SRM-which one??

[rockymtguy]

Hi All,

I am thinking of getting a SRMfor my road bike.

I am mainly a mt biker but train and race road. The amatuer has a 5% +/- accuracy and the pro 2%.

Any suggetions on where to start?

Thanks

Rockymtguy

[Chris Helwig]

I would suggest it is a cost/benefit analysis.

If cost isn't a huge factor, the +- 2% accuracy would be much nicer. This would gaurentee the wattage you use for training, the zones you use etc. are all as accurate as possible. I would also think the pro model might have a better durability.

Now if cost is a factor maybe 5% you could live with. My concern would be that if all your zones and your threshold could potentially be off by 5%, while not huge it could be significant.

[Graydon]

What you want to find out, more than the accuracty, is the reliability of the SRM. Who cares if it's out by a few watts if it's ALWAYS out by the same few watts. I've never used an SRM, so I can't comment. I do believe there is scientific articles out there... a quick PubMed search would likely answer your question.

If cost is a factor, I'd look at the new wireless powertap. Even if cost wasn't a factor, now that it's wireless, I like the idea of simply pulling off the rear wheel and instantly you can be back to lightweight race bike. Not so easy with the SRM crank.

[Chuck Norris]

Enlightening article:

http://www.biketechreview.com/archive/pm_review.htm

Read it a few years ago and it basically made up my mind for me.

[fancy]

yeah i agree with graydon. the new wireless power tap is a great idea. for that matter, even the one with the wire is great. i have the sl pro carbon version. its not that heavy as it is. but pop off you rear wheel and your bike is light again. i don't think the wires add that much weight anyway.

[Graydon]

1: Stapelfeldt B, Mornieux G, Oberheim R, Belli A, Gollhofer A.
Development and Evaluation of a New Bicycle Instrument for Measurements of
Pedal Forces and Power Output in Cycling.
Int J Sports Med. 2006 Oct 6; [Epub ahead of print]
PMID: 17024643 [PubMed - as supplied by publisher]

2: Hurst HT, Atkins S.
Agreement between polar and SRM mobile ergometer systems during
laboratory-based high-intensity, intermittent cycling activity.
J Sports Sci. 2006 Aug;24(8):863-8.
PMID: 16815781 [PubMed - indexed for MEDLINE]

3: Bertucci W, Duc S, Villerius V, Pernin JN, Grappe F.
Validity and reliability of the PowerTap mobile cycling powermeter when
compared with the SRM Device.
Int J Sports Med. 2005 Dec;26(10):868-73.
PMID: 16320172 [PubMed - indexed for MEDLINE]

4: Millet GP, Tronche C, Fuster N, Bentley DJ, Candau R.
Validity and reliability of the Polar S710 mobile cycling powermeter.
Int J Sports Med. 2003 Apr;24(3):156-61.
PMID: 12740731 [PubMed - indexed for MEDLINE]

[rockymtguy]

Thanks for all the info !

I will check out all the articles and make a decision, then let you know.

Thanks again,

Rockymtguy