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Wider Rims? To change or not to change

rklingrkling
in General Training Discussions

I have a set of HED wheels:  Stinger 5.0 front and HED 3C rear.  I have been thinking about getting a different set of wheels with a wider rim, since all the latest information is that a wider tire has less rolling resistance (the Stinger is from 2005, so the width is narrower (20 mm or so) and it's more of a V-profile (vs. toroidal), and the HED 3C is 19 mm.  I was looking at these:  http://www.neuvationcycling.com/pro...t-1497.htm.  They're not Firecrest, but the rim profile looks fairly similar (to my untrained eyes) and the width is 25 mm, so I can definitely run a wider tire without a big aerodynamic penalty.  With these wheels, I can also put a wheelcover on the rear.

What do you smart people think?  Am I better off getting a less-expensive wheelset like this (assume that Zipp and HED wheels are too expensive for me), or should I just stick with the wheels that I have?

Comments

  • jwpicciottojwpicciotto
    It depends. Is the 5 minutes you might gain on an IM race the difference between you winning your age group or not?
  • MattAaronsonMattAaronson
    At 3.9 watts per kg you're I suspect your probably starting to get to the point where there are reasonably high returns to something that will only make you go a LITTLE BIT faster. But "returns" is a strange concept since it varies based on your own personal utility function. Btw I doubt that the wheel switch you mention will really gain you 5 full minutes, ex of psychological impact on performance.
  • jwpicciottojwpicciotto

    @Matt - Exactly my point.  Even if somehow you are able to extract some amazing return out of the switch you have to ask whether the investment is worth the benefit.  For 99% of us the "benefit" we might get from this obsessive Tri focus on engineering statistics is not worth the cost.  Instead it seems to be a justification to make a purchase of something new. 

  • rklingrkling
    Well, good point. I'm not looking at it solely from a point of faster wheels, although running a disc in the back will supposedly be faster than my tri-spoke. But wider rims means wider tires and lower tire pressure (from what I understand), so the lower pressure will be more comfortable, and is also supposed to be faster.
  • harrastharrast
    Okay, first I still have a question mark in my mind about the numbers. It is pretty well accepted that wider tires have lower rolling resistance than narrower tires within a certain range of tire widths--we don't see anybody riding the bike course on tractor tires. I have read that rolling resistance decreases by about 1 watt per 1mm of tire width increase, while wind resistance increases by about 4 watts for the same increase. The first question is, is this true? Does wind resistance really trump rolling resistance? Someone more familiar with fluid dynamics will have to answer this. I can't. But it does make we want a narrower tire, at least on the front, all other things being equal. Sorry to muddy the water.
  • Dino SartiDino Sarti
    Easy answer... Which would look cooler? What's more pro? Those are the questions I generally ask when making purchase decisions.... image
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