GeorgePatton

Before didnt the tire size used to be 25mm or 28mm? I'm in the market for a new bike and my last road bike i bought was in 2016. I checked Trek and Giants new bikes under 2k and they all seem to have 32mm tires why is that? If I did buy a bike with 32mm tires would i notice a big difference coming from 25mm tires?

My current bike is a 2016 giant contend 3 and im looking at the Domane AL 3 but im put off by the 32mm tires.

yaw

Entry level bikes usually come with low quality and extra wide tyres to save cost and provide a more comfortable ride for the audience. The Domane is an endurance bike, so it will certainly come with wider rubber. I don't think their race bike line up would come that wide.

But what they come with is not so important because you can make immediate improvements, probably the best value for money upgrade of them all, to the bike when upgrading to a better tyre of choice. So that is highly recommended.

Regardless of tyre quality, the difference between 25 and 32 you will feel on the bike is drastic if you lower the tyre pressure in line with modern tyre pressure calculators. You will sense a lot more comfort and suspension, but it may come across more sluggish. That's feeling, not necessarily speed average based on the road surface you are riding on.

If it was me and the road surfaces are reasonable, and the rim internal width is reasonably wide (21mm or more), I would put on 28mm tyres (which will measure around 30 on wide rims). For me, this turned out to be a good balance between perceived agility and being able to run low enough pressures for ideal comfort without impacting rolling resistance. If aero was key to an event, and the 28mm bulge out to much on a specific wheel, I would still go down to 25mm, as long as the tyres sit nicely on the rim. No harm in trying out a few sizes over time to get it right for your weight and surfaces.

LarrySellerz

They are trying to n+1 roadies. Don’t trust the wide tires

scottfsmith

32mm is a great tire width for an endurance bike. The speed penalty is minimal and the ride comfort and handling are much improved. I’m glad to hear they are putting 32mm on new endurance bikes. Personally I use 30mm on my endurance bike which is pretty close to 32. Just make sure you don’t pump them up to your old road tire pressures.

Polaris OBark

Dog-eat-dog Kapitalizm: They are cheaping out with narrow 32mm tires, instead of putting 38mm tires on.

GeorgePatton

So if i bought a Trek Domane AL 3 could i put 28mm GP5000 tires on it?

yaw

The cycling gods command you to do it.

urbanknight

You will likely notice a more comfortable ride and maybe a tad slower average speed, but you could always put 25's on if you wish... or 28's like you asked about already.

One thing I found interesting is, after growing up in the 23mm pumped to max pressure days, I can't shake the instinctual sensing of what I perceive as a flat tire when I run anything below 70psi.

79pmooney

Likewise! I put more air in the Corsa G+ tires than I "should" just to minimize stops to see how flat my tires are going!

Russ Roth

This is true, there really is a mental feeling if you're used to older styles. If it doesn't feel hard something has gone wrong and I must have a flat or its slowing me down, even if the numbers don't play out that way.

mstateglfr 

Well of course you could. You could put a 25mm tire on if you want.
Not sure why you would want to though.

A quality fast rolling tire, like gp5k, will be great in 32mm.
The difference between a 28mm and 32mm gp5k tire is 45grams and .6 of a watt in rolling resistance when run at proper psi for width.
That's simply nothing. Like no difference that anyone less than elite will actually notice.
But the difference in feel/comfort is real. Neither is bad, it's just preference, but you won't be slower on 32mm compared to 28mm.

https://www.bicyclerollingresistance...000-comparison

urbanknight

Glad to see I'm not alone in this mental struggle.

tempocyclist

Because people are getting soft... 😜

PeteHski

+1
The pros are now routinely running wider tyres on wider internal rims. 28 mm is rapidly becoming the new default for racing, although 25 mm is still sometimes favoured on the front wheel. They even run up to 32 mm on the cobbled classics with very little loss on the smoother road sections. So I wouldn't worry about it, especially if your roads are not perfect. The main advantages are lower pressure and better ride quality.

shelbyfv

I'm old, fat and slow regardless of tire width. I'm currently enjoying 38s on the road and wouldn't consider a new bike that didn't take 32s, preferably at least 35s. Given the specs of new bikes, plenty of folks like wider tires. Or maybe we are all being duped by Big Wide Wheel....

GhostRider62

I recently shopped all the racing bikes and not a single one of them came with 32mm tires although a few will fit them. I can get 30mm GP5000 TR/S onto the one I bought but they do puff out on 25mm internal width rims.

Here is real data: 25-26mm are standard on Pinarello F, Cannondale Super Six, Specialized Tarmac, Canyon Aeroroad, Canyon Ultimate, BMC TimeMachine. 28mm on Cervelo S5 and R5, Felt AR.....

So, No. 32mm is not standard.

seypat

It could be a combo of Big Wide Tire and Big CF Frame. I find it interesting that all of these riders talk about how much the ride improved after they got some wide rims/tires, and ran them underinflated. How bad was the ride before the switch? Even with the various inserts, etc for comfort, a lot of the modern frames appear to be boneshakers/teeth rattlers. Or, maybe post 13 is the answer.

Chandne

It looks like 30 and 32 are very common now. Mine came with 32s but has 30s now. I have 32s I'll put back on soon. Now riding 25s is a pretty harsh experience. Since my 30/32 tires are relatively light and tubeless, they are no slower, so I see the preference. I would no longer buy a bike that did not at least have 32 clearance. My new one has 35 clearance which is nice. The 31 ENVE SES tires balloon out to 34+ on 25mm rims so that is nice.

GhostRider62

Comfort mostly depends on the roads.

The roads are awful in NY, VT, MA but go down South and they are often buttery in comparison. Give me a choice between running 25mm on smooth roads or 38-42 mm on bombed out pavement, I'll run 25 all day long on good roads.

shelbyfv

Yeah, overall I can't say that the stiffer bike with 38s is more comfortable than the flexy bike with 28s. What I like is the stability of the fat tires, I can just ride over bad pavement that I would have been concerned about previously. That's important to me because my vision is deteriorating along with everything else. I can understand that younger folks wouldn't have the same issues and might prefer something less truckish.

DaveSSS 

My 28mm tires with 52/56 psi are not under inflated. They're on 25mm internal width hookless rims that measure 31mm outside. The tires measure the same 31mm on these rims. The pressure values come from the zipp pressure calculator. https://axs.sram.com/guides/tire/pressure

For those who are unaware, endurance and gravel bikes are in a different category and you should expect 30-32mm minimum width tires. Racing bikes will have 25-28mm. 23mm is dead.

As for the ride, I deliberately raised the pressure by 18 psi on one of my bikes that still had 19mm IW hooked rims to feel the difference. My nice, low vibration ride turned to $hit on the chip sealed asphalt that I ride, most of the time. With the narrower hooked rims, the normal 28mm tire pressure is 62/66. 80 psi really sucked.

shelbyfv

It's interesting that regardless of the stock tire size, many of the newer road bikes have clearance for 32 or larger. The Cervelo Soloist comes with 28 but advertises clearance for 34. The very popular Specialized Aethos comes with 28(?) but clearance for 32 and reports of room for larger. These are pure road bikes, not endurance or gravel or whatever. Disc brakes give the ability to design in more clearance and there doesn't seem to be a downside, since people can obviously use smaller sizes if they prefer.

mstateglfr 

5 years ago a coworker was getting into cycling and since I was the token cyclist in the office, I talked to him a bunch about frame material, geometry, etc etc.
A handful of us rode each week and I think he and I talked about options for an hour each ride for a month and a half straight.

Anyways, I told him I would try to be neutral, but some biases would show.
And boy did they show when it came to talking about compliance.
I found myself ranting about how at that point in time, the prior 10 years had been full of brands designing bikes that were stiffer and stiffer, and then inserting all these various ways to create compliance since the frames were clearly too jarringly uncomfortable to ride on their own. Shock and suspension in the headset. Suspension and decoupling in the seattube joint. Seatstays that pivot. Seatposts that have a leaf design.
Etc etc.

It was funny- I pointed to my steel road bike with 28mm gp4k tires(30.75 actual) and commented that it has geometry I like and a design/material that works well, and therefore I don't need all those comfort designs.


He ended up buying an extremely stuff carbon road bike with multiple comfort elements designed in.

GhostRider62

My front wheel 28 mm GP5k tubeless on Zipp 303 firecrest hookless measure 31 mm. I run it 55-60 psi

My rear wheel 30 mm GP5k tubeless on Zipp 303 firecrest hookless measure 33 mm. I also run them 55-60 psi. These pressures are measurably slower than optimal but the comfort is worth it to me on my worn, broken, ****seal roads.

jaxgtr

My Emonda came with 23's, but I am running 28's and the ride is so much more comfortable. My Domane came with 32's, I run 30's on it. I personally would not go below a 28 on either bike, they ride comfort is just superior to me.