Normally when you go with a 21 on the front you have to drill out the REAR fender mounts with a 3/8" bit, raise it up and tip the back of the fender up. I run a 120/70-21 on the front of mine and would like to go a little wider. What Metzeler tire are you looking at and who has them ?
the tire is a 140 X 70 X 21 Metzler released around June of this year. Fat tire for the bagger but a 21 to boot
might be able to hook ya up with one I'll send you contact onfo
its going to be almost .300 bigger in radius than the 120/70, which is just about the max clearance you can get by drilling out the stock fender mount holes. my guess would be a new fender or fender mounts will be mandatory with this tire.
We put the new Metzler 140/70-21 on a 2007 Roadking. The stock fender will not fit without custom brackets. We are going to look into making custom brackets so that you could use your stock fender. The fender needs to be raised around 1/2". I took the bike for a ride without the fender and the 140 tire does seem to ride a little bit better than the 120. Perhaps the wider contact patch helps because it seemed a little easier to push the bike into turns. Once we get a fender on we will take it for a longer ride and give more details.
After some extended riding on the new 140 Metzler it does handle better than the 120 Metzler. Phil reported that the bike felt a little more stable on the freeways. The tire also helps the bike in the twisties probably due to the larger contact patch and the shape of the tire. Overall it rides better than the 120 and has a much higher load rating. We are still working on a bracket so people can use their stock fender or you can use a fender designed for a 23" wheel (pictured below). This 140 tire is much taller than the 120 tire so if you have a 1" lowering kit on your front end then this tire might be too tall. The tire on the left is an Avon 120 and on the bike is the Metzler 140.
How does the bike look with the 140/21 tire...is the front end raised and make the bike out of balance? I know my street glide had to be lowered 1" to offset the 21" wheel in the front to keep the level look to the bike.