Tubs v clinchers (sew-ups v wire-ons)

[snailracer]

Well, I know he rides a steel and a carbon roadie, but it's just the carbon one he has been having problems with, normally he pumps to 100ish, and the tyre will almost certainly be either a 23 or 25mm. He is also obviously a pretty experienced rider, and if I had to guess a weight, I'd go 70 - 80 kg. It's pretty greasy out there at the moment, and a few of us have had twitchy wheels.

What will your recommendation be oh wise one?

I am trying to collect actual data, rather than guessing it, so I can check the numbers against the Tire Drop article someone helpfully posted earlier.

 

[VamP]

I am trying to collect actual data, rather than guessing it, so I can check the numbers against the Tire Drop article someone helpfully posted earlier.

Good for you.

 

[thegravestoneman]

8.5 kilo road bike (Cinelli Saetta), tyres are 23s, 85 kilo or 13 stone 5 lb rider, 6'2" in height so high centre of gravity, usually around 95 front 105 back ish but not fastidious about pressures and I average about the 20 mph mark give or take (but 18 on the fixed so more control I guess). The clues are pointing to greasy roads more than any other factor. I just don't remember having such common twitchy moments but this is my first autumn/winter period in 25 years. (done about 6500 miles since February this year) think that's everything.

 

[snailracer]

8.5 kilo road bike (Cinelli Saetta), tyres are 23s, 85 kilo or 13 stone 5 lb rider, 6'2" in height so high centre of gravity, usually around 95 front 105 back ish but not fastidious about pressures and I average about the 20 mph mark give or take (but 18 on the fixed so more control I guess). The clues are pointing to greasy roads more than any other factor. I just don't remember having such common twitchy moments but this is my first autumn/winter period in 25 years. (done about 6500 miles since February this year) think that's everything.

Assuming a 55R/45F weight distribution, the 15% tyre drop graphs recommend 118psi for the rear and 95psi for the front. So, your rear tyre appears slightly underinflated (which actually improves grip, at the risk of more pinch punctures) but your front is probably about right. I don't think the inflation pressures have much to do with your cornering grip issues, so it is probably something else.