Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Myths in cycling: wider tires are slower

renehersecycles.com

Post reply on HN
Print view View original

231–240 of 419 posts

Re: Myths in cycling: wider tires are slower

#231

Post by ehnto »

rukuu001 wrote: post #187
auxym wrote: post #175

Earlier quoted context omitted.

In many ways, modern gravel bikes are a comeback of the "sport touring" road bikes that were popular from roughly the mid 70s to the mid 90s, then became mostly absent from market. Compared with "racing" bikes, they had wider tires, a more relaxed geometry, and various conveniences such as mounting points for fenders and racks. Thus, they were a much better option for the majority of riders who did not participate in…

Surly made a couple bike you could put fat tires on - their touring bike and a cyclocross bike. I don’t know if they’re still available but they were selling them in the mid-2000s

Definitely still available. That segment of the industry has exploded. Another great manufacturer for touring/adventure bikes is Bombtrack.

Many touring/adventure bikes will double as way better commuter than a road bike I feel. They are set up for comfort, long hours in the saddle, and usually have with luggage mounts.

Re: Myths in cycling: wider tires are slower

#232

Post by ehnto »

plorkyeran wrote: post #36
haswell wrote: post #12

This is one of the reasons I love the emergence of the "Gravel" category of bikes. They look and have geometry similar to a road bike, but they have enough clearance for nice fat gravel tires. I ride in Chicago (shitty roads, potholes & construction are everywhere), and love that I can put nice 38mm+ GravelKing Slick tires on the bike, and still have no problem keeping up with most road bikes. I've gotten funny looks…

Yeah, when I first got my gravel bike I thought I'd be sacrificing some road performance for better flexibility and comfort, but that didn't happen. The actual result was that my times on smooth segments were unchanged and I've beaten many of my personal bests on rougher roads (and obviously it's much better on dirt). It's not a perfectly fair comparison because I did upgrade to a nicer bike in the process, but my pr…

I ended up commuting on my big tire bike because it's so much more comfortable and just as quick.

Re: Myths in cycling: wider tires are slower

#233

Post by LAC-Tech »

dharmab wrote: post #229
LAC-Tech wrote: post #170

Earlier quoted context omitted.

Well there's shades of grey between paved tarmac and proper off road. Not a motorcyclists but I assume these adventure/dual sport bikes perform much better over say unsealed roads, and are at least workable on fire roads.

Fire roads are easy mode on an ADV bike. They can do double track quite well too. They start to struggle in mud, sand and single track.

I'd presume that pure street motorcycles would fair pretty badly on even double track.

So yeah, ADV would seem to be useful for something other than wanting to look rugged.

Re: Myths in cycling: wider tires are slower

#234

Post by ehnto »

haswell wrote: post #52
jaypeg25 wrote: post #48

Earlier quoted context omitted.

I bought a Specialized Diverge over a year ago. It was mostly to commute to and from work, but also to have the ability to take gravel paths and trails on the weekends. It's been awesome but friends have suggested I take off the stock tires and add some new ones. Is it really worth it? The tires are already fairly fat already, at least compared to road bike tires.

The Diverge was on my shortlist when I got the Topstone. At the time (2019), I think the Diverge defaulted to skinnier smoother tires. Can’t remember which tires specifically. The Topstone shipped with some pretty knobby WTBs that definitely had an impact on rolling resistance. If your tires are knobby/optimized for off-road, putting a slicker tire (the GK slicks are quite popular for good reason), I suspect you’ll n…

I have enjoyed the WTB Trailblazers as they are knobby enough to run singletrack but have a solid centerline for touring longevity and better rolling resistance. You just have to adjust the tire pressure according to what you're predominantly doing that day. Commutting I run them at 35-45psi and on the trail I run them at 18-22psi no worries.

Re: Myths in cycling: wider tires are slower

#235

Post by whakim »

photojosh wrote: post #207
krono wrote: post #31

Earlier quoted context omitted.

Yeah, my roady friends are jealous because I get to use my gravelbike off-road, and my mountainbike friends are jealous at me for being able to keep up with roadies. And all that for the price of one bike and an extra set of wheels with slicks! Canyon Grail here, yes the one with the weird cockpit :)

How off-road do you go? I have a gravel bike too, but I much prefer the MTB for rocky descents.

I also own a Canyon Grail (the alloy one, so no weird handlebar) and it's pretty capable for fire roads and some singletrack. When it gets really rocky and rooty though I find myself having less fun simply because the riding experience becomes so jarring and rattly. It's also way more fun to climb on (as in you actually enjoy the climbs as opposed to just doing them to get to the downhills) compared to a mountain bike. Where I live I have to ride ~7 miles each way to get to the trails so it makes a lot of sense as my one off-road bike.

Re: Myths in cycling: wider tires are slower

#236

Post by adnmcq999 »

louthy wrote: post #2

If that were the case, surely Tour de France riders would use wider tyres to gain more grip going around corners, especially in time-trials or stages with sprint finishes. Doesn’t a greater surface area touching the floor means more frictional effects when pushing against the road?

Yeah I haven’t read the article yet but OP is making flat-earth level claims

Even in Paris Roubaix (where there are cobbled sections) they ride 28s

Re: Myths in cycling: wider tires are slower

#237

Post by GavinMcG »

dennisgorelik wrote: post #204
PragmaticPulp wrote: post #132

Earlier quoted context omitted.

If you’re going a short distance: No, it doesn’t matter. For a longer ride or a trail ride, the loss from the tires adds up. One extra MPH means a lot when you’re doing a multiple hour ride at an average of 10-15MPH. Tire pressure influences rolling resistance significantly on larger tires. I’ll some times increase pressure on longer rides or for uphill portions. Lower pressures have more traction, so I’ll let air ou…

> One extra MPH means a lot when you’re doing a multiple hour ride at an average of 10-15MPH. Why spend your effort on optimizing your bike performance by 8% if you can instead simply shorten the distance by 8%?

How exactly do you shorten trails, or race courses?

Re: Myths in cycling: wider tires are slower

#238

Post by rhn_mk1 »

> the air inside a wide tire doesn’t add weight

This is true, but it's not weight that matters for acceleration, it's the mass, which that paragraph gets confused about. The air inside does definitely have a little mass.

The difference in mass between wider and narrower tires does have some effect on handling, even if not on acceleration.

Re: Myths in cycling: wider tires are slower

#239

Post by whakim »

haswell wrote: post #181
pmontra wrote: post #151

Earlier quoted context omitted.

Anecdotally my gravel bike is faster with 28 mm slick tires than with 42 mm sawtooth tires. Of course sawtooth vs slick makes a difference in friction. The hubs in the wheels could make a difference too. I use the 28 mm wheels when I go on asphalt roads in the mountains because I don't want the extra weight and friction. 42 mm for everything else.

> Anecdotally my gravel bike is faster with 28 mm slick tires than with 42 mm sawtooth tires. Out of curiosity, do you know this to be true, or believe this to be true? I ask because the perception of speed with skinnier tires is one of the things the article touches on. I felt similarly when I put GP5000 28mm slicks on the gravel bike, but when I looked at my ride history, I couldn’t really back that feeling of spee…

You're definitely faster with the GP5000s and it's not just an illusion. The GP5000 is an extremely fast tire - some of the lowest rolling resistance out there as measured scientifically [1]. Even the fastest 38mm tires are probably going to cost you minimum 10 watts per tire over the GP5000; perhaps even double that.

[1] https://www.bicyclerollingresistance.com/road-bike-reviews/c...

Re: Myths in cycling: wider tires are slower

#240

Post by skeeter2020 »

haswell wrote: post #12

This is one of the reasons I love the emergence of the "Gravel" category of bikes. They look and have geometry similar to a road bike, but they have enough clearance for nice fat gravel tires. I ride in Chicago (shitty roads, potholes & construction are everywhere), and love that I can put nice 38mm+ GravelKing Slick tires on the bike, and still have no problem keeping up with most road bikes. I've gotten funny looks…

The geo is actually quite a bit more relaxed than your typical racing bike, which is why I like gravel grinders (at 6'5" and 40+ years old). It's definitely a nicer ride than your typical road tire but not sure I'd go as far as comfy/soft...
Post reply on HN