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700x23c wheels can be replaced with 700x28c ones under two conditions:

1. The rims have to support the new tire size.
2. The fork and frame should have enough clearance for the new tire.

Rim Width

The width of the rims is one of the factors determining the maximum tire size that the user can install.

The rim has an inner and an outer width. Most of the time, the inner width is the one used as a reference to determine the minimum and maximum tire size that the rim can accommodate.

The table below can serve as a general guide for rim and tire compatibility:

Conclusion: If the inner width of the rim is between 15 and 20.9mm, the rim is considered compatible with a 28mm tire.

Note: The numbers in the table are not set in stone. They’re merely a guideline. Thus, some deviation is possible.

Fork and Frame Clearance

Wider tires have a greater circumference. If the frame and fork don’t have enough clearance, the new wheel will not be usable.

If the bike came equipped with 700x23c tires by default, it’s a road machine. Road bikes, especially rim brake models, are notorious for their limited tire clearance. Thus, extra precautions must be taken.

Below are a few methods that will help you determine whether the bike has enough clearance for a 28mm tire.

Initial Examination

First, see how much clearance the current tires have. If it’s just a couple of millimeters, 28mm tires will either not fit or will reduce the clearance to dangerous zones.

If the tire is one hair away from rubbing against the frame or fork, even a small stone picked by the tire may cause the wheel to jam. Hence why a minimum of 2mm clearance is needed for safe riding.

Radius Comparison

Measure the radius of the current wheel with the tire pumped to the needed air pressure and compare it to the hypothetical radius of the new wheel.

Example 1:

The diameter of the current wheel is 668mm; the radius is 334mm.

The diameter of the new wheel is 678mm; the radius is 339mm. (This value is taken from this very useful chart made by bikecalc.com)

Conclusion: A 28mm tire comes with a 5mm greater radius.

To know if the frame and fork can accommodate the new wheel, measure the closest distance between the frame/fork and the respected wheel. It should be at least 7mm (5mm for the new wheel + 2mm for safety clearance).

If the clearance is less than that, a 28mm wheel cannot be safely installed on the bicycle.

Note: The width of the rim will affect the radius of the new wheel. If the rim is wider, the radius of the wheel with the new tire will be smaller.

What Can I Do If The Bike Doesn’t Have Enough Clearance?

The options are:

1. Get a new fork with additional clearance.

This approach will allow you to install a wider tire at the front. Obviously, you won’t experience the full benefit of wider tires, but at least the front end will provide more cushioning and thus reduce the stress on the wrists, elbows and shoulders. You will also be able to roll over larger obstacles.

The downside of getting a new fork are the extra expenses as well as the work needed to install it. Also, if the bike is old, it probably has a threaded fork. Threaded forks are problematic because they have sizes. You can’t just buy any threaded fork because it may end up too short or long for your current machine.

2. Switch to smaller wheel size.

Another option is to make a 700C to 650B conversion. The smaller rim size will allow you to run much wider tires.

The main problem with this setup are the brakes. If you have rim brakes, the current calipers won’t be long enough to reach the brake tracks of the new wheels.

The common solution is to find rim brakes with a longer reach. The options include BMX brakes, long-reach calipers as well as center-pull brakes. That said, there are no guarantees that every combo will work.

If you have disc brakes, the conversion will not create brake problems because the rotor is always connected to the hub. Thus, a smaller wheel does not change the rotor’s position.

The Advantages of Switching to 28mm Tires

Wider tires offer the following benefits:

Lower Air Pressure

• The wider the tire, the less pressure is needed to prevent pinch flats. Hence why MTBs run tires at a far lower pressure than road models. The lower air pressure increases rolling resistance but provides a smoother ride reducing the stress on the joints.

Fewer punctures

• Wider tires are less susceptible to punctures thanks to the additional thickness and the lower air pressure allowing the wheel to roll over sharper obstacles with a reduced chance of piercing.

Extra Grip

• The contact patch of wider tires is larger. If two tires have the same tread pattern, the wider model will have a greater contract with the ground. This improves stability.

Larger Profile

• The larger profile of 28mm tires makes it more difficult for the tire to get stuck in a water drain on the road. Hence why larger tires are better for commuting.

The Disadvantages of Switching to 28mm Tires

• Reduced clearance

A 28mm tire will greatly reduce the clearance of the bike and make it difficult if not impossible to install full fenders. If the bike is used for commuting, this could be a major problem.

• Extra weight

It depends on the model, but in general, wider tires tend to be heavier because of the extra material.

• Problematic Conversion

If you choose to make a conversion to 650B tires, you will face issues (non-usable rim brakes + geometry changes) that could make the switch inconvenient.

FAQ: Are wider tires slower?

Studies have shown that wider tires are not slower and can sometimes be faster. In fact, there are Tour de France riders that have switched from 23mm to 26mm tires.

Also, since wider tires have an easier time absorbing obstacles, they could end up being faster for commuters too.