Time Trial / Time Trialling / TT

I'm planning on popping by the Bexley 10 again this week if anyone's heading out. Hopefully get there on time as well...

I plan on going.
See you there, T.

Plan to be there. On the road bike with clip-ons most probably.

Depending on when I can get out of work I'll other be on the road bike as-is or tt fixxor flying machine. which is yet to be legitimately tt-ed.

Be interesting to see proper tunnel results..

"The second surprise was that an aluminum Roval wheel (not a deep section wheel) with a conti tire (GP4000S with chili compound) was significantly faster than a cheap 50mm carbon rim with a conti sprinter (chili compound, not the gatorskin version). It's one reason why I really don't encourage people to buy cheap carbon wheels off ebay."

http://robbellracing.blogspot.co.uk/2012/02/using-golden-cheetah-aerolab.html

That's interesting data- he'd need to repeat that test with the tyres swapped to make it meaningful though surely?

Otherwise it's possibly rolling resistance rather than aerodynamics.

If it is the case that a 50mm blunt-V is worse than a standard 24mm profile rim then it would be interesting to see why, preferably in the wind tunnel as you suggest.

^^seeing as your bike was built for weight rather than aerodynamics this is of little concern, no?

It was built to be an all-rounder.

If weight was a primary concern I'd have 20mm tubs and no power meter.

And those silly track tubs that weigh nothing, and no bottle cages.

And, and....

You have just saved me £400. Thanks.

I usually work on 20% commission but for you, let's make it 19.5%. ;)

That's interesting data- he'd need to repeat that test with the tyres swapped to make it meaningful though surely?

Otherwise it's possibly rolling resistance rather than aerodynamics.

If it is the case that a 50mm blunt-V is worse than a standard 24mm profile rim then it would be interesting to see why, preferably in the wind tunnel as you suggest.

Not necessarily. He might've taken that into account. Only bookmarked and I'm yet to read the whole thing.

You can do increasing speed tests to separate Crr and CdA
http://nyvelocity.com/node/3350

It was built to be an all-rounder.
If weight was a primary concern I'd have 20mm tubs and no power meter.
And those silly track tubs that weigh nothing, and no bottle cages.
And, and....

No aerobars, no talk >>>>>>>>>>>>

didn't say primary concern, just that weight was prioritised over aero. I would assume your tubs to be lighter than the rovals, thus box ticked.

aerobars on club runs is going to be my thing for 2013. having passed some kind of nodder/slevless sportive on my way back in to town on Sunday it would appear it's slowly gaining traction, but early adoption scares me.

No aerobars, no talk >>>>>>>>>>>>

Wait, just you wait, soon my beauty will be revealed to the world.

Aero derailler cage?

Aero and with a big pulley at the bottom for reduced mechanical loss.
https://www.google.com/search?q=Berner+derailleur+cage

10 mile at Hog Hill tonight if anyone else is interested?

What is hogg hill like for TTs?

I don't know, I'll let you know after tonight....

It's the full circuit which is 2.0km so 8 laps. Could be boring.

Bored? Go faster.

Aero and with a big pulley at the bottom for reduced mechanical loss.
https://www.google.com/search?q=Berner+derailleur+cage

"From the results of this study, it appears that the efficiency of the bicycle chain drive depends intimately on the chain operation as it engages and departs from the sprockets on the hightension part of the drive. Owing to the high efficiencies measured under high chain tensions, friction can account for only a few percent of the overall losses."

http://www.ihpva.org/HParchive/PDF/hp50-2000.pdf

Still, they look pretty sexy. Maybe if I had an expensive tt bike..

http://shop.berner-bikes.com/drupalprod/schaltwerke

"Owing to the high efficiencies measured under high chain tensions, friction can account for only a few percent of the overall losses."

Yes, but if you can go from 98% efficiency to 98.1%, at 400W crank power that's an extra 0.4W at the back wheel.

Which would get me how much in a 10?

That's the problem with buying speed.. it never stops..

Aero and with a big pulley at the bottom for reduced mechanical loss.

Just as we'd always suspected, there are mechanical and aerodynamic penalties from derailleur gear mechs.

My report on our interclub 25.
Although there was only one fixed gear rider (who did an '8') forum users may be interested to note that the two best Hounslow performances came from riders who have done excellent fixed gear 25's recently, and have both competed at Reading Track this year.
Nic Stagg was riding his new TT bike (carbon, gears, everything modern), which is obviously very efficient, but still only gave him a limited gain over his Good Friday ride when he did 58.01 (on fixed, see report above) on the same course.

Interclub 25 -20th May 2012.
Participating clubs: Hounslow & Dist., Twickenham CC, Westerley RC and Weybridge Wheelers.

The trophy awarded in this event is for the best handicap club team performance and it was again won by the Twickenham CC.

The outright winner was Nic Stagg who recorded the impressive time of 56 minutes 51 seconds. This was an improvement of a minute and sixteen seconds on his ride in the Good Friday 25 on the same course, but this was on a day when many were actually slower than they had been at Easter, and it could be said that Nic saved the club’s honour when all the places from second to fifth went to riders from the Twickenham and the Westerley. It should be mentioned here that Stuart Stow, who took the sixth place, produced an excellent performance with 1.00.16, also improving on his Good Friday time. Both these Hounslow members have been riding at Reading track this year and perhaps there is a lesson to be learnt here.

Liam Maybank of the Twickenham took second place, as he did in 2011. His time of 58.01, which would often be good enough to win on this course, came from his first competitive ride of the year. Liam likes to mix time trialling with road racing – often a successful formula – but this year pressures from life outside cycling have caused him to start his season rather late. To go this fast in a first event should give him high hopes for the summer.

However, the most outstanding ride of the morning came from one of the Twickenham’s youngest riders, seventeen year old Rory Atkins. He started as a novice with no qualifying time to put on his entry, and finished with a time of 58.29. An outstanding performance anywhere, on this course it can only be described as brilliant.

This ride (done from an early start) appeared to put the Twickenham in an unchallengeable position in the handicap competition, because although Atkins allowance of 10 minutes did not seem particularly generous for a young novice it resulted in a handicap time of 48.29 which gave their team a head start. A long way down the start order came Mark Silver (Hounslow) riding a trike. The handicapper (Martyn Roach, of the Hounslow) clearly recognised that a three wheeler is a particularly unsuitable machine for the hilly and tortuous West of Windsor course and so gave him a generous 25 minute allowance. This resulted in a handicap time of 49.16 which at least put the club back into contention, but the outcome of the team race was Twickenham first, Hounslow second and Westerley third. The Weybridge did not finish a team.

Mark Silver goes to the Tricycle World Championships in Belgium next weekend, so this 25 was just a warm up for him, and we hope to report a successful trip next week.

The Interclub 25 was first organised in 1925 between the Twickenham, the Kingston and the Ross Wheelers (Richmond), and with numerous changes among the participating clubs has been run continuously since that time. It is intended to give encouragement to novice riders through its emphasis on the handicap system. This year’s edition (organised by the Hounslow) attracted 77 entrants, the largest field for many years: another example of the current rapid growth of cyclesport in Britain.
Result:

Handicap Team:

• Twickenham CC (Rory Atkins, Duncan Schwier and Alex Toghill)
  
  

2hours 37 minutes 12 seconds.

• Hounslow and District Wheelers (Mark Silver, Start Stow and Andrew Caldwell) 2 hours 39 minutes 20 seconds.

  3.  Westerley Road Club (John Sullivan, Malcolm Woolsey and Dave Newman) 
       2 hours 42 minutes 36 seconds.
  

Scratch (top 10):

1. Nic Stagg (Hounslow) 56.51.
   
2. Liam Maybank (Twickenham) 58.01
   
3. Rory Atkins (Twickenham) 58.29
   
4. Shane Townsend (Westerley) 59.00
   
5. Malcolm Woolsey (Westerley) 1.00.06
   
6. Stuart Stow (Hounslow) 1.00.16
   
7. Steve Home (Twickenham) 1.00.40
   
8. Rob Gilmour (Hounslow) 1.01.28
   
9. John Sullivan (Twickenham) 1.02.23
   
10. Duncan Schwier (Twickenham) 1.03.44.
    

Tricycle World Championships... time for a new bike..