wilson_smyth

My hybrid has 40mm Schwalbe G-One Allround, Kevlar, 40-622. So far they have been great tires, no punctures in 6 months and I feel reasonably fast, although i really dont measure these things as im not out to race.
I run them at max pressure of 70psi, my logic being a hard tire is more resistant to punctures, and my limited experience so far has agreed with this.

I was thinking of switching down to 32mm tires to see if it made the bike a feel more performant.
From reading around, 40 is quite wide, even for a commuter and there may be benefits to a narrower tire, without going too narrow.

What are peoples thoughts on this?

skidder

Make sure your rims will take whatever size you want to go down to. I've never used 40mm tires, almost always been in the 32mm-35mm range, and never had problems with them. Plenty of brands, tread styles, and other options in the 32-35mm range.

tyrion

That's backwards - higher pressure is more puncture prone than lower pressure.

Rolla

If you feel reasonably fast and you aren't out to race, why is increasing performance important? If it ain't broke...

Wanderer

A narrower tire, like a 35-32 on the front will improve performance, less than 40 on the rear - not so much, and comfort will suffer.

Gary in NJ

https://www.bicyclerollingresistance.com/

Look up your current tires, and then compare them to other tires you may be considering. But know that rolling resistance is a small percentage of the overall amount of power needed to move a bike. This BRR website does give good reviews and comparisons of tires. It's also good to know things like the puncture resistance. While I don't use just the numbers to make tire selections, I do use the information.

ofajen

I really can’t see much benefit to running narrower tires.

However, I would lower the pressure a bunch and run those tires at more like 50 psi.

Otto

wilson_smyth

Im glad i posted, as advice is a narrower tire wont make a huge difference and more importantly and unexpectedly, im running the tires way too hard.
Will drop them down by 10-15psi on the next spin.

Thanks all!

veganbikes

Narrow tires are so last century. Wide or die!

I have a vintage bike I am stuck running 700x25c tires and they are just so small. Even my ti road bike on 28s is a little narrower than I prefer but I love the bike and it is nice to have a pure road bike for just tarmac but even still 30s or 32s might have been nice as well.

TiHabanero

I have been commuting on 28mm tires for decades. Never an issue with flats or durability. I also have a Miyata 1000 with 38mm tires on it that I use for commuting once in a while. The fit of the two bikes is near identical. The rack, bags, lights, pedals, and drive train are identical. The different tire size makes a slight difference in the commute time. 15 miles one way takes about 10 minutes longer on the wider tire bike. Mostly I feel the difference climbing out of the river valley, and the other hills on the route. Comes down to acceleration. When the wheels have to be pushed the narrow tires do it better. I will say, the 38mm tires have never had a flat, whereas the 28mm have had two flats in the last 4000 miles. 28mm tires are the low end Conti Ultra Sport tires, the 38mm tires are Conti City Ride tires.

ofajen

Those tires are pretty different. The Ultra Sport is a reasonably light and supple road tire that weighs about 300 grams each. The City Ride is a heavy, stiff commuting tire that weighs over 800 grams each. There are wider tires that are light and supple like the Ultra Sport and would feel quick but more comfy and more stable on rough surfaces.

Otto

Flip Flop Rider

wear them out then switch

Gconan

I went from treaded 40mm tires to smooth 32mm tires on my gravel bike and on asphalt they perform so much better! Of course I lost the ability to wonder in the deep gravel, but for the asphalt it was a fantastic upgrade.

wilson_smyth

The sram pressure calculator (link at bottom) guesstimates 42 & 45 psi respectively, for front and back. That seems very low though, but now I'm thinking the internal model I have in my head of bike setup is wrong and needs recalibration. Reduced from 70 to 55psi each for my next ride but will go lower for thr one after.

Nice to have stuff to play with on the bike that costs nothing!


https://axs.sram.com/guides/tire/pressure

cxwrench

I weigh 165, I inflate the 40mm tires I have (Rene Herse, smooth) to a little under 40psi front and a little over 40psi rear. Remember, it's free to experiment, unless you flat of course. Think of it this way...if you had 50mm tires on your mtb what would you inflate them to? That's 2". You'd probably be around 30ish for off road. 55 is still way high for road use.

skookum

I might get flack for this, but I'm going to link to Jan Heine's Myths in Cycling (1): Wider Tires Are Slower

Branko D

There's nothing quite like a nice, light 23mm race tire.

cyccommute 

Based on what evidence? I know that people think that low pressures allow the tire to flex around an object better than high pressure does but, in practice, I’ve never found tire pressure to have much effect on flat frequency. I have bikes that run 110 psi to 80 psi to 40 psi on my mountain bikes. All of them have gotten flats at some point with about the same rate. The mountain bikes experience far more flats than my other bikes but they are ridden in places that are more prone to objects that can puncture the tire. Most of the time, that’s goatheads but I did flat this last week on a prickly pear cactus spike.

ofajen

I’d agree with this. That is, I’ve seen statements but not evidence that either higher or lower pressure changes the propensity to flat.

So, I choose tire pressure based on other performance considerations, like comfort, stability, rolling resistance and so on.

My rides generally include stone trails and gravel, so I run bigger tires and lower pressures.

Otto

tyrion

I heard that from Josh Poertner - I can't remember where.

wolfchild

I wouldn't run anything smaller than a 32mm tire.

Troul 

This has proven effective for my riding conditions.

Going from 28s stock R & F to the combo of 30 R 28 F has provided the best thus far.
Before settling for that combo, had a various other combos that didn't provide any or minimal benefits. Such combinations tried; 28 R 32 F - 28 R - 34 F - 32 R - 28 F - 30 R 32 F
28 R 34 F was worst, 34 R would not clear.

cxwrench

40psi on a mountain bike?!? How do you stay upright? That's crazy high.

Wanderer

40 on the rear, and a 35 on the front... A 32 will be more harsh!

The 35 will quicken steering, and make it more precise.... Therefore, performance is improved.

cyccommute 

No. Bicycle tire calculators say that is right for my weight. Years of riding experience tell me that is the right pressure for my weight. Frankly, I see any thing less than that to be far too low. I’ve never had problems with pinch flats nor with rim damage. I’ve ridden on tires that are going flat and could never stand the wallowing feel that goes along with flat tires.