I know this topic has been discussed to death but there dosent seem to be a comprehensive answer in the search function.
My question is A comparsion between the power instruments around.
what offers the best value for money…not the best unit.
And secondly; with a limited budget would you advise the purchase of a lesser unit or forgoing the unit for a number of months and getting the superior alternative???
Any advice is much appreciated as i am on the verge of making a purchase!
on a budget, get a Power Tap.
Want the best, get an SRM.
Kurt
There are not too many options out there right now. Polar, SRM, Ergomo, and Powertap. SRM is very expensive. I don’t think you would be too happy with Polar. I know the new model is better but setup is still very crucial and I am not so sure about the accuracy. That leaves Ergomo and Powertap. I have two bikes that I want to use, so I chose Powertap so that I can simply swap the wheel back and forth. If that is not an issue, either will work for you. Both are very good products. Powertap is a bit cheaper. I think you would be plenty happy with either the Powertap or Ergomo.
Mike
I have a PT Pro & an Ergomo. PT Pro for road bike as I don’t change wheels. The Ergo on racr bike as I do change wheels. Both are good tools just depends on your approach as I believe both are same price. Also I like to race AND train with power so this option worked best for me.
If you have one bike either will work just fine.
fal7
Hey hey hey hey!!! 
I’m quite happy with my PT and PT “disc” wheel thank you vey much! 
my lbs did a decent write-up
http://fitwerx.com/NewFiles/Tech%20Center/PowerMeter%20Overview.html
.
There are some down sides to using power: This is from a Tour De France diary by Mark Cavendish in Cycling Weekly “After the first third or fourth cat climb I had to go back to the car because my SRM didn’t go below 550w. I had to get some balck tape to put over the display because it was doing my head in.”
why does everyone seem to be in agreement that the srm is a superior tool??
what are the advantages??
It has been around the longest I guess so is very well tried and tested, and provided it has been calibrated it give good data. It also seems to pretty robust. I am sure the have been and still are occasional problems but you don’t tend to hear too much. I think the fact most Pro seem to use them also helps. It is fairly easy to change cranks over from bike to bike (particularly if you have DA SRMs). It measure power from both legs (unlike the Ergomo - not sure if this is much of an issue though). Less fiddley to set up than the Polar and Ergomo. Allows the use of any wheels.
My wife has a Polar CS600 and I have an Ergomo Pro. She paid $550 on eBay and I paid $1400 plus $300 for a crankset. The CS600 is an ugly installation and the disposable power holder looks like something from the Dollar Store. However, once loose connections in the battery holder were fixed, the CS600 turned out to be a very reliable and accurate unit. Bundled software is excellent and the only other complaint is that memory is relatively short. We only get about 2:20 of data at one second intervals and then recording switches to 5 sec. This is not as big a problem as it might sound, because after two hours, most people aren’t going to be doing short intervals anyway.
In direct comparison I find that the CS600 and the Ergomo Pro read the same power to within a few percent. I love all the features of my Ergomo, but to be quite honest, the answer to your question, “What offers the best value for money?” is the Polar CS600.
If you are thinking about training with power, the book 'Training and Racing with a power meter ’ by Hunter Allen and Andrew Coggan would be a good investment to begin with. It has the most comprehensive discussion of all systems available to date, and tables describing the different features, incl. pros and cons.
Yes, SRM’s are expensive, but (at least the DA version) takes just a couple minutes to switch between bikes (provided you have a decent repair stand), and I haven’t had a single issue with mine. Yes, you’ll need an extra wiring kit, but I believe the same applies if you switch PT-equipped wheels between bikes. I did extensive reading/research before deciding on SRM, and couldn’t be happier with my decision. Last, from doing my research, it seemed that used SRM’s hold their values noticably better than used powerTap’s, Ergomo’s, etc. That is not to put down the other systems, I just figure I’ll want to sell it at some point, and so I’ll get the one that incurs the least $ depreciation.
Best bang for the buck is a used Powertap. You can get those for around $500-600. PTs are more accurate than SRMs and don’t need the recalibration of the SRM. Downside of course is that you are locked to the rim of choice (and no disc version). I’ve been riding PTs for 4 or 5 years now and they read the same now as they did when I first got them.
I’ve got the older Ergomo Sport. My experiences with that and a pal’s newer Ergomo Pro (since sold) would keep me from suggesting the Ergomo. I decided to forego power at my most critical event this year than put my suspect Ergomo on my bike.
what are the differences between the various models of the srm…eg pro version.
what people say that the instalation on the ergmo is ‘‘fiddley’’ what do they mean?? …how so??
SRM versions go up in price with the number of strain gages used. The SRM has an inherent flaw, however. I believe the Amateur version only has a half-Wheatstone bridge configuration for the gages, whereas the Pro has a full Wheatstone. This means better temperature compensation (I believe the PT has a full). As temperature changes, the Amateur would need to be zeroed more often. The half bridge configuration also means it gets higher errors (5% is the stated spec I believe). If you get an SRM, the advice is always to get the pro. An advantage the SRM has over the PT is that it measures at the cranks, so it’s the most direct measurement of what your legs put out. The advantage of the PT is that it measures at the hub, so it’s the most direct measurement of what is being put to the road. Transmission losses are the big unknown.
I’ve had my Ergomo on my TT and track bike. Getting a suitable offset has always been problematic. Some power ranges it’s dead on. Go above or below and it can scatter badly. It gets to the point that I don’t use it for accuracy and only for consistency.
IJSPP, 2(3), September 2007, Copyright © 2007
Validity and Reproducibility of the Ergomo®Pro Power Meter Compared With the SRM and Powertap Power Meters
Sébastien Duc ; Vincent Villerius; William Bertucci ; Frédéric GrappeFull Article Table of Contents for Vol. 2, Iss. 3
Abstract
Purpose: The Ergomo¨Pro (EP) is a power meter that measures power output (PO) during outdoor and indoor cycling via 2 optoelectronic sensors located in the bottom bracket axis. The aim of this study was to determine the validity and the reproducibility of the EP compared with the SRM crank set and Powertap hub (PT). Method: The validity of the EP was tested in the laboratory during 8 submaximal incremental tests (PO: 100 to 400 W), eight 30-min submaximal constant-power tests (PO = 180 W), and 8 sprint tests (PO > 750 W) and in the field during 8 training sessions (time: 181 ± 73 min; PO: ~140 to 150 W). The reproducibility was assessed by calculating the coefficient of PO variation (CV) during the submaximal incremental and constant tests. Results: The EP provided a significantly higher PO than the SRM and PT during the submaximal incremental test: The mean PO differences were +6.3% ± 2.5% and +11.1% ± 2.1%, respectively. The difference was greater during field training sessions (+12.0% ± 5.7% and +16.5% ± 5.9%) but lower during sprint tests (+1.6% ± 2.5% and +3.2% ± 2.7%). The reproducibility of the EP is lower than those of the SRM and PT (CV = 4.1% ± 1.8%, 1.9% ± 0.4%, and 2.1% ± 0.8%, respectively). Conclusions: The EP power meter appears less valid and reliable than the SRM and PT systems.
great, good for you. I am sure it is fine, my athlete Mike Caiazzo raced timberman on that set up.
BUT!! I have done every ride since late 1999 on some brand of power meter, I have used them all (except Polar) and after seeing tons of broken PT’s sent back to Saris (first it was Tune, that is how far back I go) and have the athlete without the unit for at least 7-10 days, I have to say SRM is the choice if the $$$ is not a problem.
I REALLY wanted to like Ergomo…REALLY I think it has some great features. But, I have 2 clients who have or are in the process of getting full refunds from the distributor as the unit never worked right. And yes the install was perfect (face and chase BB, all torque specs met, etc).
So again, I am psyched you have a great and reliable PT, but I get a lot of private messages asking about my ST discount for SRM’s so that has to be worth something…?
So my original response stands.
On a budget, a PT and a disc cover
No budget…contact me about an SRM
KP
I know this topic has been discussed to death but there dosent seem to be a comprehensive answer in the search function.
My question is A comparsion between the power instruments around.
what offers the best value for money…not the best unit.
And secondly; with a limited budget would you advise the purchase of a lesser unit or forgoing the unit for a number of months and getting the superior alternative???
Any advice is much appreciated as i am on the verge of making a purchase!
Hands down, absolute best “bang for the buck” is the older Polar module…especially if you find one used.
(…and to be honest, I really don’t see much advantage of the newer CS600 module over the old one except for the wireless transmission to the head unit and the limited amount of 1 sec. recording.)
One key thing though, if you’re the type of person that would have the LBS install it…skip the Polar and go for a used PT. The best match of owner with the Polar is someone who doesn’t mind “fiddling” a little bit when it’s first installed to make sure it’s operating correctly. It’s not “rocket surgery” to set one up…but it does take a bit of care.
For some installation tips and a Polar vs. PT accuracy comparison, look through this thread:
http://forum.slowtwitch.com/...earch_engine#1427935
The nice things about the Polar are the relative light weight, the ability to use whatever wheels and cranks you’d like, and the altitude sensor
Hope that helps!
Me and my big mouth. Glad I live in the desert where it never rains. Got caught in a cold front (60’s and rain!) moving thru today and 2 minutes in my training PT hub died. ARGH!!! I’ll dry it out and it’ll be fine tomorrow… that or i ride the 808 PT (I hate doing that). Yeah… if I had the $$$ then maybe on the SRM. But I dont think I could sell all my power stuff and come up with enough to get one and another rear race wheel.
I echo your thoughts on the ergomo… it just doesn’t cooperate tho.
BTW… howz Amos?
IMHO the whole point of a power meter is accuracy. I have not seen any PM match SRM in this regard. This is quite possibly the best most reliable piece of equipment on my bike. Polar is absolute crap… There is a reason you can pick up a cheap Power Tap on EBAY as well and its not because the owner loved it.
SRM is the way to go…
I bought a used PowerTap SL on E-bay for $470.00. Works just as well as the PT SL I bought for $1000 in 2006. Never had a problem with either PT SL. Very easy to use. No experience with SRM, Ergomo, or Polar.