Time Trial / Time Trialling / TT

Thanks. Give me your bank details and the cost once you've been and I'll call the swiss bank manager to move the funds.

How much will that save you on a 10mi?

0.03s

Huh? I thought it was about looking cool.

0.0004m² reduced frontal area out a total CdA for duffers like us of about 0.3m² is 0.13%, that's nearly 2s in a 25 minute 10, more than I was expecting.

Given my roadbike cda is .3 my TT bike will be nearer .24 or lower. I'll tell you once I've been out properly.

What is the easiest way to work out CdA?

(I'm sure it's been mentioned - my searchfu, however, is weak.)

You can't work it out, you have to measure it. Either wind tunnel or power meter and then Golden Cheetah+Aerolab or similar analytical tools.

Is this any good as an approximation?

Yes, but what axle is in your Hed? It won't work with the modern aluminium axle versions because there's not much metal to cut into due to the 5mm Allen key sockets and the hollow end cap design.

Pretty sure it's steel. Would you mind bringing them along on Sunday, and getting me the washers and bolts whilst you're in for Skinny? Cheeerzz.

I do appreciate the ridiculousness of reducing my frontal area by 0.004m² whilst riding a barge like aluminium frame, but it'll save having to keep swapping my single bolt up skewer between wheels.

Managed a 23:36 (geared) tonight on the local 10. 15secs faster than I managed a month or so ago and still all I've been doing is my regular 18mi commute on fixed.

Stravaed it for anyone interested.

Would you mind bringing them along on Sunday, and getting me the washers and bolts whilst you're in for Skinny?

You'll need to get washers from ProBolt, but I'll get screws for all.

I do appreciate the ridiculousness of reducing my frontal area by 0.0004m²

ftfy, and IIRC that calculation included the saving from the skinny Ti axle I put in my Hed

Stravaed it for anyone interested.

Dozy git - http://app.strava.com/activities/66379150

So what's more aero. I notice a lot of sky boys have thier arms apart, seems to be related to the bar design - but sky designed the bars. But martin is close, hutch is close.

http://l3.yimg.com/bt/api/res/1.2/LPXjdaiR.fzXcsZqYNk01Q--/YXBwaWQ9eW5ld3M7Zmk9ZmlsbDtoPTE0NDA7cHlvZmY9MDtxPTg1O3c9OTYw/http://media.zenfs.com/en_us/News/ap_webfeeds/20c31c5111142f17370f6a706700a63b.jpg

http://static.guim.co.uk/sys-images/Guardian/Pix/audio/video/2013/7/10/1373488579664/Tony-Martin-012.jpg

It varies per rider, depending on the shape of the body that's following the arms, also some compromise of power from narrow elbow spacing and again the optimal compromise will be rider specific.

I slammed my arms together, out of no real choice beyond it seemed sensible. Doesn't seem to affect power. I'll have to see.

0.0004m² reduced frontal area out a total CdA for duffers like us of about 0.3m² is 0.13%, that's nearly 2s in a 25 minute 10, more than I was expecting.

That can be my next marginal gain.

It varies per rider, depending on the shape of the body that's following the arms, also some compromise of power from narrow elbow spacing and again the optimal compromise will be rider specific.

Eg. Sky Wiggo with hands even closer than Martin's.

Bottrill too. And Smart can't be wrong about it.

Tunnel time or gtfo >>>

Managed a 23:36 (geared) tonight on the local 10. 15secs faster than I managed a month or so ago and still all I've been doing is my regular 18mi commute on fixed.

I took gears to my local bumpy 10 last night in the hope of pushing my time closer to 30.00. Spent the last couple of weeks commuting on them since I've not ridden gears for a year. 30s slower instead. I'm not sure that the strategy with gears is working - I noticed that everyone who hammered past had a lower cadence. I forgot to turn Strava on though so I can't compare to see where I was slower - technology fail and effort fail.

Approximately how much time would you expect to save over a 10mTT course by switching from road kit (road bike+drops, 50mm wheels, road helmet etc) to a TT set up (Aero frame, TT bars, 50mm front, disc rear, pointy hat etc)? I know it's impossible to get a real number but rough idea would be good.

I'm trying to work out just how bad Wednesday's disastrous TT was and how much I might be able to blame on kit selection. Sadly I suspect not as much as I'd hope.

24 minutes should be achievable on a road bike. Fancy kit when your base time is 26+ is silly.

24 minutes should be achievable on a road bike. Fancy kit when your base time is 26+ is silly.

sells disc wheel and aero helmet

Approximately how much time would you expect to save over a 10mTT course by switching from road kit (road bike+drops, 50mm wheels, road helmet etc) to a TT set up (Aero frame, TT bars, 50mm front, disc rear, pointy hat etc)? I know it's impossible to get a real number but rough idea would be good.

I'm trying to work out just how bad Wednesday's disastrous TT was and how much I might be able to blame on kit selection. Sadly I suspect not as much as I'd hope.

My course PB on Harrietsham (the 10 course I've ridden most regularly) is 21:43. That was with "all the tools" i.e. TT bike, tri spoke, disc, skin suit, aero helmet, shoe covers etc. My best time on my steel tubed road bike with no aero aids i.e. shallow wheels, road lid, no aero bars etc is 23:16. This is a typical rolling course and both rides would have been in decent conditions. Based on what I've seen of others too I reckon around 90 seconds is the difference in a 10, although as you've indicated there are too many variables to really be sure, but it's as a rough rule of thumb it's probably fairly close.