I won't know how act with stickies on it , but I'm sure it will be a much more relaxing riding not having to be slipin n slidin thru the turns. Hope it ain't too boring !

Maybe the Pirelli Sport Demon 100/90H18 for front and 120/80H18 for rear

Dave wrote on 03/07/17 at 03:37:16:

I liked the Pirelli Sport Demons - however it is not available in the 90/90-18 size, and the 100/90-18 has tall sidewalls and is a very heavy tire compared to the 90/90-18.  The rear tire definitely has a shape similar to what the sport bikes use.

That's why I have decided to go with the 100/90 on the front and 130/80 for the rear; I think a street tracker should have high aspect ratio tires.

Ruttly, I agree with not using 17's on a street tracker. If I could have found good street rubber in 19's I would have gone that big, but 18's are a good compromise.

Dave, I can't believe how flat spotted that rear tire got. I wonder how much of that is due to multi-radius profile of the tire. That, combined with it being "squeezed" onto too small of a rim, is probably the culprit. You should be fine with a more rounded radius. The Kenda K671 I'm using has a rounded profile and so far I don't see any strange wear patterns developing.

Back when the Dunlop K81s were the tire to have I was running the Pirelli Phantoms and you could grind your center stand & exhaust all day long while watching your buddy with K81s sliding off the road in the your mirror.  Those were great tires but probably junk in today's standards! Wish they still made them ! They really looked cool !

A couple of items for you.  I thought I had a better picture but this is the only one I can find that (sort of) shows my steering damper.  take a look at the lower triple clamp just inside of the right fork tube.  You will see the end of the steering damper and then I hid the body of it under the tank.  I am running a Shindy damper which is also sold under the Daytona brand.  They are Japanese made and a middle of the road damper but are adjustable and fully rebuild-able.  They can be further tuned by changing the weight of the oil in them if needed.




I am not running a stock frame as you can see.  it has a rake angle of 26 deg.

Now a point of thought for those making radical changes and pushing the stock frame.  I am working on my Lyster framed project so I have set up a couple of spreadsheets to analyze frame and suspension geometry.  The stock frame of the savage has a 35 deg rake and 5.80 in of trail.  That would indicate a 2.73 offset in the triple clamps.  When one pushes the change in rake you need to also watch your trail and possibly change your offset if you go too far.

So as far as rake goes.  A bike with a 57" wheelbase will drop 1 degree of rake for every 1" the back end goes up or the front end goes down.  So if you raise the back end by 3 inches with shocks and drop the front 2 inches you would be down to a 30" rake.  That is still pretty lazy in the sport or standard world.  If you drop your front wheel by 1" diameter remember that takes 1/2" off and 1/2" deg also.

Now bring trail into the equation. Trail is a function of rake, offset, and wheel diameter.  So from my previous number crunching some fast changes can appear.  Gary touched on this in his post and I believe his numbers were from measurements and are very close although slightly high but not by much.  
Watch how the numbers change based on the stock offset of 2.73"

Wheel size   Rake  Trail  
19"               35      5.8   this is stock and cruiser range
19"               30      4.17"  Now down in modern sport standard range
18"               30      4.1"
19"               29      3.91"   lower portion of modern sport standard range
18"               28      3.82"
19"               27      3.65"  now pushing low even for sport/race
18"               27      3.54"
19"               26      3.40 "
18"               26      3.27"

Push below 30 degrees with the stock triple clamps and you start to really get a short trail.  This of course can be corrected by using a triple clamp with less offset.  This is why when you look at sport bikes the forks are much closer to being in line with the steering stem versus cruisers with higher rake have to push the forks out ahead of the stem.

If memory serves me right Dave changed triple clamps on is cafe bike when he built it.  To bring the trail back up to about 4.1" with a 28 deg rake would require a triple an offset of about 2.1-2.15" versus the 2.73 of the stock triple.

Last note would be this all assumes the axle is centered at the bottom of the fork.  If you use leading axle forks like on most old dirt bikes and the old GS-L models Suzuki used to sell then you run less offset in the triple clamp because you make up for it by moving the axle to the front of the fork lower.

All fun!   Please don't take it as preaching.  Hopefully someone will find it of interest.

Blue , How do you measure trail ?

Blue , Thanks , I will check it out !

Good stuff guys. I'm learning what I need to know. Easier than trial & error. I usually go by feel and what the the bike is telling me. Right now it says give me new tires !!!