New Tyres but what size?

[cicero]

I haven't rode a cycle for decades but have just acquired (as a gift) a second hand Viking mountain bike of sorts with very large knobbly tyres.

As I want to use it on tarmac I want to change the tyres but since my day sizes no longer make sense to me! They used to be simple 26x1 3/8 or 27x1 1/4 but no more it seems.

The tyres say 26 x 2.30 so can someone explain what that is - I've looked at a couple of websites but am no wiser.

I've seen some Schwalbe marathon kevlar advertised but the sizes don't include the above so can I fit 26x1.9 or 1.75 for instance?

This is probably a daft question but any help would be gratefully received.

Thanks.

 

[Norm]

Yes, you can go smaller, although exactly how small depends on the width of your rims. I went from 26x2.1 as standard down to 26x1.5 and the only problem was they looked strangely silly as they are so much smaller than the bike was designed with. I know it seems odd but they really didn't suit the bike.

I tried to capture how silly they looked, but it doesn't really come over in pictures...


The bike more usually looks like this... although this is with 26x2.3's


The benefits are that something like 26x1.75 will be much faster on the road.

 

[Gerry Attrick]

Hi Cicero, welcome to the forum.

All you need to know about tyre sizing is here.

 

[ColinJ]

Hi cicero - welcome to CycleChat!

As you have discovered, mountain bike (MTB) wheels take different size tyres than most road bikes. Make sure you are getting MTB size (26") and you'll be okay.

The other number is the width. I've looked at a few ads and some are doing the widths in inches e.g. 1.75, some in millimetres e.g. 28 mm which would be near enough 1-1/8"

You don't need huge tyres on the road so I'd go for as close to an inch as I could get. Less weight to turn.

 

[Norm]

The other number is the width. I've looked at a few ads and some are doing the widths in inches e.g. 1.75, some in millimetres e.g. 28 mm which would be near enough 1-1/8"

Careful with that one. As Sheldon (link by Gerry above) points out, a different unit of measurement can mean and different size and 1.75 might even be different to 1 3/4.

 

[ColinJ]

Careful with that one. As Sheldon (link by Gerry above) points out, a different unit of measurement can mean and different size and 1.75 might even be different to 1 3/4.

I defer to (the late, great) Sheldon Brown's superior knowledge, but it is clearly ridiculous if 1.75" is not equal to 1-3/4"! A thing is a certain physical size and that's what the number should be!

It's like those unlimited broadband deals that are unlimited in every sense except they have limits (a.k.a. 'a fair usage policy')!

 

[mcshroom]

HI cicero and

There are basically two common types of wheel now. 700c (close to the old 27") which are road bike/hybrid wheels and 26" wheels that are Mountain bike wheels.

You want a tyre with 26xdecimal number. (26x1 3/8) is confusingly a different size

) For confirmation tyres also have an ERTO number, and you would want one which started 559-xxx but usually that's not really needed.

You will almost certainly be able to go down as far as 26x1.5 if you want, and other than looking a bit skinny they will be fine. Schwalbe Marathons are good tyres and should fit without any problems. I have the 700c wheel versions on my hybrid atm. Other popular slick tyre for 26" wheel bikes are Schwalbe City Jets like the one's in Norm's pictures.

 

[mcshroom]

I defer to (the late, great) Sheldon Brown's superior knowledge, but it is clearly ridiculous if 1.75" is not equal to 1-3/4"! A thing is a certain physical size and that's what the number should be!

It's like those unlimited broadband deals that are unlimited in every sense except they have limits (a.k.a. 'a fair usage policy')!

It's more the 26" bit that's misleading. Mountain bike wheels are only 24" across, the 26" is (IIRC) for the diameter including a 1.75" tyre.

 

[cicero]

Thanks to you all for your advice it's appreciated.

I knew it was complicated although why it needs to be I don't know after all things seemed to work OK thirty years ago!!

Cheers.

 

[Norm]

... although why it needs to be I don't know ...

mcshroom kind of addresses it but it's down to changes over the decades for different applications.

The main two you'll find are 26" and 700c.

Wheels and tyres in 26" size are generally for off road bikes, where the wheels themselves are smaller and thus inherently stronger.

700c wheels and tyres are generally for road bikes, they are built lighter and the larger circumference reduces the rolling resistance.

Aside from that, you have 27", which are the road-sized wheels from a few decades ago, 24" tend to be for cruisers, 20" for shoppers, BMX and folders, 16" for folders... etc

Also, bear in mind that it has been decades, that you can still get tyres in 27" sizes is a testament to the longevity of some of the components that we use. Not many consumer goods still have compatible spares available half a century after production.

 

[buddha]

I recently converted an old MTB to rigid forks, slicks. And went to the extreme of 1.0 (yes that's 1 inch) tyres as I'm used to 23/25mm on road bikes - Specialized All Condition Pro 2, I think.

Admittedly it did look and feel weird/wrong at first. But handled okay after a few miles. Nice and fast too!

In hindsight 1.5's are probably a more sensible option - availability of inner tubes, pedal clearance issues etc.

 

[cicero]

Just to clarify a little is 26" the diameter of the wheel and therefore a 26" tyre fits that rim size? I assume that's the case it used to be anyway as far as I can recall - allowing for my failing memory?