Will 20 inch BMX wheels fit a folding bike (with 20 inch wheels)?
Thanks, guys, like you say &quot;it depends&quot;. But those pointers allowed we to find the answer for my own case which is:
&quot;Yes, if I get 3/8 inch BMX axles and bend (cold set) the rear frame or add spacers.&quot;
Axle Diameter
Cheap store-bought bikes like mine have 3/8&quot; or sometimes 10mm axles, which are practically the same. BMX ones are either 3/8&quot;, or are 14mm, which is a good bit larger.
It's not quite game-over for the 14mm BMX axles though because some have flats on them so they fit 3/8 dropouts as well. If the axles are solid you can file the flats yourself - but a lot are not.
Opinion was pretty unanimous - do NOT file-out the dropouts to take he larger axle.
Front Wheel
The width of the road and the BMX axles are both generally 100mm so the 3/8&quot; BMX front wheel often drops straight in.
Rear Wheel
The rear axle is significantly wider on a road bike - 130mm on the road vs 110mm on a BMX. The BMX axles might be over-length enough to fit if you put in a 10mm spacer each side. Or you can bend-in the rear frame if it is steel to take the narrower axle (cold setting).
Just want to reinforce that the full answer is indeed &quot;it depends&quot;, and this answer is specific to for cheap store-bought bikes with steel frames.