Dusty Bin
Guest
Why do you keep deleting my reply? I haven't called anyone names on here. The only abuse has been from the other guy.
How much faster would "x" make me?
- Thread starter Machin
- Start date
Page may contain affiliate links. Please see terms for details.
Why do you keep deleting my reply? I haven't called anyone names on here. The only abuse has been from the other guy.
Dusty Bin
Guest
Agree completely.
If you or anyone else is able to give the OP a method of calculating "the impact of clean/turbulent air on the performance of deep section wheels in a group riding scenario [which is] ... precisely the kind of issue that such a calculator would have to take into account", rather than just arguing about it, please do - as I am sure he would be very interested and would like to add it to his Calculator.
If you wish to discuss that matter in a manner that would be beneficial to the OP, please start another thread and so do.
If you wish to discuss that matter in a manner that would be beneficial to the OP, please start another thread and so do.
Dusty Bin
Guest
How do you suggest we arrive at a viable conclusion without first discussing the issue?
Dusty Bin
Guest
So, just to be clear - you want us to continue with an entirely relevant and pertinent discussion which is pursuant to the thread title - but in a different thread??
But, presumably, once we have worked it out, we could come back here and tell the OP the good news?
ColinJ
Puzzle game procrastinator!
- Location
- Todmorden - Yorks/Lancs border
I think it is a mistake using height and weight ranges since they will give approximate answers - for example, the difference between 120 kg and 140 kg is massive. You must be taking a figure representing the range - e.g. 130 kg and using that in a calculation, so why not just let people enter exact weight and height data and use that?
Similarly, I'd like to be able to enter the total weight of the bike, and any clothing, tools, spares, food and drink.
Even though I always wear a helmet, lots of people don't so at least include an option for that, and maybe the 2 cap options. (And bald/shaved head?)
It would be nice to be able to enter data for wind speed and direction too.
Similarly, I'd like to be able to enter the total weight of the bike, and any clothing, tools, spares, food and drink.
Even though I always wear a helmet, lots of people don't so at least include an option for that, and maybe the 2 cap options. (And bald/shaved head?)
It would be nice to be able to enter data for wind speed and direction too.
Dusty Bin
Guest
Don't forget - this whole debate is an exercise in approximation - it almost certainly does not stand up to any form of scientific or technical scrutiny, as we discovered with gds58 last night. In that sense, I can't see that absolute precision on anything is required here.
Last edited:
OP
OP
Machin
Regular
Thanks very much for your inputs. I went with the selected ranges because it actually doesn't make that much difference to the final result (within reason) because the calculator calculates the improvements relative to your actual ride, therefore the effect of the starting weight/height is a lot smaller than you might think. Take as an example, we have two people, Rider 1 who is 5ft 11" and 77kg, and Rider 2 who is 6ft 4" and 85kg (i.e. one range higher in each aspect than the previous rider), the effect on some of the different scenarios (all other inputs left as default) as calculated by the program is shown below:-
Test______________________Rider 1_______ Rider 2
5% decrease in rider weight:__-27.1secs _____-26.8secs
Riding on the drops:_________-1min57.5______-1min57.7
200g Lighter seatpost:_______-1.3secs_______ -1.2secs
Aero helmet_______________-33.8secs_______-31.7secs
You can see that the calculated difference between these two people in those scenarios is very small; indicating that the chosen ranges are close enough to avoid big jumps in performance gains.
Remember that whilst the program says that rider 1 will improve their time by 1min57secs by riding in the drops rather than on the hoods, in reality one person meeting the criteria of "Rider 1" will most likely have a much better "in the drops" position than another person also meeting the criteria of "Rider 1"... e.g. depending on how high their handle bars are set to begin with, whether they ride with straight arms or bent arms, etc, "Rider1a" might improve by 2mins10secs, whilst "Rider1b" might improve by "only" 1min:45secs; much more variation than the effect of different starting height and weight of the riders.
Likewise with something like aero wheels; the program says aero wheels will improve a rider's time by (for example) 34.7 seconds over 18 miles, in reality one set of aero wheels might improve the time by 40 seconds, and another might improve the time by 30 seconds... depending on the shape of the rim, shape of the spokes, the tyre:rim interaction, etc. Again; variation in individuals and kit is bigger than the effect of making the height/weight ranges smaller.
In a way this is very similar to the height/weight example's above, bearing in mind that the idea of the calculator is to take one of your existing rides and then advise approximately how much quicker/slower each of the scenarios would make you, if you were to do the exact same ride again (e.g. the exact same wind, your power output, whether you waved to your next-door neighbour, etc etc). The program works by initially estimating your power output over your ride based on the options you provide. The calculated power isn't divulged because it doesn't actually matter to the accuracy of the performance improvements; what does matter is that the calculator uses the same estimated power as the basis of all the performance improvement calculations.
E.g. If you did a ride of 17.5 miles in an hour the program might estimate your average power to be 170 watts (number plucked out of mid air!). If you were actually riding with a tail wind your actual power might've been only 145 watts, whereas if you'd had a head wind your power might've been 200 watts, but it doesn't have a big effect on the results because all the improvements are relative to the estimated power value. e.g. a 5% power improvement is a 5% improvement regardless of the starting value. Similarly if your drag reduces by 50% the power to drag ratio (which is the main factor determining bicycle speed on the flat) will double whether the starting power was 145 watts (tail wind scenario) or 200 watts (head wing scenario).
I hope that helps to explain why I've done what I've done; I could add those features, but they would make less difference than the variation you should expect from differences in the actual kit, riding position, training regime , etc that you are actually using.
Last edited:
ColinJ
Puzzle game procrastinator!
- Location
- Todmorden - Yorks/Lancs border
Yes, I was thinking more in absolute terms, than relative terms.
Tin Pot
Guru
Hi, thanks for posting an interesting subject. I'm scientifically minded, but without the cycling-specific knowledge I'll set that aside and assume the maths & science behind your site is correct.
So my feedback as an enthusiastic novice;
Just what I've been looking for! Quantative analysis beats the crap out of qualative.
Expect to be confronted. I am bringing Quantative analysis to a completely different field, where at times it seems people will say anything to avoid the facts of the matter.
I'm surprised that the gains are so significant for a cyclist of my poor calibre, an aero bar/TT bike saving me half an hour over 82miles starts to justify the cost...great news for vendors of TT bikes, but will vendors of aero wheels/helmets/overshoes/BB be as happy?
Apart from the estimated nature of the savings, are there any other caviats that should be displayed prominently?
Well, a TT bike is fairly specialist piece of kit, and the return on your investment in terms of speed will not be linear. The main issue is that the position is different to a road bike, and as such your power delivery is compromised. The extent to which that is the case varies from individual to individual, and depends on a number of factors, such as time spent in new position, suitability of position to athlete, aero gains vs. power loss trade off etc.
But in even in a best case scenario hoping for 30 minutes over 82 miles is over-optimistic.
But in even in a best case scenario hoping for 30 minutes over 82 miles is over-optimistic.
Rob3rt
Man or Moose!
- Location
- Manchester
