badger1

Roubaix (current) comes stock with 30mm tires; I believe all except the S-Works one which is still on 28s.

You might be right re. the FS, although ... even with 32s at proper pressure I do notice a substantial difference between open and closed (I have the hydraulically damped one).

SoSmellyAir

mstateglfr All good points re: cassettes and chain stays, individually.

I am not that physically flexible so a race bike is probably out of the question for me. So, for me personally, I would prefer an endurance bike that is just a more upright dedicated road bike (e.g., lighter, with shorter chain stays and wheelbase), without any compromises to give it more all road capabilities, which is well covered by contemporary gravel bikes already. For example, there is a whole other thread on how putting road wheels and tires on a gravel bike brings it pretty close to a contemporary endurance bike.

Putting Road Wheels on a Gravel Bike: Is this a thing? - Bike Forums

But the market seems to be moving away from dedicated road bikes with an endurance / more upright geometry.

merlinextraligh

[QUOTE=PeteHski;22893712]The difference in aero hardly matters to pro racers, never mind an average club racer or recreational rider. A lot of teams were racing on 30 and 32 mm tyres at Paris Roubaix this year. While you can say that’s only because of the cobbles, there is still 200 km of 50 kph road to cover. If there was a significant loss of speed on those wider tyres, they wouldn’t be racing them simple as that [//QUOTE]

Then why wouldn’t they race the 32’s all year long in every race?

Sy Reene

[QUOTE=merlinextraligh;22894208]weight and handling?

surak

Wider tires as standard on low-mid tier bikes make a lot of sense when you consider, as the brands do, who buys those bikes. The benefits of wider tires to those potential buyers include being:

• plusher because they can be run at lower pressure, noticeable on test rides by buyers who are often looking for comfort and compliance (riders who want to race are usually going to swap out whatever came with the bike, just like saddle, pedals, etc.)
• better on the worsening road conditions in many places
• less likely to flat, both pinch and puncture type, which for new riders will be the most common mechanical and not one they might even know how to fix
• trendy for buyers who're gravel curious but don't want to ride a tank all the time as their N=1
• less intimidating for riders coming from hybrids and mtbs

​​​​​​The market for these bikes are the people who aren't looking for an out and out racing bike. It's for the ones driving the trend to disc brakes (wider tire clearance, more braking confidence in all conditions) and lower gearing ratios.

scottfsmith

Since people are still debating whether 32mm are worse than 28 as far as overall performance goes I found the study I was not remembering before. It is on this YouTube:


These were field tests with different width rims and tires, 28 and 32mm tires and wider (more for 32mm) and narrower (more for 28mm) rims. The following figure from the video is the crux: the dark green is the best overall and is the 28mm tires with the narrower rims. Interestingly on the wider rims there is no advantage at all of 28 over 32. The yellow is the wider rims with the 32mm tires, not bad at all with only a couple watts penalty at the common lower speeds. The two worst lines are rim-tire mismatch: either wide rim narrow tire or wide tire narrow rim.

Anyway this is my view of why pros are almost never going above 28mm for regular road races. For Paris-Roubaix etc you can save 15-20 watts on the bumpy stuff so its probably worth losing 5 watts on the rest of the race .. plus better handing and less flatting with a bigger tire.

Calsun

Bought two Specialized Creo road bikes and they came with 28mm tires. The Specialized Tamrac "performance" bikes come with 26mm tires.

shelbyfv

28s on an ebike is unexpected for sure! Hopefully there is room to go larger. Given the clearances on the newest bike designs it will be interesting to see if they level off at 32 or keep growing. 5 more years should give some perspective.

Chandne

The Creo 28s are around 30.5 measured. They came out several years ago so 28 was kinda fat then. My Moots RCS came with 32s though was a shop frame-up build. 28-30 is very common now, it seems, but more manufacturers are doing 32s now where 30 was their max.

PeteHski

Simply because 25-28 mm is still marginally quicker on smoother roads and that’s what their rims are currently optimised for.

I just think the pros of going wider outweigh any small loss in speed. I’ve run 28, 30 and 32 mm tyres over the last few years and the wider tyres with lower pressure give a better ride, more grip in crappy conditions and less flats. They are also quite likely to be faster on rougher roads. I’m not riding cobbles, but my local roads are nowhere near as nice as typical European Pro stage races.

Unless you are a pro racer, why would you give up all the advantages of a slightly wider tyre for some tiny gain in speed on smoother roads?

urbanknight

Unless there is an even more significant loss of speed from running narrow tires on the cobbles.

merlinextraligh

and that was never my point. My first post said, other factors may well trump aero, particularly depending on your priorities.

My sole point is that if you are talking speed, aero is one factor in the equation that needs to be considered.

merlinextraligh

As a pure anecdote, we’re currently in the middle of the Ride Across Portugal. I did a quick look at all the bikes. 28mm seems to be the modal class, with a couple of 23-25, and one 32mm. The one pro here I believe is on 28s.

PeteHski

I think we mostly agree on this. I didn't mean "you" personally. If I was only ever racing crits on smooth surfaces I would probably use 28 mm tyres, maybe even a 25 mm front. But for literally anything else I prefer the advantages of 30 or 32 mm. Once you have committed to wheels optimised around wider tyres it becomes a no-brainer and the aero differences are very marginal.

mstateglfr 

But if that factor cant be turned into actual data, should it be a factor? Yeah there might be an aero difference, but with so many variables(wheel width, wheel depth, hooks or hookless, tire width) to account for, how is anyone supposed to speak confidently about that factor?
Rolling resistance is known due to easily available test data. Weight is known due to easily available test data. Feel/comfort is known due to countless user views. But aero difference? I genuinely have 0 idea what the aero difference is between a 28mm and 32mm tire when they are on the same rim. And I definitely dont know the aero difference when they are on different rims(rim profiles that optimize each tire size).
So if I have 0 idea, I dont think it should be something I factor in when making a decision. How would I ever factor it in?

Aero differences for varying sized GP5k tires, on the same rim and on optimized rims, is definitely something I would be interested in reading about. I am not aware of aero testing or GP5k tires though.
And if there is a difference, is it 1watt, 10watts, or 50watts? The actual difference is critical when factoring in aero, and we dont know that difference.

PeteHski

The example data in post no. 56 is enough for me not to worry about aero as a major factor in choosing tyre width. I also know that my wheels are optimised for 28-30 mm tyres so happy days.

base2 

27x1&1/8, 27x1&1/4 is the same width as 28-32mm. So, we have well over 40+ years to judge from. Maybe 19-23mm was the aberration?

Darth Lefty 

Right. If you are buying a road bike your knees are too old for MTB or running and 32's will carry you gently over the hill

Jrasero

It depends on the price and type of bike. An entry priced bike will sometimes preference comfort over performance due to the demographic and price point it's selling at, but also the type of bike matters too. If this was an all road or adventure bike yeah 32c wouldn't be out of place.

Now with this said, unless you are buying a pretty high end bike the tires you get are normally just okay to even bad. I would suggest buying a better set regardless after you wear out the stock ones

DB77

I live in New Hampshire. The winters in the Northeast are absolutely brutal on the roads. Many towns are full of potholes and cracked roads. Riding around on anything less than 28s is just not enjoyable.

Chandne

I have pretty good roads where I ride and super smooth asphalt bike paths up near 10,000 ft where I can do 50-80 miles without hardly running across a vehicle. I still find 32s better than even my 28s. The bike with the 28s is lighter by 3 lbs. I still have flat, mild downhil, and steep downhilll PRs on the 32s. The lighter bike is slightly quicker on the climbs as it should be but I am very close on the 32s. I would never use 28s again but am limited by the frame on that bike and the carbon is so compliant yet quick that I keep that BMC around. If I lived where roads were rough, I may even consider those new Specialized Mondos and move to 35s.

DB77

Must be nice. The small town I live in is great in a lot of ways but the town maintained roads are awful. Quite a few pothole that are 3-5 inches deep. Can you imagine rolling through one of those at 20mph or faster? You learn where they all are to avoid them.

Chandne

Wow, that is stressful. You could fly off the front if not careful and wary. Our smooth paths…

Redbullet

I would try a simplified summary:

“Old school”: skinnier and lighter – the better (see 23 mm tires and rim brakes). Good aerodynamics, good climbing, relatively less expensive, thus, accessible to the larger public (not offered anymore today).
“New school” – mainly pros’ world and too expensive for larger public: Increased tire width, disk brakes. Penalty in weight and aerodynamics vs. “Old School” compensated by expensive optimized wheels and expensive weight reductions elsewhere. Marginally better ride quality (mainly on harsher and longer roads), marginally lower rolling resistance. Overall, marginally better than “Old school”.
“Larger public bikes”: mimics the “New school”, but without compensating losses in aerodynamics and weight penalty for keeping prices still appealing. Overall, lower performance than the first 2 alternatives, but still more expensive than “Old school”.

After years of riding 23 mm tires and recently 28 mm on reasonable roads, I would also assess that everything above 28 (or 25) might not be the norm, but only be necessary for special hard riding conditions.

Calsun

The narrower tires we the result of the limitations of sewup tubular tires. My first road bike with clincher tires used 23mm tires and the ride was never a problem. My new e-bike uses 28mm tires to help with the weight of the bike and the rider and provide a softer ride. I would only go wider than 28mm for a gravel bike (42mm tires) or a mountain trail bike (50mm tires). There is also the aspect of the bulk of an extra tube or tire to pack and have available.