Power Meters / Powermeters (SRM, Powertap, Quarq, Ergomo, Vector, Stages, power2max, P2M, 4iii, InPower, Cinch)

Add various amounts of tiny spacers to Your Chain links. gradually increasing chainline from chainring out to the sprocket.

Problem solved.

This is what I'm currently doing. Won't work with a bushed chain though, had to switch to SRAM. I think a 108mm Phil ISO BB will give me a 40mm chainline and reduce q factor, so it's a win win (if it works).

Did someone say Q Factor

Nope, this is LFGSS, it was probably X Factor

Did someone say Q Factor

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Ha - very good :D

Interested to hear how all of the new Powertap track owners are going to solve the 40mm chainline problem.

There's about 5mm of wiggle room to use a thinner DS lock nut (and correspondingly wider NDS one) without modifying the axle. If you use it all, you end up with centre-to-flange dimensions of 16.5mm/33mm, which is a bit worse than a typical road hub but not disastrous.

Every time I open this thread there is a new issue with these Powertaps..

Manual zero on every ride
Splined cog that might undo if leg brake a lot
and now the chain line is wrong(?)

What next, it'll tell me how average I am at cycling?!

To be fair you should do a manual zero at least once on every single ride you do with a powermeter - it's not limited to Powertap track meters.

I've never had the unscrewing issue, but my PT-track is a G3, I don't know if there is any difference there.

Also, my chainline has been fine - I just used track cranks and all was ok.

The average part is tricky, though.

Useful to know on the manual zero and pretty sure I have a track chainset and frame. It is here now anyway, fit and find out time!

If you don't calibrate the PM then odds on it'll tell you the wrong thing - which, given that you've paid a non-trivial amount of money for it, is undesirable I would suggest.

That's a little embarrassing as I've been using a PowerTap PM on the road bike for a month now.

With a road powertap it is mainly just to make sure that the calibration value is ~512 as it does an auto-calibration on it's own.

The track hub does need a fresh calibration each time for the sake of accuracy though.

It's just one of those things that are best practice - and also allows you to spot if somethings wrong BEFORE putting yourself through the wringer for 8 hours, then finding that your power meter was off by 70 watts and therefore all your data is useless.

Splined sprocket cannot undo, unless your lockring isn't torqued correctly and comes off. I reckon it's better than a threaded sprocket.

A threaded sprocket will usually stay on even if your lockring falls off. Splines are better than threads, but sprocket security isn't a reason.

First 19 mile commute done, impressed. With power on both bikes I can start to build up a better picture of all my riding and start making use of the fitness & freshness charts in strava or Golden Cheetah.

Assuming people find those useful indicators(?).

Interested to hear how all of the new Powertap track owners are going to solve the 40mm chainline problem.

One's going on the Ti Brompton so I'll have to machine new end caps anyway in order to reduce the OLD to 110mm. Anyway, it's a Brompton, so perfect chainline isn't really an issue. On the Macinato I'll just ignore it, but maybe buy a shorter bottom bracket if there's clearance between the chainring and the chainstay. The Shiny Track Bike and the Fixed Winter Trainer will have bottom bracket lengths which will give the correct chainline and, since I'm building those frames myself (long term project), I can dimple the chainstays if necessary to give enough clearance. Easy!

I never even checked the chainline for my PT Track hub, just whacked it straight on the Tempo and have done 1000km or so with it like that. Will look at it tomorrow.

Never done a manual zero either, and all my power data has been consistent across both hubs (geared and track) over thousands of km. Edge 705 so not sure if I can see the calibration value...

Chainline is a tiny bit off on my track PT but I can live with that. Finally got a sprocket from Hubjub (although the other one they sent was the wrong size, sigh ...) so will have a go on the turbo this evening. Initial impressions are good - the torque is VERY stable, even when in reverse and when spinning (torque reads zero - the same as the offset - when the cranks are free running forwards and backwards with no pressure on the pedals). I have a Joule 2.0 which is better for checking these things live than a Garmin 500. Had to add a few spacers here and there to get it into the turbo on a 130mm spaced road frame but seems like it'll be solid enough for indoor work.

Now I'll just find out that I've been riding at 100w or something for the past month having had to rely on Tacx iMagic "power" recently.

You can see it

Had to add a few spacers here and there to get it into the turbo on a 130mm spaced road frame

Pictures please. In your P3?

It looks horrendous. I'll get it done a bit better (had to file away some of the PT axle caps to fit in the dropouts) and take a photo - was in my Olympic themed P2C.

All the data looks good - I ran the Joule and Garmin at the same time, watching the offset and torque values on the Joule the whole time and it didn't change at all (515 from start to finish) which I was very happy with:

http://www.strava.com/activities/226204537/analysis

Right - I can get WI sprockets here in SF. If you want any let @howard know via PM, ASAP if pos.

James Hewitt (jamesphewitt):
Stryd: the first wearable to measure running power. Interested to see how robust the data is. http://www.wired.com/2014/12/review-stryd/?mbid=social_twitter http://pic.twitter.com/WkdAbHRX0B

http://twitter.com/jamesphewitt/status/542643192089157632

If thats ant+ I'm all over it.