Zwift Chat

[Breedon]

Hmm that's quite a drive, but the offer is still there mate.

 

[CXRAndy]

Zwift drafting is for me different to Bkool. In Bkool you could physically feel an easing in resistance on the trainer. With Zwift it's much less so noticeable, like Dean described, you can ever so slightly ease off, but it's the speed which is very apparent. Once off the pack 2-3mph drop in speed is seen. Get back on and speed rises.

 

[CXRAndy]

Hmm that's quite a drive, but the offer is still there mate.

Or if he's passing Lincolnshire he can try a Kickr

 

[LBHIFI]

Paul I read somewhere that you need like 25% more power to increase 10% in speed.
https://www.gribble.org/cycling/power_v_speed.html

That may be true only for a specific speed gain.
Air resistance increases exponentially with speed, so that extra km/h becomes harder and harder to achieve.

 

[bobinski]

Come on now boys, Someone must have a Neo or a kickr close enough for Carl to try

 

[CXRAndy]

I agree Lars, as speed increases, lots more power is required just to overcome air resistance. Zwift and a like will have this calc built into their simulation I bet

165lb rider would need

200W=20.72mph
220W=21.49mph
240W=22.21mph
260W=22.89mph
280W=23.53mph
300W=24.14mph

Greater and greater effort in power for ever reducing gains in speed

 

[bridgy]

Paul I read somewhere that you need like 25% more power to increase 10% in speed.

Here is a website which has a calc power v Speed
https://www.gribble.org/cycling/power_v_speed.html

Thanks Andy - that's interesting. Are you suggesting that the higher power reported on the Bkool accurately reflects the higher speed too? So if I was able to do 4.01 w/kg on the Neo I would only go 54 seconds quicker (roughly speaking, allowing for differences in drafting etc)?

 

[CXRAndy]

I think there is an error in Bkool Pro which over calculates the power and speed. Or is speed which is slightly wrong and power is calculated from that- I think its the latter. I really don't know, just that everyone who moved away from the Bkool Pro and has used either a calibrated trainer with a built in PM or a separate PM has come down to earth with a bump, so to speak

Aside, I did a little number crunch with that calculator for hills. A 75kg rider needs to 240W to climb a 6% hill where I need 95Kg, 300W to climb at the same speed.

 

[berty bassett]

if whorty don't mind slumming it - next time hes going st neots he can pop into mine if he wants
i am about 15 mile away straight down kimbolton rd

 

[berty bassett]

Aside, I did a little number crunch with that calculator for hills. A 75kg rider needs to 240W to climb a 6% hill where I need 95Kg, 300W to climb at the same speed.

ah yes but thats potentially 20kg more muscle

 

[bobinski]

I think there is an error in Bkool Pro which over calculates the power and speed. Or is speed which is slightly wrong and power is calculated from that- I think its the latter. I really don't know, just that everyone who moved away from the Bkool Pro and has used either a calibrated trainer with a built in PM or a separate PM has come down to earth with a bump, so to speak

Aside, I did a little number crunch with that calculator for hills. A 75kg rider needs to 240W to climb a 6% hill where I need 95Kg, 300W to climb at the same speed.

Another aside- it seems in Zwift a heavier rider is only penalised at gradients over 3%. Some gnashing of teeth over whether accurate or not and tests being undertaken and presumably Zwift contacted.You can often see bots riding at constant watts and different weights testing all this out. I cannot claim to understand it but there is some emerging evidence that IRL aero and so drafting is more important up to and including gradients of 3 possibly 4% and then after that gravity is the increasingly greater factor on speed relative to weight and power needed.

 

[bobinski]

I reckon the faster you can spin on a pro the greater the power and speed advantage. There will be unit variance. But if I am right that explains why the advantage drops on gradients and then as they steepen and the turbos even out, the pro having no significant advantage over a Neo etc. Also, anyone who runs at less that 100% realism or whatever will spin more coz there are fewer gears and if they are on a pro the advantage is greater.

Paul, can you show us your cadence data?

 

[CXRAndy]

Paul averaged 85rpm, so nothing silly like 110rpm

 

[CXRAndy]

ah yes but thats potentially 20kg more muscle

I wish, its wrapped in blubber

 

[bobinski]

Paul averaged 85rpm, so nothing silly like 110rpm

On both?

I might have to get premium again