preferred-google-button
log in
register

Powertap – here’s the rub.

  • Creator
    Topic
  • November 29, 2014 at 11:28 am #22800
    Eebijeebi

    This is not a dig at the product as I think it’s very good. This is merely a head’s up to others wanting to get into power.

    I went for Powertap because it was pretty much the cheapest and simplest way into a power meter. So far it’s performance has been exemplary, software update and battery change not an issue.

    The problem now though is that one simply wont do.
    Eying up some carbon wheels for the spring when I hope to be moving along swiftly enough that I wont be ‘all the gear, no idea’. That means buying another one (but I knew that would happen).

    Riding on the trainer flat spots the tyre (is that only me?) which I didn’t I foresee. Last weekend punctured rear though the flat spot. New winter tyres gone on today.
    So to not flat spot the tyre again means swapping tyres every turbo session – or buying another Powertap wheel just for the trainer.

    So, to be in a sensible situation (unless you go with riding the flat spot on the road) you need a minimum of two, or three if you want two sets of road wheels.

    That adds up to circa £1800, although not in one go, but obviously some other systems would have been cheaper in the long run and not restrict wheel options – and that’s the head’s up really. Yes I did read up and research and in the end I wouldn’t have done differently as I was so keen to get into power. Others may not be so rash. I imagined I’d end up needing two – but three may have tipped the balance and convinced me otherwise.

    I always knew I’d need two but I doubt I’m a one off case and most PT users may end up needing three.
    I’m not complaining so please don’t pick holes – just putting what I’ve found into the power meter discussion pot.

    I imagine I’ll move away from PT rather than buy the second and third.

  • Creator
    Topic
Viewing 15 replies - 1 through 15 (of 30 total)
1 2
  • Author
    Replies
  • December 4, 2014 at 4:48 pm #822129
    0
    flobble

    I recently switched from
    I recently switched from Powertap to Vector for exactly the same reasons as the OP.

    I built up the PT in my deep section race rims, to which I added a disc cover when racing triathlons.

    But happy as I am with the PT, in peak race season I got fed up with changing from race tyres to turbo tyre and back again. And when I’m trying to cram in training sessions around a busy job, commuting and a young family, that time matters a lot.

    I find the time to change the Vectors from one bike to quicker than changing tyres, especially with latex sealant loaded inner tube to content with.

    Since I do most of my workouts on the turbo (even in race season) on the TT bike in the aero position (specificity…) the only thing required is a quick wheel change.

    And I can now choose whether to fit a disc, deep section wheel or even that trispoke rear I’ve hardly used depending on how windy it is.

    Makes life simpler all round, so it was a good (if expensive) decision.

    December 3, 2014 at 8:35 pm #822127
    0
    mtbtomo

    Flipping heck, I just
    Flipping heck, I just downloaded Golden Cheetah. I could lose days in that software!! :B 🙂

    December 3, 2014 at 2:07 pm #822125
    0
    KirinChris

    Strava at Premium level is OK
    Strava at Premium level is OK but not great if you want detailed analysis.

    Training Peaks is very good. I haven’t used WKO+ which I understand is very similar to TP, but it’s a programme and not available for Mac. TP is web based.

    Golden Cheetah has some great features like drag coefficients and so on but it’s not really a commercial software with an easy interface.

    I’d start with Training Peaks – I doubt many people really need more than that.

    December 3, 2014 at 9:02 am #822123
    0
    Nick T

    WKO+, Golden Cheetah,
    WKO+, Golden Cheetah, Training Peaks etc

    December 3, 2014 at 8:46 am #822121
    0
    mtbtomo

    Can I ask, what software do
    Can I ask, what software do you guys use to look at the power data collected by these devices?

    All the reviews on the web show mega detailed graphs etc but from what I can see Strava premium is a bit simplistic? Trainerroad seems for indoor workouts only?

    What else is there – especially to look at the data collected on an outdoor ride? Or do I need to? Other than staying in the correct zones during the ride?

    December 3, 2014 at 8:33 am #822119
    0
    Eebijeebi

    Yes Paul, a flat wear band
    Yes Paul, a flat wear band around the whole circumference.
    It’s down to traction against the shiny cylinder of the trainer (not braking) and however ‘tight’ I seemed to have the cylinder against the tyre I’d get some wheel spin starting up or on sudden increase in power.
    I didn’t see it as an issue until I punctured on the road though the flat band.
    Having said all that, since the tyre has developed a decent size flat band it has better grip and slips very little against the cylinder so I have myself a trainer tyre!

    December 2, 2014 at 10:55 pm #822117
    0
    paulrbarnard

    Do you mean you are getting a
    Do you mean you are getting a flat band round the tyre through excessive wear? or a flat spot on the tyre? If it’s a flat spot it’s probably down to using the rear brake to stop your wheel. I’ve seen people do it out of force of habit when they finish a session. Almost guarantees a flat spot. Simplest thing to do is to wind the cam out on the caliber so that the lever moves a long way. your probably remember you shouldn’t be pulling it before it hits the rim.

    Oh on the power meter front, if you can afford them buy as many as you want. You don’t need anyones permission to spend your money. You earned it so enjoy it.

    December 2, 2014 at 12:02 pm #822115
    0
    5th

    @abudhabiChris
    With my
    @abudhabiChris
    With my analytical head on, I may have an explanation as to why my 5s power is higher on PT than Stages: if you started and ended a short sprint with your right foot, you would potentially lose 2rpms of power as it only counts the left foot efforts whereas the PT counts everything; at low cadence this could give you a few % error (my 5s power is about 5% lower on Stages than PT), for longer durations it would obviously make less difference which is probably why my figures converge. Either way it makes cock all difference to what effort you put in and if you’re using the same PM you’ll get relative consistency anyway.

    Or maybe it was because my best 5s power came from trying to out sprint someone who recently took home some rainbow bands from the Masters track champs and I was going absolutely balls out? I lost, naturally, but I’d beaten him the day before so I didn’t mind 😉

    December 2, 2014 at 4:57 am #822113
    0
    KirinChris

    @5th But I do that sort of
    @5th But I do that sort of thing on the race/training bike, not on my TT bike, and that was my point.

    There’s often a 15 second sprint at the end of a block, or horrible things like 40 seconds sprint, 20 seconds rest, repeat for 10.

    So if there is greater variation for 5 seconds at each change then it’s affecting 10 seconds out of every 60 over 10 minutes. Probably the normalised power for the block would be much the same but the short bursts would have more variations.

    That’s not the end of the world of course and probably don’t matter shit to be honest, unless I’m Marcel Kittel 8> which I most definitely am not.

    But given the similar prices and subject to the wheels/bikes considerations it was enough to make me swing to PT on the road/race bike and Stages on a TT bike.

    Plus I have Campy on my road bike so I couldn’t use Stages anyway, but the Trinity came with Shimano so I’m really making life difficult for myself. 8}

    December 1, 2014 at 11:11 pm #822111
    0
    5th

    @Pierre – you’re absolutely
    @Pierre – you’re absolutely right, poor explanation on my part. SRM measure at the crank spider so measure all the power, but don’t present it as L/R and last time I checked no-one shelling out thousands of pounds for their systems seemed to care.

    @abudhabiChris – you’re overthinking your algorithms; the Stages does nothing more sophisticated than taking the power output of the left crank and multiplying it by two – it can’t know anything about what the other crank is doing so there’s no point doing anything more complicated. Having used Stages and PT back to back for a prolonged period the only thing I noticed was a possible greater sensitivity over very short (<5s) sprints, but I think I was trying harder on the PT generally. Valid point about using what you're given, but I'm sure a team at that level could choose who they wanted as supplier.

    December 1, 2014 at 7:29 pm #822109
    0
    KirinChris

    fenix wrote:
    I just throw a

    fenix wrote:

    I just throw a cover on my wheel for the races I do.

    I thought covers were not UCI legal?

    December 1, 2014 at 6:43 pm #822107
    0
    Eebijeebi

    How very true. Not likely to
    How very true. Not likely to use posh wheels through winter but no reason to not use rear on the turbo with a different/used tyre. Only seasonal tyre swaps. Discovered at weekend that bike shop do a heavy duty tyre just for trainers which will solve that expensive flat spotting issue.
    Brilliant – wasn’t expecting a resolution to my situation when posting, but got one anyway.
    Thanks chaps.

    December 1, 2014 at 6:32 pm #822105
    0
    fenix

    I’ve got a PT as a training
    I’ve got a PT as a training wheel. I use it on the turbo as that’s where I get my best sessions. It’s hard to ride to power on most of my outdoor rides.

    If you look at trainerroad – you can train to virtual power on there from most turbos. All you need is a laptop and an ant+ stick. So you can use any wheel / tyre. Maybe you want to check occasionally that virtual and real power is similar.

    Then all you need is one race wheel ?

    I just throw a cover on my wheel for the races I do.

    December 1, 2014 at 5:26 pm #822103
    0
    step-hent

    I’m sure you can get away
    I’m sure you can get away with two and cover all the bases you want:

    1. Pair of alloy training/winter wheels – these will cover outdoor use in winter and can be wet ride or turbo wheels in summer (depending on whether you use the turbo in summer);

    2. Pair of deeper (perhaps carbon) wheels – main wheels in summer, and then pop them on the turbo with a cheapo tyre in winter. You most likely wont want to use them outside anyway.

    So that brings it back down to the level you had expected originally. Still painful to have two power meters, but I ended up with two crank based ones too – one for the winter/wet weather bike and one for the summer/dry weather bike. So it’s not unique to powertap.

    December 1, 2014 at 4:16 pm #822101
    0
    Scrufftie

    It takes me about 15mins to
    It takes me about 15mins to switch the Vectors from one bike to another. Most of the time is spent on the mechanical removing and refitting of the pedals, it then takes a couple of minutes to calibrate them and you’re off. I’m surprised that anyone, especially, a mechanically-minded person would be troubled. You do need a two way torque wrench to fit properly but there is quite a spread of suitable torque readings and I reckon it would be about how anyone would fit their pedals; i.e. pretty firmly on.

    The head unit (I use an 810) knows that the pedals need recalibrating and takes you through the process. Basically, it’s just pedalling at 90rpm ish for a short while.

    I wouldn’t leave home without them

  • Author
    Replies
Viewing 15 replies - 1 through 15 (of 30 total)
1 2
  • You must be logged in to reply to this topic.