Should I go with the 4.25″ or the 5″ rear rim?
That is a preference. The 4.25″ will fit all bikes without rubbing. The 5″ is wider and accepts a wider tire but does not fit all bikes. There are a few differences between the two.The offset is still about the same from the center of the rim. Both need to be offset from the chain so the tire does not contact the chain while riding.
The 4.25 will fit with minimal headache and adjustments. The 4.25 normally uses a 150 rear tire. The 4.25 has a lighter feel and seems to corner better. On our test bikes the 4.25 felt quicker and easier to turn.
The 5.0″ is a little wider but with not a lot of room in your swingarm the little wider seems a lot wider. You can run a 160 tire. That will give you a lot more surface area on the ground. The 5″ has a little less balloon effect so the tire is a little flatter. You will have a larger contact area so you will get better traction. On our test bikes the 5″ was a little heavier. We also felt that while riding. Didnt seem to corner as good as the 4.25 It was harder to dive into the corners. Do the tires last longer because there is more surface area on the ground? Not really, a tire last as long as your riding style allows it. It is extremely hard to install on some bikes. We had to remove the rear brake caliper on a few of the models to get the tire between the swingarm.
4.25″ – Easier to mount. Less weight. Better handling. Better turning. Less tire options
5.0″ – Tighter fit and may rub the chain. Better traction with more surface are on the ground. More tire options. Adds weight. Does not turn as well. Feels heavier. May need to offset the rim once on your bike to get a better fit on some models. 5″ will not fit XR650L, CRF250L, WR250R/X, KLR650
Most of our customers when asked why they are going with the 5″ said. I just want the widest tire I can get. Just for looks. Our conclusion – for normal riding the 5″ is basically for looks. Like when you put oversized tires on your truck. They dont do anything for performance. Just look cool. Unless you can source a set of race tires (cant use them on the road) the 4.25 had a better feel and better handling. These are our opinions you cant really go wrong with either choice. Your riding your dirt bike on the road. Cant beat that.