Tyre sizes

[Pale Rider]

Ah, rim size marking, that's another one.

For that we have the snappily titled European Tyre Rim Technical Organisation (ETRTO) to thank.

Your rims are 622 in ETRTO speak, which is why the Smart Sam tyres in the link are also listed as 622 size in the various widths.

 

[stuarttunstall]

I really rate Smart Sams. I have 27.5 x 2.35 on a MTB and at the moment 26 x 2.1 on my tourer (in off road mode)

They seem OK to me, although having not ridden for a long time I have no experience of other tyres yet... The bike is nice to ride and seems comfortable.. Will try locking the forks tomorrow to see how that feels..

 

[stuarttunstall]

Ah, rim size marking, that's another one.

For that we have the snappily titled European and Tyre Rim Technical Organisation (ETRTO) to thank.

Your rims are 622 in ETRTO speak, which is why the Smart Sam tyres in the link are also listed as 622 size in the various widths.

Lol... now I am confused Why is nothing simple these days lol ...

 

[Vantage]

Most 700c tyres are sized to fit into the narrow spaces of road bikes because people believe that narrower is faster. Which frankly, is bollocks.
32mm and over tyres are aplenty but tend to be listed as 'city, touring, trekking or cyclocross' with cyclocross being nobblier tyres and many are 35mm to around 45mm.

 

[TheDoctor]

It's not too confusing, although it is a bit... The rim size is the diameter of the rim seat in mm. It's exact, and critical.
Things like 29" and 26" are referring to the diameter of the tyre tread, and are approximate.
A 700c road bike tire, frinstance, has a rolling diameter of about 700mm, around 27 inches. The rim is 622 mm diameter, and the height of the tire gives you the rest. A 29" tire fits on a rim with the same diameter of 622mm, but it's a taller/wider tyre, so the rolling diameter increases.
Using the ERTO naming saves a lot of confusion.
In 26" tyres, there's a 26 * 1 1/4, 26 * 1 3/8, and the mountain bike sizes of, say 26*1.5, and there might be others for all I know.
These three are all for different rims, even though they look much the same they're not interchangeable.

 

[SkipdiverJohn]

For general purpose riding a 700 x 35c tyre with a strong construction and decent puncture resistance is hard to beat. There's enough air volume for comfort, but not so much rubber contained in the carcass that the tyre is unduly heavy. It's essentially the nearest metric equivalent of the old 26" x 1 3/8" width traditionally found on 3-speed light roadsters, whereas old-school heavy roadsters had 28" x 1 1/2" tyres which would be approx 38 mm wide in modern parlance. These two sizes evolved over many years and became the standard on English flat bar bikes for the very good reason is they were found to be the most fit for purpose sizes. You won't go far wrong with a strong 35-38 mm wide tyre.

 

[SkipdiverJohn]

Rather than being an "inferior" manufacturer-only fit version of the tyre supplied for lower cost, it's entirely possible they are simply old stock made before the carcass construction was improved.
I would imagine that for manufacturing convenience, Schwalbe would want to produce as few variants of their tyre carcasses as possible - not have multiple different quality grades of the same tyre.

 

[stuarttunstall]

It's not too confusing, although it is a bit... The rim size is the diameter of the rim seat in mm. It's exact, and critical.
Things like 29" and 26" are referring to the diameter of the tyre tread, and are approximate.
A 700c road bike tire, frinstance, has a rolling diameter of about 700mm, around 27 inches. The rim is 622 mm diameter, and the height of the tire gives you the rest. A 29" tire fits on a rim with the same diameter of 622mm, but it's a taller/wider tyre, so the rolling diameter increases.
Using the ERTO naming saves a lot of confusion.
In 26" tyres, there's a 26 * 1 1/4, 26 * 1 3/8, and the mountain bike sizes of, say 26*1.5, and there might be others for all I know.
These three are all for different rims, even though they look much the same they're not interchangeable.

Thank you, great explanation for a new to cycling chap like me..

 

[Alan O]

Hi

Now I know this is a VERY stupid question ....

And just to come back to this - if you don't know the answer, asking the question is never stupid. Stupid is not knowing and not asking.

 

[stuarttunstall]

Lol...I know, just seemed stupid to me, but I have learnt a lot of stuff about cycle tyres ..thank you all

 

[stuarttunstall]

Out of curiosity I have just emailed Schwalbe to see if they will explain the difference, reading there site 50 is there "minimum" standard and as you have said may be an OEM tyre, but I suppose it could be misprint...

Will let you know what they say... taken from there site....

The density of the carcass fabric is expressed in EPI or TPI (Ends Per Inch, Threads Per Inch). The range of carcasses used, for example, for bicycle tyres are 20, 24, 37, 50, 67 and 127 EPI.

In principle, the more close-meshed a carcass is woven, the higher the quality of the tyre. A dense carcass is important for low rolling resistance and good riding properties. At the same time, puncture protection increases, because carcasses with a high strand density are difficult to puncture.

However, this does not apply to the extremely fine 127 EPI carcasses, as each strand is sheer and quite vulnerable. The best compromise for low weight and resistance is around 67 EPI.

In most of our top tyres we use a 67 EPI carcass. Weight and rolling resistance can be reduced even further by using a 127 EPI carcass. But at the same time, these tyres are more vulnerable to damage. Therefore, we intentionally use the 127 EPI carcasses only for light competition tyres, where weight is an important factor.

Most bicycle tyres worldwide are certainly manufactured with coarse 20 or 24 EPI materials. This material has no longer been used at all by Schwalbe for a couple of years now. Even very low-priced Schwalbe tyres already have a state-of-the-art 50 EPI carcass.

But be cautious when comparing EPI indications, as often the number of strands of all carcass layers are added together. An indication of 200 TPI results e.g. from 3 layers of 67 EPI each underneath the tread. With all EPI numbers above 150, it should be assumed that the figures have been calculated by adding up the strands in all layers. Schwalbe only indicates the material density in one carcass layer. Commonly, there are 3 carcass layers underneath the tread.

 

[stuarttunstall]

Good, honest reply to my question from Schwalbe UK

Hi Stuart,

Thanks for taking the time to get in touch with us, your question is a good one!

You are correct; the version you have on your bike is an OEM tyre that is slightly lower performance than what you find in an aftermarket tyre. The tyre you currently have will be slightly slower rolling, less protected and will probably wear out quicker than the aftermarket verion. But they are produced to help cycle manufacturers reach thier chosen price points.

We do a full aftermarket version of your tyre in both wired and folding beads. Both of these feature the higher tpi carcass and more substantial puncture protection. In addition to this the compound of the tyre is much better too. It just depends how much you want to spend really. The wired version is heavier, but also cheaper than the folding version.

Width is also up for discussion as we don't do a direct 42mm counterpart, but we do a 40 or 45. If you can fit it in the bike I'd always recommend a wider tyre as they roll quicker and are more stable and comfortable.

I hope this information helps, but if you have any more questions, then please don't hesitate to contact me.

Kind regards

Ben Tomkinson
Schwalbe UK

 

[stuarttunstall]

I must say I like the customer support from Schwalbe, I asked what tyres he would recommend and came back with this reply.... Honest, he does not pay for tyres lol

No problem, we all ride bikes so talking/emailing about them is always good!

Personally I'd say the G-One All Round....my personal favorite, and despite the fact that I'm lucky enough to get free tyres and I can try anything, I've had 6 sets on the bounce. Very tough, very fast and extremely grippy! The 700x38mm is quite high volume and very comfortable.

We do a cheaper performance version, and a higher end micro skin version that's tubeless, and I'd recommend that, as it's even quicker and tougher. Well worth a look.

Hope this helps!

Regards

Ben