they're fine in all seasons, hence the name "4-seasons". you certainly wouldn't want to use them in a race, but for commuting and general getting around town riding, the conti grand prix 4-season is a great all-around performer in my opinion. it hits that weight/performance/durability venn diagram sweet spot just perfectly for me, but tires are an incredibly personal thing, so YMMV.




nope, i never ridden on T serves, so i can't comment on how the two compare.




even better than having multiple wheelsets is having multiple bikes. N+1 ;)

In my world it makes no difference.....slow is slow.

In the real world,I guess we'll be seeing tall fat tires on electric cars since they are better at gas mileage?...:)

IMO you can't go wrong with either tire, both are excellent. The difference between the two probably comes down to personal preference.

Interesting assertion.

Smaller wheels have a lower moment of inertia, but must spin faster at the same road speed.
Smaller wheels are lighter (all else equal), but must spin faster at the same road speed.
The spokes of smaller wheels must move through the air at a higher speed, but the air resistance against the spokes acts with more leverage on a larger wheel.

I'm not sure if all of those effects balance or not.

All else equal, larger wheels handle road irregularities more efficiently.

You'll notice the same trend with auto wheels.

They're not idiots ... they know this.

Air resistance of bike+rider has nothing (minimal) to do with spokes width.

The term employ was "speed" not "acceleration."

I wasn't referring to spoke width. I was referring to spoke length and the air resistance on the spokes at the wheel spins.

No it wasn't. Speed was correct. :)

Good point about the quality and construction of the tire making the biggest difference.
I have ridden quality tires (gator skin or equivelant) from 23 to 32 mm. Personally on a commute I can’t tell the difference between the speed of a 23, 25, or 28mm tire. When Racing, I can but that is mostly about the sprint.
32mm is starting to be a bit slower for me. 28mm is the sweet spot.

FYI, on a mountain bike knobby, I ride about 17mph. on a road bike (that I normally commute on) I ride about 20-21mph.

However, at slower speeds, (say 15mph), a bigger tire will have less rolling resistance (basically less deformation, and follows the road contors better) and actually be faster at speed (although because of weight, slower to accelerate). When riding at 15mph or slower, I’ll take the bigger tire. At those speeds, the lower rolling resistance are more important than the weight and aero advantages of a big tire.

I know this ... I'm saying that the "drag" due to the difference in spoke width is negligible compared to everything else in a "commuting" context.

On the whole, it is an interesting question. Nevermind introducing frame flex and transfer on the power to rear wheel, grip, etc...

Nonsense like this doesn't belong in a tire width discussion thread! ;)

As is the difference in speed due to wheel circumference, but you brought that up. I was simply trying to determine if your claim was obviously right or wrong. It turns out that there are enough factors that go each way that I'd need to see (or do) the math to come to a conclusion.

My car runs 13 inch wheels, the summer tyres are 155 while the winter wheels are 185.

The car gives up a little ride quality on the smaller and narrower summer tyres but the mileage and the accelleration improve noticeably... the wider winter tyres do handle better but that is a function of them being very good tyres (Nokian).

BMW did a bunch of wheel tests and found that the move to oversized rims and tyres degraded the performance, handling, and economy but the market demands are what made them concede to running a slightly less efficient wheel / tyre and with cars you just need to boost the engine to compensate whereas on a bicycle, the engine is pretty limited.

My Moulten is set up as an all rounder with 16 inch wheels and 1.25 tyres at 85psi... it does not give up a thing to a comparable bicycle with 26 or 700c wheels.

My P20 rolls on 1.5 marathons at 70 psi and is set up for touring and there is no difference between this and my expedition bike that rolls on some fast rolling 26 by 2.0 tyres.

I also ride a few bikes with 32 mm tyres and they aren't slow by any measure and the ride improvement is worth it.

Generally speaking:

The wider the tire the heavier the tire. Heavy tires are slower than lighter tires. A wider tire will also require a wider tube, which is heavier. And there is the issue of wind resistance, which goes up exponentially.

However, on rough roads and offroad, the opposite can be, and often is, true.

That's because in the US/NA, you run them at low speeds (below 80mph).

There's a noticeable difference in stability with wider tires and larger circumference above 120 or 130 mph due to the reduction in rev/sec reducing the perception of smaller defects from the wheel manufacturing process. Especially when the road surface is of high quality.

I'd love to see that BMW study because I don't believe what you're saying is true for the global market where speeds are higher and road quality is better due to lower environmental variation.

Also, this is anecdotal. In what testing conditions are you referring to?

From what I know: with the same outer wheel diameter (rim+tyre widths) - having a larger wheel and a lower tyre profile (i.e. thinner tyre) provides for less comfort, but better high speed handling (up to a point).


For snow, wheels that are big, but narrow are the best. They don't look very nice, but go anywhere:

http://tocmp.org/lada/niva/Lada%20Niva%202er.jpg

A couple of years ago I switched from 700x28 GP 4 Seasons to 700x35 Marathon Supremes. The Supremes are designed as a touring tire while the GP 4 Seasons are designed as a training (ostensibly for road racing) tire, so apart from width the Marathon Supremes have higher rolling resistance due to their construction. On the bike I could feel that difference. The Marathon Supremes roll really well for a touring tire, but they felt more sluggish than the GP 4 Seasons. So I decided to collect some data to see how much slower they were. I didn't approach this scientifically. I just got on the bike and rode to work going as fast as I could. I figured the difference between that and the best times I had recorded on the GP 4 Seasons would tell me how much slower the Marathon Supremes were. I ended up beating my previous best time for that route.

To summarize, even accounting for the difference in tire construction that typically comes with wider tires, you aren't likely to see a measurable difference in speed if you're focused on speed. On the other hand, the wider tires will almost certainly feel slower. They may also cause a bit more fatigue to maintain the same speeds, or you may ride slower because your legs are telling you that you should.

Sure. I have 15" steel rims and winter tires on my Audi currently. I also have 17" alloys with summer tires.

To be fair, I did state circumference, which suggests that the wheel/tire combo gets larger. If it stays the same, it more of a discussion concerning tire sidewall stiffness.

Ladas are great. I was at my lifetime favourite party when I called a Belorussian a Lada after calling an Italian woman a Maserati, she wasn't super pleased, but the night ended well anyway. We had a long discussion about why it's "White Russia" after I saw three women consecutively vomit in the sink ... those Swedes can party but the Finnish liquorice vodka tends to do that to people ;)

Talking about wheel size, rotational velocity is higher for the smaller wheel, but where the rubber meets the ground, tangential speed is the same for both wheels. Therefore the (linear) speed of the spokes through the air is the same at the rim, top and bottom. Since the spokes are shorter, I'd say there is less aerodynamic drag on them.

If the tires are thicker on the same wheel, the wheel doesn't turn as fast ... let's see how this reasoning holds up. The spokes still have to travel the same distance horizontally in the same amount of time, so that's the same. Chopping up and down though, that would be slower. So the drag from spokes would be less with a thicker tire. Whether that's more or less than the extra aerodynamic drag from the tire being larger, I guess that would depend on a few other things.

Russian (girls) can drink A LOT! :D

So can the Swedes, but she really impressed me compared to the continental ladies.

People from that party often meet (in London last weekend we we're with a Danish ex-colleague talking about it) and still discuss it. It was in housing for foreign scientists working in Stockholm and the building functioned as a large sundial.

https://www.google.co.uk/search?q=we...tM7aZ&imgdii=_

I'm not so sure.

The smaller wheel must rotate faster for the same tangential speed, so the linear speed of the spokes on the smaller wheel should be faster.

Think of what the tangential speed is at the ground, in the center, and at the top. That's the speed that the spokes (and hub) are moving through the air, at those three points. Do those speeds change when the radius changes?

The spokes do not extend all the way to the ground. The wheel and tire profile must be considered, and as long as either of those are non-zero (true for any spoked bicycle wheel), the spokes of the smaller wheel will have a higher linear speed.

The speed difference and rolling resistence between 700x28 or 700x38 or 26x2.00 is irrelevant for commuting, it's so minor that majority of people wouldn't even notice it. Speed and rolling resistence may be important for racing but not for commuting.

You didn't consider what I suggested :(

At the ground the tangential speed is zero. At the center of the hub it is the velocity of the bike. At the top, it is twice the bike's velocity. These numbers are the same regardless of the size of the wheel, therefore the spokes will have the same linear speed.

The spokes do not extend the ground, nor to the center of the axle, and those are the only two points along the wheel assembly's radius at which the linear speed will be the same for the spokes of different size wheels. Everywhere else, which is the entire length of the spoke on actual wheels, the linear speeds are different.

My reasoning was incorrect. It's not clear whether, all else equal, the linear speed of the spokes of the smaller wheel would be faster or slower.

The spokes would have the same linear speed at corresponding points along the spoke lengths, assuming the same bicycle speed, if the wheel assemblies were proportionally identical. In other words, the larger wheel would have to also have a proportionally larger hub and a proportionally taller tire. With all else equal, the smaller wheel has a proportionally larger hub and a proportionally larger tire & rim. The two factors result in opposite, but not necessarily equal, effects on the linear speed of the spokes.

I agree, it doesn't really matter so long as you arrive at work on time.
In my experience, my fastest commute times have been on 28mm tires. The next fastest were set on 23/25 followed by 32/35. My commute is all uphill then downhill then uphill so that might factor in the equation. YMMV