Best tyre shape for cornering grip

I have 2 sets of wheels – one

I have 2 sets of wheels – one 15 mm and one 17 – used on the same bike for a 30k round trip open road commute for 5 years.Average moving speed around 30ks.I run 23s on the front and 25s rear at 85psi.

On the right day if I concentrate hard I can detect a slight difference in ride quality.Not better or worse just different.

There’s nothing in it.

 

Whatever anyone says, wider

Whatever anyone says, wider rims are miles more comfortable. Running a 23 on the front on 18.5 wide internal rims on two bikes now, absolutely zero problems of any description.

I’m normally quite skeptical about ‘innovations’, but this one works.

The OP asked “What tyre shape

The OP asked “What tyre shape is the best for cornering grip.?” The answer is, incontovertibly, “a round shape at correct inflation”. With a round shape you have the most contact with the road at all lean angles, and the most predictable cornering as there is no ‘shoulder’ to lean over. and a ’round’ shape is more stable (not so tall) as a ‘U’ shape. So, whichever tyre gives you the roundest shape at your preferred inflation is the best shaped tyre for cornering.

PS, if you have an upside down ‘U’ shape as described by some, you may just be cycling on the ceiling!

shay cycles wrote:

VeloUSA wrote:

Here’s my experience: The bulbous (incandescent lightbulb looking) tire has weaker sidewalls. This is caused by the bulbous outward push on the sidewall. I took a downhill corner at 20+ MPH I could feel the front tire roll and losing grip which forced me to back off speed.

The problem there is almost certainlt tyre pressure rather than profile – your pressures are lower than the minimum in the tyre spec and a very long way below the max. Too low tyre pressue will always cause that kind of issue.

 

My bad, I should have noted the PSI with the narrow rims were 105/110, not below minimum.

I’ve been running 32mm

I’ve been running 32mm Specialized Borough Pro CX folders on the rear of my commuter for about 7 years, that’s on an Open 4 ceramic currently and an open Pro ceramic before that, the Open 4 is particularly narrow. All up my minimum bike/bags etc + me is 113kg, often in excess of 125kg. I’ve been able to take the right hander at the mini roundabout 200m from home at 17/18mph amongst many thers. I’ve worn out two in the centre, no sidewalls issues, I’ve got two left incl the current one, going to go with the Jack brown Blue when they’re through, I’ve been using the JB on the rear of my audax/tourer.winter racer which also has an Open pro, again no sidewall problems.

These aren’t particularly heavy duty tyres, the Spesh is a 350g job with knobbles on the edges, very thick tread in the centre but very pliable sidewalls so if narrow rims with wider tyres was going to show up as problematic then it certainly would with my weight+ use, maybe you’ve been unlucky or are underinflating. 

 

BBB wrote:

BBB wrote:

Lots of throwback nonsense here. 

I run 28mm tyres on 25mm INTERNAL rims. The bike corners like on rails. 

Quite a number of road rims have internal width of about 20mm or more and 25mm tyres are a perfect match for that. Sidewalls are better supported so less pressure is possible for the same effective width. 

Don’t be stuck in the ETRTO matrix world, people.

You might think it corners on rails, however having a U shaped tyre as per the OPs description means that the rim is NOT suited to the tyre.
and what exactly is the ‘quite a number’, how many of those that are equipped with a 20mm internal bead are running 25mm clincher tyres, probably a tiny %.

We’ve already seen the fallacy of wider tyres are faster being exposed in real world use/real world pressures, maybe having very wide rims will save you a small % point in aero terms so that the tyre is closer to the ri width but the reality is that stretching tyres far beyond their design spec means you are getting distortions that are not good for the tyre nor good for efficiency. Or are you saying that a tyre that has a U shape is ideal?