My old Soul was on a pretty heavy build (Pikes, heavy wheels and tyres and not a particularly light drivetrain) until recently when it lost 5lbs, with a good chunk (maybe even most) of that being in the wheels and tyres. As well as being quite a bit lighter it also not only feels faster but results on Strava suggest it is actually a good bit faster in practice (I’ve even had a couple of KOM’s on it). How much of that is me riding it faster ’cause it feels better, and how much is due to the weight loss, is debateable though.

How much of that is me riding it faster ’cause it feels better, and how much is due to the weight loss, is debateable though.

The weight drop may make a few seconds difference so if you were previously 3 seconds off a KOM that may do it for you but more likely because you are just trying harder…

Yep saving weight on wheels can make a big difference (especially in this case!), as can lighter cassettes (even though they are consumable).

Sometimes if wheels don’t feel lively, it can be as simple as tensioning up the spokes a bit more.

But lighter rims/tyres always a good idea.

Sometimes if wheels don’t feel lively, it can be as simple as tensioning up the spokes a bit more.

If you’ve let things get so bad that your spokes are that slack, best overhaul every bike you have for your safety!

I purchased a new set of wheels yesterday, Bontrager Aeolus 37 Pro, also put some new tyres on (Bontrager R4 Classic 28mm).
Old wheels (tyres, tubes, rotors and Cassette) are 1980g rear and 1420 front. New wheels with tyres, tubes, rotors and cassette are 1686 rear and 1250 front. Total saving of approx 500 grams.
I did my usual short loop yesterday, 27 miles with 1200 feet of ascent. 12.7 mph wind, 209 watts average (with power meter) and 19.7mph average speed.
On the old wheels/setup, exactly same loop, 8mph wind, 196 watts and average speed of 19.5mph. Both wheels are approx 40mm deep (vision Merton 40s and the Bontrager are 37mm).
My conclusion was very little difference speed wise. They felt nice though and look good.
Here’s a link to the pics showing the details:
https://photos.app.goo.gl/Lgg24VuHecP47X9s8

Exactly. In contrast I have just switched back to some 25c Marathon Plus at 600g for each tyre and I was flying around this morning and felt faster than I have for the last few weeks.
How I feel on a particular day is gong to make way more difference than if my bike is 500g lighter

Timely GCN video posted today here

To save you the 20 minutes it makes absolutely no difference saving weight on wheels over anything else. The extra effort to get the wheel spinning is then stored as kinetic energy in the wheel (flywheel effect). Only losses are if braking a lot and even on a criterium race where 2% of the race was breaking it was calculated as a 0.7 second save over an hour.
An on a hill climb the few seconds slower time is just because of the extra weight and not where the extra weight is.

And while I will admit to lighter wheels feeling nicer I am probably not noticing the loss of a bit of flywheel effect when going up on undulating roads.

The difference in losing weight in the wheels vs the whole bike is the bike feels more zingy when accelerating and is more lively when going over obstacles as mass removed is from the front and rear.
Also you can do the change in one go without having to fiddle with lots of bits and pieces.
Crits I’ve done most recently have a short course with a U turn, suspect less wheel weight would help save energy for the acceleration from 20-50km/h

Crits I’ve done most recently have a short course with a U turn, suspect less wheel weight would help save energy for the acceleration from 20-50km/h

The extra energy from the acceleration is not wasted so makes no difference. The only time the energy is wasted is when braking for the u-turn not accelerating out of it.

Good point about lighter unsprung weight on an MTB but we are talking a presumably unsprung gravel bike here…

I’m not convinced about that gcn vid. Guy talks alot about the science, but This fella actually tested it on the bike rather than on a computer, and the results are as most people would expect.

Lighter wheels accelerate faster and so will feel great.

(they also hold less momentum and can be decelerated more quickly which is why the overall “speed” will be the same)

Sounds like a great improvement. Sometimes upgrading for lighter components can be very incremental to the point that after changing 5 things you may as well have bought a better bike. This sounds like a weak leak that’s been identified and sorted.

Tpbiker, I’m not sure that link is the best to be honest. I don’t think you can class water in the tyres as an extra weight for wheel mass. Too much moving/sloshing around, the tyre is very likely to perform differently With water rather than air.
It’s a good indication of how little difference there is, even using water, we don’t know how much weight the rider lost riding up the alpe 4 times in a day, we don’t know whether the weather conditions remained constant. For example, was there a slight tail wind on one of the runs? As the results are so close I’d say that the difference is marginal.

I’m not convinced about that gcn vid. Guy talks alot about the science, but This fella actually tested it on the bike rather than on a computer

I will believe a person who has actually done the proper modelling and has the right background rather than a person who fills his tyres with water. The guy on the GCN video is not alone by the way, it is well recognised the the whole weight on the wheels things is an old wives tale.

I have one bike with really light wheels and tyres and my fatty with really heavy wheels and tyres. Its very noticeable the difference in the momentum between them in that the heavy wheeled bike holds speed better but is slower to accelerate. so in terms of energy usage over a undulating ride the net difference is negligible if there at all.. However if you are accelerating then braking the heavy wheeled bike will take more energy overall to maintain the same average speed

All that information makes sense actually as the main time I notice the wheels is when accelerating from slow speed or getting going from a stop/gates etc.

So lighter wheels result in (very slightly) quicker acceleration, easier to slow down and a livelier feeling bike generally, but they also lose momentum quicker so require more energy to keep going – Does that basically sum it up?

In which case, rides with lots of stop-starts it’s better to have lighter wheels, long rolling rides it’s better to have heavier rides.

For example, was there a slight tail wind on one of the runs?

Wasn’t it up Alpe D’Huez? Quite zigzaggy IIRC 😉

Does that basically sum it up?

The effects are absolutely tiny – mostly psychological.

The result in overall speed is tiny but the effect is very noticeable. My bike feels immediately nicer to ride if I drop 200 grams from each tyre but I don’t feel the difference in flywheel effect in the same way even though I know it is there.
As I hardly ever have to stop (I don’t even need to have brakes on the bike) then I just use heavier and nigh on puncture proof tyres safe in the knowledge they are no slower.

In a straight line, on a smooth road, at a constant speed, without drag and friction, you wouldn’t feel much/any difference (other than initial acceleration) from a light wheel rim over a heavy one, but in the real world, on a broken surface, with changes in direction (even small ones) a heavier wheel will require more energy to maintain momentum than a light one. Gyroscopic forces, changes in angular momentum, energy lost to impact all require replacement. Yes a heavier wheel has more KE, but Work is Delta KE, that delta is what all of the above are robbing you of and all of them are greater in a wheel with a heavier rim. The differences might be marginal, but they are there.

Finally got the ‘good bike’ out on the road yesterday.

It’s testament to the fact that lighter bikes (1.5kg) feel soooooo much better, all else being equal. Maybe some of that is due to stiffer wheels (and I’m not even sure they are stiffer, just assuming they are) but otherwise it could only really be down to the weight. But yeah, no real difference in times or average speed compared to my usual trundle with my wet weather commuter, mudguards n’ all.

I’ll get a chance to compare more at the weekend, I’m still running approx 1.2kg of cheap commuting tyres and butyl tubes but will switch to my GP4000s and latex tubes, should save 400 or 500g alone!