[danburbridge]

Ride comfort (on a rigid bike) is primarily a function of the tyres (size/inflation/construction).

A bike with cheap 23c tyres at 150psi will rattle the fillings out of your teeth.

The same bike with decent 25c or 28c tyres at e.g. 50-70psi (depending on rider weight) can float along with a magic carpet like ride.

[Yetanfou]

Why call those 23c tyres "cheap"? Why mention price at all? Ride comfort is a function of tyre size, not tyre price. You can buy very "exclusive" expensive 23c tyres, pump them up to 7 atm. and have just as hard a ride as the person who just overtook you on his "cheap" 23c tyres.

That "magic carpet" ride does come at a price but it is not monetary: the softer the tyre, the more resistance and with that the slower the ride.

[_Wintermute]

> That "magic carpet" ride does come at a price but it is not monetary: the softer the tyre, the more resistance and with that the slower the ride.

Unless you're riding on a velodrome, pumping your tyres up to 120+psi doesn't decrease rolling resistance, infact the the opposite is true. If the tyre can deform around small bumps it rolls much more easily. This is why very expensive and fast tyres have casings with a high thread count (sometimes even made of silk) so they are more supple.

[danburbridge]

I am not suggesting that all 23c tyres are cheap, but that tyre quality (which comes at a cost) as well as size has an important part to play in comfort.

My 23c handmade FMB tubulars (definitely not cheap) are a much nicer ride than cheaper tyres.

Rolling resistance is far more complicated, on anything other than a wooden velodrome, the road surface actually means that there is a sweat-spot in terms of pressure - too low and rolling resistance will be high, as you say, this decreases up to a point at which the effects of the microbumps in the road start to cause energy losses through hysteresis and eventually the tyre bouncing over tiny bumps.

For a 23c tyre and a 70kg rider the optimum tyre pressure is actually typically in the 80-90psi range (5.5-6ATM) although again this is dependant on tyre quality, an expensive tubular tyre with very supple silk sidewalls can be run at higher pressure than a touring tyre with tough reinforced sidewalls.

[gameswithgo]

>Ride comfort is a function of tyre size

And tire construction. Though price likely does not correlate well with how supple the tire construction is.

[Angostura]

Yup; I prefer the hard ride and not to feel like I'm peddling a tractor.

[ljf]

Very true - but a great seat post and saddle can help - I stuck a carbon seat post on my alu bike and it was amazing, and even on my full carbon I moved to a carbon seatpost and carbon (unpadded) saddle - soaks up the vibration even though I have the tires at 100psi. People often comment on the lack of padding on the saddle, but with a nice pair of bib shorts it is fine. And 250g for the seatpost and saddle ;)

To clarify - vibration that it best dulls is 'road buzz' which you can really get on a alu bike, esp with high pressure tires. A carbon seatpost and seat can be as little as £50 for both - I got my seat post from wiggle and seat from china - happy with both - and recommend to all my friends.

Yes this will have little impact on 'bumps' - though the saddle def soaks some of them up.

I posted this to refute that 'only' tires have an impact on ride - frame, wheels, seat post, saddle, bars and bar padding, shorts etc can all have a positive impact on ride - and allow you to ride at a high tire pressure and get all the benefit of lower rolling resistance.

[fyhn]

True enough, but the more magic your carpet is, the more likely you are to get flats.

[matthewowen]

Eh, this is another area where construction is a factor. Flats due to low psi are usually pinch flats, which is a clincher issue. If you can bear the expense and inconvenience of running tubulars, pinch flats are no longer a concern.