"The 33"-Road Bike Racing - Hell of a deal for a Powertap but...

What PT hub is that? Comp?

http://www.competitivecyclist.com/road-bikes/product-components/2009-cycleops-power-tap-compdt-rr-1.1-complete-wheel-5905.380.0.html?utm_medium=email&utm_source=Email+marketing+software&utm_content=146591978&utm_campaign=Power+Tap+Comp+Complete+Wheel+Sale+_+diyuki&utm_term=Power+Tap+Sale

It's the new bottom of the line. It has a steel axle and is fairly hefty and wired. IIRC. Still....I looked at that deal as well this morning thinking about passing it around to friends who don't have PT's

Cycleop's lowest end power meter. Other than being wired, and weighing 576 grams, it looks like it works as well as any other PT.

[edit Psimet you beat me to it.]

Wired...but, not bad if you can stomach it. Heft is OK if you are training with it though. I train with with a heavier wheelset than I race with. I wouldn't race with it though (not just the hub, but that wheel either) since I have other wheelsets at my disposal.

Hell I race on a 32h wired PT as it is.

hmmm... been considering getting one of the Neuvation PT wheels... but this one looks good n bulletproof. too bad it's wired.

PT owners, help me out: what's the real world pro/con for wired / wireless PT?

It's the old Pro version. I have one and cannot say what the differences are between it and the wireless version.

I do tend to prefer wired cycle-computers due to RF interference problems.

That seems a good price for a new one. You might find the same thing used on ebay, but maybe not save much money.

The new Comp does not have HR monitor.

hmmm... been considering getting one of the Neuvation PT wheels... but this one looks good n bulletproof. too bad it's wired.

PT owners, help me out: what's the real world pro/con for wired / wireless PT?

If you can get over the unsightliness of the wires themselves, and don't mind installing the receiver on multiple bikes, and weight isn't an issue, there's basically no downside. All the data is there.

This is a dang good deal. That said, I paid even less than $660 for a used PTap SL 2.4 on a 32h Open Pro rim (w/DA cassette and rubber! Screaming deal). Given the choice between new wired version or my 2.4, I'd take the 2.4. I like wireless and like how it's so much easier/cheaper to add to a multiple bikes, all you need is a mounting bracket for the computer.

hmmm... been considering getting one of the Neuvation PT wheels... but this one looks good n bulletproof. too bad it's wired.

PT owners, help me out: what's the real world pro/con for wired / wireless PT?

I have a wired PT. Con's of the wired Powertap, you have 2 wires cluttering up your bike, and you can't run it with another head unit such as a Garmin or an Ibike Aero. And you need a wiring kit (about $60) for each additional bike.


If you don't plan to run it with a Garmin, and aren't OCP about looks, I don't see much downside to a wired PT.

The new Comp does not have HR monitor.

I havent used my HR strap for 6 months with my PT.

does it just not come with a HR strap? or is it truly non-compatible with the standard cycleops HR strap?

PT owners, help me out: what's the real world pro/con for wired / wireless PT?

Pro: I move it between my racing bike and my cyclocross without issue of wires.

If you plan to leave it on one bike and can stand the wire running from the back tri, I see no reason not to.

^ I'm betting it would work with a Cycleops coded strap. My bet is that the Comp uses the same wired 2.4 head unit that other wired powertaps use. But its just a guess.

The new Comp does not have HR monitor.

IMHO, that's not a "deal breaker". I never wear a strap anyway...power is all you really need :)

As to the questions of the pros/cons...the only con is having to get separate harnesses for a second or third bike if you want to switch it amongst a couple.

I actually think it's funny that it's called "wired"...since there's still a "wireless" connection to the hub itself. It's just that the receiver is on the end of a harness instead inside the head unit ;) "External Receiver" would be a more accurate description...

That IS a heck of a deal...and I'm glad to see that harnesses and head units I can use with my old yellow cap PT Pro will be around for awhile longer :-)

Oh yeah...I'll be willing to bet that one could drop the weight of that hub if they swapped on the alloy freehub body. I would stick with the steel axle though, instead of the 12mm alloy one.

Let's put it this way...I'd choose that over the other options at the same (or similar) price point (such as the Polar CS600 or the iBike models) ANY day. :thumb:

I have a wired PT. Con's of the wired Powertap, you have 2 wires cluttering up your bike,...

If you set the cadence to "hub sense", you can eliminate one of those 2 wires ;)

Besides, as my friend Robert Chung likes to say "cadence is a red herring" :)

IMHO, that's not a "deal breaker". I never wear a strap anyway...power is all you really need :)

As to the questions of the pros/cons...the only con is having to get separate harnesses for a second or third bike if you want to switch it amongst a couple.

I actually think it's funny that it's called "wired"...since there's still a "wireless" connection to the hub itself. It's just that the receiver is on the end of a harness instead inside the head unit ;) "External Receiver" would be a more accurate description...

That IS a heck of a deal...and I'm glad to see that harnesses and head units I can use with my old yellow cap PT Pro will be around for awhile longer :-)

Oh yeah...I'll be willing to bet that one could drop the weight of that hub if they swapped on the alloy freehub body. I would stick with the steel axle though, instead of the 12mm alloy one.

Let's put it this way...I'd choose that over the other options at the same (or similar) price point (such as the Polar CS600 or the iBike models) ANY day. :thumb:

Yes, that's a no-brainer.

If you set the cadence to "hub sense", you can eliminate one of those 2 wires ;)



True. One of the bikes I have set up for my PT doesn't have a cadence sensor. However, I've found the hub based cadence to be a bit less accurate, particularly at lower watts.

I've already got a Polar HRM anyway. :D
Pondering... pondering... :rolleyes:
(PS - I think the "roll eyes" emoticon looks more like "pondering;" consequently, I am using it here as thus.) :thumb:

that's a really good price for what is a good powermeter on a great rim. it's the set up I have, if the wires are installed well, it looks pretty clean. only complaint I have is that the wire running from the sensor to the head unit is really frail, using zip ties will eventually pinch/sever the wire and then needs to be replaced. attaching with tape doesnt look as clean IMO, but doesnt fubar the wires.

I'd buy that in a second if I were looking for a power meter, that's less than I spent for a used one last november.

It's about made me to decide to hang on to my used wired SL. At that price new, I'm thinking that I can't get very much for mine used.

True. One of the bikes I have set up for my PT doesn't have a cadence sensor. However, I've found the hub based cadence to be a bit less accurate, particularly at lower watts.

That's true...and I've also found that the "rounder" your pedal stroke, the less reliable the hub-sense cadence is as well.

But, let me ask you this, how do you use that cadence information?

That's true...and I've also found that the "rounder" your pedal stroke, the less reliable the hub-sense cadence is as well.

But, let me ask you this, how do you use that cadence information?


I really don't use it that much. The one annoyance is when I'm doing fast pedals (120 rpm in a low gear) If I do it on the bike with just hub cadence, I know its reading high, and I tend to want to cheat.

Otherwise I mostly just use it as a reminder to keep my cadence up, which I can tend to let drop if I'm not working very hard. But it's accurate enough for that.

Notice I haven't bothered to replace the cadence sensor on the bike that doesn't have it.

...only complaint I have is that the wire running from the sensor to the head unit is really frail, using zip ties will eventually pinch/sever the wire and then needs to be replaced. attaching with tape doesnt look as clean IMO, but doesnt fubar the wires.


The small clear tape strips that Saris supplies work best, but you do end up with a limited quantity of them. The trick to using zip ties is to make sure the wire is "nestled" in the "crook" formed where the tail of the tie enters the head...and DO NOT tighten the tie too much. It only needs to be snug enough to keep the wire from moving by itself.

With the CC wheel, I assume I'd just need a computer, download cable of some sort and a wiring harness. Is that correct?

I like wireless and like how it's so much easier/cheaper to add to a multiple bikes, all you need is a mounting bracket for the computer.



Wouldn't you have to have about 5 bikes for the purchase of the wireless over wired to even out with the purchase of 4 extra wired mounting kits?

With the CC wheel, I assume I'd just need a computer, download cable of some sort and a wiring harness. Is that correct?

Yes, I would also like to know this. Thanks! :thumb:

its all included.

that's a really good price for what is a good powermeter on a great rim. it's the set up I have, if the wires are installed well, it looks pretty clean. only complaint I have is that the wire running from the sensor to the head unit is really frail, using zip ties will eventually pinch/sever the wire and then needs to be replaced. attaching with tape doesnt look as clean IMO, but doesnt fubar the wires.

I'd buy that in a second if I were looking for a power meter, that's less than I spent for a used one last november.

What about wrapping the part of the wire where the zip tie will secure it in a small amount of electrical tape; sort of to create a small barrier between the wire and the plastic of the zip tie?

But, let me ask you this, how do you use that cadence information?

For all the people saying that they use hub sense and it is not as accurate, Why would you do that? You are knowlingly skewing your power readings leading to inaccuracies since the power is calculated from the cadence.

I dont believe that is true in the context of how powertaps calculate power and cadence.

For all the people saying that they use hub sense and it is not as accurate, Why would you do that? You are knowlingly skewing your power readings leading to inaccuracies since the power is calculated from the cadence.

Ummm...no. The power in a PT is calculated from torque at the hub X hub rotational speed. "Hub sense" cadence is merely a superfluous measure that is attempted to be derived from the torque peaks in the signal.

That is why one way to determine if a unit is zeroed properly is to look for times where power was NOT equal to zero when coasting...

ummm...no. The power in a pt is calculated from torque at the hub x hub rotational speed. "hub sense" cadence is merely a superfluous measure that is attempted to be derived from the torque peaks in the signal.

That is why one way to determine if a unit is zeroed properly is to look for times where power was not equal to zero when coasting...

+1. - in other words you know how many times the hub is going around. It's a direct read. What is "estimated" with hub sense is the cadence....remember (directed at the question about cadence) the hub/computer has no idea what gear you're in. It knows the speed of the wheel, but it has no way of knowing what the corresponding cadence should be without:

1. Direct read form a cadence sensor
2. By trying to interpret another data stream (in this case torque) based on an assumption (that you don't pedal in 'smooth circles')

IMHO, that's not a "deal breaker". I never wear a strap anyway...power is all you really need :)

[snip]


That's true...and I've also found that the "rounder" your pedal stroke, the less reliable the hub-sense cadence is as well.

But, let me ask you this, how do you use that cadence information?

Threadjacking for a moment, I think you're missing out on data with unreliable cadence and HR.

I'll submit HR isn't a good indicator of effort, but over time it's pretty fantastic if you're doing the same workouts and want to track progress in your cardio system's response to stress. Also, it's a decent indicator when something is amiss - if you're not eating enough during training it might be abnormally low, or it might be reading sky high, like when I thought I might be dealing with a fever and sure enough was hitting 195+bpm on pretty simple exercises. My point is, having HR often helps quantify progress over time and the difference between perceived effort and what's really happening, just like watts does.

As for cadence, get a real crank sensor. The difference in data is amazing. What do I do with it? At least one workout every week. Just today I was doing cadence step up intervals - keeping power between 200-250w and starting at 100rpm and increasing that by 5rpm every minute until I'm bouncing. There's no way that workout would work with a hub sensor, I've tried. If you have anywhere near a decent stroke the hub sensor is crap.

^ not having HR and cadence might lead to missing out on data, but it's data that either doesnt matter or can be accounted for with other more reliable factors.

the cadence one spins = who cares. for a local reference, Ramon Benitez fights the biggest gear of anyone I know and rides alot of good strong racers off his wheel - over blue knob mountain on raceday.

one can easily do spinups or accelerations or jumps or the workout you describe based on feel, or by tapping their knee for 15" and multiplying by 4.

HR tells you you're alive. I found that a high HR or low HR or whatever is subject to too much interpretation, in fact, I stopped wearing the HRM long before getting the watt thingy because it was just too much noise. my HR during winter months would be like a hummingbirds, then in summer, it'd be like 20 bpm lower for no reason. did that mean I was in better cardiovascular condition? that I was under-rested? that I didnt get enough sleep? that I was dehydrated? that I was too hot? too cold? that I'm old and frail and should take up golf? noise, just noise.

if you think you're getting a fever, take your temperature ... point being, if you think something is amiss, it probably is and you dont need an HRM to tell you so.

I've run my PT Cedence on hub sense along side my Garmin 305 with a cadence sensor. I map my cadence and HR on the Garmin while loggining virtual cadence and power on my PT.

I check the cadence between the two often. We're doing a ton of indoor intervals where they are cadence dependent.

From my experience the cadence from the PT seems to be consistantly high by 5-8 rpm. The key word is consistantly. I find the data follows very evenly...it is just offset by that 5-8 rpm.

It is close enough that I recently stopped using the Garmin to track HR and cadence.

Ummm...no. The power in a PT is calculated from torque at the hub X hub rotational speed. "Hub sense" cadence is merely a superfluous measure that is attempted to be derived from the torque peaks in the signal.

That is why one way to determine if a unit is zeroed properly is to look for times where power was NOT equal to zero when coasting...

So how does it differentiate between these 2 situations.

Both have:
Constant hub rotational speed (same MPH)
Contant torque reading from the hub (same force on the pedals)

In one case you apply the torque while pedaling at 110 RPM. In the other case you apply the torque while pedaling at 60 RPM.

According to you the powertap would display this as the same power since they have the same hub rotational speed and torque reading at the hub.

In actuality the higher RPM would have a higher power output due to the increased cadence. correct or no?

So how does it differentiate between these 2 situations.

Both have:
Constant hub rotational speed (same MPH)
Contant torque reading from the hub (same force on the pedals)

In one case you apply the torque while pedaling at 110 RPM. In the other case you apply the torque while pedaling at 60 RPM.

According to you the powertap would display this as the same power since they have the same hub rotational speed and torque reading at the hub.

In actuality the higher RPM would have a higher power output due to the increased cadence. correct or no?

It's not a constant torque. There is natural variance in torque unles you have a PERFECT spin with constant force application through the entire arc of the spin. So...it looks for the spikes in torque per revolution which usually corresponds with the downstrokes where more power is transmitted.

This issue being discussed then is that it can sometimes get a little murky if you do achieve a few fairly even pedal strokes. Even then it is not usually off by much in my experience.

....in other words I can really concentrate on spinning smoothly and watch the display change without an appreciable change in my cadence. Luckily I'm not anywhere near smooth.

its cadence..... who cares if its 94 or 97... you know its higher than 90 and lower than 110...

So how does it differentiate between these 2 situations.

Both have:
Constant hub rotational speed (same MPH)
Contant torque reading from the hub (same force on the pedals)

In one case you apply the torque while pedaling at 110 RPM. In the other case you apply the torque while pedaling at 60 RPM.

According to you the powertap would display this as the same power since they have the same hub rotational speed and torque reading at the hub.

In actuality the higher RPM would have a higher power output due to the increased cadence. correct or no?

No. Your error is in assuming that a constant torque at the hub means the same force on the pedals.

If your speed is the same, and torque at the hub is the same, but the cadence is varied, this can ONLY be accomplished by being in a different gear. So, by definition, the force at the pedals will be different.

Is this price just a special sale or will it be around all year?

i'm guessing that when they run out it's over. i would imagine there aren't a huge number of these

^%$* me. If i didn't need a frame that fit better, I could have a powertap!

Anyone know where this model mounts the speedo sensor? front or rear?

Is this price just a special sale or will it be around all year?

Competitive Cyclist is not really known as a site with the best deals. My guess is other online shops will have similar pricing if not lower soon.

Anyone know where this model mounts the speedo sensor? front or rear?

no speedo sensor needed :)

Competitive Cyclist is not really known as a site with the best deals. My guess is other online shops will have similar pricing if not lower soon.

exactly what I was thinking... knowing Competitive Cyclist, the new pricing must be in the $400-500 range lol..

Anyone know where this model mounts the speedo sensor? front or rear?

Like all PTs, it's inside the hub :thumb:

^^^^

so if you want to race with a different wheel, you'll need a separate computer if you want to see distance and speed?

So how does it differentiate between these 2 situations.

Both have:
Constant hub rotational speed (same MPH)
Contant torque reading from the hub (same force on the pedals)

In one case you apply the torque while pedaling at 110 RPM. In the other case you apply the torque while pedaling at 60 RPM.

According to you the powertap would display this as the same power since they have the same hub rotational speed and torque reading at the hub.

In actuality the higher RPM would have a higher power output due to the increased cadence. correct or no?

This is an impossible scenario. If your hub speed is the same in both cases and the pedal RPM's are different, then you are not in the same gear, therefore the hub torques (with equal pedal pressure) are different.