justtrying

I am thinking of changing my tire size from 700x38 to possibly a 700x32 or a 700x30. How much will it effect the smoothest of the ride. I know to get a little faster I have to just keep spinning but this old guy needs all the hel he can get

therealjoeblow

Your ride will get harsher as you will need more tire pressure to hold the same total weight with a narrower tire.

Honestly, I doubt you will go any faster. The higher the pressure, less suspension in the tires, and then that all transfers into your body to absorb the energy from the bumps, which slows you down. There is science documented behind it:

https://janheine.wordpress.com/2010/...-and-pressure/

https://janheine.wordpress.com/2015/...a-and-details/

https://janheine.wordpress.com/2015/...re-revolution/

The style of tire makes more of a difference.

I run Continental SpeedRide 700x42's, which actually measure 38mm when fully inflated to between 50 and 60 psi. These are very fast tires on pavement, that handle gravel and dry dirt exceedingly well too. I would not want to go any narrower for mixed riding.

Cheers
TRJB

AU Tiger

When I went from 28 to 35, it made a huge difference in comfort. So I imagine you would notice a similar difference in the other direction. And the 35s didn't have much impact at all on my speed - certainly not enough to warrant going back to the narrower tire.

gilpi

Here is something else to confuse you or help you

Bicycle Rolling Resistance | Rolling Resistance Tests

Many factors affect rolling resistance, quality has a lot to do with it and yes I am in the camp of the thinner the faster with some exceptions though some will disagree.
Knobby tires on the road will slow you down and yes the wider the more comfy. So a lot depends on the type of riding you do.
I personally use a road bike for street riding using 23 or 25cm wide tires, while they are excellent for some fast cruising on nicely paved roads, there are plenty of beat up secondary roads here in NJ and the thinner tires will beat you up and definitely slow down your ride over those bumpy roads.
So it's all about finding a happy medium for your type of riding.

justtrying

Thank you all for your responses. I guess I will keep the same size. They are smooth. I stay on asphalt for all of my riding

canklecat

Ditto, the rolling resistance tire review website. It'll give you an idea of which tires in the 700x32-38 range offer a good compromise between low rolling resistance, puncture resistance and smooth ride. For example, Schwalbe Marathon Green Guards seem to offer remarkably low rolling resistance for durable all around touring and commuting tires.

Nowadays the conventional wisdom seems to be going a little wider, and running somewhat lower air pressure to minimize road vibration and chatter for a more efficient power transfer. That's essential to me. I have a busted up back and neck with permanent C2 damage and limited neck mobility, so comfort is key. But I don't want mushy, sluggish tires either.

Like @therealjoeblow, I run Continental SpeedRides on my hybridized mountain bike and love 'em for smooth and rough pavement, chip seal, dry gravel and even some no-path rides on grass, pastures, etc. If I had a drop bar road or gravel bike with the right rims I'd try Conti's similar Cyclocross Speed tires in 700x35 for all around riding.

But if I rode pavement exclusively I'd Google around for owner feedback on slick or lightly treaded tires that rank well in low rolling resistance testing.

NYMXer

I have the same exact bike, a Giant Cypress, and I recently went from 42's to 32's. The ride is a little bit harsher (that's okay, I'm use to 25's on my road bikes), but certainly not objectionable.
I would think that a lot of your consideration should include what type of surface you ride on. I ride a variety of grass/gravel rail trails, paved rail trails, open roads and village streets. I think that bumpy city streets would be the harshest or all and open roads the smoothest.

justtrying

Canklecat & NYMXer,Thank you for the information.

amos77

Exactly my experience too