They also have different rules regarding start and finish locations. There are courses that start at the top of a big hill but finish at the bottom in the UK.

Regarding traffic assist, I was in the UK in the early 90’s and driving up the A1 early one morning and drove past a TT being held on the A1! That would be like holding a TT on a USXX highway, like US 40 or US 50.

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Kevin

http://kevinmetcalfe.dreamhosters.com
My Strava

After deaths this year, the chatter on the UK TT forums is that is changing and they will no longer be permitting (as in allow or giving permits) to events on certain motorway types.

In the US it does bug me to no end that folks putting on TT's often "don't have a clue" about standardized distances. Seriously? The layouts are such you could super easy have moved the start/finish setup. Our regional "40k" is short of 40k by like 300 yards. WTF!!! There's a u-turn on the route they could move back the 150 yards no problem. Sweet baby mountain dew drinking Jesus, ugh.

Then everyone does 40k! Why not 25mi? Another oddity.

The UK TT forums defines the standard distances in a FAQ section IIRC.

I recall comments last year on that UK based time trial forum about how shocked many of them were that the UK riders didn’t dominate the Masters Worlds. Finally a voice of reason reminded them of these same points raised here.

It’s an apples and oranges thing when comparing UK TT speeds to other countries

Most of the time an RD has a *reason* why an course is short or long and it’s not that they don’t have a clue or are being lazy.

Why is IM Chatt 118 mile bike. Because to make it 112 would be too many logistical issues.

Now for official *records* of course it’s gotta be what it is measured too. But most times races have oddities due to limitations the RD is confined too.

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Brooks Doughtie, M.S.
Exercise Physiology
-USAT Level II

I believe that is a Flo disc. I would like to know his tire width and PSI.

I was asked this a long time ago from a world tour guy who saw other teams doing this...at the time I used scale model car wind tunnel data to ballpark this (think this plot is from Katz):

https://drive.google.com/file/d/12gejyMlDfGZyLOF-b6mnbsXZAJK6KZX_/view?usp=sharing

more recent car based CFD work seems consistent with old scale model car tunnel work:

https://www.researchgate.net/...5b729fe4572/download


even better are these bike specific articles:

https://www.sciencedirect.com/...ii/S0167610515001531

https://www.researchgate.net/...e6f1846a438/download

...probably need to be within 2 car lengths and not side-drafting like in the pic to be of some benefit to the rider?


-k

Looking at the results at UCI Gran fondo tt worlds today, I think it’s fair to say us brits aren’t too bad at the tt game. Bear in mind that it’s not just the conditions that we have, it’s a well defined and popular sport over here with dozens of races every week.

From a previous moto-doping thread (in the summer) on here (but covers following cars too).
. . . . great graphic in tweet (drawn from Blocken's work at Eindhoven):
https://twitter.com/...860543340544/photo/1
Car 2m behind gets you a 7% power saving (@?50kph) and 3.7% at 3m.
https://link.springer.com/...7/s12283-020-00332-z

Based on the photos we have it's more like 10m and not directly behind. So maybe 0.1-.2%.

Beautiful answer.

What are the UCI rules? I'm curious. I sometimes follow my wife in a UCI TT. ;)

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Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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No one is saying that the Brits are bad. The point is that it's an unfair comparison if you're only considering speeds. It's worth noting that while the placings of the top Brit masters racers at Worlds are well represented, the average speeds they're doing are more in line with what the rest of the world typically does and not what they themselves typically do when racing at home on DCs with gift hills.

Heavy traffic also brings heavy traffic on the turns. Whilst the turns are generally quicker than going round a cone, time it badly and they can be a nightmare, I have had to come to a dead stop and wait before now.

The course Marcin did the 42:XX on has - I believe - 6 roundabouts to either cross or turn at - I am assuming he didn't have to slowdown much though. It does of course also have a bloody great hill you go down but don't come back up. The other two UK courses riders have gone under 45 minutes on don't have gift hills but do have lots of traffic.

In the UK we also have straight out records - so 25, 50, 100 & 1000 miles etc in one direction with no need to retrace. Those records are much faster obviously.

Sub 45 for a 40km/25 mile out and back with minimal traffic is seriously impressive.

There's a course in southern AZ that's 11.7 miles point-to-point, no turns, gentle curves, etc... with about a -2% average gradient the entire way. Way back before aero optimization became a thing, a local ex-pro in his mid-40s averaged speeds on par with Evenopoel's recent La Vuelta TT speed. It's quite common for fairly mid-pack amateurs in the lower categories as well as masters into their 60s to average well over 30 mph for the course.

2.4.023 The following vehicle shall follow at least 10 metres behind the rider, shall never overtake him nor draw up level with him. In the case of a breakdown, technical support may be rendered only with the rider and vehicle stationary and the following vehicle shall not hinder anyone else.


...what's the stopping distance of a car on dry pavement at 50kph?

-k

Thank you for doing the leg work finding that!

Stopping distance:
TLDR: I remember death gripping my brake levers when I saw the brake lights, and as the rear bumper approached my white knuckles, I remember thinking "damn... I didn't realize cars could stop that much faster than bikes."

Full story: I was once young and dumb (I like to pretend that I'm old and wiser now. Humor me.) and I chased an old beater car and driver who took an aggressive swipe at my wife after she had crashed in the middle of the road and was slowly/gingerly pulling herself from the road. Chased for half a mile downhill and caught him as we hit a flat straight section. He slammed on the brakes. I might have scrubbed about 1/4 of my speed by the time his vehicle had come to a full stop. I jumped. The rear of the car ripped the bike out from under me, meanwhile I flew over the trunk onto the roof, sliding onto the hood and off the front of the car. I distinctly remember my awe at the physics of car tires and pavement and some expletives expressed in my brain towards the driver for using them against me. Amazing how fast thoughts can fly through ones brain in a single second!

Conclusion: I'm pretty sure that car stopping distance is shorter than cyclist stopping distance in virtually all cases. Only exception I can think of is if the cyclist hits a fixed object that fully stops their body-bike-system momentum. I don't think a crash with no fixed object would be problematic. Human bodies treat pavement like a slip'n'slide at 50kph.

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Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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📱 Check out our app → Saturday: Pro Fuel & Hydration, a performance nutrition coach in your pocket.
Join us on YouTube → Saturday Morning | Ride & Run Faster and our growing Saturday User Hub

That was the first LP I bought!

Here's some proposed figures reported with what our best riders are like: https://cyclingtips.com/...C8EHE5Ur6CLilJJiiOi0

Well your best amateurs, on the recreational TT circuit. Of those I think only John Archibald approaches "your best."

Off the top of my head, Thomas, Wright, Bigham, Hayter, Dowsett would be amongst "the best."

Granted, the amateur/recreational comparison is fair for Lockwood in NM.

No need to be pedantic. This is from our national 10 mile championships and I think any very good amateur numbers are more valuable to people in this thread than seeing what a world tour pro can do with abilities or resources likely beyond them.

(Note: Archibald has world class results in both TT and track pursuit).

Sorry, maybe it was clear we were talking about amateur TT.

Seeing the effect of boutique amateur courses is pretty apparent though when the best amateurs cross over into sanctioned courses at national championships, etc.

I’d argue with that first that it’s important to note that a lot of the British scene revolves around power/CdA style courses whereas the sanctioned courses or continental tt’s involve a lot more of a bike handling or power to weight aspects. It’s a completely different style of racing that really becomes apparent when you speak to world tour pros about it.

That said, that article indicated that our best amateurs are circa 400w for 16km which is still impressive - especially when I know many of them have a CdA pushing 0.17.

Very impressive. That's roughly conti-pro power. And despite your claim about resources, I'd argue that some of these amateurs put *more* resources and a lot more time into TT than all but the very best pros. I mean that as a compliment - I admire the taking a craft to the limit. Also the UK amateur scene is certainly deeper than the U.S. amateur scene.

Apples to oranges here. But I can and have beat Simpson in TT’s. I have yet to beat Lockwood. 😬

Few of my quick observations. 1.) that chainring is massive! But if he went even bigger could it keep the chain a bit more straight and reduce friction even more?(maybe the picture is on a downhill and he’s having to spin out) 2.) SLF aero system on the RD,I would be curious to know if he has a SLF bottom bracket as well. The chain doesn’t look like it’s covered in powdered sugar, what kind of coating do you think he has? 3.) traditional skewers, if he got something like the TriRig version that in theory would save a watt or two. 4.) those Aerocoach bars are becoming more and more popular

I agree on resources - I’m heavily involved in that myself and I know lots of others who have poured more into it that I have. I’ve also worked with two national teams now and they knew a lot less than many of those I respect in the sport domestically. My point was in relation to some of the top world tour teams that have slowly but surely invested properly. Mind you, some of the other teams - notably those from traditional European nations - are still a long way behind the curve.

It’s actually power comparable to the likes of some non tt-specialist Pro’s. Bigham has made our GB team more than once and prior to this year was putting out a comparable power output (if not less - but obviously with superb CdA) to those in that article.