Could someone explain this. I rode my normal wheels Bontrager Race light (700cc, 1700g) for about 40 miles and then tried a friends Mavic Kyserium ES's (700cc, 1500g) because i am considering an upgrade. I was expecting to feel a difference in quickness (spin up) and wheel rigidity when doing short sprints. I did feel these things, particularly the rigidity. However, the most suprising finding was that the wheels made my bike feel taller, as if I went from 650cc to 700cc (weird!). I asked my mechanic at LBS and he thought that the rotational weigth difference could explain this phenomenon. The feeling was at both low and high speeds, so i am wondering if it might be flex rather than weight? Does anyone have experience with this, and if so, is it a clear indication of a major upgrade in wheels?

However, the most suprising finding was that the wheels made my bike feel taller, as if I went from 650cc to 700cc (weird!).

What does "taller" mean? You feel like you are a half inch higher off the ground?

The Ksyriums are certainly less aerodynamic than the Race Lites. They also weigh more than 1500g (but then Bontrager lies about their weights also). I also doubt they are really stiffer... they just look stiffer. Frankly, I wouldn't call it much of an upgrade.

Rotational weight? Nonsense. Flex is unlikely in that 1/8" flex in the radius seems like it would be huge and that is only 3mm. It could be the difference in height of the tires or, if the Mavic is narrower between the brake surfaces it could allow the tire to stand taller when inflated.

You could check the unloaded diameter of each tire/wheel combo to see if there is a basic difference in size.

One other thing you could do would be to sit on your bike and have someone measure from the ground to the rear skewer. Repeat for both wheels and be sure to use the same skewers so that they can be measured to the same point. With this method you would account for any vertical "flex" .

Frankly, I wouldn't call it much of an upgrade.
Boom ! :thumbsup:

If you could ride both blindfolded (without crashing) you wouldn't notice most of what you feel you did. Repeated runs, I'd give you 50/50 on picking what was underneath you.

No slam - just saying that the differences between wheels are much less than folks think it is. I've side-by-sided a mess of wheels, and have often caught myself thinking 'boy, the xxx of these really helps' - then realized I'm riding the other set.

If I had to make a guess, your buddy had a higher inflation than you did, and you felt a bit more road vibration than on your wheels on that day. That 'felt' a bit more 'skittish', which your brain translated as 'harder to balance - must be further up.' Slightly less grippy tires could have the same effect.

FWIW, I have two bikes that are set up identically as far as fit measurements and overall geometry. The one with the 36 spoke, heavy as hell, 20 year old wheels feels 'taller' than the one with the light, deep, 20-spoke carbon rims. Have no idea why. The new bike is Ti, the old one a legendarily stiff Cannondale. Maybe?

Curious - did both have identical cassettes? Could be part of it.

If you could ride both blindfolded (without crashing) you wouldn't notice most of what you feel you did. Repeated runs, I'd give you 50/50 on picking what was underneath you.

MAVIC's own reported results, along with independent testing of tires by others (see Bicycle Quarterly) shows that riders cannot reliably tell when they are on stiffer or faster wheels. 50/50 is pretty much spot on!

MAVIC's own reported results, along with independent testing of tires by others (see Bicycle Quarterly) shows that riders cannot reliably tell when they are on stiffer or faster wheels. 50/50 is pretty much spot on!

You took the words right off of my keyboard.

On a related--to the thread, that is--note, my pants feel tighter every time I see Natalie Portman.

Thanks for the info! This was my first road bike review post and i will be making many more.

Could someone explain this. I rode my normal wheels Bontrager Race light (700cc, 1700g) for about 40 miles and then tried a friends Mavic Kyserium ES's (700cc, 1500g) because i am considering an upgrade. I was expecting to feel a difference in quickness (spin up) and wheel rigidity when doing short sprints. I did feel these things, particularly the rigidity. However, the most suprising finding was that the wheels made my bike feel taller, as if I went from 650cc to 700cc (weird!). I asked my mechanic at LBS and he thought that the rotational weigth difference could explain this phenomenon. The feeling was at both low and high speeds, so i am wondering if it might be flex rather than weight? Does anyone have experience with this, and if so, is it a clear indication of a major upgrade in wheels?

Were the tires the same size? I'm not implying that a 25c will make a bike feel 'lower' than a 23c, but it might account for a different 'feel'.

Wow, a new almost impercievable characteristic that we'll have to add to wheel reviews...

"The Zipp 1660 was stiffer and more compliant but yet I still felt taller in the saddle than with the 808s. My view to the horizon was clearer and the sunset was definitely more vivid"

Is reviewing wheels starting to approach the pretentiousness of wine tasting yet???