Skinny vs. Fat
Harley Wheels & Harley Tire IssuesDiscuss Skinny vs. Fat in the Harley Tech & Harley How-to forums; I test rode a bike with a 200mm rear tire and what a terrible handling ride. The salesman said it was because I'm not used to "pressing the corners". My ...
I test rode a bike with a 200mm rear tire and what a terrible handling ride. The salesman said it was because I'm not used to "pressing the corners". My Fatboy glides around the turns compared to this thing. I actually liked the wide tire option up until that point. Are the new Harleys like this? The V-Rod has a 240mm on it. So are the fatties just for profiling?
My understanding as to why bikes with fat rear tires have a hard time turning goes like this:
When you're going in a straight line the contact patch of the front and rear tires are in line with each other. When you lean over, if the rear is a lot wider than the front, the rear patch sticks out to the inside of the line the front tire is in. This makes the bike want to go out in the turn rather than in and you have to actually horse the handle bars to make the bike turn into the corner. On some bikes you have to steer the bars out (which is the opposite of what you would think you should do) which causes the bike to lean more and therefore turn into the corner better. On other bikes you have to turn the bars in. Jist depends.
On high powered road racer type bikes they have to have wide rears just to put all the power to the ground but their tread profiles are more angled than you see on tires made for "choppers". Some of the chopper tires are actually kind of flat profiles and make the bikes handle like a tricycle as they go from side to side.
There was a guy back in Michigan in the 60's that did demonstration runs at the local drag strips on a bike with a direct drive Chevy engine mounted transversely in (I think) and Indian frame with a wide car slick on the back. They started the bike on a stand and then just dropped it to go. Smoke and screaming V-8 just overwhelmed the senses as he wove wildly from side to side down the strip. Absolutely insane! His name was Potter and they called him "The Michigan Madman".
Oh, by the way, the short answer is, yes it is all for profilin' purposes. I think I've read that HD did some changes to the geometry of the bike to make the bikes handling not deteriorate too much with the fat rear.
Wider than a 150 and its nothing but a bar hopper. 150 140 130 and you have a bike for the hills and twisties....I run metzlers on 3rd set....I put an 02 Fatboy wheel which allowed me to use a 150 metzler on my 2000 WG techs said wouldnt work, but the solid wheel is centered where the laced wheel is offset.....
i wouldn't say it necessarily true that anything over 150 is profilin'.my fat bob has 180 in back,but has 130 up front,which is pretty fat for a front tire.because the sizes are pretty close,it tracks very well.now i look at a night train,with its 200 rear and skinny skinny front tire,and i gotta believe that thing doesn't handle the best.can any night train riders out there either confirm or deny that belief?
Tipper 1, take a look at the supper bike race series, and then make that statement about any thing wider than a 150 being a bar hopper I say judging from what we see on the race track not (not drag strip) that wide up to a point is working for them, although it does seem that there is a limit to just how wide 180 maybe 200 on the racebikes sounds about right for the street too again its just my way of looking at what the racers are using on the track
Skinny vs. Fat 
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