RollCNY

Now my face is Red.

Herbie53

I never noticed that. This thread delivers.

RollCNY

OK, I have a serious post to make, and it goes to @Smokehouse 's discussion of increased descending speed with new wheels.

My first bike was a Diamondback Insight $300 beaut, and I replaced it with a Specialized Sirrus. I set the Sirrus up as aggressively as possible, and felt it was a vast improvement over the Diamondback, except for the S500 stock wheels. They were flexy, and made me think I had a flat tire on every aggressive hill climb. As I am a big guy, every hill climb is an aggressive hill climb.

So I replaced them with Easton EA50 aero's, and the flat tire feeling greatly decreased. And because that decreased, I would hit hills harder. And because I hit the hill harder, I would carry more speed over the crest. And since I was already going fast on the crest, I could hit 32-35 mph and tuck for the backside descent faster. And because I tucked sooner and felt faster, I would rest my chest on the flat bar and get as deep as possible, and kick my butt to the top tube. And heck, since my nipples were on the bar, I could rest my hands comfortably right next to the stem.

I pretty quickly noticed that my max speed on a frequent 12% descent had improved by 1.5 mph. And it was all because of those wheels.

I bought them to fix flexy flat tire feel, and they did it wonderfully until I cracked the freehub body. But that is a different story.

Looigi

It's all "unsprung" if there's no suspension.

rpenmanparker 

I know, huh!

lsberrios1 

The rider is the only sprung weight in that equation. Good observation, i did not have that in mind. Coming from motorcycles and car forums it's all about unsprung weight. However i do believe that the bike itself acts like a spring all the way down to the contact patch. Reason why stiffer bikes (less springy) make for better and quicker power transfer.

WhyFi

Bull****tery aside for the moment, I have a not-at-all-thought-out theory that a lot of the sensation of increased speed and nimbleness that many associate with lighters wheels (rims/tires particularly) is because of a diminished gyroscopic effect - this could mean less effort when leaning the bike over in a turn or flicking side-to-side (when sprinting, for instance). This may explain the divide between riders that report a much easier 'spin up' effort and those that are dismissive because of calculations that show spin-up power differences (of a static wheel) that would likely be imperceptible to the rider.

gc3

^^^^ you're alleging this is "all bull-sh*ttery aside"....? ^^^

WhyFi

StanSeven

Mine does. Also twice a year Zipp comes by and brings a lot of wheels to test. You call, make an appointment for testing, bring your bike it and they set you up for one or more tests. They sell a lot from those weekends.

rpenmanparker 

I like that. There has to be something that gives the impression of speed and nimbleness. Small forces affecting handling could be much more significant than a small weight difference affecting acceleration, even rotating weight.

Smokehouse

Hmm…

Some things are hard to explain or prove. I shed nearly a pound switching wheels (1950g vs 1500g). They ride considerably different…it's hard to "put on paper" but the difference is immediate.

I swapped back to my stockers for winter riding and the sluggish, more "clunky" feeling was back. I had forgotten how they felt until I put them back on...

pgjackson

If you knew what you were talking about you would know that those stickers create unnecessary drag. The fraction of a mm thickness of the stickers create repeated rotational drag and disrupt the natural airflow around the tire. That could mean the difference between winning and losing. I gained about 1.5 mph by simply removing my stickers. This is science.

pgjackson

Whoa...hold on. Reason and logic have no place in this conversation. You will get nowhere with your line of thinking here. Everyone knows that more money means greatly increased speed. That is a fact. Every advertisement in Bicycle Magazine tells us this. You better go out and get your super-light inner tubes and aero seat post or else you just won't be able to hang with the peleton.

gc3

wait a minute, wait a minute....flashy big logo decals look cool....if I look cool, I'm much more motivated...If I'm more motivated then I try harder, therefore I go faster....now, THAT'S science...

pgjackson

Or it could all just be someone desperately wanting to feel the improved effects to justify in his mind his tremendous loss of $$$ on high end wheels. I think they call the the Placebo Effect. Just sayin'.

pgjackson

Crap. Guess I have to buy new stickers.

WhyFi

NSS. I would have thought placebo effect being a potential cause for discrepancy was so obvious that it didn't warrant mentioning. Thanks for demonstrating that the bar is lower than expected.

pgjackson

Awesome.

rpenmanparker 

Wait a minute. I thought Placebo was an opera singer. Placebo Domingo. The Placebo effect: you think you're hearing music, but it is just your imagination because he looks like a singer. Does he cycle too? Big guy!

SHBR

I would have been brutally honest with him and would have said something to the effect of, you break it you buy it.
It depends on how close of friendship you have though.
I found being direct often cuts through the B/S and often earns respect even if they might feel offended at first.

Smokehouse

typing on an iPad always gives interesting autocorrects...

I apparently typed "dousing" and meant cousin. My XL cousin wants to get on my bike (he has a domane)...and I tell him no...

lsberrios1 

A roubaix can easily carry 250#. Now i dont know about the wheels you have but unless they are high end carbon wheels or low spoke alum it should be fine.

Smokehouse

I have a Tarmac Sl2…with a CG-R seat post and ROL Race Sl wheels. Now…I'm not completely sure what the rider weight limit is for the Frame or seat post…but ROL lists the weight limit for those wheels at 210lbs, which my cousin is far beyond.

I'm willing to say he wouldn't crush them…but I'd rather not take a chance.

FatBottomedGirl

This thread has gotten wildly out of hand.
Although I still find some interesting information.
So thanks for that !!