fulcrum R3's vs Campy Eurus?

[dmp]

tried to search this with no luck.

I am considering an offer to trade my Fulcrum R3's (2008 vintage I believe) for a set of '09 or '10 Campy Eurus wheels (the trade is predicated on esthetics - my friend would like all black wheels, and his Eurus's are silver, and he's not concerned about the extra 150gms. For me, I would love to lose the 150gms even though I prefer the black wheel set!). My main concern is how much less forgiving will the ride be on the Eurus's? My LBS manager (who I trust) thinks I may find the ride a lot rougher due the added stiffness of the alu vs steel spokes, and I'm just looking for other opinions to corroborate or disagree. I'm 129lbs (59kg), and ride a Pinarello Paris, and I'd give our pavement surfaces a 3.5-4/5. The wheels are not local, so unfortunately I can't make a comparison ride. FWIW, I am also thinking strongly of getting a set of wheels made up with Stans 340's and Alchemy hubs that would come in at about 1300g; the Eurus's (or Fulcrums) would then go on my steel Pinarello.

[bm0p700f]

Radial stiffnes of a wheel is primarilary dependnet of rim stiffness if steel spokes are used as steel spokes are so much stiffer than aluminum.

Wheel stiffjness = Rim stiffness/(1+(rim stiffness/spoke stifness))

If spoke stiffness is high the bottom term is near 1 so wheel stiffness ~ rim stiffness!

Alu spoke due to there large diameter as stiff as steel spokes so wheel stiffness ~ rim stiffness. So which wheel has the stiffer rim you may ask well it does not matter for comfort.

I am talking about radial stiffness here as that what would be important for comfort if it worked that way. The radial stiffness of a wheel will be in the order of 3000-40000N/mm regardless of what spokes are used cross pattern e.t.c. With the load required to produce 1mm of radial wheel deflection (1mm of delfection is hardly suspension) producing a vertical acceleration in the order of 8g I would challange you feel the difference in comfort bewtween the Fulcrum's and campy wheels. Essentiaslly wheel are so stiff they barely deform radially. Greater radial deflection would be a kind of suspension or vibration damping and simply does not happen in reality.

I think your LBS manager is talking from assumptions (quite reasonables ones as well) but these assumptions are not held up when the forces on a wheel are analaysed.

[sawyer]

Any experienced rider will tell you that steel spoked wheels are normally more forgiving than big alu spoked wheels. I've not ridden F3s, but have Zondas (same front, similar rear) and have owned and ridden pretty much all of them (Eurus, Shamals, Mavics etc. etc.).

You will notice the difference. Eurus are really stiff good climbing wheels though.

[dmp]

bm0p- so you are saying that there will not be an appreciable difference if the rims are of similar stiffness (which I think they are- similar rims, although slightly lower profile on the front and higher on the rear on the Eurus's) and spoke profile (which are similar).
Sawyer- the profile of both spokes (wide blade) are nearly identical if not identical. Does that change your opinion? I thought the Zondas have steel spokes.

[Kjetil]

Zondas/R3s will behave better in cross winds than Eurus'/R1s.
There are more losses than gains if you move higher up in the hierarchy than Zonda/R3 (or mavic ksyrium elite), at least if you factor out the marketing claims.

[bm0p700f]

I think different issues are being confused here. I will define what I mean clearly. By forgiving ride the radial stiffness is all that is important as any flex here will absorb energy but as it does not matter what spokes are used ecause the radiallly wheels are so stiff as to not deform (vertically) in any detecable way when riden (as I have already explained) then this a dead end.

The acoustic properties of Alu spokes and steel spokes will be different. Given we can feel sound this is maybe what is being described as a more forgiving ride on steel spokes.

The lateral stiffness of both wheels will probably be different though and this is what sayer is on about when he says they are good climbing wheels.

There are three types of stifness in a wheel, 1) radial, 2) lateral, 3) tortional. We should be more clear (all of us) when we use the term stiffness and say what stiffness we are on about. Other wise we can start talking cross purposes far too easily.

[hjb1000]

I've ridden the Zonda's (pretty much the same as the R3) and they are great wheels.
Steel spokes are better in the sense they are a lot more durable and reliable, as well as cheaper when replacing.
Also the weight difference between the Zonda and the Eurus is very marginal considering the price difference.

[Stolichnaya]

Nothing you can't tune with proper tire and pressure choice.

[sawyer]

bmp - you may be right. The upshot, whatever the explanation, is that Zondas (thin steel spokes) have a notably more forgiving ride than say Shamals (same number of much fatter alu spokes) with same tyres, bike, pressure etc. The difference is quite dramatic in fact - similar to going 23 >25mm tyres or dropping 25psi.

Stolichnaya - the problem with your comment is that you want to optimise tyre choice and pressure for speed primarily ... comfort of course comes into it, but if you can have that comfort from a different wheelset without compromising speed, or a frame, saddle or pair of shorts for that matter, why not?

To the OP. F3s nowadays have thinish steel spokes compared to fat Eurus spokes from 2006 onwards (may have slimmed down slightly from 2010 or so onwards).

[dmp]

Sawyer (and Kjetil), I know that the new Zondas have a smaller cross section spoke, but my R3's are 3-4 years old and have the wider bladed spokes of the same cross section as the Eurus (if I'm not mistaken, the new R3's retain the wider blades, too). The Eurus wheels in question are 2010's.

bm0p- then what is the factor that seems to account for the difference that some people are describing? Is it the resonance differences between the metals that makes them feel different, or are there other factors that are confounding (like tire inflation, tire type and width, etc)? I guess I am still left in confusion as to whether I should just stick with what I have or make the trade!

[bm0p700f]

Only you can decide that which wheel is best. People do feel differences between wheels so there has to be something in it but certain causes can be ruled out. What is described as a forgiving ride is so subjective and sound/vibration must play a big part in that. The spoke/rim will act as vibration/sound dampers to greater or lesser extent. Therefore spoke/rim differences between wheels should affect the "feel".

I would imagine a wheel which transmits sound/vibration well (same thing) will feel harsh like a deep v carbon wheel or disc. Where as a wheel which dampens a bit more those vibrations could feel more forgiving. A bit like putting wider tyres on and running lower pressures. This is the only resonable explaination I can think of short of doing FEM analysis on both wheels to see how viration is transmitted.

Only you an decide if the ride is acceptable or not and the only way to find out is try them.

Edited for spelling.