Continental Tyres Undersize?

[Kenny]

Having read Gubbins post about his spill on ice I decided to fit my Continental TopContact Winter tyres I bought about six years ago, but never got round to fitting.

The marked size is 700 x 37 but when i fitted them I discovered they were only 31mm wide.

I checked the size of a Continental TouringPlus tyre (same marked size) I have fitted on one of my other bikes and found it too was undersized at 32.5mm wide.

I generally fit Schwalbe Marathon Plus on my bikes and they are always near enough the stated size.
It's no wonder Continental claim lighter weights for their tyres when they're much smaller than their marked sizes.

Has anyone else noticed this or have I just been unlucky and had some rogue tyres?

 

[danielrlee]

Tyre width changes with the width of the wheel rim. A narrow rim will give a narrower, taller, rounder tyre profile, where a wide rim will give a wider, lower, flatter profile.

That aside, I used to run Continental Diesel 2.5" freeride tyres that only measured 2.3", so maybe Continental tend to be a little narrower than their listed size.

 

[Kenny]

My rims are standard size and the 700 x 38 Marathon Plus I removed measured 37mm wide, close enough to the marked size unlike the Continentals.

 

[Foghat]

Not rogue - the incompetence of Continental's tyre-size-labelling supremo brasses me off too.

I've recently addressed the specific issue of the Top Contact II Winter Premium tyre HERE

Bizarrely (or not), Continental's regular Top Contact II '37mm' is reasonably close to its nominal width.

I do like these tyres, though. The Winter one should ideally be produced in 28mm, 32mm, 37mm and 42mm real widths so they can be used on a wider range of bikes in winter, as they are very good on frosty and lightly-iced surfaces and have less of the monster-drag that comes with metal-studded winter tyres. They also grip on metal road covers, unlike metal studs.

Some more thoughts on the Winter version HERE

 

[Kenny]

Thanks for the information Foghat.

When you consider my tyres are the older original version, you'd think that Continental would have corrected the miss-sizing with the newer mark II version.

It's disappointing as I like to fit larger tyres, where clearance allows, as they give a more comfortable ride.

I'm using these tyres with Kenda thorn resistant tubes, for better puncture protection.
The're made with 4mm thick rubber so it takes very little air to inflate them.

Think I may be in for a more jarring ride than usual.