View Full Version : Benefits of bladed spokes


imetis
03-13-2007, 08:35 AM
I just ordered a new wheelset with aero profile rims and bladed spokes weighing in at just over 1800 gms. My current wheelset is AC420 with round spokes at 1460 gms. I'm wondering if the bladed spokes will provide enough aero benefit to make them faster than the other lighter wheels. Any thoughts on that? I've tried searching and not found any really good data on bladed vs round efficiencies.

My intent is to use this new cheap wheelset for training, so it really doesn't matter, and I'll find out when they get here, and ultimately race the faster wheels, but I'm curious whether anyone has seen good studies on the subject.

ttug
03-13-2007, 08:39 AM
Check out analyticycling.com. You may want to google it for the correct link as my spelling is very very bad.

Wheel weight etc etc and blades spokes? What is the course, what is the rim profile, what type of bike etc etc etc etc too many variables prevent a correct answer. However, in all honesty, there are some very very strong opinions on this topic. I am not an exception, but hey, go nuts with the numbers and save your money.

bas
03-13-2007, 09:10 AM
I just ordered a new wheelset with aero profile rims and bladed spokes weighing in at just over 1800 gms. My current wheelset is AC420 with round spokes at 1460 gms. I'm wondering if the bladed spokes will provide enough aero benefit to make them faster than the other lighter wheels. Any thoughts on that? I've tried searching and not found any really good data on bladed vs round efficiencies.

My intent is to use this new cheap wheelset for training, so it really doesn't matter, and I'll find out when they get here, and ultimately race the faster wheels, but I'm curious whether anyone has seen good studies on the subject.


sometimes i'd love to compare crosswinds with non bladed and bladed rims.

sometimes that front wheel just goes loco and turns in a strong cross wind.. not sure if its the bladed rims or other.

but i'm sure they cut up cicadas just as well..

Fixed
03-13-2007, 09:26 AM
I just ordered a new wheelset with aero profile rims and bladed spokes weighing in at just over 1800 gms. My current wheelset is AC420 with round spokes at 1460 gms. I'm wondering if the bladed spokes will provide enough aero benefit to make them faster than the other lighter wheels. Any thoughts on that? I've tried searching and not found any really good data on bladed vs round efficiencies.

My intent is to use this new cheap wheelset for training, so it really doesn't matter, and I'll find out when they get here, and ultimately race the faster wheels, but I'm curious whether anyone has seen good studies on the subject.

I read that a properly aero shaped cylinder (like a spoke) will have the same drag as a round cylinder 1/10th the same cross section. Bladed spokes are not real aero shaped, but partially so. So, I assume they will have less drag. Now, the question is how much drag is there from the spokes to begin with, then how much less would the aero spokes have? No idea, other than "less."

Typically, unless you're climbing 10% grades at less than 10 mph, good aero wheels are faster than lighter, non-aero wheels.

Argentius
03-13-2007, 09:26 AM
Bladed spokes make neat swooshy noises, that's how they help!

It's really hard for wind-tunnel type studies to measure the benefit of bladed spokes, since they move all around, and in the real world, the rider is facing wind from all kinds of angles.

Consensus seems to be that they help a bit against head-on wind, and probably don't against side winds, but I'm not too sure.

One thing that DOES seem to be agreed on is spokes are a large part of drag. The more spoke area, the more drag. AC420's have a reasonably low spoke count, and reasonably short spokes. Lots of people like the lightweight AC350's, but they have lots of spokes, and they are longer.

That will make a difference on its own. Campy Shamals were pretty darn aero, if I recall...

uzziefly
03-13-2007, 09:30 AM
So why does Zipp have lotsa spokes?

I loe my race x lite carbon aeros with 16 spokes. :)

cdhbrad
03-13-2007, 09:39 AM
Zipp 303s use 18 Frt and 24 Rear spokes, same as the AC 420s . The AC 350s I just sold with a TT bike had 28 Frt and 32 Rear. I preferred the feel of the 420s over the 350s, that's I sold them with the bike.

The Flash
03-13-2007, 07:06 PM
I have both sets, as well as the Hurricanes with a powertap....420's for TT's and races without heavy turning. The 350's for climbing and hill courses and the Hurricane's for crits and training....

For the most part, I use the Hurricanes 90% of the time....

The Flash

RSPDiver
03-13-2007, 08:03 PM
Seems like I've seen it stated on this board as fact that DB tapered spokes, thinner in the middle, actually maintain an aero advantage over bladed spokes, and are much less prone (perhaps obviously) than the bladed spokes, especially very wide ones like on the Mavic Ksyriums. I've held onto that info, true or not, as I begin considering a race wheelset. Can anyone confirm or refute?

homebrew
03-14-2007, 04:06 AM
Seems like I've seen it stated on this board as fact that DB tapered spokes, thinner in the middle, actually maintain an aero advantage over bladed spokes, and are much less prone (perhaps obviously) than the bladed spokes, especially very wide ones like on the Mavic Ksyriums. I've held onto that info, true or not, as I begin considering a race wheelset. Can anyone confirm or refute?
Thats the problem with this question. Not all bladed spokes are the same. Not all bladed spokes are even areo. Kysrium are not areo, they are thick with a flat leading edge. cxrays are very areo in contrast. When riding Ksyriums you hear the spokes beating the air. the cxrays are silent. I don't know if campy makes the spokes for there Boras but the are very areo as well. In all my NON Scientific comparisions areo spokes do make a difference esp as speeds increase.

Kickit
03-15-2007, 11:44 AM
The big advantage of bladed spokes is they look really cool. No studies necessary, just ask anybody... :thumbsup:

imetis
03-15-2007, 11:56 AM
That they do, especially laced like the Starlites that I just ordered

http://www.vueltausa.com/images/products/road-wheelsets/rollovers/starlite-al.jpg

Description at: http://www.vueltausa.com/products/road-wheelsets/starlite-al.htm

zeeke
03-18-2007, 07:18 PM
That they do, especially laced like the Starlites that I just ordered

http://www.vueltausa.com/images/products/road-wheelsets/rollovers/starlite-al.jpg

Description at: http://www.vueltausa.com/products/road-wheelsets/starlite-al.htm


Holy cow those are heavy.

imetis
03-19-2007, 06:48 AM
Looks to me like 1800ish grams is pretty standard for all but very expensive road wheels. Anyway, that was the point of this thread, do the blades add enough efficiency to make up for the weight?

I'm going to put wire bead gatorskins and a 105 cassette on them to really make them heavy, then the AC420's with Pro2 Race tires will fly on race day :)

Kerry Irons
03-19-2007, 10:47 AM
Looks to me like 1800ish grams is pretty standard for all but very expensive road wheels.

Or about 1640 for a totally stock, Campy Chorus, 32 spoke, 3X, 15/16 DT competition spoke, Velocity Aerohead wheel set. :)

imetis
03-19-2007, 11:07 AM
Which I'm sure cost significantly more than the $200 including tubes & tires I paid for these.

uzziefly
03-19-2007, 11:20 AM
Or about 1640 for a totally stock, Campy Chorus, 32 spoke, 3X, 15/16 DT competition spoke, Velocity Aerohead wheel set. :)


If not for that word Campy, it'd be great. :D

Ok just kidding there.