Maybe a dumb question (or two)

[withm]

That chart is dated 1989!

Don't you think that in the last 21 years there have been some improvements to tire technology that might render these suggestions just a little bit dated, and suspect?

While I'll grant that the lower pressures on that chart might provide a cushier ride, if the maximum inflation marked on the tire is 120psi I am finding it hard to accept that the tire inflated to that pressure is in any way overinflated.

I'd also bet that you might go a little faster with a little more air in the tire.

[pll]

Perhaps it might be dated, but I lack better guidance (got anything more recent?). Less pressure on the tire buys you a slightly more forgiving ride, which is important to some people including myself (with an old aluminum bike). Going slower because I put slightly less pressure in the front tire? Very marginal effect, at best. Nobody here has stated that if you inflate tires to their maximum, they would be overinflated.

[pll]

Searching I just found the following blog entry with similar calculations about optimal tire pressure:

Bike Tinker: Optimal Tire Pressure for Bicycles

Using the spreadsheet provided there, for a 170 lbs bike + rider weight and 23s, the rear tire would require 104 PSI and the front 67 PSI. Here's one of the charts in that blog -- in this one you need to check the wheel load against the PSI (they assume about 60% of the rider's weight + bike weight is carried by the rear wheel):



Again, I would take this as guidance only, since tires, roads and even riding styles can be different.

[sandra]

Got new tires today. We don't really have a great bike shop here. I bought my bike in New Orleans which is 2 hours away. Hubby and I had decided to take my bike to New Orleans, get the tires and get one of my free tune-ups and just enjoy the day.

My son is in Afghanistan and my DIL asked yesterday if I could drive her for a procedure today (she was going to be under general anesthetic). Hubby took my bike to New Orleans for me while I was doing that.

He ended up getting me Hardcase Continental Gatorskins but he ended up getting 28s. He said he looked at the 25s and didn't think that I would like them because there's not much difference in the 25s and the 23s. I had 23s on my first road bike and had a few wrecks. He thought the 28s were a better trade off to still keep the stability. He said if I didn't like them we could take them off and he'd put them on his bike.

I tested them out late this afternoon on a short ride and there's a noticeable difference. I think these will be just fine. He's a keeper for doing this for me.