Brett 12

So I am ready to buy a wheelset for my upcoming build project....(campagnolo 10s)

I am thinking of getting the Velocity "Spartacus" wheels (Deep V and 20/24 spokes).

Considering that decreasing spoke count and having Deep V rim reduces drag (spokes near the rim move the fastest....deep V reduces length of spoke).

How much faster in mph could a cyclist be on flat ground if the old wheelset was 36/36 spoke and box type rim? How about reduction in power output to say maintain 20 mph? 30 mph?

Total spokes would be reduced from 72 to 44 and then there is the issue of the Deep V reducing spoke speed as well.

I figure somebody with analytical software knows the answer to this........or maybe it is all just marketing hype?

Ralph Turney

Brett 12,

I have that wheel on the front of my old bike after I turned the original one into a taco. I don't think it made any difference at all, except that the wheel 'looked' light years ahead of the 15 or 20 year old mavic that was on it.

michaelyons

whay your basicly describing is a bontrager race x lite aero. mine are 16 front and 20 back with the deep v rim. I did notice a difference in sustainable speed. I cant say that they made me faster, but definately smoother in the 25 to 35 mph range.

mike

Brett 12

Velocity offers 16/20 for riders under 180lbs. I'm getting the 20/24 (plus I think the extra spokes make it look better). They even have a 24/32 version also (Actually they can even make a 40 spoke rear Deep V.....that would be overkill city though )

Something tells me that it might reduce effort at 20 mph by 1% (just a wild guess) 30 mph maybe 2-3%.....but then again if you were time trialing that 1-3% could mean the difference between 1st place and 8th place if competition was really close.

I'm just wondering if anyone has hard numbers.....I think there is a forum member called "SSP" that has some analytical software.

RoadToad

I have no hard evidence, but I just got the 16/20 version spartacus wheelset. They are conceivably (maybe all in my head) faster than my old, heavy Alex DA16's. I like them and they are tons lighter. That in itself was a big bonus. Check your PM by the way...

RT

55/Rad

It's not so much about reducing effort as it is about possible gains given the same effort.

I can't tell you anything about the Spartacus but I can tell you that I feel a noticeable difference between my Rolf Vigors and my Bonty Race X-Lite Aeros. The Aeros weigh almost 300 grams more - which led me to believe I'd feel it more on the hills. But that's not the case - climbing seems very similar but the sustained speed on flats appears to be improved.

55/Rad

miamijim

Without getting into it too deep a 100 gram decrease in drag will save you:

30 secs @ 30mph over 25 miles
40 secs @ 25mph over 25 miles
50 secs @ 20mph over 25 miles
70 secs @ 15mph over 25 miles

A typical 36 spoke wheels has a drag of 260+- grams while a dsik wheel has a drag of 110+- so thers a 150g difference between the best and worst of wheels. In a nutshell...its not going to save you much....

BTW...the above chart is correct...I cant explain why you save more time at lower speeds...I only copied it from the book.

Brett 12

That would definitely be noticeable in a Time Trial.......on the typical training ride maybe not. ......looks like 1-2% increase in speed.

miamijim

Brett keep in mind that a 100gram decrease is drag is not dpendent on where it comes from. If you save 100 grams on more efficient rind position or from a dcrease in spoke count its all the same. Whats interesting to note is TT racing. As soon a rider compromises his riding position he might as well be ridding a Huffy from Wal Mart.

terrymorse 

On that note, here's a web site that compares the cost and benefit of Aerodynamic Changes to bike and rider. Scroll down the page for the table.

Who knew that shoe covers gave such a bang for the buck?