ibike Power meter

BILLYHOLMES said:

[font=Times New Roman]Has anyone got any user data on the ibike power meter, accuracy, repeatability and general day-to-day usage?[/font]
[font=Times New Roman]Bill.[/font]

I'm not sure if this qualifies as "data" but here is my assessment having used the iBike for the past 7 months. If you have questions about it that aren't answered here you can PM me or just reply to this post.

Pros
*easy install + set-up
*works every day
*use the wheels you want to use
*weight penalty is minimal
*amazingly responsive support from the iBike team
*"wicked" inexpensive as they say in chowdah town
*works with CyclingPeaks

Cons
* looks like an iPod on steroids
* wattage and time aren't on the same screen (needed when doing short intervals
* doesn't have "live" TSS like the Ergomo
* no heartrate
* some have issues with data spikes and drops on descents and rough roads

gene r

Cons:
- Provides less than usable data for portions of rides while drafting, making all numbers from a given ride while with a group essentially useless in post ride analysis. (that is, normalized power, average power will both be off which means TSS will be off which means.. well.. the whole PMC will be poorly reflected). If you never ride with a group or use groups to train with or race in, this might not affect you.

- Cannot change positions without changing effective frontal drag, thus changing calculated power output. If you ride on the hoods 99.9% of the time, this won't affect you. If you like to change positions during a ride, this will effect you.

NomadVW said:

Cons:
- Provides less than usable data for portions of rides while drafting, making all numbers from a given ride while with a group essentially useless in post ride analysis. (that is, normalized power, average power will both be off which means TSS will be off which means.. well.. the whole PMC will be poorly reflected). If you never ride with a group or use groups to train with or race in, this might not affect you.

- Cannot change positions without changing effective frontal drag, thus changing calculated power output. If you ride on the hoods 99.9% of the time, this won't affect you. If you like to change positions during a ride, this will effect you.

*I've heard this criticism ("bad data in a pack"😉 but have not experienced it myself. If its off compared to other PMs its consistently off so I have a baseline that is consistent.

*The issue around changing positions is definitely a shortcoming. I ride the hoods 99% of the time. If I were changing positions frequently I'd look at other PMs.

gene r

LT Intolerant said:

*I've heard this criticism ("bad data in a pack"😉 but have not experienced it myself. If its off compared to other PMs its consistently off so I have a baseline that is consistent.

gene r

You would be the exception then. I've seen it reported by others. I think you (Gene) are the guy that didn't like my poo-pooing the iBike on the NEBC list a few weeks ago. I haven't gotten around to getting back to you but I will.

another con: can't be used on a trainer or rollers because there is no "air intake" happening during this activity.

Any time you estimate something rather than directly measure it, you are introducing another set of variables that can produce even more error. People with Power Taps and SRMs have enough issues as it is, why make things more difficult on yourself? And don't try to tell me that you are measuring torque with an iBike because you are not.

Can the power data be downloaded into Cycling Peaks? [Edit] Yes-it is sorry!!

Is data like grade, etc downloadable into any gps type software to analyze or make maps/graphs later?

The most tempting thing for me is the weight savings over my PT set-up and the ability to swap from bike to bike much easier.

I agree-this unit has a list of cons a mile long though.....

Steve_B said:

You would be the exception then. I've seen it reported by others. I think you (Gene) are the guy that didn't like my poo-pooing the iBike on the NEBC list a few weeks ago. I haven't gotten around to getting back to you but I will.

another con: can't be used on a trainer or rollers because there is no "air intake" happening during this activity.

Any time you estimate something rather than directly measure it, you are introducing another set of variables that can produce even more error. People with Power Taps and SRMs have enough issues as it is, why make things more difficult on yourself? And don't try to tell me that you are measuring torque with an iBike because you are not.

I'm the exception? Don't know if that insight is defensible. That's not been my experience when conversing with other iBike users. Maybe you're seeing/hearing something different.

All I know is when I've compared data with PT users (and run a side-by-side tests with a PT on my own bike) I've seen similar patterns in the data. So the iBike may be "estimating" versus "directly measuring" power, but it does a damn good job of estimating and giving me the baseline I need to measure/manage my training.

I'm not saying the iBike is perfect, I'm just saying that for MY purposes it works. I can discern my FTP and measure progress against it over time. If I were a more serious (and talented) rider I might demand the precision that a PT or SRM offer, but that's not a requirement for me. For others it might be.

gene r

I just thought of another potential problem. Lets say you train on different bikes that have different drag due ot tire size, subtle fit differnces, like going from my cross bike (for commuting and rainy day training) to my road race bike (with 1.25" longer reach from saddle to bars), then using all this accumulated data I set myself up a target wattage for a 40k time trial in a full aero suit, helmet, wheels, etc.

Have I just set myself up for disaster in the TT by over or under estimating my FTP due to changes in aerodynamic drag? I suspect that I will be a couple of lbs lower in drag when in full kit and bike.

Help because the weight savings and other features are starting to appeal to me. On a personal note it sucks though that I will not be ableto sell my PT equipment because I will need it for all the time I spend on the trainer at home (6 to 13 hours a week this winter).

Ray

rayhuang said:

I just thought of another potential problem. Lets say you train on different bikes that have different drag due ot tire size, subtle fit differnces, like going from my cross bike (for commuting and rainy day training) to my road race bike (with 1.25" longer reach from saddle to bars), then using all this accumulated data I set myself up a target wattage for a 40k time trial in a full aero suit, helmet, wheels, etc.

Have I just set myself up for disaster in the TT by over or under estimating my FTP due to changes in aerodynamic drag? I suspect that I will be a couple of lbs lower in drag when in full kit and bike.
Ray

I have no direct experience with this issue Ray becuase I use the iBike on my road bike exclusively, for now. I just ordered a mount for my TT bike so I'll be toggling between the two bikes once I get it set up.

Others who have used the iBike on their road bike and TT bike store different aero profiles (yes, you can do this), and then switch to the profile that is specific to the bike in use.

If you want input from those that are using the iBike on multiple bikes today you can post your question on the iBike User Community or search the threads as this has been asked by others. Here is the link...

lists.topica.comiBikeProPowerMeterOpen ↗

Good luck.

gene r

Thanks for the link. I called ibike and learned a WHOLE lot today. Given the time it was very interesting to learn about the ability to do Cd and Crr testing (assuming you can find a calm day and have a laptop) via coastdown tests. very interesting to me since I want to get as aero as I can without hurting my ability to breath and pedal.Though it does sound like my best bet is to have both options which is ridiculous from a financial standpoint. PT for group rides, time trials, indoor training and the ibike for solo rides, hilly road races, Cd testing and analyzing routes (hill grades, vertical climbing etc.).

Ray

rayhuang said:

...which is ridiculous from a financial standpoint...

Ray

Like they say Ray, "it's only money". Or as Bob Brinker would say, "your last check should go to the undertaker, and it should bounce."

My favorite bumper sticker besides YOUR PROCTOLOGIST CALLED AND HE FOUND YOUR HEAD, is I'M SPENDING MY KIDS INHERITANCE.

gene r 😄

I've been using the iBike since September and I'll throw in a couple points. Hope these are useful to Ray and Billy:

- regarding the effect of drafting on the unit, I notice little effect in a pack but a definite effect in a small group, like 2-4 people. This is comparing to perceived effort, so take it with a grain of salt of course. My watts numbers seem about 10-20% low in a small group. The theory I've seen floated around is that in a pack, the draft is large and fairly uniform, whereas in a small group, it's small and varied. So the iBike's single pressure reading at the handlebar is more likely to be accurate in a pack. So think about what kind of riding you do before deciding if it's right for you.

- you can use the iBike on a trainer ... sort of. You use it just as a speed recorder and then use your trainer's power/speed curve to convert those speed readings to power readings after your ride. I set up a simple web utility to help with this at:

http://curveship.dyndns.org/trainerpower

Be sure to check the section on that page about accuracy, however.

- It seems that 90% of the people criticizing the iBike on the net have never used one, whereas 90% of the people who have used it like it. It's a good device, and a very good device for the money. But so is a powertap or an SRM, so you need to make your own decision.

Hope that helps. The iBike list glen mentioned is a good resource.

Is the lesser accuracy of iBike use in a bunch such an issue? If you are serious with your training, in terms of power output, why would you want to ride in a bunch and let others set your pace? Isn't a major purpose of PM is to guide you to ride at a particular power level and train accordingly?

Of course, I can understand this particular limitation would restrict its use in a race where you would be in a bunch. I guess the only time to use it would be when you are deep in a bunch or pulling at the front. Ignore data in between.

Does this make sense?

ahaile said:

I've been using the iBike since September and I'll throw in a couple points. Hope these are useful to Ray and Billy:

- regarding the effect of drafting on the unit, I notice little effect in a pack but a definite effect in a small group, like 2-4 people. This is comparing to perceived effort, so take it with a grain of salt of course. My watts numbers seem about 10-20% low in a small group. The theory I've seen floated around is that in a pack, the draft is large and fairly uniform, whereas in a small group, it's small and varied. So the iBike's single pressure reading at the handlebar is more likely to be accurate in a pack. So think about what kind of riding you do before deciding if it's right for you.

- you can use the iBike on a trainer ... sort of. You use it just as a speed recorder and then use your trainer's power/speed curve to convert those speed readings to power readings after your ride. I set up a simple web utility to help with this at:

curveship.dyndns.orgtrainerpowerOpen ↗

Be sure to check the section on that page about accuracy, however.

- It seems that 90% of the people criticizing the iBike on the net have never used one, whereas 90% of the people who have used it like it. It's a good device, and a very good device for the money. But so is a powertap or an SRM, so you need to make your own decision.

Hope that helps. The iBike list glen mentioned is a good resource.

Thanks for all the input guys. I am going to think about it, as you say the data is patchy but there are many who complain about the Power Tap that suffers from this, that and the other.
For the price ($350 on ebay) it's a long way from the cost of a SRM or the PT and for that matter the Polar.
Bill.

Thanks. LIke everyone else-I have certain things that make an ibike very tempting and certan thngs that make it not so appealing and thats for me to decide (with everyone input of course, which I am thankful for btw).

I have enough problems with my PT that I cannot say that its perfect either (HR, Power dropouts and not having a wheel when I have to send it in to be fixed!!).

Seems that both companies ahve great customer support and are very active in improvinig there systems.

Ray

sogood said:

Is the lesser accuracy of iBike use in a bunch such an issue? If you are serious with your training, in terms of power output, why would you want to ride in a bunch and let others set your pace? Isn't a major purpose of PM is to guide you to ride at a particular power level and train accordingly?

Of course, I can understand this particular limitation would restrict its use in a race where you would be in a bunch. I guess the only time to use it would be when you are deep in a bunch or pulling at the front. Ignore data in between.

Does this make sense?

Good points. I never even see my PT when i ride in a fast group ride. I might glance down on occasion to see how many watts up a hill, but I look at wheels, not data!!

I also realized while talking to iBike that I look at Data not as a whole ride (averages), but I always pick and choose what I want to see and like you said-that datas not when I am coasting n the middle of the group. As long as its accurate when I am setting tempo or grinding up a hill or doing sprint work, its good.

Ray

sogood said:

Is the lesser accuracy of iBike use in a bunch such an issue? If you are serious with your training, in terms of power output, why would you want to ride in a bunch and let others set your pace?

Well, the reality is that there are technical benefits to training in a group. Riding a paceline, setting even paces, managing effort while in the draft, and for some - hanging on to the pack.

The majority of my monthly kilometers is solo and maybe 3-4 times out of two months I take part in a local group ride at high tempo to race pace. Our group rides are typically 4+ hours of riding.

One of the uses of the power meter is to gauge your overall effort of any ride. That time you spend in the draft is having an effect on your muscular usage. If you're in a rotating paceline of 5 guys and taking equal percentage of pulls, that means 80 percent of your ride will be underestimated, and the overall average power/normalized power output for the ride will read low. This likewise underestimates the TSS calculated for the ride.

All this completely depends on how anal retentive you are about the data you're getting from the powermeter. For me, every ride counts.

NomadVW said:

Well, the reality is that there are technical benefits to training in a group. Riding a paceline, setting even paces, managing effort while in the draft, and for some - hanging on to the pack.

The majority of my monthly kilometers is solo and maybe 3-4 times out of two months I take part in a local group ride at high tempo to race pace. Our group rides are typically 4+ hours of riding.

One of the uses of the power meter is to gauge your overall effort of any ride. That time you spend in the draft is having an effect on your muscular usage. If you're in a rotating paceline of 5 guys and taking equal percentage of pulls, that means 80 percent of your ride will be underestimated, and the overall average power/normalized power output for the ride will read low. This likewise underestimates the TSS calculated for the ride.

All this completely depends on how anal retentive you are about the data you're getting from the powermeter. For me, every ride counts.

Yes, I can see where you are coming from.

I think the point of iBike is that it provides a balance b/n price and functionality. If one has deep pockets, who wouldn't love a Ferrari, or SRAM PM? But for a large group out there who aren't anal retentive, who has a budget restriction, who would like to get the benefits of a PM based training scheme up and going, I'd say that iBike is an attractive product. Poo poo'ing iBike strictly on technical grounds is fair enough, but poo poo'ing iBike as a product is a poor response when no alternative solutions are provided for this group of riders.

[quote="ahaile"]...I notice little effect in a pack but a definite effect in a small group, like 2-4 people...My watts numbers seem about 10-20% low in a small group. The theory I've seen floated around is that in a pack, the draft is large and fairly uniform, whereas in a small group, it's small and varied....

- It seems that 90% of the people criticizing the iBike on the net have never used one, whereas 90% of the people who have used it like it...QUOTE]

Interesting observation. I did a small group ride at lunch with 8 riders and lots of rotating and pulling through in really windy conditions on flat terrain. A friend on the ride uses a PT (and a polar)a nd it was interesting to get his AP/NP and compare it to mine for the 35 minute effort. His watts/kg were 3.3 AP and 3.99 NP, and mine were 3.26 AP, and 3.91 NP. Pretty darn close for a crappy power "estimator" IMO.

Your last observation had me in stitches because it rings true. What's interesting to me is even the coaching community doesn't make an issue of the iBike. I had a chance to sit down and review my data going back to last August with one of the leading experts on training with power and he didn't question the data or the device.

All I know is when the next gen of PMs comes to market and I toss the iBike on the scrap heap I'll feel that I got a helluva lot of value out of the thing.

gene r

I understand that there is a large group of folks that want the iBike for it's value as a lower priced training tool. If that portion of the community is glad to have it, I'm glad for them.

However, comparing power files from two separate riders - even on the same ride - is essentially useless based on someone's profile, ride position, efficiency in the group, etc... If they aren't side by side

I'm not saying that the iBike is useless, but it's important for people to know that it has definite limitations. I did my research before buying the PT SL back in October of last year, and while some of the "cons" have been fixed by firmware updates, some are not possible to fix because of the nature of the device and the way that it derives its power values.

I do often wonder how many people who have purchased the iBike have convinced themselves they like the device because that's the device they just spent $400 on.

Edited to add: As much as many convince themselves the PT is better in part because it costs more?