Shawnus

Hi

Just got my first second hand commuter bike and was wondering if someone could help me out.

The bike has Alex ACE-17 Double Wall Alloy Trekking 36h rims.. none of this info means anything to me.
It also has 700x40c Schwalbe Roadcruiser tyres. They are suppose to have puncture protection too! But that didnt really help when I got a puncture last week. I fixed the tube but I am going on a long ride (55miles) for charity in a month so I was going to buy a new tube.
This has left me baffled with tyres and tubes..
The tyre has 28x1.6 written on it and as I said 700x40c. 700x25 - 35 seem to be more common, will they fit on my rim? How do I know what it is capable of?
And tubes.. the most I have seen which is not the same brand as mine is 700 x 28/38 Schrader.. does this mean it it should be for tyres 28-38?

Ok, I'm a noob, but I want to understand these things!

Thank you

FrenchFit 

Those are big hybrid tires.

I believe the 28x1.6 is the rough translation of 700x40 centimeters to inches. Disregard the inches number.

If your rim takes schrader valves, stay with schrader or you'll have to use a washer to protect the tube-valve.

Using a 700x25-35 schrader tubes means it will be overinflated and thin in your 40c tire. If you are worried about punctures this is not a way to go.

The tubes you are looking for can be found on-line, do a Google search. Harris Cyclery has them for one.

cyccommute 

Welcome to the confusing world of bicycle tires

The 700 in 700C refers to the outer size of the tire. It's not really 700mm but we all say it is. A 700C is about the same size as a 27" tire (US), a 28" tire (US and England) and it is exactly the same size as a 29" tire. Not that any of those actually measure to that outside diameter but...hey...it confusing!

The width...again another measurement that really isn't a measurement...is the width of the tire at the widest point, assuming a round tire which the tire may or may not be 'round'. Most are a little more oblong than 'round'.

Your Roadcrusier tires are 40 mm wide or 1.5" wide. Since tubes stretch (tires not so much), you can run narrower tubes inside the tires. The 700 x28/38 should work but they are going to be stretched somewhat inside the tire. It's not a huge problem but stretching makes them a little thinner.

For tires, you could use a 700x35 or 700x32 tire easily. 700x28 may be getting too narrow and a 700x25 would be on the narrow side. It depends on the width of the rim. Look here for a dizzying amount of information on a very confusing subject. Near the bottom of the page is a chart on which tires fit which width rims. The chart is rather conservative, however. I have 58mm (2.3") tires on 17mm rims for a mountain bike. They are low pressure but they aren't abnormal in the mountain bike world. I would be a little more conservative when mounting narrow tires on a wide rim however...not as conservative as the chart but I wouldn't mount 23mm tires on a 23mm wide rim, for example.

Shawnus

hey guys, thanks for the responses Very quick and helpful.

Good link for that site too, guess I'm investing in some new tyres

MichaelW

For a fast, general-purpose commuter bike, 28-32mm is about right, up to 35mm for rough roads.
The efficiency of a tyre is more to do with composition than simply the size, in fact for the same composition AND at the same pressure, a wider tyre is more efficient.
Narrower tyres are lighter in weight, can hold higher pressures and have better air resistance. This counts most when you are trying to go very fast.

Schwalbe tyres are very good, the standard commuter tyre is Marathon, a bit higher grade than Roadcruiser. They make tougher or faster variants of the basic Marathon.

Retro Grouch 

A couple additional points:

1. There is no puncture proof. There is only puncture resistant. But I guess that you've already found that out.

2. When you fixed your flat did you check the inside of the tire? It's common for thorns and broken glass to stay in the tire and continue to puncture all the new tubes that you feed it. A smart habit to get into is checking the inside of your tire every time that you fix a flat.

3. Bicycle inner tubes today come in such a myrid of sizes and valve configurations that most bike shops don't stock all of them. Given the choice, I'll always choose a tube that slightly undersized to one that's a litle too big. The undersized tube will easily expand to fill the tire volume. A too big inner tube is easier to catch under the tire bead which can lead to a pinch flat or blow out.

Shawnus

thank you all very sound advice. I think I will be doing some bike customisation very soon

Sixty Fiver

Our common system of sizing comes from the French and the letter code used to denote width of the tyre with A being wider and C being narrower with B somewhere in the middle.

700C now describes all tyres that have a 622 mm bead seat and the A and B designations are no longer used for this size.

In the US, Canada, and continental Europe a 28 inch tyre is 622mm and some companies often mark these with both the fractional 28 by x and the more useful metric 622.

In England a 28 inch tyre has a 635 mm bead seat and was used on full sized roadsters and is still being used by Pashley Cycles of England on some models.

For the OP - Unless your tyre was severely damaged it should still be fine and even the best tyres will get flats and keep on rolling for many thousands of happy miles.

For a higher volume tyre like yours you can use a tube for a 27 inch tyre as there is really no difference between them and in checking see that many manufacturers package the same tyre in different boxes when it comes to 700:40 and 27 by 1 3/8.

Just check the inside of your tyre to make sure the offending material has been removed or it will cause another flat.

Sixty Fiver

Odd tyre sizes are a fact of my existence... I run some very obscure wheels that need tyres I can't pick up at an LBS that have to be special ordered (of they are still made) or scour the net for spares.

meanwhile

Good technical knowledge, but...

1. Given the above, why stop at 35mm for a commuter tyre??? Tyre aero doesn't become more important than RR until around 25mph. Believe me: you don't commute at 25mph.

2. Correct tyres size depends a lot on rider mass - when a 160lb rider should be on a 35 then a 220lber should be on a 40mm

4. 35s are excellent at absorbing road noise, but at a 40 is a *lot* better if you hit a 2cm pot hole, especially if it was camouflaged as a puddle and you weren't expecting it. A 70mm balloon tyre is better again. As for a 28... well, its better than a 23 if you hit something. But if I was told that I was going to hit an inch deep pot hole and when I wasn't expecting it, with a dump truck right behind me on a wet road, and then given a choice between being given a pair of 28s and a $1000 and a pair of 35s and no moolah, then I'd take the 35s. Which isn't to say that the narrower tyres are dangerous - cycling is very safe - just that the wider tyres can be useful if you can get into certain types of trouble and that they don't have any real disadvantages, so why not run them?

5. As you say, tyre composition has a big effect on rr. RR results from energy being stolen to bend the tyres' rubber to re-mkae the contact patch as they rotate. Thinner tyre walls reduce the energy needed but make for a weaker less durable tyre. Some (more expensive!) rubbers bend more easily than others and some (expensive!) technologies can make thinner tyres more durable. It's rare to find these except in narrow tyres. The Schwalbe Evolution series (more below) and Panracer Jack Brown are the main exceptions I can think of.

The Evolutions are a big step up from the basic Marathon - better in every way, pricey, but very high mileage. With increasing degrees of tread they are the Supreme, Dureme and Extreme. The reason these tyres are so good is that they use low-bending energy rubber to reduce rolling resistance and anti-puncture tech that doesn't increase RR much - both developed for racing tyres. They're very grippy tyres too - you can feel the grip just by running a finger over them.

Conti and Vitorria also make some very nice tyres, but Schwalbe seem to be the only maker that is really aggressive about putting racing grade technology into general purpose tyres. Like you say, tyre composition is crucial for getting low RR, and the Evos are the main option for getting fast rubber in wider than 28mm sizes.

Also @ the OP:

ONLY CERTAIN WIDTHS ARE SAFE FOR A GIVEN RIM WIDTH! CHECK A CHART LIKE THE ONE HERE -

https://www.sheldonbrown.com/tire-sizing.html

cyccommute 

Nope. A = 642mm rim, B=635mm rim, C = 622mm and D = 587mm which GT tried to introduce...disastrously...before the '29er' fad.

Yes and no. 28" decimal tires are 622mm. 28" fractional can be 635mm or 622mm. The 635mm is for a 28" fractional tire but you can also run across 622mm rim 28" fractionals in Europe, too. Since England is part of that area, I suspect that you might find some of these tires there too.