Aero or weight??

A couple of thoughts:

Unless you're on very steep climbs aero almost always trumps small weight differences. Sure a 10 pound aero wheel wouldn't be great but for a couple of hundred grams one way or another you'll have to do a lot of low speed uphill riding before weight is more important than aerodynamics. Yeah, light wheels are nice but wheel weight, even outer rim rotating weight that has the biggest impact on moment of inertia is not as important as many folks think. There's a real nice example over on the analyticcycling web site of the extreme case of acceleration out of crit corners where they demonstrate how even in the first hundred meters out of a tight corner the more aero but heavier wheelset accelerates more quickly than the lighter box style rims. And that's in the situation where light wheels will help the most, the only other case where it can make a difference is on steep climbs where your speed is too low for aerodynamics to make much difference but lower weight is always nice while climbing.

In terms of aero and price. Sure if you're talking 50mm deep carbon clincher rims that are also light that'll cost some cash. But there are plenty of reasonably priced wheelsets that are still very aero. I really like the American Classic 420s which are light and pretty aero with their 34mm rims. You can find the 2008-2009 models as new old stock if you look around and those were a really good deal and both fast and light at sub 1500 grams. Rolf Vigors use the same rims with low spoke counts and are also aero and light but a bit more expensive but deals can be found if you look around. The Reynolds Solitudes are a very nice semi deep (31mm IIRC) alloy wheelset that's pretty light and a real bargain even at full retail. There are others in this class as well if you look around. Even the Performance brand Apollos are pretty nice semi deep aero wheels that are fairly light and very strong.

Anyway there are a lot of good deals to be had on light/aero wheelsets if you don't need full carbon but if it's really that or a power meter, I'd get the power meter as a better investment in your training but that's just me...

-Dave

As always, thanks for the advice Dave. We are actually sponsored by ROLF, and get some pretty sweet deals on their wheels. Based on their website the Vigors are 1.4% more aerodynamically efficient at 25mph than the Ksyrium SL, at least if I am interpreting correctly, the way they do their study is a bit confusing. Do you think I would notice a big difference going to something even slightly more aero like the Vigors? Will it be one of those things, that once I give a set a try I will regret not going with something more aero sooner? I just really like my Ksyriums.

rolfwheels.comtechinfo aero results.phpOpen ↗

bgoetz, this may not apply to you all, but if I could just add a small remark to consider for anyone in this situation below. My thought of consideration only matters if you use longer training routes.

I lead group rides and a couple months ago a guy came to our ride with deep carbon rims on a 65 mile ride. At more than 30 miles from the cars he flatted. He was carry an extra tube and pinched it during the install. He patched it and then a mile later he flatted again. He patched it again. A few miles later it blew again in the middle of back woods nowhere. None of the group (20+ riders) could help him since none of us were carrying tubes with stems that long. Even though I carry two tubes and have semi-aero rims and my stems were way short. Fortunately he was able bum a ride back to the parking lot. I know this was a rare thing to happen, but it did happen and it made a mess of the ride and a pain for him.

So for anyone reading that may want to do longer rides please do not go to a club ride with deep carbon rims unless you carry a couple of tubes and a good patch kit. IMO - it is good to keep a set of training wheels and set of racing wheels. Just sayin'

.....and I forgot to mention. Congrats on the bike build. These are exciting times. [IMG]/img/vbsmilies/smilies/smile.gif[/IMG]

It is amazing that when anyone of our group gets a new bike we all huddle around to look at it. True cycling addicts get excited even when others get new bikes.

As Dave pointed out aero will always trump weight unless fairly steep hills are involved and even then it's a trade off between how much you might lose on the hill with regards to the gains everywhere else out on course. You'd be looking at a long 7%+ hill before you'd start to notice any major difference in performance. Feel... well, they might feel slower and heavier up grades that aren't quite as steep but the actual numbers might tell you otherwise. It all depends on where you ride the most.

Factor in that you don't have to buy wheels in pairs. Sure, the bike might look a little odd but if you're a flatlander then something like a HED Stinger 6 or a 9 on the front may actually trump a pair of lesser wheels, especially given the performance of those HED wheels in crosswinds etc. A front wheel on a road bike typically gives a bigger aero benefit than the rear.

If you know someone who has a set of Zipp 404s or 808s (or even the hybrid set - the 606) for sale and you know they've been taken care of, then that might be a good option too.

My personal take is this: If you're in the market for some wheels and you don't have a powermeter then I'd give that priority. Not only can you train with a more feedback (and something like WKO makes for one hell of a training diary and analysis tool) but you can always work on getting your position a little more sorted too, whether it be for more power, same power more comfort or even more aero less power more speed... you get the idea. Sure you can track progress via results in events but when it comes to a couple of years down the road and you're wondering why you were flying 24 months ago and now things aint quite the same you have pretty much everything there - the numbers and the notes (if you fill in the notes section with meaningful stuff). Stuff like that is priceless. However, it does require a significant investment of time on your part to make the best use of it... It can be just a CPU that sits on the bars or a veritable Pandoras box.

... plus you could always borrow or rent a set of really aero wheels should your plans include riding a TT or two during the course of the year and if you ever want to own a set, well, they're only really a credit card and phone call away - which is something you can't say about lots of really good training.

Quoted post said:

Originally Posted by Felt_Rider [IMG]/img/forum/go_quote.gif[/IMG]
So for anyone reading that may want to do longer rides please do not go to a club ride with deep carbon rims unless you carry a couple of tubes and a good patch kit. IMO - it is good to keep a set of training wheels and set of racing wheels. ...

Good advice to always be prepared, especially if you have unique needs but it's really easy to keep a spare valve extender in your patch kit. It weighs a handful of grams and takes up almost no room. That's exactly what I do for TT training on deep clinchers, then any tube works fine.

Quoted post said:

Do you think I would notice a big difference going to something even slightly more aero like the Vigors?

I haven't looked at Rolf's aero data, but the Vigors at 34mm have to be a lot more aero than the Ksyriums. I raced a couple of seasons on AC 420s and have raced on Zipp 404s clinchers and a set of 50mm deep full carbon tubulars. The AC 420s hold their own against either of the carbon models and are very, very fast wheels. I currently race the tubulars on dry days but go to the 420s for any wet weather racing as carbon brake surfaces are awful when wet.

Here's one comparison of wheel aerodynamics that include the 34mm AC 420 and the Mavic's. Looks like about 6 watts per wheel saved by switching to the deeper 34mm rims at 50kph. Twelve watts of free power in the fast sections is nothing to sneeze at. I've gotta believe the Rolf's re a bit more aero with their low spoke counts.

-Dave
ooops, forgot the link: http://www.rouesartisanales.com/article-15505311.html

Dang, it seems like the Ksyriums are the worst when it comes to aero properties 🙁. Makes me feel kind of bad about my selection of wheels.

Well, this has always been the great debate among wheelbuilders and enthusiasts alike. Although, the answer in the end is it depends. A more aerodynamic (and usually heaver) wheelset is going to feel like it is hard to get up to speed. However, once up to speed, it will maintain that average with less effort due to a bit of extra mass. A lighter, less aero wheelset on the other hand will feel as if it accelerates much more responsively. Again, the downside is that it will be tougher to maintain your average speed due to less rotating weight. So, with that said you must take your riding conditions into consideration. If you live somewhere where it is flatter and you can maintain a pace for a sustained period of time, then you may want to lean in the aerodynamic direction. If you live in a mountainous area, though, they the lighter and more responsive wheelset would probably be a smarter choice.

www.zencyclery.com

I like the wheels you have, and if I were to have to trade wheels for better components I would take the components over the wheels you mentioned Just one persons opinion. Good luck.

Quoted post said:

Originally Posted by daveryanwyoming [IMG]/img/forum/go_quote.gif[/IMG]

Yeah, light wheels are nice but wheel weight, even outer rim rotating weight that has the biggest impact on moment of inertia is not as important as many folks think. There's a real nice example over on the analyticcycling web site of the extreme case of acceleration out of crit corners where they demonstrate how even in the first hundred meters out of a tight corner the more aero but heavier wheelset accelerates more quickly than the lighter box style rims.

Hallelujah!

I've said this before on here a few times, so look away now if you don't wanna see the same boring analogy, but the 'concern' about rotating wheel mass on a bike is complete bollocks and the biggest myth in cycling (probably along with pedal stack height making to a difference to "power transfer" and "feel". What a farkin joke! If someone with one short leg uses a 1cm shim, do they suddenly lose power?! Sh1t like this does my farkin head in :-)). The only time external wheel weight makes any 'real' difference is when the bike is up on a stand, or maybe on a home trainer set to low resistance. :-) My fastest-feeling wheels are my stiffest, which are 2140g DT RR 1.2s, with 32 spokes! Rah!!! :-) They feel faster to accelerate than my Open Pros with db spokes, even though the Open Pros are about 400g lighter.

Sure, heavy wheels contribute to an overall heavy package, which ain't good for up long, steep hills, but other people have already mentioned this.

When I first heard the rotating weight 'theory', I seriously thought the person telling me about it was joking. I thought, "hang on! The tire is being held down very firmly on the road by my not-so-light weight, so while I'm trying to haul the ~89kg (combined weight) of me and my bike out of corner, how the hell is taking a realtively p1ssy 150g off the rims gunna make any difference at all, let alone be noticeable?!!" I laughed at the guy, but then he took offence, and spent the next 20min trying to explain it to me. He came up with the usual flywheel bollocks, so all I could do (coz he wouldn't listen) was keep telling him that a flywheel is a LOT different to an 80kg guy on a bike with a power-to-weight ratio of a fully-loaded dump truck driving through 2-foot-deep mud, riding out of a crit corner with very grippy tyres.

I'm not big on using automotive analogies for cycling discussions, but let's compare a 1500kg car to 72kg rider on an 8kg bike, both accelerating up the road. Suppose the rider, with his combined weight of 80kg, generates 800W (generous?) when 'darting' out of a crit corner; that's a power/weight ratio of 10W/kg. Say the 1500kg has a 200kW engine; that's a power to weight ratio of ~133W/kg. Now, to get the car to the same power to weight level of the rider, it gets a 15kW engine! Can anyone with a 1500kg sedan imagine how sluggish it would be if it suddenly went from having a 200kW motor to having a 15kW motor?!?!?! Then, while struggling to haul this weigt up to 40km/h, imagine what little difference a few kgs off the tyres would make. Eh, whatever...."just for fun", as my Polish buddy says in his terrible English. :-)

You can fudge the numbers with the cyclist (less weight or more output) as much as ya like, but he'll still have a sluggish power-to-weight ratio.

Anyway, to the original poster: although they're not really carbon wheels, Cosmic Carbone SLs are reasonably aero, and are being sold for ok prices at the moment, coz people think they're too heavy. And yeah, I reckon the 'Great Wheel Test' pretty much killed Ksyriums around here as a race wheel. They were ubiquitous for a long time, but seemed to disappear quickly. It probably also coincided with cheaper carbon wheels coming onto the market.

For further reading, check out Alienator's posts on this thread: :-)
http://www.cyclingforums.com/forum/thread/469545/lighter-wheelset-question