Originally Posted by
headloss
My bad for assuming that a 24" tire is a 24" tire, clearly something I need to investigate more having never had a need to do so. Why do you not think you can swap wheel sizes between the 507 and 520? I'm still trying to grasp all of the dimensional issues...
Different rim widths.
Tire Sizing Systems
The ETRTO/ISO numbers 507 and 520 refer to 507mm and 520mm, which are the bead seat diameters of the rims. As Sheldon explains it, a 507 tire is too narrow to properly fit into a 520 rim, which means a higher chance of tire or rim damage, and a 520 tire is too wide to fit into a 507 rim, which means rim-mounted brake shoes are gonna smack up against the tires resulting in sidewall damage.
Also, Brown's Law of Tire Sizing:
If two tires are marked with sizes that are mathematically equal, but one is expressed as a decimal and the other as a fraction, these two tires will not be interchangeable.
I
think that the OP can swap out the original rims for 520s. The cantis would have to be adjusted to make up for the extra width, I think...just hope that this means taking a spacer or two out of the brake pads and not an entire brake replacement. However, according to
this, 507s are more durable, but 520s are better for speed.
That said, I think they did their best to make right by you. What else can they do? I don't want to point fingers and blame the victim but I do believe that it is the customer's ultimate responsibility to realize that a tire is an odd size and ensure that an adequate stockpile can be built up before purchasing the bike in the first place. I go through this line of thinking before every bike purchase (after learning the hard way), will spare parts be available if I buy X_Product?
For me, the problem isn't that the tire is the proprietary size, the problem is that the bike may not be able to accommodate as many standard sizes as possible. If the bike came with a tire that was 1.125" wide, but was able to fit tires as wide as 2," then I can get a lot of longevity out of the bike because there are at least four tire sizes that fall under that range. However, if the bike can only fit 1.125" to 1.5", then we have an actual real problem because the available tires I can choose from are severely restricted.
And yeah, there go my plans to get any Kona CX bikes. Crappy supply chain? Customers and distributors left in the dark? Lack of support in the East? Tires that can't be found anywhere but their site? Damned shame, their CX bikes looked so nice.