3/13/15 11:08 PM

Learning more and more about what makes a wheel more comfortable.

Build:

Pacenti 28 Hole SL23. We got 8 of them for a pretty special price too hard to pass up on.

Hubs are BHS [BikeHubStore.com]. 11 speed, Rear 210 grams and front 79 grams. I think these are Bitec with better bearings in them. They spin very nice and feel tight and smooth, especially the front.

For this build I used Sapim Lasers [2.0/1.5/2.0] with DT forged Alloy nipples for all except drive side trailing spokes which I used Sapim Race [2.0/1.8/2.0] with brass nipples for those 7 pulling spokes. Three Cross both wheels. My fish scale indicates 2.9 lb for the pair with tape.

First out ride yesterday. Even with the 23C rear Service Course Michelin Pro4 @ 95lb VS the removed 25C Conti GP4 Chili @ 87lb the ride is just as good. Considering the pressure and 3mm difference in size aired up, this surprised me. Not sure how much credit to give the Pro4 VS the lower spoke count and more stretchy spokes in the wheel.

The previous rear wheel is 32 spoke with Laser/AL Nips non drive and Race drive side with brass nips. Similar rim, HED Belgium. Very close in spec to the SL23. The SL23 is actually even a little wider. Enough so that I had to do an adjustment to let out a little cable. The BHS rear hub is where much of the .7 lb rear wheel weight was lost.

So the 6 year old gets some new sneakers.

XT 650B set next, I just gotta know. All the parts here, just gotta get to those...

<img src="http://coupekiss.host-ed.me/images/ttf/Scott-SL23-BHS-wheels-side-med2.jpg" width=584>

3/14/15 10:43 AM

I hate to burst your bubble, but I don't believe for a single second that anyone can tell the difference in spoke gauge or count when riding wheels. The differences in rim deflection - if there even are any at all - are going to be in the single digit thousandths of an inch. Tire compliance is several orders of magnitude more than that. This is a classic "princess and the pea" situation.

If you really want to test differences in wheels, you have to do a double-blind test, changing only one variable at a time. I this case, you've changed almost everything, yet you're attributing the perceived difference in compliance to just two of them (spoke count and gauge) which are the least likely to make a difference (except perhaps for the hubs). If you've got nothing better to do, it may be fun to do a more scientific test, but the result will likely not be satisfying.

Unfortunately, bike mags and websites are full of wheel reviews that allege that they can feel differences in wheels. They ride them on different bikes, with different tires and tubes, frequently without comparing them back-to-back with anything, but claim that they can feel the difference in the wheels alone, based on memories of what other wheels feel like. It's utter hogwash.

OTOH, significant weight savings in wheels can be felt when accelerating the bike, though it's not likely that they make an perceptible difference in steady-state riding.

3/14/15 11:46 AM

"I don't believe for a single second that anyone can tell the difference in spoke gauge or count when riding wheels."

More concerned with what I believe frankly. You won't be bursting anything here. I use my own empirical observations and can give less of a shit about magazines and what they say is good and why. I have quite a few builds under my belt at this point and deem the differences are perceivable. Having said that, ones perception is not always accurate, I am cognizant of this. But possibly being wrong about why you perceive something does not mean you do not perceive it.

I also feel the difference in the windup from the lighter DB spokes, and also radial NDS which I avoid and dislike. The only Radial lacing on a rear I have used that didn't were the Dura Ace Tubeless which are radial on the drive side, something my brain juggled with when I saw that. ;)

But no one cares about anyone's opinions. me yours, nor you mine. ;)

I do agree with you the lighter wheels re:acceleration being predominant trait. But if I am right, you don't care. ;)

Also find wheels/tires not so much to the light side a better choice for a flattish century for example.

3/14/15 1:10 PM

I am going to put the tires off the other wheels on the new wheel and vise versa. And will come back a repost, and possible eat some crow?? We will see.

3/14/15 2:14 PM

Yes, +1 firmly to what Brian writes. But at least you will have fun finding out for yourself. Thumbs up for doing an experiment and on the color coordination.

3/14/15 6:54 PM

Joining the bubble bursting crowd here. MAVIC did a blind test where they built wheels that were significantly different stiffness and had multiple riders try them out. Riders could not reliably tell which wheels were stiffer.

3/14/15 7:26 PM

read all that crap before, just like you have typed all that before.

Mavic, the kings of high tensioned wheels. ;)

3/15/15 9:00 AM

...that at least Mavic's test was controlled and as scientific as one could ask for when dealing with human perception. They at least made an attempt at objectivity.

As for feeling windup, tire casing deflection is once again a much larger component than any difference in spoke stretch. Again, we're talking a few thousandths of an inch at most at the spokes.

Other key variables I forgot to mention are:
- The road surface - One would have to ride the same roads and essentially the same line on those roads to make a valid comparison.

- Weather - Temperature, humidity and wind all affect the rider's perception of the ride experience. Temperature also affects tire pressure, which greatly influences compliance. In cases of very high temps, the road surface compliance may be affected, depending on the material used. That could easily be far more than the difference in rim deflection. I imagine that we've all ridden on asphalt that felt soft at some point.

- The rider, which is of course the biggest difference - Fatigue level, mood, hydration, blood sugar level and more all affect the perception of a ride. I know I'm much more sensitive to the road surface when I'm fatigued/hungry/dehydrated.

Rider size/weight makes a big difference, as if affects the compliance of the entire bike.

However, the 600 pound gorilla in the room is rider expectations and beliefs . If you think that you'll feel something, you probably will, whether it's been there all along, something has actually changed or it's not there at all. The fact that you're concentrating on it means that you will feel it.

BTW, I don't want anyone to take any of this personally; I question my own perceptions too, all the time. The perceptions of my own that I trust the most are the ones that occur when I'm not expecting anything and I happen to notice something that surprises me.

Also, I fully understand the fun of experimenting and I enjoy it too. Trying new things is often worth it for the entertainment value alone, regardless if whether there are any practical implications.

3/15/15 7:01 PM

The rim's width effects the inflated height/width profile of the tire casing, which in turn slightly affects the tension of the tire casing, since this tension is proportional to both inflation pressure and to cross-sectional area.
A wider I rim typically requires a lower inflation pressure to mimic the ride quality of a given tire on a narrower rim.

This only applies to those comparisons, as by magazines and other road-testing authorities, of the ride quality of wheel A vs. rim B, but which might lead to incorrect conclusions.

And in general, lighter wheels seem to me to offer a more-supple ride feel that likely isn't the result of flex parameters, so fewer spokes may actually offer something here, as might the more-significant increase in lateral flex of the wheel.