Bike specs says it accommodates tires up to 28mm. These tires are 28mm fully inflated—call me crazy, could I go bigger?

    by Jamesbev

    21 Comments

    1. Many manufacturers spec a max tire width with 4mm of clearance all around. so you’ve got some wiggle room if you’re talking about moving up to a 30mm from your 28. Also, is your 28 actually measuring 28? Is it new? It may swell over time. how wide is your rim? Take a 5 mm Allen key and see if you can slide it all around between the tire and the frame. Then you’ve definitely have room for a 30mm tire. And by eyeball it looks like you have room too.

    2. Manufacturers recommendation on tire clearance tends to be conservative. You can _usually_ go one size bigger, but bear in mind you may have difficulty with a warranty claim if you do and anything bad happens

    3. Tires are finicky! You might only be able to fit some knobby off-road 28s in there but you might be able to fit some smooth tread road tires that go up to 32c. I’d recommend snagging one 32c tire and putting it on both the front and rear to check the spacing. If it fits on both sides, hell yeah, if it only fits on one side then you only have one tire.

      Best of luck and happy riding!

    4. that looks like the fork. Fork usually isn’t the issue. Usually behind the bottom bracket on the chain stay where you’ll get rubbing from big tires.

    5. Listen, you can fit bigger, but why. You risk damage to the frame, you risk something getting stuck, you risk wheels suddenly stopping There’s a reason manufacturers recommend what they recommend.

    6. I feel like the manufacturer-reported max tire clearance is usually pretty conservative to account for minor fluctuations.

      If they say it will fit up to 28mm, that means it will fit all models of 28mm tire from all brands under all reasonable circumstances, which probably means they’ve left at least a couple millimeters worth of a margin of error and you could probably fit a 30mm or maybe even a little bigger from most manufacturers under most conditions.

    7. ADDITIONAL INFO: I am reddit-inept and can’t figure out how to edit the original post, so I’m adding more context here.

      This is my road bike of several years. I already have a gravel/touring bike with bigger tires. I still really enjoy riding this bike but I’m getting older and comfort is becoming way more important. I know the ideal solution would be swap this bike out for an endurance bike, but before I drop any crazy money on a new bike I’m trying to see if I can improve the comfort on my existing ride. Lots of other posts on reddit (and my own experience) suggest the best way to increase comfort on a bike is to increase tire size and appropriately decrease tire pressure. I’ve already optimized tire pressure, so moving on to tire size as an option.

    8. Some good comments. Tire and rim set up can cause variations too. But also be aware tires do stretch out a bit too. My GP new are bang on the 28 but are around 30 by the time I retire them. It’s not a lot but if it’s close can cause concerns.

    9. Ok_Caregiver_9585 on

      Depends on the wheel tire combination. Different brand and model tires will have measure differently for the same nominal size. It looks like you could go up a size if everything else is held constant. Helps to make sure wheels are true if you are going to run tight clearances.

    10. When you are riding 40 mph downhill you don’t want your bike out of spec. They used math, physics, material science and many other disciplines to make the specs. Their job is literally to design bikes that keep you safe. They spend years thinking about these issues. Why would you risk your life ignoring all that because it “seems like it will fit”?

      If you want wider tires, buy another bike and live to ride another day.

    11. Not sure if anyone has mention the back wheel clearance but look around the bottom bracket area it can be a bit tighter there.

    12. I just had to change some tires and one thing I learned is that the specified width is often not accurate. My “25mm” tires were actually 28mm wide when mounted. And it can go both ways depening on the tire and rim. So make sure you measure them and don’t go only by the specification.

    13. What’s the clearance, in millimeters, between the tire and the fork?

      You can check that with a standard hex wrench, they’re as wide as the indicated wrench size.

      If clearance is at least 4-5 mm for both front and rear tires you’re probably good to go to 30mm, maybe even 32mm, but if it’s less than 4mm I’d stick with the 28s.

      I wouldn’t ride tires with less than about 3mm clearance, tires and wheels do flex while riding.

    14. delicate10drills on

      You’re crazy if you think stones just slightly smaller than that gap aren’t sometimes flying up in there.

      Unless you only ride on the boardwalk, leave the gap.

    15. When you get weight on the bike, or hit a bump, its cause the tire to distort. Like when you put your ass on a church pew, it flattens out.

    16. A lot of it has to do with the manufacturer. I have a specialized allez that came stock with 28s on it and have had some 28s rub on the seat tube if fully inflated. So, I just run 25s. I honestly can’t tell a difference between the two anyway.

    17. Careful, I ground a hole in my titanium chainstay running a tire that seemingly fit fine, but rubbed when I flexed the frame enough.

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