As if you didn't already know ....

Tech FAQ: Again, bigger tires roll faster!

wider tyres for better rolling resistance is such a MAMIL thing to get fired up about and any discussion of this nature belongs on the BNA forum

I dunno. I see many skinny hipster youngin’s that have to be dragged kicking and screaming just to use a 25mm tyre. They’re still thinking “snake oil”.

A suitable BNA thread would be “Fat tyre’s for Jesus !!!

I agree there is logic in going from 23 -> 25 for a road bike. Beyond that, you’ll have trouble fitting a 28 in most modern frames though. And let’s not forget the aerodynamic effects!!

My favourite tyre of all time is the Vittoria Evo Pave which they say is 24c. Haven’t measured it though.

25’s fitted to my crabon for strada bianchi at christmas are still on …and lovin’ em. gator 28’s i bought for my commuter only measure 25.5…bummer, shoulda gone 32.


That’s solely due to no rims as yet being built/otpimized for tyres fatter than 25mm. It’s only a matter of time and it’s fo sure that rims are getting wider to improve aerodynamics.

For the most, and for the speed at which most people ride on (30km’h or less) the rolling resistance benefits outweigh the aerodynamic disadvantages. Zinn makes mention of this and also of the fact that Zipp and HED are making wider rims to improve aerodynamics and airflow at different yaw angles.

I’d also counter that a flapping jacket worn by a rider would make far more drag that a 28m tyre compared to a 25mm tyre. The rider and their position is still overwhelmingly the largest contributing drag coefficient factor. Optimizing the rider is something we could all benefit from and will make far more impact than a few mm’s of tyre width.

Tyres vary widely and not all manufacturer’s claimed width’s are true/correct.

Would rim width not also have something to do with it as that will determine your tyre’s profile and therefore contact patch? Or is that simply reinforcing the point as the 23c tyre gets stretched out wider making a wider contact patch? A23/TB14 being a case in point.

I rocked 25’s in Londinium as they were better on the damp greasy streets. Getting the choice in 25’s over here is not so easy, as not everyone wants or likes a gatorskin.

Yes, to both. What Zipp and HED are doing is extending that widepoint further/deeper along the rim to make for a smoother airflow and thus make them more aerodynamic.

I don’t have an the issue at hand but there’s a Bicycle Quarterly article where they did some actual wind tunnel testing and showed that fenders and even handlebar bags can improve aerodynamics. It’s all about the flow of air not how narrow something is. They also showed that hands on hoods is more aerodynamic than the hands of the drop position … yet, out of habit I always go to the drops when descending, hard to break habits.

MAMIL hands on hoods position is often like a superman position so this is no surprise

there are a lot of MAMILs in zipp/hed heartland

True: forearms are flatter and make for less frontal area. Lower the body/head and you’re going to descend at top speed.

Where is this mythological Zipp/HED heartland? They’re all riding on Fulcrum’s up here.

california - the spiritual home of the MAMIL

This diagram explained it well for me:

makes sense.

Perth on a Sat/Sunday morning is a close second…

some of us have known this for some time:

I have A23’s with 23mm tyres on my roadie, I was thinking about putting 25’s on the other day.

But looking at the frame I don’t think I will have enough clearance.

I would have thought running a wider rim would give less height in the tyre but it dosen’t appear that way.

The graphic above doesn’t make sense for me (in fact it’s a little stupid). Why would you run the same pressure in a wider tyre as a narrow one? Tyre pressure has minimal effect on rolling resistance … the whole reason behind using a wider tyre is that you can run lower pressures and thus benefit from both comfort and a lower rolling resistance of a wider casing.

In as much, yes … but I don’t recall either Cameron Myer or Brunswick CC hiring a wind tunnel and publishing quantitative tests confirming such. Maybe I’m not privy to Brunswick’s inner circle of secret testing :wink:

mostly it’s folks testing their livers, but that’s a different story.