General Cycling Discussion - Does 100 grams per tire make that much of a difference?

I'm getting ready to change tires and I'll be moving from All Condition Armadillos to either Continental 4000s ot Michelien Krylion Carbons. The Micheliens are about 15 grams lighter and the Contis are 100 grams lighter for each tire. Since 100 grams is "only" about 3 1/2 ounces, is that really that big a deal. I'm a recreational/enthusiast rider and don't race. Your opinions and experiences please.

Rotational weight 'weighs' twice as much as non-rotational weight. So those 200 grams is now 400 grams.

i don't think at a non-racing level that really matters much.
might get crap for that, but whatever.

'gascostalot' made a good point though.

I'm a casual rider too, and struggle with this comparison. i've been thinking about trying to skim weight from my heavy mtb, and tires seem an obvious place to do it. If i could shave 200 - 400 grams, am i really making a significant change to my bike?

I think that rotational mass is one factor that the recreational user is MOST likely to notice and appreciate.

Rotational weight 'weighs' twice as much as non-rotational weight. So those 200 grams is now 400 grams.

Only under acceleration and even then acceleration effects are so small compared to the major players (drag, gravity, and rolling resistance) as to be insignificant. So the impact of those 200 gms is about 200/80,000 (0.0025).

No, it doesn't make a difference at all. Enjoy your ride! :thumb:

Unless you are an elist racer competitive at the very upper levels of racing who does it for 3 weeks at a time like in the Tour de France... shaving a few hundred grams isn't going to do a thing.

Changing from heavy studded winter tires to lightweight XC tires was the only time I've ever changed a part and felt the weight difference. There was such an obvious difference in increased acceleration and sharper handling. Rotational mass matters, espesially in situations with lots of direction and speed changes like mountain biking. Perhaps it makes a bit less difference on the road, but it is still important.

Rotational mass matters, ...

Of course it does. It matters about 0.01%. Some people think that's a lot. Given the higher speeds and accelerations on the road it matters more there than on dirt
http://www.biketechreview.com/archive/wheel_theory.htm
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I might guess that a recreational rider is going to be dealing with a lot more speed changes than a pro (at least on the road).

I might guess that a recreational rider is going to be dealing with a lot more speed changes than a pro (at least on the road).

Have you ever raced? Training rides don't come close to the accelerations in a race. Recreational rides are even further behind.

Nope, I have not, and I suppose my guesswork shows it.

Can I still salvage my hypothesis that a recreational masher is going to be doing a lot of catch-up on the cranks, and so lighter wheels would be very noticeable?

If even this is wrong, I will go ride a Varsity up a long hill as punishment.

jim

100 grams is about 1/4 pound. Spin 1/4 pound weight at the end of a 14" string and decide for yourself. Personally, tires are the one place I can note minor weight differences. But having said that, 100g is quite nominal compared to tire construction. Same for frame design.

The weight isn't the only thing when going from Armadillos to Conti 4000s. The sidewalls are much more flexible on the 4000s and the rubber compound is softer/stickier. Not as flat proof as the Armadillos to be sure but a much smoother ride. I think these differences are probably even more noticable than the 100 gram weight savings.

100 grams is about 1/4 pound. Spin 1/4 pound weight at the end of a 14" string and decide for yourself.

Decide what? That there's a centripatal force on the weight from the string? My spokes pretty much take care of that for me. On the other hand, I can spin up a wheel with the pedals using a single finger easily, and that's at an acceleration much faster than any rider can accomplish and includes all the rotational, aero drag and drivetrain losses.

I ride a "commuterized" MB in the city with a lot of stop & go. Going from 26x2" to 26x1.5" made a world of difference in acceleration. Part of that was the lower gearing (4%) from the smaller rear diameter. Same as going from a rear 25T cog to a 26T.
When I made the change, I could only afford 1 tire, so I did the front. I was so impressed, I changed the rear as soon as I could. It really helps me get across an intersection (and out of "harms way") from a stop much quicker.
Steady "cruising", the effect isn't so noticeable.

Decide what? That there's a centripetal force on the weight from the string? My spokes pretty much take care of that for me. On the other hand, I can spin up a wheel with the pedals using a single finger easily, and that's at an acceleration much faster than any rider can accomplish and includes all the rotational, aero drag and drivetrain losses.

The spokes don't magically eliminate the mass. It's a very simple way of giving folks some idea of what kind of force we're talking about. I thought it was sufficiently obvious that it wasn't necessary to point out the differences between the two.

In real terms, when I switch to studded tires in winter (1Kg/ea), the difference is remarkable. It takes about two weeks to adjust in terms of acceleration from lights and up steep hills. 100g in road tires might be noticeable under some conditions, but even then it's likely a function of design.

Changing from heavy studded winter tires to lightweight XC tires was the only time I've ever changed a part and felt the weight difference. There was such an obvious difference in increased acceleration and sharper handling. Rotational mass matters, espesially in situations with lots of direction and speed changes like mountain biking. Perhaps it makes a bit less difference on the road, but it is still important.
Yes, it does make a difference. It's not just the weight though, churning those lumps of rubber sticking out the surface of the tire ( knobbies ) takes some effort too. The difference between two types of road tire would be less I think.

A lot of this is subjective, without something like power measuring cranks, it's difficult to get an objective reading. I recently switched from semi studs to Big Apples, they're faster, but not as fast as slicks at high pressure, but I'm having difficulty defining exactly how much slower.
One thing is definite, they are much more comfortable, they are also faster than other tires would be at the current pressures, ( 35PSI ) I'm going to be playing around with pressures and see what they feel like. To give some idea of the ride difference, one short cut takes me over some hard packed grass tracks, the semi studs had the fender rattling constantly, with the BA's they hardly rattle at all, and when they do it's brief and muted. Like riding a new bike.

Only under acceleration and even then acceleration effects are so small compared to the major players (drag, gravity, and rolling resistance) as to be insignificant. So the impact of those 200 gms is about 200/80,000 (0.0025).

Agreed,

In fact the rolling resistance difference may in fact be a greater benefit than the weight.

The otehr side is that tires are often the best gms/$ if you do start being a weight weenie.

On the gross level often lighter, more expensive tires are often of better quality than heavier tires. But these days this is not always true as some manufacturers go for the only look at the weight crowd.

I think that weight is the least significant factor.

The biggest single factor in ride quality and performance is how supple the sidewalls are. Armadillos have ultra stiff sidewalls so I'm thinking either of the other tires are going to ride more smoothly.

What Armadillos do offer is puncture resistance that is second to none.

Well at a multiday ride last year the following happened. A guy I know had a brand new carbon fiber bike that was very light. So Diane took the sucker apart and filled the tubes with rice about 2 lbs of it. The guy did not notice anything different until miles down the road he happended to notice that one of the bar end plugs was a bit loose. He pulled it off and out came rice! With Diane's help later, he managed to get it all out.

I suspect that very few riders can tell if a bike is a lb lighter or not.

I did pull off my frame pump, tool pack and water bottles for a short race once. I noticed that the bike did definitely feel lighter. But all that stuff probably weighed over 5 lbs.

I can only speak from my mountain bike experience. Lighter tires made a huge difference in how nimble the bike felt and how quickly it accelerated. I don't have enough experience with lightweight road tires to make the same claim.

Imagination makes a big difference.

One of the better improvements you can make to a bike is to lose weight on it. But 1/2 lb on a 30 lbs bike is not going to be noticed.

But lighter tyres will mean less rotational weight-at the extremity of the wheel. Less effort involved in getting the bike up to speed and anything that takes less effort is good in my book.

The rotating weight also has gyroscopic effect. When I switched to lighter tires, I didnt notice improved acceleration but I did notice more responsive handling. However this may have also been due to compound of tread.

I'm a casual rider too, and struggle with this comparison. i've been thinking about trying to skim weight from my heavy mtb, and tires seem an obvious place to do it. If i could shave 200 - 400 grams, am i really making a significant change to my bike?

Only if you are riding the mtb. on the road.