What Does 700x38c Mean On My Bike Tire And Tube?

Two things matter the most when buying a bike tire, and that’s quality construction and correct size. Our focus today is on the latter, and we’ll mainly put a microscope on 700x38c tires. So, what does 700x38c mean?

The 700 signifies the nominal or outer tire diameter while the 38 represents the tire width, both expressed in millimeters. So, a tire measuring 700x38c means its outer diameter is 700mm while its width is 38mm.

Don’t worry about the letter C, as it is part of an outdated French classification system that distinguishes tires of the same size depending on their thickness. In that case, ‘A’ represents the thinnest tires while ‘D’ represents the thickest.

Let’s dig deeper!

what size is 700x38c

What Does 700x38c Mean On A Bike Tire?

As I mentioned, 700x38c means that a given tire has a 700mm (or roughly 27.5 inches) outer diameter and a 38mm width.

Another important note is that the dimensions 700x38c also indicate a rim’s or wheel’s dimensions. So, 700x38c could also mean a bike rim or wheel with a 700mm (27.5 inches) outer diameter and a 30mm width.

But since we are talking about the outer wheel or tire diameter, the inner diameter may differ slightly among different tires. For that reason, 700c tires may come in 28-inch and 29-inch (29er) options.

So, don’t sweat over the 700c part, but your focus should be on the wheel width (which in our case is 38mm).

And as I mentioned, the letter C is only part of an old French way of differentiating tires of the same outer diameter based on thickness.

But since the classification system is obsolete, some manufacturers prefer not to use the latter. In that case, you are likely to find tires measuring 700×38 instead of 700x38c.

What 700x38c Tire Should I Get? 700x38c Tire Size In Inches

While the wheel size of 700x38c tires is always 700mm (27.5 inches), the tire width may come as a range. So, you should pick a range with a 38.

In that case, options like 700×55-42c or 700×38-50c are ideal if what you want is a 700x38c.

However, most of them are specific, measuring 700x38c, which means you don’t have to stress over the range.

Here are two 700x38c tires for your consideration:

1. Schwalbe – Marathon HS 420 Bike Tire (Best for All Standard Bikes)

The Schwalbe – Marathon HS 420 Bike Tire is an archetypical bicycle tire that you can fit on an MTB, city bike, urban bike, or hybrid bicycle.

Thanks to its GreenGuard 3mm thick layer, the tire can resist easy puncture and absorbs shock.

Schwalbe – Marathon HS enjoys anti-aging sidewalls, which means it can tolerate low inflation and crack.

Overall, the acceptable pressure range for the bicycle tire is 65-110 PSI.

Schwalbe – Marathon HS 420 Bike Tire

2. Panaracer GravelKing Slick Folding Tires (Best Tubeless Option)

If you plan to upgrade to a tubeless 700x38c tire, the Panaracer GravelKing Slick Folding Tires is a decent bet. And when you do upgrade, you’ll reap the fantastic benefits of tubeless tires.

Overall, these tubeless tires are built for off-road. They allow you to ride on gravel, pavement, and dirt almost seamlessly. All is thanks to the tire’s pure rubber construction.

These tires have a foldable design for easy storage. Furthermore, they have lower rolling resistance and enjoy superb puncture protection.

How About the Tube? Which One Should I Get for My 700x38c Tire?

If your bike tire measures 700x38c, then you should get a 700x38c tire tube. Note, nevertheless, that you may have to consider a wide range of tube width as long as it has a 38.

For example, consider tubes measuring 700×35-43c or 700×32-47c or anything else with a 38c.

Here are two 700x38x tubes for your consideration:

1. LotFancy 2-Pack 700x38c/35c/40c/43c Bike Tubes

(Best for 700x38c MTBs, Beach Cruisers, and Kids Bike Tires)

The LotFancy 2-Pack 700x38c/35c/40c/43c Bike Tubes suit bike wheels with a 38-43mm diameter. The pack, however, suits mountain bikes, cruiser bikes, and kids’ bikes more.

Since it’s a 2-pack, you can replace both of your inner tubes. The tubes have a Schrader valve and are made of premium butyl rubber.

Thanks to their airtight seal technology, the tubes don’t lose air quickly.

Overall, LotFancy 2-Pack 700x38c/35c/40c/43c Bike Tubes are durable and heat-resistant.

What’s more, they come with nylon-plastic levers that give them natural toughness.

700x38c inner tube

2. CrabTek Bike Inner Tube 700x38c/35c/40cc/43cc

(Best for 700x38c Mountain Bikes)

If you are looking for the perfect 700x38c tube for your MTB, you won’t go wrong with the CrabTek Bike Inner Tube 700x38c/35c/40cc/43cc,

This 2-pack tube comes with a 33mm Schrader valve for easy inflation and two rim strips to protect against spoke punctures.

The tubes are generally strong, given that they are made of high-quality butyl rubber. So, they last you longer than the average inner tube.

Furthermore, CrabTek Bike Inner Tubes are easy to install and come in a wide range of width (35-43mm).


1. What Size Is 700x38c?

A 700x38c tire is a bicycle tire with a nominal diameter of 700mm (roughly 27.5 inches) and a width of 38mm (approximately 1.5 inches).

2. What Does C Mean In Bike Tire Size?

The letters A to D are part of an old French system of denoting a tire’s thickness. In that case, ‘A’ represents the thinnest tire while ‘D’ represents the thickest.

So, letter C shows a tire slimmer than one with the letter ‘D’ but thicker than one with an ‘A’ or ‘B.’

3. What Does 700c Mean For Bike Tires?

700c means that the tire’s nominal diameter is 700mm) or roughly 27.5 inches). The letter C next to it was used in the old days to distinguish tires of the same diameter, depending on how thick they are.

So, it means that a C tire is supposed to be thicker than an A and a B tire. The system of classification is, however, obsolete.

4. Is A 28-Inch Wheel the Same As 700c?

700c is the same as 700mm, which signifies the tire’s outer diameter. If you convert 700mm to inches, you’ll have roughly 27.5 inches.

So, no, a 28-inch tire is not the same as a 700c. But since the difference in inches is small, you could argue that the tires are almost the same size.

5. Will A 700c Tube Fit A 28-Inch Tire?

A 28-inch tire is not the same size as a 700c. That’s because it’s slightly big, perhaps by a half-inch.

But since the difference is minor, you can still install a 700c tube in a 28-inch tire and get to ride normally.

6. How Do I Know My Inner Tube Size?

The simplest way to know your inner tube size is to check your bike tire sidewall dimensions. If the tire measures 700x38c, for example, then you should get an inner tube that measures 700x38c.

7. What Size Inner Tube Do I Need For A 700x38c Tire?

A 700x38c tire requires an inner tube with a 700mm diameter and 38mm width. Simply put, it requires a 700×38 inner tube.

A majority of these tubes come with a width range. So, you only need to find a range that includes a 38c.

8. How Wide Is A 38c Tire?

A 38c tire is a tire with a 38mm (or 1.5 inches) width.

9. Will A 700x35c Tube Fit A 700x38c Tire? 700x35c Vs 700x38c

Given that both have the same outer diameter (700mm), then yes, a 700x35c tube can fit a 700x38c tire.

Note, however, that the tire will be slightly wider and so you could be tempted to over-inflate the tube.

10. What’s The Difference Between 700 And 700c?

There’s no difference nowadays between a 700c and a 700 tire. Both tires have the same outer diameter (which is 700mm).

You should note, nonetheless, that the French used to use letters a-d to express tire thickness. Concerning 700 tires, 700a tires were the slimmest while 700c and 700d were the thickest.

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Closing Thought:

So, what does 700x38c mean? As we’ve discussed, the dimensions 700x38c refer to a wheel, rim, or tire with a 700mm outer diameter and a 38mm width. So if your tire measures 700×38, you should get a similar replacement and a tube that matches it.