Ok…I’m getting pretty annoyed with my powertap (pro) wheel/hub. First of all, it constantly drops data (on two different harnesses and the batteries have been replaced in both hub and computer) and its been REALLY bad the last week after getting caught in the rain. Borderline useless.
Anyways, if that isn’t annoying enough, the freehub(?) doesn’t seem to rotate freely. If I put the bike on trainer (or mount on something else) and spin the pedals and then let them go, the pedals continue to go round and round and round until the wheel gets under 16-18mph or so. yay. The chain isn’t becoming slack between the cassette and front rings. I tried this with two other wheels I have and they behaved as you’d expect on the same bike (the pedals only spin for a second or so…mostly due to the inertia of the pedal/crank).
So, I have no clue how the hell all that stuff is put together but I know the fact that my P3 looks like a fixed gear when I spin the powertap’d wheel isn’t normal. I take the wheel down to a LBS and they look at it carefully and just shrug and say something about not having access to the inside of the hub/bearing/whatever. Very helpful.
So watt is going on and how can I fix it? I know its costing significant speed when coasting but I’m not sure whether or not it is also costing me watts when pedaling. Either way I want it fixed. Any suggestions? Links to fixing hub stuff? Do I need to send it in for service at Saris? Is this something I can fix myself? Does anyone know someone in the East Bay (Bay Area) that is good with this sort of stuff?
First and foremost, there’s a difference between “what’s” and “watts.”
Second, I wouldn’t worry too much about the freehub. It’s not a big deal aside from the annoyance of it, and it’s not really costing you any speed when you coast, and certainly not when you pedal. Not sure about the user-servicability of a PT freehub, but you just need to remove the freehub, clean it, drip some oil in there, and you’ll be good-as-new.
that is not uncommon for your wheel to spin the cranks at high speeds in the stand…my Zipps and Record hubs do that too…I chalk it up to an awesome smooth BB.
Hey OT, I understood the underlying humor of the ‘‘Watt’’ as you were referring to your powertap. I can provide zero help on the mechanical side though.
you just need to remove the freehub, clean it, drip some oil in there,
How?
that is not uncommon for your wheel to spin the cranks at high speeds in the stand…my Zipps and Record hubs do that too…I chalk it up to an awesome smooth BB.
Are you sure its “normal”? If I crank the pedals by hand so that the rear wheel is going 30+mph and let go…the pedals won’t stop rotating for quite a while (maybe 15-30 seconds) until the speed of the rear wheel gets down to 16-18mph. My wheel with the white industries hub and my wheel with the velocity hub don’t do it. It means that the wheel is using some energy to drive the pedals in circles…that can’t be good…no?
depends on how tight the pawls are - my Velomax wheels dont. I would say “loud” wheels will do it more than quite wheels in my testing (yes I have been that bored).
“It means that the wheel is using some energy to drive the pedals in circles…that can’t be good…no?”
Yes, that’s what it means. However, it’s not sapping enough energy to even worry about - basically, there’s less drag in your bb bearings than in your freehub bearings. Unless you’re coasting, your freehub bearings aren’t even in use. When they are in use, their effect on your overall speed is so far down the list of variables that Sheldon Brown says “The freewheel is the least important bearing on a bicycle, since it only turns when it is not carrying any load.”
If it’s keeping you up at night, service the freehub or have someone do it for you.
Sounds like the bearings are on their way out, usually on the freehub side. Your LBS can actually service the freehub bearings, all it takes is a couple of hub spanners (14/15mm from memory) and you remove the axle and grease the bearings. I try to do mine every 1500 miles (each month), the drive side is cup and cone and the non drive side of the pro is sealed.
They do have instructions in your powertap manual, or you can go online to the website. Unfortunately I have become experienced in powertap pro service. With my wife’s SL issues next time I will try pulling that one apart as well.
If you need some more directions or photo’s PM me, it aint rocket science if some high school dropout dipstick at the LBS can handle it.
He is a great mechanic, and will take the time to go over the issue with Cycleops until he gets it sorted out. He has built many, many wheels for me, including my PT, and he stands behind his work. Much better service than you will get from any of the local shops around here.
I have a set of old Ksyriums that have the same problem. The freeehub needs to be rebuilt. I don’t think that the bearings wear out per se (?) but more like too much junk gets collected in the assembly. A thorough disassembly and cleaning should be enough to get it smooth again. Google “powertap hub disassembly” or whatever and see what shows up. It may be difficult or it may be easy, who knows - E
Thanks for the tips guys. I might try servicing myself when I get time but maybe I’ll give that wheelpeddlar guy a call. A reasonably priced, high quality, mobile bikeshop? Awesome.
Actually, with the set-up on the PT hub…it IS a problem, or at least can be. I’ve had it seize up to the point where the chain wound up so much it ripped off the rear derailler hanger (which fortunately was replaceable…).
Without going into too much detail, having a cartridge bearing in one side and loose balls in the other can create some problems…
In order to get the play out of the cartridge side when it starts to wear, it’s easy to overtighten the adjusting cone and crush the washer behind the cassette body, in turn causing the binding. It’s easy to overtighten since you can overtighten the cone and STILL have some play in the wheel.
Once the cartridge wears you either have to a)send it back to Graber, or b)make the bearing adjustments to the ball side and run the hub feeling a little loose.