what actually is FRIC, help with profile please

[geoffsuperturbo]

just checked the tilt plot, there is massive vibration as far as i can see and i do not understand how it can happen when all tubing is rock solid and clamped to the stem. is this a GEN 1 issue? i dont see how the unit could be more firmly in place

[whynotride]

First off, don't give up. Fernando was a HUGE help to me in understanding and dialing in the unit.
Second, the mount that he showed pictures of is mine. I will tell you that regardless of how stiff/tight.whatever the extension seems to be, it probably isn't.
The mount I made was using .075 stainless and is about 2" long and there is still some flex. Not bad but it can move. From what I can see, the movement in yous is just in a different plane.
Last, you are shooting yourself in the foot trying to get a good cal with a G1 mounted like that. The G1 always had vibration issues and moving it farther from the stem or bars amplifies the problem. While I understand using the G3 for the workouts, why not use it for both bikes? It holds two profiles and the G3 is clearly superior for vibration. Besides, you can do at least one interval workout without the unit to get good numbers. People did intervals for years without anything as sophisticated as the iBike.

[racerfern]

just checked the tilt plot, there is massive vibration as far as i can see and i do not understand how it can happen when all tubing is rock solid and clamped to the stem. is this a GEN 1 issue? i dont see how the unit could be more firmly in place

This is probably a Gen 1 issue which is probably magnified by the mount. Try the same calride, coastdowns, etc with a Gen 3 and you'll see the difference.

[geoffsuperturbo]

First off, don't give up. Fernando was a HUGE help to me in understanding and dialing in the unit.
Second, the mount that he showed pictures of is mine. I will tell you that regardless of how stiff/tight.whatever the extension seems to be, it probably isn't.
The mount I made was using .075 stainless and is about 2" long and there is still some flex. Not bad but it can move. From what I can see, the movement in yous is just in a different plane.
Last, you are shooting yourself in the foot trying to get a good cal with a G1 mounted like that. The G1 always had vibration issues and moving it farther from the stem or bars amplifies the problem. While I understand using the G3 for the workouts, why not use it for both bikes? It holds two profiles and the G3 is clearly superior for vibration. Besides, you can do at least one interval workout without the unit to get good numbers. People did intervals for years without anything as sophisticated as the iBike.

yes i suppose i could try using the GEN 3 for both bikes, i was put off trying as i have been having pairing issues with both units. today i began the TT bike ride with the GEN1 and got pulse but no speed. took a while to get it going, had to do the pairing process several times and wasted a lot of time, then after that my ride i came home to ride the training bike and found i had speed but no pulse in the GEN3 for the whole ride. very annoying having to fiddle around everytime i want to ride. cadence still hasnt come to life either, cannot get it to pair up.
hence i was trying to stop switching units from bike to bike in case it messed up the pairing process and i got this problem everytime i ride, if i had a hammer at hand at the time i would have at least 1 less ibike by now.

[geoffsuperturbo]

will try to repeat a cal ride and coast downs with the GEN3 and see what i get. looks like i'll just have to use the gen1 on my road bike so i can mount it on the stem.
thanks for the help guys
when i begin again with cal ride should i go back to the beginning with a fast start, then cal ride and CD's? that will start with a clean slate i suppose.

[racerfern]

will try to repeat a cal ride and coast downs with the GEN3 and see what i get. looks like i'll just have to use the gen1 on my road bike so i can mount it on the stem.
thanks for the help guys
when i begin again with cal ride should i go back to the beginning with a fast start, then cal ride and CD's? that will start with a clean slate i suppose.

OK, with a Gen3 do a tilt calibration, wind offset, then do a calride. IIWY I would skip the coastdowns. Then do the FAST START entering all your particulars. Finally, connect your iBike to the computer and download the calride data AND download the profile the Gen 3 created. Post it up and lets have a look.

[geoffsuperturbo]

ok great, i'll try that. i actually did a fast start last night while sitting at my PC, but i suppose if i do set up again and select fast start no before my ride, the details will be ignored? i have also changed to profile 2 now, i will use that for TT bike and prof 1 for training

[geoffsuperturbo]

ok here is what i got. my settings are to auto analyze so you might want to revert to original at some point. Crr will need to be lowered closer to .0033 to be accurate for my tyres. hope i got the right files that you wanted, cheers

[racerfern]

Good job! I made the Crr change to the profile and also raised your wind slightly. Load this up and see how it works. Then if you want we can work on the pairing issues you have.

[Todj]

The only comment I'd make on the profile (hopefully helpful) is that a Crr of 0.0033 seems awfully low to me. You probably have much better road surfaces than we have in the UK, but even on my own TT bike which has Vittoria CX tubulars at 120psi I've struggled to get below 0.0055.

With regards to the pairing issues when swopping the iBike between machines, I have the same problem sometimes as well. If one set of sensors are 'awake' then, after changing to the other profile, I sometimes have to take the iBike right out of the garage until it gives 'WLS Fail', at which point it will then re-pair with the correct sensors.

Just my $0.02. Hope that helps.

[geoffsuperturbo]

The only comment I'd make on the profile (hopefully helpful) is that a Crr of 0.0033 seems awfully low to me. You probably have much better road surfaces than we have in the UK, but even on my own TT bike which has Vittoria CX tubulars at 120psi I've struggled to get below 0.0055.

With regards to the pairing issues when swopping the iBike between machines, I have the same problem sometimes as well. If one set of sensors are 'awake' then, after changing to the other profile, I sometimes have to take the iBike right out of the garage until it gives 'WLS Fail', at which point it will then re-pair with the correct sensors.

Just my $0.02. Hope that helps.

there have been a lot of testing on rolling resistance on the internet, some guys have been doing rigorous testing and posting the results (sorry cant remember the site but i'm sure it will appear in a google of rolling tyres) they say the tyres i use are .0026 approx, when tested on the usual rollers and according to them for smooth roads multiply by 1.1 or for rougher road 1.3. which comes out around .033, thats the reason i use the number, it's nothing i came up with.
i have the .0055 ibike setting for my training bike, my TT bike obviously rolls a lot better, i dont need testing to see the difference of how much quicker i roll on good tyres, so if i made my TT .0055 then i'd have to raise the training bike a lot and it would have a Crr of riding on cobbles i expect. fortunately a lot of the A road i race on has been resurfaced with smooth asphalt or well bedded down by heavy traffic so is quite smooth. i agree though, some other roads can be quite rough and a short section of my cal ride had 200 metres of holes and bumps, i'm amazed no vibration showed up in the data. thanks for the pairing advice, i had more problems today, set off for the cal ride and found i had no speed, hopefully things will settle down, i hear the "click" of the cadence sensor when the magnet passes by, but on my last try the ibike still wouldnt pair. that was on the GEN1, i may have more luck on the GEN3.

[geoffsuperturbo]

great thanks a lot, i will load that up. i felt the watts seemed a bit high on the display after the cal ride, not by a huge amount though. a lower Crr may drop the watts i expect, i suppose a fitness test is the real gauge of how good the profile is. if i dont race on sunday i'll try to do a fit test as soon as possible to see what numbers i get.

ok i loaded the profile, just happened to notice the aero and CdA are identical to a previous profile i made, only difference is the fric is 7. something instead of 14.
i also noticed the cal weight in the profile that you sent me is only 170lbs, i'm pretty sure it was 183 when i sent the profile to you. as 183 is the correct total weight can i go ahead and edit that number?
also couldnt help noticing in the cal ride slope ranges from -8 to +10, surely out and back will have the same road and same slope so how can there be a 2% difference?

[Todj]

Hi Geoff,

You might find the link to this spreadsheet useful. Just put in your Cda,Crr and weight (note: in kgs) and the formulae will give you the theoretical watts:-

http://www.demon-cycles.co.uk/files/cda_crr%20v0.01.xls

The bottom of the page shows the assumptions used and the credits for where I lifted the algorithms from.

I created this spreadsheet as a sense check on the figures that the iBike is giving me and the alignment has been pretty much spot on. Due to a disability I can't get as low as yourself so my Cda runs 0.270 and, as mentioned above, lots of grit surfaces in the UK (US speak = chipseal??) give a Crr of 0.0055.

On my TT bike the iBike is stem mounted and I have run the remote wind sensor to just in front of the right hand brake lever.

p.s. Good to hear that somewere on this planet has decent roads surfaces. Two bad winters here in the UK and you wouldn't believe how poor our tarmac has gotten.

[geoffsuperturbo]

thanks for trying todj, but i put in my details and the watts seem a lot lower than i see in the ibike, that is using .0055 and .0033 in your chart. it gave 260 watts for riding at 30mph .0055, seems kind of low to me for such a high speed average but may be possible i suppose, but how fast would wiggins be going if he's 200 watts higher than me at 30mph? i'd be doing a 25 in 50 minutes and he'd be? 37 or something? over 40mph average not likely. he may beat me between 10 or 11 minutes but no more, and 4 and a half in a 10, if anyone knows how to work out the difference in wattage between wiggins pace and mine, feel free to jump in. i'm 71.3 kg but no doubt Brads bike is a lot lighter than mine is at 9.7kg

back on topic, i'm regularly higher than 260 on the ibike (and not going 30mph) and if i used .0055 on my race tyres i'd be easily above it without trying, so would need to lower the aero a lot or something else to compensate. if any of the time triallists in britain are posting their power tap outputs, i may be able to work out what mine should be, but i havent seen anyone doing it so far. so i just have to wait and see what the ibike tells me in my fit tests. i'll do a fit test on both bikes and see the difference and maybe fernando will be able to look at both files and tell me which one is closer to being right and tell me how to adjust the other to get similar results.

[Todj]

Geoff, what numbers did you pump into the spreadsheet?

I think I picked up from elsewhere that your Cda is 0.230, and putting in your Crr of 0.0035 and your all-up weight of 82kgs, it calculates 30mph as 376 watts.

[geoffsuperturbo]

i am going to try a new set up on the TT bike, i'm going to try a RWS type set up and see how i get on. i have moved the mount onto the stem, changed the stem to lower angle. the unit is very solid which is good as i'm having another try with the GEN 1 ibike for reasons which will become clear later.