In the January 2016 edition of Motocross Action Magazine one avid reader has been enquiring about rear tyre size preferences.
Sometimes it’s down to personal preference, but it turns out that as with many things, when you take a closer look, it’s never quite as clear cut as it seems.
The reader writes:
“Dear MXA,
I ride a 2015 Honda CRF450. I currently run 120/19 rear tyres. I’m thinking of switching back to 110/19 tyres because I can feel the difference between them. What size rear tyre does MXA prefer?”
Before explaining MXA’s preference, it’s worth noting that width numbers on rear motocross tyres are not comparable when moving from one brand to another.
According to Dunlop, they measure the width from shoulder block to shoulder block. However, this is not an exact science, as measurements are therefore dictated by block arrangement, shape and angle
.
In theory, this means that a Bridgestone 120 could be smaller than a Dunlop 110. If you’re sticking with the same brand, then the 120 will be wider than the 110, but once you start switching brands, who knows!
If you do change brands, go with what you know. If you prefer the 120 Pirelli but decide to move to Michelin, try the Michelin 120 first. If that doesn’t feel right, try the Michelin 110.
Explaining their preference MXA say:
“Every MXA test rider prefers to run a 110 rear tyre. Why? A rear 120 makes a poor-handling bike feel even poorer. Most MXA test riders think that the 12s are harder to roll over in turns and make the bike stand up more in ruts. They also have a tendency to push the front tyre in flat corners. On the bikes that come stock with 120 rears, we almost always return to a 110 rear.”
Sounds like a case of trusting your instincts, and going with what feels right!
