FlashBazbo

Yes, the wheel upgrade has been the easiest, most effective upgrade you can make to a stock bike for a long time. But I had not run the numbers in a long time. So bear with me . . .


I recently bought the cheapest real road bike in the shop. It's an E5 Allez Sport and it's my dedicated trainer / night ride / inclement weather bike. (It's an incredibly ugly bike.) The wheelset is Specialized Axis Sport "house brand." They are typical low-profile metal wheels. To be honest, the wheels are so spindly that I didn't really expect to realize much weight savings. This is a 20.8 pound bike out of the box. Weight is clearly no object.


I decided to upgrade with a set of Mavic Ksyrium Elites. ($488 delivered by Merlin Cycles.) There's nothing exotic about these wheels and, for the purposes I plan to use this bike, their reputation for bullet-proof, worry-free sturdiness is the primary reason for the purchase. I wasn't going for light weight, necessarily. And before weighing the wheels, I had my doubts I was going to really gain much.


But after weighing in both sets of wheels . . . the Ksyrium Elites save 1.3 pounds over the Axis Sports. ONE POINT THREE POUNDS! I'm impressed and a little amazed. (I didn't think the Axis wheels were that heavy.) It's a pleasant surprise. Granted, the wheelset cost me almost as much as the bike did, but I'm feeling pretty good about the change.

Sy Reene

You'll certainly see marked improvement on your trainer rides. 😜

Bah Humbug

Are you telling me I don't need an 858NSW to hold the front of my bike up on the trainer?

Seattle Forrest

Don't ti skewers save like 1/4 pound for $30 or so on a quick release bike? Maybe wheels are the #2 upgrade.

FlashBazbo

But if you buy the Ksyrium Elites, the Mavic ti skewers are included! (And they aren't included in the 1.3 pound weight savings.) Numbers 1 AND 2 in a single upgrade!

FlashBazbo

Well . . . ac-tu-al-leee . . . another reason for the wheel change is that the Axis rear wheel gave out a "whump whump whump" sound on the trainer. Off the trainer (unloaded) it wasn't out of round, but ON the trainer, I wondered how long it might hold together. A single spot on the wheel made noise with every revolution.


With the Mavic, the problem is gone. Even the lack of noise (and worry) is a marked improvement!

raria

You right that wheel upgrades are great bang for buck: 1.3 pounds for $500. so about $350 per pound.

I find that cheap bikes get fitted with those horrible Kenda Kwest k193 tires which weight like 450grams each! So a decent pair of 250 gram tires for $60 in total will save you nearly a pound!

datlas 

No MEILENSTEIN comments yet?

Elvo

Skinsuit and aerobars are by far the best watt per $ performance upgrade you can do unless you mostly ride slowly up hills.

Seattle Forrest

To be fair, he said it's his new rain, night, and trainer bike.

Hiro11

The stock wheels must have been some serious heavyweights. The Ksyrium Elites are fairly typical 1.5-1.6Kg wheels. Your stock wheels must have been in the 2.2-2.3Kg range.

The impact this will actually have on the "performance" of the bike remains to be seen. The whole "rotational weight" argument seems like hogwash to me.

mstateglfr 

You mean physics?
Heavier wheels are slower to get up to speed. Its really quite straight forward. More mass means more effort to get up to speed in the same amount of time compared to a lighter wheelset, or it means longer to get up to speed at the same effort as the lighter wheelset.

Seattle Forrest

Ski poles are made as light at the tip as possible, for the same reason. Less swing weight means less effort over the course of the day.

raria

Amen. Lighter tires, or wheels have a huge improvement in acceleration. Now people are always telling me, this only applies when climbing (i.e. your are constantly accelerating, decelerating when climbing with each stroke). But just remember that every time you enter a turn you slow down and have to accelerate when leaving it.

WhyFi

Math tells us that it shouldn't make much of a difference in 'spinning up' lighter vs heavier wheels, but perception tells us that it's quite noticeable; I still think that it more of a gyroscopic thing where the heavier wheels are resisting change in orientation (like when you're sprinting out of the saddle, rocking the bike back and forth under you) more than resisting spinning up.

aplcr0331

FlashBazbo

Lots of false dichotomy going on there. Is the choice really between sitting upright and a full tuck aero bar? No. The real choice would be riding the drops and an aero bar. Regular jersey to skinsuit? No. More likely race fit jersey to skinsuit. (And is ANYONE not named Fred going to wear a skinsuit for his or her daily ride?) 0 degree yaw numbers never show any real benefit from race wheels. (And is anyone not named Fred riding Tri-spoke wheels for his or her daily ride?)


And, of course, once the grade exceeds 5%, none of these aero numbers matter anymore.



If you want to talk about something non-weight related that makes a difference, talk about rolling resistance numbers. They work all the time and they're usually bigger than the optimized aero numbers.

HTupolev

Inertia doesn't work just one way: shifting mass to the rims will make a bike decelerate slower when rolling uphill as well, so this argument doesn't really work.

Probably.

SethAZ 

It would be interesting to see what improvements those things would make for an individual rider doing solo rides at 18-20mph. All the aero stuff based on 40km TT rides is cool and interesting to see, but for the OP and his type of riding the numbers would change radically. In particular the differences that are already the most expensive on this chart, like the aero frame, would be even worse deals in terms of benefit seen per dollar.

At the end of the day I think a typical solo hobbyist rider will see the most bang for the buck that they will actually notice just by going from a really stiff, heavy tire like the Gatorskin to something lighter and more supple, like the Grand Prix 4000II or one of the other, similar tires from other brands. And go from the 23s the bike probably came with to something like a 25mm or 28mm if it will fit. That is a difference they will actually feel, immediately, on their very first ride, and it costs what, under $100 for a set?

Bah Humbug

There is also talk over on ST of whether the fact that power is produced in pulses causes micro-accelerations with each pedal stroke and that gets noticed over time. We don't produce power as smoothly as an motor and a driveshaft, obviously, no matter how "round" your pedal stroke. Of course, if that were the case then the heavier wheels might do a better job of smoothing out the pulses. Who knows? Not me, but I'm open to the notion that people might be perceiving aspects of wheel weight and inertia that our freshman-level physics don't account for.

Bah Humbug

What data shows a 3-spoke rear is better than a disc?

RPK79

I got a KOM last year on my gravel tires / heavier wheels on a segment I hit many times before and after and have never come within a minute of that time again. The segment is sheltered enough that wind does not come into play enough to make much of a difference one way or another.

Racing Dan

So now you get LESS training ;-)

ReneV

The Win Tunnel series from Specialized on youtube makes the point that seconds saved is almost independent of speed.

Seattle Forrest

I do!!

Oh, wait, I looked it up, turns out what I ride every day is called a "birthday suit." Sorry for the confusion, carry on.