, repeatable data sets, you should keep your efforts the same for each setup. Using a constant power output for each run will show your speed differences between setups pretty accurately. You could also do each run at a consistent HR range, but be aware that HR is your body's response to the workload you're producing, not a measure of the work itself.

I did the same type of tests yesterday, using a two-mile stretch of road. I found that my best position had the arm rests a centimeter higher than I used in my first TT last month. I increased the height by 5mm each run until my speed started dropping off, then re-ran the course in the prior best configuration to validate the earlier run. My best position took 15 second off my second-best position over the two miles.
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Old 08-05-10, 01:15 PM   #128
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I'm quoting YMCA and putting it in this thread so it'll be stickied..

Quote:
Originally Posted by YMCA
Team Time Trial
I wrote these tips for TTT's a few years ago when I was coaching some squads.


1) Start easy. The first half mile or so is to get settled. Have your steadiest/experienced rider start first and roll it up to a manageable speed. Then after a few turns, the group should find what is sustainable. Usually a point where the weakest member can only roll through and off and the stronger rider pulls for 30” or so.

2) Smooth and steady. The pace should rarely fluctuate. The stronger rider should pull longer, not faster. The weaker rider should not slow the pace, rather sit on if needed.

3) Converse often. Talk to each other as you go. Don’t just expect the others to know what you are thinking.

4) Figure out what order you will take off in. That way there isn’t a jumble in the first few seconds. This does not mean it has to stay in that order throughout.

5) Do not drop your extra rider. In other words, if the 3rd person across the line counts, then make sure you have four riders still together for as long as possible. This way if there is a crash or flat, you still have 3 riders to finish.

6) Sacrifice extra riders as you get closer to the finish. If you only have to finish 3 and have 5 riders left near the end, but a couple of them are just hanging on, have those two riders do one last long pull at pace until they blow.

7) Pull off into the wind! Very important. If the wind is from the right, riders should be pulling off to the right. If it from the left, pull off to the left and make sure to leave enough room for the echelon, so nobody gets caught out in the gutter.

8) No quick movements. TTT’s are done on aerobars and have little room for error, as you are not near the bakes. So no herky-jerky stuff.

9) Nobody should be over their limit in the first half. Better to sit on if needed and then give whatever you can in the second half. This doesn’t mean you shouldn’t be pushing hard, but if you blow in the first couple miles and make the group slow for you, then the damage is done.

10) Read rules 2, 3, and 7 until you can recite them in your sleep.
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Old 08-09-10, 06:13 PM   #129
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thanks for the great thread, thanks to your advice i posted the 10th fastest bike split in my last triathlon out of 285 other people, and about 50 elite/fast age groupers.
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Old 08-11-10, 12:19 AM   #130
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can anyone suggest aero shoe covers that accommodate the boa knob on back of shoe. (i have lake cx236)
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Old 08-14-10, 09:47 AM   #131
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Quote:
Originally Posted by VoodooRada View Post
I did the same type of tests yesterday, using a two-mile stretch of road. I found that my best position had the arm rests a centimeter higher than I used in my first TT last month. I increased the height by 5mm each run until my speed started dropping off, then re-ran the course in the prior best configuration to validate the earlier run. My best position took 15 second off my second-best position over the two miles.
A 5mm difference saves you 3 minutes on a 40k? That translates to 40-50W savings, or reducing drag by 15-20%. Sorry, no way that's gonna happen.
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Old 09-13-10, 08:44 AM   #132
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Has anyone run a Hed Jet Disc / Jet 9 combo? Comments?
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Old 09-15-10, 09:29 AM   #133
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Quote:
Originally Posted by bcellis View Post
I've been trying to read as much as possible about aerodynamic field testing (with a powermeter) to determine optimum position, equipment, etc. It sounds like it's definitely feasible and sounds like a few people here have had good success with it. There's talk of roll-down tests, "half-pipe" courses, etc. I'm just wondering if there's any reason NOT to do this type of testing at a high school track.
Sorry I missed your question. Perhaps you've already tried this and discovered the answers you sought.

For everyone else, the answer is: it depends. It depends on how small of a difference between setups you want to measure and how careful you are. In principle, a running track can work but different protocols and approaches are designed to be robust so that when small disturbances in the test conditions occur (as they inevitably do) you still have a chance at detecting an effect and knowing whether it was real or just random noise. Basically, both "classic" and "half-pipe" approaches achieve this robustness by a big range in test speed so you can drown out extraneous noise. Rolldowns or constant speed or constant power runs will work under perfect conditions -- but if the conditions aren't perfect you'll have a much harder time trying to identify small differences.
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Old 10-30-10, 12:22 PM   #134
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Hi all, I picked up a new Fuji D6 TT bike this week. I have spent a lot of time in the TT position over the years, actually have found it my most powerful position. However, my TT frame was a steel frame custom built in 1995, and is a more relaxed position, with about 74 degree seat tube angle, and not much drop between the saddle and the bar pads. I could stay in that position all day long and crank, I must say.

The D6 has a more aggressive position in both those regards. I have no problem with the lower drop, in fact, I am probably going to take a spacer or two out of the stack to get even lower, as my back is not perfectly flat yet. Clearly I am going to be doing a lot of dialing in over the next month or so.

I must say, I've been out of the TT position largely the last several years and mostly road riding. My speeds so far on the bike are only marginally faster than my road bike but I expect that will change as I get more power from training in the TT position. (caveat, first two rides were quite windy).

I'm looking for some feedback on the aero bars. The bike comes with stock Profile T2 alloy clip-ons, which are relatively straight. I find the initial set-up from the shop kind of narrow, and think my arm placement is constricting my lungs a bit being too close in. I find myself taking longer, deeper breaths as a result and working harder to do so. I even got a stitch in my side on longer hard efforts, and my mouth and throat get dry quickly. I widened the placement a bit, and its a bit less so, and not sure whether I should widen them more. Is this something I will grow into as I train in this position, or am I sapping myself on energy and oxygen uptake and should I widen them out until its not an issue?

My previous clip-on's on the older TT bike were Syntace C2, which I loved. They fit like a glove and the upward angle on the hand grips was so comfortable and stable I could stay on them all day, I was totally confident in the control, and I could even get out the saddle a bit with that grip for a little sprint or extra power when I needed it. The new Profile bars are less comfortable in the wrists, causing me to bend them forward and downward, and I am constantly repositioning my hands, not finding a sweet spot for very long. However, the good thing about the Profile are the for and aft adjustability, which the Syntace lack: I would have to change stems to accomplish that. Referring to a thread I found on slowtwitch.com, I found this interesting:

http://forum.slowtwitch.com/gforum.c...=search_engine (post #101)

Quote:
Hey all,

Not sure when the data's from, but I figured I'd add a couple of points that might or might not be useful.

1. Upturned verus flat hand holds on aerobar basebars: We designed, built, and tested both for Saxo when making the Shiv. We tested at 0 and -15 degrees. The flat hand hold bar on the fully built bike (-tare) was 502 gF at 0 degrees and 389 gF at -15 degrees. The angled hand holds were worse by 7 gF at 0 degrees (509 gF) and better at -15 degrees by 21 gF (368 gF).

We since have finished an extensive study at A2 testing the same exact control bike over 6 months of testing -- full yaw sweeps of the exact same bike tested ~1 month apart at the same tunnel, same protocol. At 0 degrees, the data over 6 months is within 9 gF. At -15 degrees, the data is within 35 gF (more vortex shedding, component of side force load cell, etc -- we should expect data at yaw to be worse than 0 deg).

So -- TAKEAWAY -- same shape, design of basebar with only the upturn changing, the drag difference is almost immeasurable. So, we've gone with the upturned hand holds as you simply don't crash when going down hills/hitting bumps! Confidence in handling with aero performance is key.


2. Note that the tare values at A2 are about 180 to 150 to 180 gF across -25 to 0 to 25 degrees.

3. Kestrel's Cervelo data seems high to me but the trends seem to indicate the same wheels were used between the Kestrel and the Cervelo. I'd assume tares have not been subtracted. Looks like bar spec could be significantly different though. I'll wait to hear more because the data's confusing to me too.

Thought the bar stuff might be interesting though.

Cheers,

Mark
--
Mark Cote
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Road Engineer/Aerodynamicist
Any thoughts on whether I should switch to a bar like the Syntace with an upward bend, and if so, are there any that have fore and aft adjustment that you would recommend?


edit: adding product images:




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Old 10-30-10, 12:43 PM   #135
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Profile has a ton of bars you can consider. I have the T2+ and had pain in my left wrist which was due to my elbow hanging off the back of the pad so I moved the pads all the way back (front mounting hole) and worked on my position to get my upper arms as perpendicular to the ground as possible. That helped a lot. I'm just starting TT so I've got a lot of work to do. Like you I'm only a little faster than my road speeds at similar power so I'd guess that my non-aeroness is to blame. Jersey is a little flappy (curse you weight-loss), none of the other aero clothing/gear either. PBK/Ebay will be my friend this winter. GL
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Old 10-30-10, 03:02 PM   #136
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Quote:
Originally Posted by kensuf View Post
Has anyone run a Hed Jet Disc / Jet 9 combo? Comments?
Haven't used one but I am about to trade in my Hed standard tubular for the Hed jet disc clincher through their crash program (my disc is 8 speed spline and I need 10 speed). The Hed rep pointed out its a C2 rim so its got a 23mm track instead of 19mm, so supposedly lower rolling resistance which should mean faster even without the disc: lower tire pressures due to smaller sidewall, and less rolling resistance, minus the sew-up hassles. My experience is my Hed standard disc was fast on the flats once I got it up to speed, but even slight upgrades it felt like a boat anchor. One long overpass and I was blowing up over the crest, and/or dropping lots of speed. I now live in pancake flat Southern La., so I'll use the disc on non-windy days, and some 50mm carbon tubulars I have for winder days or when there's overpasses to climb. Also, the rep favored the Jet over the Stinger because of the aforementioned, and internally spoked wheel, so less deflection than the stinger. Hope that helps some.
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Old 11-25-10, 04:24 PM   #137
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how many hours/week do you spend on your tt bike?
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Old 11-26-10, 03:05 PM   #138
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how many hours/week do you spend on your tt bike?

2 hours this time of year. 2-4 during the season and pretty much full time the 4-5 week period before my A race.
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Old 01-19-11, 09:19 AM   #139
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so i got a dedicated TT bike this season and i'm really pumped to try to get some TT results, both at state and in my stage races this year.

I am setting aside a minimum of 1 day a week for TT workouts for the time being.

what are some good TT or TT bike specific workouts i can do in mid-base period?
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Old 01-19-11, 10:49 PM   #140
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If the bike is still relatively new to you I think adaptation is probably the biggest goal. Time in the saddle first and then move toward tempo/SST work. It is also valuable to do shifting cruise intervals in late base especially if you have been inside for most of the winter. Shifting cruise intervals would be something like 4-6 sets of 6-8 minute intervals where you do 60 seconds @ ftp and then 30 seconds at CP30. I can't remember the exact recovery period, but I think it is 3-5 minutes.
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Old 01-20-11, 12:43 AM   #141
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Quote:
Originally Posted by danahs View Post
how many hours/week do you spend on your tt bike?
3-5 in season.

Quote:
Originally Posted by badhat View Post
what are some good TT or TT bike specific workouts i can do in mid-base period?
I climb a fair bit, nothing stupid but 3-5% grades are good, tend to work the muscle groups harder than the flats and (I think) speed adaptation a bit. Roads with rolling hills are also good to ride at SST to make you work on staying "connected" to the pedals.

I'd go 2x a week BTW.
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Old 01-20-11, 12:58 AM   #142
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Quote:
Originally Posted by orcanova View Post
The Hed rep pointed out its a C2 rim so its got a 23mm track instead of 19mm, so supposedly lower rolling resistance which should mean faster even without the disc
Depends on the tire. Some adapt well to the C2, others not so much.

Quote:
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I now live in pancake flat Southern La., so I'll use the disc on non-windy days, and some 50mm carbon tubulars I have for winder days or when there's overpasses to climb.
Use the disc all the time. Change the front according to the wind. If you're not having control issues go as deep as possible, 98% of TT's the net is far better.
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Old 01-20-11, 02:41 PM   #143
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I'd go 2x a week BTW.
what if my one day - tuesday as it currently sits- was two rides (commute) a morning effort where i could do like 2x20s or speed work or something, and then after work a longer effort with climbing or sst action?

still think 2 a week is better?
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Old 01-20-11, 03:09 PM   #144
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what if my one day - tuesday as it currently sits- was two rides (commute) a morning effort where i could do like 2x20s or speed work or something, and then after work a longer effort with climbing or sst action?

still think 2 a week is better?
Yeah. Once a week is a bit light to really get adapted. It's as much about time as the type of workout, the range of motion on your muscles changes between the two, and you're using core, shoulders and arms differently as well. After a couple of months or in the off season once a week is probably fine.

Just one guys opinion though based on me.
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Old 01-20-11, 03:11 PM   #145
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good stuff.

i'll find a second day for TT work.

thanks man
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Old 01-25-11, 01:27 PM   #146
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just wanna say, not realy advice or a question, but man i am enjoying the hell out of my TT bike.

probably means i'm doin it wrong (heh), but man it is such a good feeling to just rocket down the road, drillin it.
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Old 02-01-11, 04:04 PM   #147
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I want to try running my bottle on top of the stem at a few TT's (one as part of a stage race and the CA state TT in a few months). Do you think the officials will have a problem with this? Does anyone have a link to TT bike rules for USA cycling?

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Old 02-01-11, 04:32 PM   #148
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You shouldn't have any problems at all.
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Old 02-12-11, 11:24 PM   #149
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I'm trying to figure out why my TT power is 243W avg over 20K but my road power is only 224W avg. Could be so many things. Could be that I'm just pushing harder with my legs since my upper body is more relaxed. Test, test, test.
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Old 02-13-11, 08:56 AM   #150
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Quote:
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I'm trying to figure out why my TT power is 243W avg over 20K but my road power is only 224W avg. Could be so many things. Could be that I'm just pushing harder with my legs since my upper body is more relaxed. Test, test, test.
i think i actually produce more power on my tt rig then on my road bike. it's weird
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