Originally Posted by Bolo Grubb
If I under correctly modern mountain bikes have 135 mm space for the rear drop outs and road bikes are 130mm spacing.
what is the reason for this? are the cassettes different size or is it the hub? Are MTB hubs wider to make them stronger?
Yes I am a newb that knows nothing.
I can think of a couple of likely possibilities. The first is just to reduce the dish and to maintain a better spoke braceing angle on mountain bike wheels. The second is to provide a little more space on the non-drive side of the hub to mount a disc brake.