[HazemBata]

I am looking to buy a ti frame soon. One of things I will miss is the inherent vibration dampening of carbon fiber frames. I am looking to compensate for ti's inability to dampen vibration (relative to carbon) with the wheels.

I know that carbon rim wheels help dampen vibration. I have also read in numerous places that the Topolino's carbon/kevlar spokes also reduce vibration.

So my question is this: all else being equal, which will dampen vibration better, a carbon rim wheel with metal spokes (zipp, reynolds, etc) or Topolinos with carbon/kevlar spokes and an aluminum rim? I am looking for responces from people that have ridden both.

Thanks.

 

[alienator]

Lower inflation pressure and/or wider tires. That's what'll better damp vibes.

 

[filtersweep]

Lower inflation pressure and/or wider tires. That's what'll better damp vibes.

Exactly- Wheels should be stiff. Use the fork or other parts of the bike to soak up bumps and vibrations...

BTW- while I ride carbon, I have never heard a Ti rider complain about a nasty ride.

Having owned carbon wheels, I would say there is nothing inherently vibration dampening about them. The carbon is usually so they can build a deeper, lighter rim- it really serves no other purpose.

I have never ridden Toplinos, but I do not like their design at all.

 

[rruff]

So my question is this: all else being equal, which will dampen vibration better, a carbon rim wheel with metal spokes (zipp, reynolds, etc) or Topolinos with carbon/kevlar spokes and an aluminum rim? I am looking for responces from people that have ridden both.

So... you are looking for a lot of placebo induced opinions, rather than science? Truly, you wouldn't be able to tell... the vertical deflection of the rim and spokes is vanishingly small. You might get a little flex out of the seatpost if you have a compact frame. The stem, bars, and fork all flex quite a bit. Thick handlebar tape and a comfortable saddle will also help. #1 though, is use supple tires and the lowest pressure you can without getting pinch flats.

If you want to go *fast* then go with the aero rim and aero (ss) spokes.

 

[Ligero]

So... you are looking for a lot of placebo induced opinions, rather than science? Truly, you wouldn't be able to tell... the vertical deflection of the rim and spokes is vanishingly small. You might get a little flex out of the seatpost if you have a compact frame. The stem, bars, and fork all flex quite a bit. Thick handlebar tape and a comfortable saddle will also help. #1 though, is use supple tires and the lowest pressure you can without getting pinch flats.

If you want to go *fast* then go with the aero rim and aero (ss) spokes.

This is one time that I think the correct question was asked and I don't think that what he is asking for is a placebo. He is asking which pair of wheels will reduce vibration better and not which wheels will be more comfortable by the wheel absorbing impact through flexing of the rim. One of the reasons higher spoke count wheels feel more "comfortable" is because they use more spokes which help absorb vibrations before they get transfered to the frame, they are not flexing.

One of Topolinos claims to fame is that their carbon/kevlar spokes absorb vibrations that would otherwise be transfered to the frame and then to the rider. So he is correct that the Topolinos would do what he wants. I don't think that he should buy a pair but they would work for his needs. The reason I don't think he should buy a pair is because first I do not like pre-built wheels, especially ones that you cannot fix your self, second is because they have a history of having bearing problems and third is I think they just look cheap! For the amount of money that Topolinos go for I would expect them to look a little higher quality, they look like they are injection molded plastic (which basically they are) and should have a price tag at least half of what they are going for.

 

[Mark McM]

Adding spokes increases damping?

One of the reasons higher spoke count wheels feel more "comfortable" is because they use more spokes which help absorb vibrations before they get transfered to the frame, they are not flexing.

I'm not sure how this can be. Metal spokes have nearly zero hysteresis damping, so they provide essentially no vibration damping (at least as compared to other components in the load path, like the tires, saddle, handlbar tape, etc.). Adding more spokes will increase damping of the spokes from nearly zero to still nearly zero.

In addition, in order to damp a motion (vibration is simply an oscillitory motion), there has to be motion to begin with. Since the spokes are so stiff (vertically), there is very little flex, and therefore little energy available to be damped.

If you added extra springs to your car's suspension, would the suspension absorb more vibration, or would it be stiffer and absorb less vibration? Adding extra spokes to the wheel would have the same effect.

 

[HazemBata]

Thanks for all the replies everyone. But as Ligero pointed out my concern is vibrations, not bumps.

Carbon definatly dampens vibration compared to metal. I have test riden carbon and aluminum frames back to back and the difference is very noticable.

How much dampening that translates into for carbon rims....well, that's the question.

 

[alienator]

Thanks for all the replies everyone. But as Ligero pointed out my concern is vibrations, not bumps.

Carbon definatly dampens vibration compared to metal. I have test riden carbon and aluminum frames back to back and the difference is very noticable.

How much dampening that translates into for carbon rims....well, that's the question.

And the same still applies. The best damper on the bike, aside from a rider's jelloee mass, is the tire/tube combo. As a damper, it, uhm, damps vibes. You can't say that CF composite is absolutely a better "damper" than metal. It depends on the system, the metal, the CF composite. Whatever the material, you're pretty unlikely to notice any difference in damping.

 

[rruff]

One of the reasons higher spoke count wheels feel more "comfortable" is because they use more spokes which help absorb vibrations before they get transfered to the frame, they are not flexing.

That sounds pretty suspicious to me... but who knows...

It seems like a definitive test could be done using accelerometers mounted at various places. Does anybody here have access to the equipment to do this?

 

[Mark McM]

A quick demonstration of damping in tires

And the same still applies. The best damper on the bike, aside from a rider's jelloee mass, is the tire/tube combo. As a damper, it, uhm, damps vibes. You can't say that CF composite is absolutely a better "damper" than metal. It depends on the system, the metal, the CF composite. Whatever the material, you're pretty unlikely to notice any difference in damping.

Anybody can do a quick test to get a feel (literally) of the damping and compliance that the tire provides. Remove the tires from the wheels, and ride on the bare rims - even on relatively smooth pavement, you'll still get a teeth rattling vibration. Hitting a modest bump will practically toss you off the bike. This will give you an idea of the amount of shock absorption that the tires normally supply (and the amount of damping and compliance that the rest of the bike doesn't supply).

Don't want to damage your rims from riding direclty on pavement? Just leave the tires on and completely deflate then. You'll still get a little compliance and damping from the thin layer or rubber, but the ride will still be very rough and harsh - again showing that damping and shock absorption are primarily from the inflated tires (and very little from the rest of the bike).

 

[Jesse D Smith]

Anybody can do a quick test to get a feel (literally) of the damping and compliance that the tire provides. Remove the tires from the wheels, and ride on the bare rims - even on relatively smooth pavement, you'll still get a teeth rattling vibration. Hitting a modest bump will practically toss you off the bike. This will give you an idea of the amount of shock absorption that the tires normally supply (and the amount of damping and compliance that the rest of the bike doesn't supply).

Don't want to damage your rims from riding direclty on pavement? Just leave the tires on and completely deflate then. You'll still get a little compliance and damping from the thin layer or rubber, but the ride will still be very rough and harsh - again showing that damping and shock absorption are primarily from the inflated tires (and very little from the rest of the bike).

I tried the experiment you suggested and I wound up wiping out on a fast decent. Since you failed to provide a disclaimer warning of the possibility of such a danger, I feel you are responsible and owe me restitution. I take cash and paypal only.

 

[oneslowmofo]

Have both on my Moots

I've got a pair of Campy Hyperon clinchers and the new Topolino C29s (30mm deep rim with the carbon/kevlar spokes). The topolinos definately mute road buzz better than the campys but it's splitting hairs as they both are far better than my old Ksyriums SLs.

To address your issue those, I've got a C50 and the moots. They both mute road buzz far better than the aluminum frames that I've had (with the exception of the Cyfac Nerv). I don't think that you're losing much with going to ti unless you go with a Litespeed Ultimate or Vortex.

Here are a couple of pics with the Moots with both.

 

[orange_julius]

To address your issue those, I've got a C50 and the moots. They both mute road buzz far better than the aluminum frames that I've had (with the exception of the Cyfac Nerv).

From one Nerv owner to another: That's an interesting observation!

My roommate has an alu/carbon Cyfac that used to be called Proxidium Carbon model, with a carbon monostay system, and without the dimples on the carbon parts. It is definitely more buzzy than my Nerv. Maybe the combination of the dimples and the double-stay does work to dampen vibration?

Your comment definitely adds to my thoughts on considering (carbon) deep-rim wheels for my ride.