Road Bike Racing - iBike Power Meter

Some may perceive me bashing power meters in that other thread. While I'm not (just stating that many people probably put out large chunks of change for what ends up being a drastically under-utilized tool), I'm thinking that when I do get a power meter, I'd look into the iBike (http://www.ibikesports.com). Looks like a cool tool along with altitude, hill gradient, wind speed, and calorie counter functions, but at $500 or less depending on where you buy it.

Anybody have any experience with these or can you direct me to actual user reviews? I'm always skeptical of magazine reviews of ANY product (high shill factor, IMO), but user reviews count for a lot.

Some may perceive me bashing power meters in that other thread. While I'm not (just stating that many people probably put out large chunks of change for what ends up being a drastically under-utilized tool), I'm thinking that when I do get a power meter, I'd look into the iBike (http://www.ibikesports.com). Looks like a cool tool along with altitude, hill gradient, wind speed, and calorie counter functions, but at $500 or less depending on where you buy it.

Anybody have any experience with these or can you direct me to actual user reviews? I'm always skeptical of magazine reviews of ANY product (high shill factor, IMO), but user reviews count for a lot.


The one guy I met who owned one told me it was for sale because he had just ordered a powertap SL.

The Ibike is not a power meter, it's a power estimator. Without a strain gauge, it's just guessing.

Poster NoRacer has one and he has had success with it. I believe he wrote a review about it if you want to seach for it.

The ibike has annoyed me like no other product I've ever purchased in the last ten years.

I've spent far too many hours making adjustments to the the mounting, stripping off everything and remounting everything again, sending stuff back and getting new stuff in the mail, tech support calls, tech support emails, reading manuals, reading web sites, asking for online tips...

I think it's an interesting gadget but despite all my efforts and those of very good tech support offered, I can't get reliable numbers from this device. You can't rely on it alone for power data. You will need another power meter if you want to "train with power" or otherwise monitor your power progress over time.


WARNING: Retailers for it are shady and will dodge refund requests.

There are PowerTap options around the same price range. Save your money and buy a product that makes good on its claims.

The Ibike is not a power meter, it's a power estimator. Without a strain gauge, it's just guessing.

+1

The Ibike is not a power meter, it's a power estimator. Without a strain gauge, it's just guessing.

There are other, accurate ways of measuring power than with a strain guage.

Power taps don't necessarily have to "cost large chunks of change either." If you're someone who's in the market for a new wheelset or just a rear wheel anyway, the incremental cost have having a rear wheel with a power tap pro or an SL built up is much less than the retail price listed of the power taps. For example a Zipp 303 with a power tap pro retails for $1,299. A Zipp 303 rear wheel generally retails for $1,072.95. You get the addition of a power tap pro for $226.05 instead of the retail price of $899. The incremental cost is a little more if you go the SL route. Either way still much better than from what I've read about the ibike.

I only used the Zipp 303 as an illustration and of course you normally get discounts off retail prices, but there's lots of choices of other wheels out there that you can get similar pricing results having a power tap built up in a rear wheel.

from every review I have read about the ibike, it does a surprisingly good job determining average power, however for more acute measurements it is easily thrown off. Since one of the main factors in its power calculations is wind speed, it is thrown off while drafting, so if you are doing a lot of pack riding/racing this is not for you. Also, it will not work on a stationary trainer. For a few hundred bucks more, you can get the powertap pro. just my 2c

My problem with the iBike is that when it comes to Power Meters, why get something where you are going to have so many random fluctuations, that from ride to ride, you are never sure whether the increase/decrease is due to sensor fluctuations or whether due to actual performance.

To me, buying the iBike is being penny-wise, pound-foolish.

from every review I have read about the ibike, it does a surprisingly good job determining average power, however for more acute measurements it is easily thrown off. Since one of the main factors in its power calculations is wind speed, it is thrown off while drafting, so if you are doing a lot of pack riding/racing this is not for you. Also, it will not work on a stationary trainer. For a few hundred bucks more, you can get the powertap pro. just my 2c

The ibike is useful for a few things and wind speed is one of them. You can use it to feel how much air you're getting while drafting and that's useful. The real time gradient feature is also useful, especially when you're taking turns with pulls. Letting your buds put out more effort than you on their pulls just because you can know small changes in grade, is a big plus.

The biggest hassle is getting out during a ride and realizing the numbers are wrong, or just suspecting they're wrong. If you have no backup, like another meter or HR monitor then your effort-based workout can be hosed. Nothing like fighting madly into a headwind at 24 mph and seeing you're magically only sustaining 75 watts to get the job done.

Some days I have only 90 minutes or two hours to get in my ride. If I want to ensure the iBike is working properly, I need to completely re-do the set up every time I use the device (only 5-10 minutes actually), otherwise small differences in wind offset, level or strange coast down numbers could hose the workout. Still that's precious time that I'd rather spend riding and not monkeying with the device. I've also killed days by doing 20 bad coast downs trying to get it right, instead of the LSD plan I'd had.

I've owned/used an iBike, but now use an SRM. The iBike does an admirable job (not getting into the power estimator vs direct power measurement debate) under controlled circumstances. For example if you are riding steady state against a headwind or up a grade it calculates power within +/- 10 watts of the SRM. You can set a baseline, calculate TSS, and measure improvement using the iBike, but its just not as precise as the SRM.

I found that the iBike was easy to set up and use, but others have had different experiences. Here is a good place to solicit opinions on owning an iBike.

http://lists.topica.com/lists/iBikeProPowerMeter/

If you are looking to train w power in an inexpensive way (1/7th the cost of an SRM) the iBike is a bit quirky but certainly sufficient IMO. If you have the extra scratch to spend, and price is not an issue, the SRM certainly offers a higher level of precision that I feel is worth the investment.

gene r

Like I said in the other thread, I still think you're better off looking on eBay or something -- used PT's can be had for $500 or so.

I'm using an ibike right now, seems to work ok...but as others have mentioned, not sure I trust the reading each time. It was a gift, so I figured I would use it while I save up for something else...

Anyone using an ergomo?

The conclusion I'm coming to is that it's decent, but definitely not without it's quirks . . . The stand-alone feature of it (no special hubs, cranks, etc.) was most tempting, and the low weight doesn't hurt either. I guess I'll keep looking around . . .

I got my powertap pro + rear wheel setup for 450 used and it works perfectly like new. Why anyone would spend 500 on a lesser product is beyond me. Then again some people just have to have things "new" i guess.

NoRacer had a long thread with some long user reviews, including mine. Search the archives and it should pop up.

FWIW, I've been training with an iBike for a year and just picked up a PT Pro a couple weeks ago. I wasn't really upset with the iBike, it was just that a deal came along that I said, heck, I'll play with a new device. I'm still getting used to the PT, but so far I've found that my training rides are identical with the two. My FTP, zones, etc. as reported by the PT are the same. Average and normalized wattage for an interval are (usually -- I'll get to that in a sec) identical between them.

The main thing I like about the PT compared to the iBike is that, with the PT, the number is just the number. With the iBike, that was true for 95% of the time, but there'd be brief periods, usually under 10 seconds, where rough road or a crosswind would throw off the reading. As far as training, those bad periods weren't too much of an issue -- I could tell when they were happening and just rode by effort level for the few seconds until the iBike came around. But it meant that I always had to be evaluating the iBike number a bit -- does that seem right? With the PT (so far) that's something I don't need to worry about.

The other advantage I hope to get out of the PT is that, with the iBike, the occasional outages didn't play well with CyclingPeaks' Mean Maximal Power curve. Let's say one of the rough road sections lasts longer than usual, a minute. Well, the MMP curve will now say that you blew the doors off your old 1-minute power. The other long-term tools in CyclingPeaks, like the PMC, aren't as affected, but MMP was bad.

Two main downsides to the PT in comparison: no elevation or grade data, and reliability. The vast majority of PT owners I know have had to send theirs back, some several times. Honestly, it's gotta be the least reliable bike device out there. I know, I know, someone always pops up who hasn't had any trouble, and every generation the device gets better, and they've got good customer service. All those are true, but still.

Joe: I saw your post on the iBike board. Were the negative coastdown values you got in the friction or aero coefficient? If it was the friction, then my guess is it's a tilt issue. Have you tried running one of your ride files through my altimeter v. accelerometer script (http://curveship.dyndns.org/cgi-bin/aah/altvaccel.pl)? If the difference line (red) is trending upward, then your bike setup will be prone to negative friction coefficients. I can go into more detail if you want. FWIW, I'm probably one of the more knowledgeable guys outside of Velocomp on this thing. Hmm ... I should probably say that that may be one reason I've had good success with the unit.

NoRacer had a long thread with some long user reviews, including mine. Search the archives and it should pop up.


FWIW, I'm probably one of the more knowledgeable guys outside of Velocomp on this thing. Hmm ... I should probably say that that may be one reason I've had good success with the unit.

+1

Joe: I saw your post on the iBike board. Were the negative coastdown values you got in the friction or aero coefficient? If it was the friction, then my guess is it's a tilt issue. Have you tried running one of your ride files through my altimeter v. accelerometer script (http://curveship.dyndns.org/cgi-bin/aah/altvaccel.pl)? If the difference line (red) is trending upward, then your bike setup will be prone to negative friction coefficients. I can go into more detail if you want. FWIW, I'm probably one of the more knowledgeable guys outside of Velocomp on this thing. Hmm ... I should probably say that that may be one reason I've had good success with the unit.

You're exactly right. It was friction. I think the problem with the negative number had something to do with the mount being far up on my 120 stem and then extending forward. As speed tended toward 8 mph, I would often turn my bars to stay balanced. With the changing tilt getting very radical here, this would introduce some tilt-related mayhem. I was also getting bad air -- this is my TT set up.

I think all in all, it's my aerobars that have caused so many problems. It was reporting much better numbers and with more reliability when I just had the road bar set up.

I think the short of it is that I have to buy my own PowerTap SL (borrowed one for 30 days and it was wonderful but minus some fun iBike numbers). If anyone on the BikeForums wants to buy mine (iBike plus cadence, newish and in perfect shape) for $300 right now, it's yours. Otherwise, I'll put it up on eBay after I get my PowerTap.

You're exactly right. It was friction.

My guess as to what is/was going on: for some reason, your weight on the bike and bars are causing the iBike to tilt upward slightly, compared to when you're not on the bike. When this happens, some gravity leaks into the resistance calculations during the coastdown and subtracts from the friction coefficient. If the error in tilt is bigger than about 0.4% or so, it'll turn the friction coefficient negative and the unit will say "bad coast." (Most people are in the opposite situation, with the iBike tilting slightly downward and with inflated coefficients.) Now, so long as the error stays consistent, you'll get good power numbers (the error in the friction coefficient is cancelled by an equal and opposite effect during riding). But you said your coastdown was quite negative and you had good reason to believe the watts numbers from your ride were bad too. I'm guessing that the front end of your TT rig is somewhat flexy and isn't providing a stable enough platform for the iBike to work.

You're exactly right. It was friction. I think the problem with the negative number had something to do with the mount being far up on my 120 stem and then extending forward. As speed tended toward 8 mph, I would often turn my bars to stay balanced. With the changing tilt getting very radical here, this would introduce some tilt-related mayhem. I was also getting bad air -- this is my TT set up.

I think all in all, it's my aerobars that have caused so many problems. It was reporting much better numbers and with more reliability when I just had the road bar set up.

I think the short of it is that I have to buy my own PowerTap SL (borrowed one for 30 days and it was wonderful but minus some fun iBike numbers). If anyone on the BikeForums wants to buy mine (iBike plus cadence, newish and in perfect shape) for $300 right now, it's yours. Otherwise, I'll put it up on eBay after I get my PowerTap.

Not being obnoxious but you just stated the thing was completely unreliable, that you'd tried returning it. Why would you be asking for 70% of the price of a NEW iBike (and that's retail price of $429, Amazon sells it new for $389.95 w/cadence included). If it was a product that worked well but was simply used, $300 sounds fair but from your description, I'd say $150 is much more of a fair price.

Not being obnoxious but you just stated the thing was completely unreliable, that you'd tried returning it. Why would you be asking for 70% of the price of a NEW iBike (and that's retail price of $429, Amazon sells it new for $389.95 w/cadence included). If it was a product that worked well but was simply used, $300 sounds fair but from your description, I'd say $150 is much more of a fair price.

VALUE
Value is not what is put into an item
Value is not what is paid for an item
Value is not how much an item is loved or enjoyed by the seller
Market sets value

I could get $350 for this on eBay. The demand is still very high. Anyone who's read the thread knows the pluses and minuses of the device. There's still value there for the right buyer. Not everyone has/needs aerobars like I do. One man's junk is another man's treasure!

VALUE
Value is not what is put into an item
Value is not what is paid for an item
Value is not how much an item is loved or enjoyed by the seller
Market sets value

I could get $350 for this on eBay. The demand is still very high. Anyone who's read the thread knows the pluses and minuses of the device. There's still value there for the right buyer. Not everyone has/needs aerobars like I do. One man's junk is another man's treasure!

A lot of people don't do their research or are blinded by the initial low cost of some systems. So iBikes, Ergomos, and to a lesser extent, PTs, are passed on to the next chump via eBay.

A lot of people don't do their research or are blinded by the initial low cost of some systems. So iBikes, Ergomos, and to a lesser extent, PTs, are passed on to the next chump via eBay.

so which one do you own?:rolleyes:

There are other, accurate ways of measuring power than with a strain guage.

you keep a brake-dyno and a 100% grade hill handy?

One man's junk is another man's delusion.

Thank god for idiots with money.

Thank god for idiots with money.

Pcad does count his blessings.

i'm a chump that got an ibike for 200$ on ebay. i had no idea what to expect with everyone talking about "estimates of power" and problematic coast downs and this hard tilt calibration... and so on.

it took maybe twenty minutes to install because i made it really clean. it took maybe one minute to do the tilt. i did the coast-down in one take. so far for rides that i know really well and can gauge my effort, the ibike gives me very consistent numbers from ride to ride which my internal effort-meter says is good. for me to get faster and stronger, that's all i need. consistency.

i'm wondering how much of the trouble everyone has is related to so-so installs or so-so calibration/input. i only mean, some care is require by the user. not a big deal if you just take a deep breath and go slow the first time. i just saw something about a negative friction? totally user error, right?

the thing is nice for the money if you ask me. maybe i don't know any better since i've yet to spend 500$ on a used other thing. for the guy talking about pennywise and such, i got 200$ i'll throw down when you're ready to pay the rest for a pt or srm... just let me know :) ...can i get a new one? can i? can i?