Archive for May 29th, 2021

Dan Bigham Talks Time Trial and Aerodynamics

05/29/2021 12:02
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Aero Guru, Dan Bigham Interview: With the decisive Giro d’Italia time trial on Sunday, Ed Hood thought it would be a good idea to talk to a man who knows all about aerodynamics and the ‘race against the clock’ – Dan Bigham. Chrono specialist and aero guru.

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Aero specialist – Dan Bigham

If you watched Stage One of the Giro on Eurosport or GCN then you’ll have heard that someone had the great idea to recruit British professional rider, Dan Bigham to join the commentary team as a ‘chrono specialist.’ It was a delight to listen to his informed, ‘no waffle’ observations. Bigham studied motorsport engineering at Oxford Brookes University and worked in Formula One before moving into cycling. As a rider he’s achieved much, winning multiple British titles on the track and against the watch, as well as a medal at the UCI Road Worlds in the TTT.

As an entrepreneur/organiser he put together the HUUB Wattbike team which became a major force in World Cup team pursuiting, winning the Minsk and London rounds before the UCI decided there would be no ‘trade’ teams in the competition – a decision they have subsequently reversed. Recently the Ribble Weldtite rider has become an aerodynamics consultant to likes of Jumbo Visma and the Danish national team pursuit squad – helping them to their stunning 3:44 world record.


HUUB Wattbike team pursuit

Here at PEZ we thought it would be good to put to Dan all those sad questions that trouble bike obsessives like us.

PEZ: This one has been troubling me for 30 years, Dan – if Fignon had tucked his ponytail in, would he have won the ’89 Tour de France?
Dan Bigham:
No – but it would have been closer, ponytails just aren’t aero. . .

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ponytails just aren’t aero

PEZ: You listed an ‘aero checklist’ during your Giro commentary?
Position, helmet, skinsuit and tyres. All optimised for that specific rider, course and conditions. Despite what the marketing guys might say there’s very little difference between the top wheel and frame brands in terms of performance. It still matters, but relatively less so than people think. Tyres are now very, very important – in the Giro prologue, over that distance you could be looking at saving 20 watts between the best and worst options that were used. That’s 10 seconds on that course, any rider would bite your hand off to save that.

PEZ: Aero is so important now, some riders, like Jacques Anquetil understood that in the past but how come it’s taken so long for the teams to cotton on?
If your position is bad but you’re putting out big power then it often masks the aerodynamic atrocities – and with the drug abuse there was in the sport that was the case, they were generating the power that covered up how poor they were aerodynamically. But it’s simple, if you can’t put more power in then you have to look at reducing the ‘power out’ side of the equation. So now riders and teams are now looking at how you reduce the ‘power out’ side of the equation, and there’s now an arms race on the aero front. GB cottoned on early and reaped the rewards at Beijing, London and Rio but other nations have caught up and are looking at other aspects which GB seem to have neglected – strength and conditioning, nutritional interventions and pacing for example.

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John Archibald and his POC helmet

PEZ: POC helmets, the fastest?
They look cool, they’re different but they’re not necessarily the out and out fastest on every rider – they are quick but much depends on how they suit the rider’s body shape. They’re very popular because folks see that certain fast guys use them; that used to be the case with the KASK Bambino when SKY rode them. You’ll find that the big pro teams are taking multiple different helmets to a time trial nowadays, with an optimal choice for each rider.

PEZ: Concealed cables, worth all the hassle of convoluted cable routing?
They make a massive difference, a cable is a cylinder which is aerodynamically a very poor shape; for every exposed 20 cm of exposed cable you lose around one watt (at 50kph).

PEZ: Dropped seat stays, much of a benefit?
Pretty small, you could around 0.5 watts due to the reducing the frontal area of the stays.

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The Lotus Hope bike has big gaps

PEZ: Forks: What’s best, the big ‘arched’ approach or ‘old school’ tight to the spokes?
The big crown avoids ‘choking’ the air as it passes through the crown, there’s a lot of air goes in there but in certain cross wind situations the tight to the spokes approach is better. When you look at the new GB Hope machines they are working to shed the fork wake in to the rider’s legs, reducing total drag of the system.

PEZ: Rim v. disc brakes?
There’s no easy answer, you perhaps sacrifice a couple of watts but it depends on the design/integration, as well as the yaw angle (wind direction). In terms of performance the discs give you much more consistent braking but a down side is that you can’t use radial spokes so spoke drag goes up; however because you take the brakes away from the crown you can design a slimmer head and crown – and there’s no doubt that with development, discs will get faster. If I was pushed I’d lean towards rim brakes on the road as we currently are, but in around one/two years I would probably jump across as the R&D efforts of manufacturers come to fruition.

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Solid chainring for Ganna

PEZ: ‘Solid’ disc chainrings – worth investing in?
The advantage is just about measurable, but what is more important is crank profile, the right crank cross section will move through the air more cleanly but you also have to consider stiffness and ‘Q factor’ [width between the pedals, Graeme Obree famously reduced this to a minimum with his washing machine bearing bottom bracket, ed.].

PEZ: I’ve been told that 44 mm is the optimal depth for an aero front rim?
I disagree, it depends on the rider, the course, the weather conditions, wind direction and much more. The ‘optimal wheel’ is only optimal for the conditions in which are optimising around, so there is a different ‘optimal wheel for every rider, course and conditions you can imagine.

PEZ: How come we’re now told that a wider tyre is faster than a narrow one?
It’s down to the contact patch on the road, a narrow tyre gives a long, narrow contact patch whilst a wider tyre gives a broad but shorter contact patch, hence for a given contact patch size the tyre sidewall deflects less, therefore less energy is absorbed as the tyre rolls.

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PEZ: Clinchers faster than tubulars?
Yes, it’s to do with the way they fit the rim, the rim/tubular glued interface isn’t as efficient as a clincher located on a bead. The data in the public domain make it very obvious. There are far too many old schoolers who make decisions based on subjectivity rather than objectivity. [that’s me and my Silk 3’s ‘singing on the tarmac,’ Ed.] Please carry on! It means the rest of us get a performance advantage.

PEZ: Tubeless?
There’s very little difference in terms of rolling resistance to a tube-type clincher, but if you puncture nine times out of 10 the tyre will self-seal and you may not even know you’ve punctured and will just keep riding, a big advantage, obviously.


Big rollers

PEZ: Over-size derailleur rollers?
There’s a bit in it, the main manufacturer claims 2.4 watts at a 250w output, but it’s more like 0.5 to 1 watt, so it is worthwhile but I’d put them low down the ‘must do’ list.

PEZ: Waxed chain?
Definitely, not just for performance but a high performing chain lubricant will extend the life of the chain. Not using a high quality chain lube is a false economy because it is actually wearing away your chain, reducing its lifespan significantly, maybe up to 10 times faster compared to the best lubricants!

PEZ: Chain line, surely the straighter the better?
This is where the big chain ring advantage comes in; if you’re riding a 10 mile time trial and going to do an 18 minute ride then you’d be on 53 x 11,12,13 but if you went up to a 58 ring you could run 12,13,14 whilst on a 62 you could run 13,14,15 – there’s a 0.2% loss in drive train efficiency for every sprocket you’re running away from a straight line hence why all the top testers are running bigger rings. It’s nothing to do with ‘huge gears’ as some people suggest. Rider’s power and cadence stays the same, you simply shift up the cassette to get the same ratio.

Jan-Willem Van Schip
Jan-Willem Van Schip and his narrow bars

PEZ: Narrow bars a la Jan-Willem Van Schip and – Dan Bigham.
They make a massive difference, I’ve had a bit of stick from traditionalists about them being dangerous – but look at the track, those big Dutch sprinters are going as narrow as 30 and 32 cm. Whilst Azizulhasni Awang the Malaysian keirin specialist rides 28 cm. – and those guys are riding at 80 kph in very tight bunches and higher banking loads. On the road they haven’t been adopted yet, but it will happen in the near future. My ‘thing’ is being in the breaks or away solo in which case you’re so much more aero.

PEZ: Are you still working with the Danish team pursuit guys; and will 3:44 be fast enough in Tokyo?
Yes, I’m just back from a month in Denmark, I’m not going to put any numbers out there but I think the winning time will be faster than that. . .

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GB TT champ

PEZ: What’s 2021 about for Dan Bigham?
I’m pretty motivated; I have stage races in Estonia and Slovenia coming up with the Ribble Weldtite team; a big target is the time trial in the Tour of Britain, the national time trial championships, the Chrono de Nations and the hour record is on the agenda.

# With thanks to Dan for his time and sharing of his vast knowledge. #

The post Dan Bigham Talks Time Trial and Aerodynamics appeared first on PezCycling News.


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GIRO’21 Stage 19: Yates Claws Time On Climb To Alpe di Mera, But Is it Enough?

05/29/2021 0:05
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Giro d’Italia Stage 19: The battle for the 2021 giro d’Italia is far from over. Simon Yates (BikeExchange) attacked on the final climb of the Alpe di Mera for the stage win and took back time on overall leader, Egan Bernal (INEOS Grenadiers). Yates is now 20 seconds from second placed Damiano Caruso (Bahrain Victorious) and 2:49 on Bernal.

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Stage win for Simon Yates and he moves closer to the pink jersey

Simon Yates won Stage 19 of the Giro d’Italia after 166 kilometres from Abbiategrasso to Alpe di Mera (Valsesia). João Almeida (Deceuninck – Quick-Step) and Egan Bernal finished second and third. Egan Bernal retains his lead on the general classification.

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Another tough day ahead for Egan Bernal

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Giro stage 19 route: A mountain stage featuring a succession of climbs, with lengthy false-flat, drags in between. The route travels the lowland around river Ticino, reaching the foot of the Gignese. After a technical descent into Stresa, the route runs along the lake, passes Gravellona Toce and Omegna, and clears the Passo della Colma. Past Varallo, the route continues along the valley floor up to the foot of the closing climb in Scopello. The final climb rises steadily at 9-10% for 10 km, with pitches maxing out at 14%. The road is quite wide, with a number of hairpins. The home straight is on tarmac road.

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Maglia Rosa – Egan Bernal (INEOS Grenadiers), Maglia Ciclamino – Peter Sagan (BORA-hansgrohe), Maglia Azzurra – Geoffrey Bouchard (AG2R Citroën) and Maglia Bianca – Egan Bernal (INEOS Grenadiers), worn by Aleksandr Vlasov (Astana-Premier Tech)

Almost immediately after the flag was dropped, the battle for a place in the break started. AG2R Citroën, Intermarché-Wanty-Gobert and Trek-Segafredo immediately had men attacking off the front. After 25 kilometres, two riders from Alpecin-Fenix, Dries De Bondt and Louis Vervaeke took a small lead together with Eduardo Sepúlveda, Fabio Felline and Andrea Pasqualon, but 5 kilometres further on, and everything came together again.

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Simon Yates has to make a move – Today or tomorrow

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The Giro starts stage 19

Teammates Max Walscheid and Łukasz Wiśniowski also tried unsuccessfully to escape. Only after 43 kilometres did the ‘break of the day’ come about. Quinten Hermans and Andrea Pasqualon, of the Intermarché-Wanty-Gobert team, joined forces with Larry Warbasse, Nicola Venchiarutti, Giovanni Aleotti and Mark Christian. Oscar Riesebeek tried to cross to the leading group as did Samuele Zoccarato. However, it was too much and they were caught by the peloton.

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The peloton rolls out of Abbiategrasso

The escape of six riders took a 4 minute lead in the run-up to the Alpe Agogna, the first climb of the day. Christian was first over the top, ahead of Venchiarutti and Pasqualon. Behind, BikeExchange and Deceuninck – Quick-Step, the teams of Simon Yates and João Almeida, kept the race under control. Due to the pace set by Rémi Cavagna, Mikkel Honoré and Iljo Keisse, the gap to the leading group started to decrease and the peloton split on the run-in to the intermediate sprint for the Maglia Ciclamino jersey.

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A fast start to the day

Pasqualon took the intermediate sprint for 12 points and jumped to 6th place in the points classification. Daniel Martínez, 7th overall, had some problem. Egan Bernal’s right-hand man was in trouble for a while, but with the help of Filippo Ganna, the Colombian climber was again able to take his place in the peloton. The peloton rode steadily in the run-up to the Passo della Colma.

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BikeExchange had plans

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The break of the day: Mark Christian (eolo-Kometa), Lawrence Warbasse (AG2R Citroën) and Nicola Venchiarutti (Androni Giocattoli-Sidermec)

Venchiarutti was dropped from the leading group on the Passo della Colma. At the top, 38 kilometres from the finish, Warbasse was first ahead of Hermans. The lead of the remaining five attackers was only 1:20. In the peloton INEOS Grenadiers took control. The British team, together with Deceuninck – Quick-Step, led the thinned out chase group onto the descent.

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The peloton was not hanging about

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Bernal has to watch Caruso and Yates

The leaders had 17 seconds when they started the climb to Alpe di Mera with 9.7 kilometres to go. Christian didn’t want to give up and rode away from his fellow escapees after the first kilometre of climbing. The eolo-Kometa rider form the Isle of Man wasn’t ahead of the peloton for much longer and the race was all together for the final climb. João Almeida opened the action with 6.8 kilometres to go, after which Yates counter-attacked together with George Bennett, Aleksandr Vlasov and Damiano Caruso.

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Almeida was the first to make a move

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Yates went solo

Bernal chose his own pace and sat on the wheels of his two teammates; Jonathan Castroviejo and Daniel Martínez. Yates then rode away the other off his wheel and continued solo. Yates quickly took a nice gap. Carthy made the jump to Almeida, Vlasov and Caruso, but Martínez managed to pull the four in again. Yates was still pushing on solo. With 2.5 kilometres to go, Bernal was on his own. The Colombian only had Almeida on his wheel, it was too much for the others.

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Bernal fought well, gained time on Caruso and didn’t loose much to Yates

Yates had a nice lead and, despite a late counterattack from Almeida, he won the stage. In the general classification Yates is now at 2:49 to Bernal, and the difference to second placed Caruso, who finished fourth, is only 20 seconds.

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The stage win for Yates

Stage winner, Simon Yates (BikeExchange): “I’m really happy! The team did a great job right from the start of the stage, a fantastic team effort and I’m happy to have finished it off. I really wanted to win a stage in this Giro, I’m not sure where I am now in the general classification but I’m really happy about this win.”

Giro d’Italia Stage 19 Result:
1. Simon Yates (GB) BikeExchange in 4:02:55
2. João Almeida (Por) Deceuninck – Quick-Step at 0:11
3. Egan Bernal Gomez (Col) INEOS Grenadiers at 0:28
4. Damiano Caruso (Ita) Bahrain Victorious at 0:32
5. Aleksandr Vlasov (Rus) Astana-Premier Tech
6. Daniel Martin (Irl) Israel Start-up Nation at 0:42
7. Daniel Martinez Poveda (Col) INEOS Grenadiers at 0:49
8. Koen Bouwman (Ned) Jumbo-Visma at 1:25
9. Tobias Foss (Nor) Jumbo-Visma
10. Romain Bardet (Fra) DSM
11. Hugh Carthy (GB) EF Education-Nippo
12. George Bennett (NZ) Jumbo-Visma at 2:46
13. Alessandro Covi (Ita) UAE Team Emirates at 3:20
14. Jan Hirt (Cze) Intermarché-Wanty-Gobert Matériaux at 3:23
15. Eduardo Sepulveda (Arg) Androni Giocattoli-Sidermec
16. Attila Valter (Hun) Groupama-FDJ at 3:30
17. Matteo Badilatti (Swi) Groupama-FDJ at 3:34
18. Felix Grossschartner (Aut) Bora-Hansgrohe at 4:01
19. Lorenzo Fortunato (Ita) eolo-Kometa at 4:12
20. Jonathan Castroviejo Nicolas (Spa) INEOS Grenadiers at 4:37
21. Stefano Oldani (Ita) Lotto Soudal at 4:48
22. Michael Storer (Aus) DSM at 4:56
23. Vincenzo Nibali (Ita) Trek-Segafredo at 5:14
24. Diego Ulissi (Ita) UAE Team Emirates
25. Luis Leon Sanchez (Spa) Astana-Premier Tech.

Giro d’Italia Overall After Stage 19:
1. Egan Bernal Gomez (Col) INEOS Grenadiers in 81:13:37
2. Damiano Caruso (Ita) Bahrain Victorious at 2:29
3. Simon Yates (GB) BikeExchange at 2:49
4. Aleksandr Vlasov (Rus) Astana-Premier Tech at 6:11
5. Hugh Carthy (GB) EF Education-Nippo at 7:10
6. Romain Bardet (Fra) DSM at 7:32
7. Daniel Martinez Poveda (Col) INEOS Grenadiers at 7:42
8. João Almeida (Por) Deceuninck – Quick-Step at 8:26
9. Tobias Foss (Nor) Jumbo-Visma at 10:19
10. Daniel Martin (Irl) Israel Start-up Nation at 13:55
11. George Bennett (NZ) Jumbo-Visma at 21:30
12. Koen Bouwman (Ned) Jumbo-Visma at 28:44
13. Pello Bilbao Lopez De Armentia (Spa) Bahrain Victorious at 32:20
14. Attila Valter (Hun) Groupama-FDJ at 38:18
15. Davide Formolo (Ita) UAE Team Emirates at 41:16
16. Lorenzo Fortunato (Ita) eolo-Kometa at 42:19
17. Diego Ulissi (Ita) UAE Team Emirates at 49:17
18. Vincenzo Nibali (Ita) Trek-Segafredo at 50:02
19. Gorka Izagirre Insausti (Spa) Astana-Premier Tech at 50:29
20. Tanel Kangert (Est) BikeExchange at 52:32
21. Louis Vervaeke (Bel) Alpecin-Fenix at 55:31
22. Gianni Moscon (Ita) INEOS Grenadiers at 1:01:42
23. Antonio Pedrero (Spa) Movistar at 1:03:19
24. Jonathan Castroviejo Nicolas (Spa) INEOS Grenadiers at 1:10:11
25. Mikel Nieve Iturralde (Spa) BikeExchange at 1:12:36.

The post GIRO’21 Stage 19: Yates Claws Time On Climb To Alpe di Mera, But Is it Enough? appeared first on PezCycling News.


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