Ergomo Validity shot down....

acoggan

Can you clarify your question?

(If you mean that tightening/loosening the crank arm fixing bolt or chainring bolts of an SRM can change the offset, the answer is "yes"...just like tightening/loosening the b.b. changes the offset of an Ergomo.)

Roadie_scum

AIS is the Australian institute. They have some of the best mechanics in Australia. And my experience of scientists is that they are very careful to follow instructions and tread carefully when setting up equipment. Otherwise they would never get valid results. I'm not a bad mechanic, but I'm willing to put it out there that the AIS would install a BB better than me. Some AIS guys tested a bunch of power meters in field conditions. It hasn't been written up completely in a scientific study but some results and discussion were published across several issues of Ride Magazine. In this example, Ergomo was found to overreport by 13% on the average, and not be consistent about it. Powertap and SRM were very good indeed. iBike was 'surprisingly accurate' going uphill, but obviously gets thrown out by a range of factors.

acoggan

Which isn't all that suprising, really - it's accounting for the power required to overcome wind resistance that's tricky.

Roadie_scum

True that. It makes me think, though, if you live near a long, constant climb and only want to use your PM for pacing efforts, iBike might be better than Ergomo and certainly much cheaper. I would want to see more info, but from the AIS test, it tracked the SRM very closely on climbs - not that surprising, as you say.

Of course, when you can buy a powertap pro hub off ebay for 3/10ths of not much, or a new one for a reasonable price, why go for something that doesn't work?

Speedskater

That was what I wanted to know, thanks.

yawg

Thanks Robert and Andy. Procedure worked great. I went with 20kg and the PT was within ~1% for the gear ratios I tested.

greg

9202

I "WAS" thinking about getting a PM. My LBS discussed the purchase and recommended that I not waste my money on an Ibike, Polar, or Ergomo. They said that have sent back at least a dozen Polar units for various reasons and have never been able to get an Ergomo working accurately.

They said that if I "really" wanted a PM, get an SRM, but even those have been known to have issues.

At this point, I am really baffled by the whole power meter market and wish that there was an easy answer. Maybe next year.

Speedskater

When I read your LBS having problems with about every PM, the question arises if it´s the PM or your LBS causing this problems. It´s like PEBCAK on computers (Problem Exists Between Chair And Keyboard).

jbvcoaching

Unless Quark becomes the first powermeter in history to enter the market with zero issues, I wouldn't bet on it. If you want a powermeter, you're going to have to look at the shortcomings of the few viable systems and how they impact your own situation, and then decide if you can live with them (and if they're worth the money and effort).

If you think that's going to be too frustrating for you (I've been using powermeters for over 6 years, I understand how frustrating they can get), then maybe wait a few more years.

The nice thing about the PMs that have been on the market a while (SRM, wired PT) is that pretty much all the shortcomings are known and either resolved by the company, or there's a fix out there on the internet.

9202

Appreciate the thoughts, very helpful and gives me a lot of realistic information.

With respect to the "other post", there is no one better IMO, than a shop that specializes in training and unstallation of a large amount of power meters. Their experience is of course limited to their locale, but the sample is still significant.

When one shop has to send back numerous units, people would be foolish not to pay attention.

From what I have read, it appears that the most bang for the buck seems to be PT and perhaps the best overall unit may be the SRM.

Thanks folks.