Rake & trail

[Morpheus]

   When extending the rear swingarm 12" to the maximum allowed w/base of 68", what effect does this have on handling?

Stock frame has 24* caster and 89mm/3.5" of trail.

Will this make the bike more stable in a straight line, like when you rake the neck?

How about when you drop the fork heads down to lower the bikes nose?

Thanks for any and all comments or sources of printed subject matter to research.

                                     Morph

[Seldom Seen Slim]

I don't understand where you get the idea that there's a maximum allowable wheelbase of 68".  In modified you're allowed to go up to ten percent over stock wheelbase, whatever that is -- so there's no way that you could get under 68" with a 12" addition.  In special construction there's no limit at all.

As for how it'll affect handling -- longer wheelbase will slow down turning/handling but won't necessarily be a good thing - at least 'til you're used to the changed handling.  If you don't make sure there's enough weight on the real wheel you might give up traction in exchange for that slow handling.

[bak189]

24 degrees is for going around corners..............27 to 30 degrees is for going in a straight line.........3.5
trail is OK.............with that  long extension on the arm you might need ballast to get traction (depending on power unit)...

[Morpheus]

Gentlemen.... the rulebook(s) i've seen, although a few years old, have stated in Modified class, over 250ccs., you're permitted a maximum of 68 inch wheelbase. 60 inches under 250ccs. This is for ECTA and SCTA.

This may be outdated/superceeded/revised but was a general question concerning handling.  I'm awaiting my new yearbook for the  2010 season.

It also states that OEM or Production replacement frames may be used having "similar" geometry. Similar meaning I "assume" stock production specs.

Bike will run in the 500cc Modified classes.

Thanks.......    Morph

[ol38y]

Sir... If you're more concerned with handling, read Slims second paragraph. If you want to know what the rule is, read his first paragraph. 

[willieworld]

if you are talking about modified  production you can stretch the wheelbase 10% over stock----frames shall be based on an OEM type frame or production replacement having similar geometry---willie buchta

[Seldom Seen Slim]

Well -- maybe in the "olden days" there was a rule discussing absolute length (68" or whatever) -- but in the '09 rulebook there's no mention of length - other than the 10% over stock WB in modified.  I stand by my earlier comments.

[willieworld]

in 2006 the wording changed in the rule book from the 68 maximum to the 10% longer than production ---not quite the olden days for you and i slim ----  although you are a babyboomer       LLLLLLLLOOOOOOOLLLLLL                                             willie buchta

[Morpheus]

Thanks Guys for your input and remarks. Will wait for the new rulebook so I don't get caught between a rock and a hard place, next time.   

John & Nancy, Happy Holidays... same to all the rest of the group and their families.

                                      Morph

[Seldom Seen Slim]

Pretty early in the Boom, Willie -- I was born in March of 1948.  I think I've heard that the boom extended through the late 50s-early 60s. 

[willieworld]

1m a war baby  1-29-45    ---from the war ending to i think 1965 the baby boomers were a bulge in society that changed the look of things and still is hope they dont use up all of the SS     willie buchta

[Glen]

Will you two kids quit arguing, Your making me look old.