Description of the Problem
When inflated, the rear tire comes in contact with the frame right away or when rotating the wheel.
There are three possible points of contact:
a. The half of the chainstays attaching to the bottom bracket (the narrowest section of the rear triangle)
b. The chainstay bridge (the tube connecting the two chainstays)
c. The seatstay bridge (the small tube connecting the two seatstays)
The reasons why a bike tire might be rubbing against the frame are:
1. The wheel is not properly inserted/seated into the dropouts.
If the frame has forward or rear-facing horizontal dropouts, it’s possible for the wheel to get tilted to one side.
To fix this problem, the user has to open the quick-release and pull the wheel backward while making sure that the rim is laterally leveled.
Old-school road bikes (some of the prime candidates to create this problem) have two small bolts at the back of the dropouts.
Ideally, those bolts are inserted an equal amount into the dropouts. Then, the user pulls the wheel back until the skewer or axle touches the head of the bolt.
This ensures that the wheel is centered.
Conversely, vertical dropouts (image below) do not create this issue because the wheel does not have room to maneuver.
Nonetheless, it’s still recommended to check the wheel because it may not be fully seated from a vertical standpoint.
2. The Wheel Is Not Dished/Centered
It’s also possible that the wheel isn’t properly centered for the particular frame. When that happens, one side of the spokes is pulling too much on the rim and positioning the wheel closer to the frame. In most cases, this leads to the wheel rubbing against the chainstay.
To combat this problem, the user has to perform an operation known as dishing a wheel.
The procedure is not terribly complicated but requires some experience. To get the wheel away from the chainstay, the user has to reduce the tension of the spokes on the rubbing side, increase the spoke tension on the opposite side, and re-check the overall spoke tension in the end.
A rough run can be done with the bike in the frame. Ideally, however, a dishing gage and a truing stand will be used to re-center the wheel.
3. The Tire is Too Big For The Frame
Back in the day, I bought a second-hand road bike that came with a set of 32mm tires. When I put the bike in a repair stand, I saw that the rear wheel was rubbing against the chainstay.
Re-dishing the wheel helped but didn’t completely eliminate the problem because the tire was simply too big for the frame’s clearance. For that reason, I switched to 25mm tires.
Keep in mind that wide tires greatly increase not just the side profile of the wheel but its overall diameter too. Thus, a wide tire could rub against the chainstay or seatstay bridge too.
4. Out of True Wheel
Another common source of the aforementioned problem is a wheel that’s out of true.
The wheel has to be true laterally and radially. The lateral truing minimizes side to side movement. If that condition is not met, the wheel will be rubbing against one of the chainstays.
Meanwhile, radial truing ensures that the wheel is as round as possible. If the wheel is shaped like an egg, and the tire is fairly big, the wheel may hit the seatstay/chainstay bridge.
Wheel truing isn’t easy, but it’s not as mystical as a beginner might think. Ideally, the user will bring the wheel to a mechanic who has the experience and the tools needed to true the wheel.
If the budget is low, however, the cyclist can true the wheel in the frame by using either the brake shoes (if the bike uses rim brakes) or a set of zip-ties strapped around the seatstays and the seatstay bridge to true the wheel to an acceptable degree.
5. A Bent Rim
If the bike has been subjected to great stress, the problem may be coming from a bent rim.
In that case, you won’t be able to fully true the wheel regardless of how much you play with the spokes.
To fix the issue, you will have to re-straighten the rim. If that’s not possible, a new rim or wheel will be needed.
6. The Wheel Is The Wrong Size
It’s rare, but it’s technically possible that the wheel on the bike is designed for a bigger frame.
You’re highly unlikely to experience this problem if you’re buying a new bike from a reputable shop, but it’s not impossible when purchasing from the second-hand market.
The seller might have installed a wheel from another bike to make the machine look complete.
The only way to avoid this issue would be to check the bike in person or ask the seller for a video of the bike.
7. Bent Frame
It’s also possible that the wheel is fine, but the frame itself is bent due to external damage.
In that case, the frame will have to be repaired or replaced.
FAQ: What are the dangers of wheel rubbing?
A wheel rubbing against a frame might cause the following:
- Damage to the paint
- Thinned out chainstays that may potentially fail if the rubbing continues for a long time.
- Higher rolling resistance
- Stress on the rim, hub, and rear axle
Summary: What You Need to Know
If the wheel is rubbing against the frame, the issue should be addressed right away to avoid critical damage to the frame’s tubing.
The most likely sources of the problem are:
- The wheel isn’t properly seated into the dropouts.
- The tire is too wide for the frame.
- The wheel isn’t dished properly.
- The wheel isn’t true.
- The rim is bent.
- The wheel is the wrong size for the bike.
- The frame is bent.