Velocity Thracian wheel set

Quoted post said:

Originally posted by Robert Milligan
I now have 1000 miles on new wheels. They are fast.

I have a question. Hostel Shoppe's description of the wheels say that they are a pound of rotational weight less than my current wheels. What is rotational weight as opposed to regular weight? What would better wheels get me?

Any thing that goes around, such as crank pedals chain and wheels. One pound of rolling weight=12
pound of body weight. Bob Milligan V2

bentcruiser said:

I have a question. Hostel Shoppe's description of the wheels say that they are a pound of
rotational weight less than my current wheels. What is rotational weight as opposed to regular
weight? What would better wheels get me?

I assume you're referring to their statement:

A wheel set with 32 hole Shimano LX Hubs and Wienmann Zac 19 Rims weighs 2030 grams. The
Thracian wheelset is 428 grams (almost a pound) lighter and that's rotational weight were
talking about!!

Actually what they are saying is that compared to the lower end wheelset, the Thracian wheelset
weighs 428 grams, or 0.944 lbs less. That is if you compared the wheelsets on a scale the lower end
wheelset weighs about 4.5 lbs, and the Thracian wheelset weighs about 3.5 lbs. I don't know what
"rotational weight" is but they apparently are saying that since a wheel turns, a wheel with a lower
weight (that is, with a lower mass) will also have a lower rotational inertia. Actually that's not
necessarily true, but in practice if the lower mass wheel has had mass removed from it's rim and
tire (not just it's hub) then it will also have a lower rotational inertial.

In practice, when you're riding the a bike at a constant speed the rotational inertia of the wheel
will have no effect on the effort it takes to move the bike up a hill. It will only be felt when you
are accelerating or decelerating. Unless you're a racer and trying to improve your sprinting
performance the rotational inertia of the wheel is probably something you don't really need to care
about. If you're trying to improve your hill climbing ability it's only the mass (the weight) of the
wheel that matters.

For most of us the main benefits of the Thracian wheelset would be it's lower weight and improved
aerodynamics. From what I understand even track racers who win races depending on their sprinting
ability often run wheels with heavy aero rims which actually hurts their sprinting performance but
so little that the improved aero performance is a better trade off.

Rick Moll

Robert Milligan said:

Any thing that goes around, such as crank pedals chain and wheels. One pound of rolling
weight=12 pound of body weight. Bob Milligan V2

I'm glad you like your new wheels, but that 12:1 ratio is not correct. For hill climbing, all
weight, rotating or not, just counts
1:1. For acceleration, mass at the outer radius of the wheels counts
2:1, and the effect of other rotating mass depends on its ratio of tangential speed to that of the
bike speed (or the outermost part of the wheels). If r is the ratio of part tangential speed to
bike speed, the effective mass for acceleration is (1+ r*r) times the actual mass. For example, a
pedal, when ridden in a 75 inch gear (or
3.98 M development), when used on a 170mm crank, moves at .178 times the speed of the bike. Its
effective mass for acceleration is (1 + .178^2) or about 1.03 times its actual mass.

What is more interesting is how little the differences in rotational mass (moment of inertia,
really) matter to bike acceleration, compared to other factors. The website
analyticcycling.comanalyticcycling.comOpen ↗ lets you compare differences in wheels on actual acceleration
performance, and the differences are tiny.

Dave Lehnen

"bentcruiser" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Robert Milligan said:

I now have 1000 miles on new wheels. They are fast.

I have a question. Hostel Shoppe's description of the wheels say that they are a pound of
rotational weight less than my current wheels. What is rotational weight as opposed to regular
weight? What would better wheels get me?

--
Derek, Burley Canto

I was considering that set of wheels but spoke with Mark at Poweroncycling. He told me that set was
heavier than a set of Velocity Razors.

Quoted message said:

I was considering that set of wheels but spoke with Mark at Poweroncycling. He told me that set
was heavier than a set of Velocity Razors.

Just about any wheelset is going to weigh less than Velocity Razors, assuming the same hub. The
Thracians use the Velocity Deep V which is a very strong rim, and thus will weigh more than the
Razors. Considering that the average recumbent rider may be a bit heavier, the selection of Deep V
by Velocity actually makes alot of sense.

I ride Velociy Aerohead 650c which is similar to the Razors in that they are a very light rim but
the wheelset was built by one of the best wheelbuilders around. Choosing a rim is like many
component choices.... a question of weight versus durability. When in doubt go with durability.

I don't know about weight, but my Velocity Thracians are 2 mm wider than the Alexi DA-16s that came
on my Rex. But the hubs on the Velocity Thracians are like silk.....

-Dennis Tresenriter -Groveland, Illinois

Jim C said:

"bentcruiser" <[email hidden]> wrote in message
"]news:[email hidden]... I was considering that set of wheels but spoke with Mark
at Poweroncycling. He told me that set was heavier than a set of Velocity Razors.

Jim, What hub was Mark talking about? I seriously doubt the Razors would be lighter than the
Thracians. I held my 406 Thracian before the tire was mounted. It was like holding a feather. I have
Thracians on my custom Giro and a 32 spoke Razor (Ultegra hub) on my Leprechaun. I find it very hard
to believe 32 spoke Razor rims are lighter than the 20/24 spoke Thracians.

"Jim C" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

"bentcruiser" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Robert Milligan said:

I now have 1000 miles on new wheels. They are fast.

I have a question. Hostel Shoppe's description of the wheels say that they are a pound of
rotational weight less than my current wheels. What is rotational weight as opposed to regular
weight? What would better wheels get me?

--
Derek, Burley Canto

I was considering that set of wheels but spoke with Mark at Poweroncycling. He told me that set
was heavier than a set of Velocity Razors.

"Don" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

Jim, What hub was Mark talking about? I seriously doubt the Razors would be lighter than the
Thracians. I held my 406 Thracian before the tire was mounted. It was like holding a feather. I
have Thracians on my custom Giro and a 32 spoke Razor (Ultegra hub) on my Leprechaun. I find it
very hard to believe 32 spoke Razor rims are lighter than the 20/24 spoke Thracians.

I don't know what hub and can't see that would make a difference as I would assume he was basing his
comment on the weight of the rim or wheels with the same hub, wouldn't make sense otherwise. In any
event I doubt the weight diff is significant and the Thracians look great.

Jim, I think it would have to be different hubs. The Thracian wheels are 20/24 spoke Velocity sealed
bearing. I am not sure they are available separately. In fact, I do not think I have ever seen hubs
with less than 28 spoke holes sold separately.

As I said in my previous post, I have a Razor (black with machined side wall) on my Haluzak. I
forgot to add that it is a very good rim and a great choice. I have the Thracian set on my custom
Giro and I am very pleased with them also(only 275 miles so far).

"Jim C" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

"Don" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

Jim, What hub was Mark talking about? I seriously doubt the Razors would be lighter than the
Thracians. I held my 406 Thracian before the tire was mounted. It was like holding a feather. I
have Thracians on my custom Giro and a 32 spoke Razor (Ultegra hub) on my Leprechaun. I find it
very hard to believe 32 spoke Razor rims are lighter than the 20/24 spoke Thracians.

I don't know what hub and can't see that would make a difference as I would assume he was basing
his comment on the weight of the rim or wheels with the same hub, wouldn't make sense otherwise.
In any event I doubt the weight diff is significant and the Thracians look great.

Tracian uses Aeroheat, not Deep V.

"PJ" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

Quoted message said:

The Thracians use the Velocity Deep V which is

Quoted message said:

a very strong rim, and thus will weigh more than the Razors.

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[email hidden] (Don) wrote in message news:<[email hidden]>...

Quoted message said:

Jim, I think it would have to be different hubs. The Thracian wheels are 20/24 spoke Velocity
sealed bearing. I am not sure they are available separately. In fact, I do not think I have ever
seen hubs with less than 28 spoke holes sold separately.

Some Shimano and Campagnolo hubs are available with 24 spoke holes. American Classic hubs go down to
16 holes. You just have to know where to look.

Jeff