Jarrett2

I'm still in the process of understanding wheel weight, strength, rotational mass, etc.

I hear (and have felt to a small extent) that lighter wheels make a bike feel snappier and easy on climbs, etc.

I'm wondering how much of that is related to the front wheel and the rear wheel.

If you had two different wheel sets where as pair they weighed the same, but separately the weight was distributed differently, would that make a difference in feel?

For example:

Wheelset A: Rear wheel 60% of total weight + Front wheel 40% of total weight

versus

Wheelset B: Rear wheel 75% of total weight + Front wheel 25% of total weight

Given that that wheelset A and B weigh the same in total, would they feel/ride differently? Which would be "better?"

Can saving more weight in the front wheel positively affect the ride or to feel it, does the weight savings need to be in the rear wheel?

topflightpro

The rear wheel is naturally going to be heavier because it has a larger hub and more spokes - You need more spokes on the rear wheel because the rear wheel is torqued more through pedaling.

That said, the lighter you can make your rear wheel, the better, as it is the rear wheel you are turning when you are pedaling. Dropping weight in the rear rim will be more noticeable than dropping weight in the front rim

prathmann

Whenever I pedal the front wheel turns just as fast as the rear one. So from an energy standpoint it shouldn't make any difference since you need to supply enough energy to spin both wheels up to the same speed. But from the standpoint of how responsive the bike 'feels' a lighter front wheel can have a greater impact especially when you're in a sprint and moving the bike from side to side and also making steering adjustments.

Doge

The front. The front also moves more.M
My gut says (I have a real good gut) it has more than twice the change in momentum the rear does.

znomit

I was pulling wheelies up my least favourite climb last night. Could use a heavier front I guess.

spdracr39

When I asked my wheel builder this question he gave me a lightweight wheel for the front with a slightly heavier rear wheel for added durability. He said the total rotating weight is the factor but lightweight rear wheels tend to have more problems.

Doge

The front moves more because its the part you move to stay upright (unless you are a new rider that uses your knees to balance). The movement is not the issue alone, it is the hitting the small bumps in the road that are scrubbing off your momentum and forcing you to turn the front to both regain balance and maintain speed.


If you ride a mile - the front also travels farther than the rear.

CliffordK

Yes.
The majority of the spoke tension,and thus weight on the rear is being absorbed by the right spokes.
Assuming you're using rim brakes, the rear also gets all the torque from driving (disc brakes also transfer torque through the spokes). I'm not sure about rider weight distribution, but I think it also tends towards the back.

So, in theory, 32 spokes in the rear would be like 16 up front.

It doesn't really solve the weight question, but you need extra strength in the back for a standard bike. Perhaps a tandem has better weight distribution.

rpenmanparker 

For accelerating the mass it doesn't matter how the wheel weights are distributed. For handling you will feel the lighter or heavier weight in the front more.

Ice41000

If they spin same speed (and they do), it doesn't matter.

CliffordK

It is also possible that wheels with heavier hubs and lighter rims will accelerate and spin better than the opposite, light hubs and heavy rims, but overall the difference will be minimal.

chaadster

It has been said already, but yes, a lighter wheel up front will be more noticeable and improve feel. A heavier wheel at the rear may improve durability, but that depends on the build and the comparison.

okane

...its germane to this issue but almost every flat I've ever had is the back tire. 3000 mostly road miles on my newest bike and 5 rear flats. Front tire still looks like new and I had to replace the rear when I somehow picked up a large wood screw that tore the casing. Went to one of those flat resistent rear tires which is a bit heavier and dare I say, have not had any flats in the last 800-900 miles.

I asked at the LBS if my experience is typical and he said rear flats are much more comman than fronts**********

Before hearing this I thought it was just the bicycle gods having fun making me get my hands covered with chain lube!

grolby

This turn of phrase really needs to die, it's so misleading. When you pedal your bike, you are not "spinning up" a 1500g pair of wheels. You are using those wheels to apply a force to accelerate your own butt + bike, a mass at least an order of magnitude greater than that of the wheels.

grolby

Well, except for on rollers.

Latif

My experience as well. Between my three bikes and 2&1/2 years riding, about 15 rear, 1 front. Perhaps it has to do with more weight on the back

prathmann

Can't speak for Clifford, but I was using that phrase very deliberately since this thread is specifically about the effect of lighter wheels as opposed to all that other mass which is being accelerated - and which is indeed more than an order of magnitude greater. The effect of lighter wheels compared to other masses in the rider+bike system is rather small, but that's the only part of the system under discussion right here and when accelerating the tire and rim half of the energy is going into "spinning them up" and the other half into forward motion of the center of mass.

And yes, rear flats are far more common than front ones. Partly due to the greater loading of the rear tire and partly as a result of the front tire kicking up objects that are lying flat on the road just in time for the rear tire to come along and get stabbed by them.

Doge

Consider the side to side movement of the front - particularly the unavoidable jarring off course that takes place causing a correction.

Doge

They don't. The front turns faster.

Assuming tires are same diameter, try this. Line up both wheels valve stem's at the bottom. Ride around the block. When you get back both valves should be in the same O'clock spot unless one is spinning faster.

Doge

This shows - they don't. This is after 45 sec.
To my guess - about a 20% difference in spinning and 50% difference in energy if they were equal mass. About every scientific test I read seems to think bikes ride on a plane. They don't. Dumb tests. Don't believe them.

Ice41000

I am aware of that, but is negligible. For most of the rides wheels are doing the same thing. How much slow tight turns you do during couple hours ride? And how much those matter?

Doge

It matters enough to make a difference in which wheel you want the lightest. You are constantly pushing against the gyroscopic wheels. Every small bump that takes you off course (100 times a min) needs to be corrected by turning the front more than the back which follows.

Silvercivic27

Bunyanderman

no

79pmooney

The old "rule" for the fastest set-up with two different tires was to put the highest quality, lightest tire in back. I would expect the same to be true for wheels.

This is for speed. Not durability. Not safety, just speed. Best stuff in back.

Now, you will feel the good stuff a lot more if you put it in front because you feel the steering wheel far more.

Ben