motorcycle front fender

[racer x]

 I am thinking about the drag from my front wheel. I think a typical landspeed regulation fender would help . My concern is I don't want to make a front rudder or something that will cause a nasty tank slapper.Both may result in knocking down a cone or two. I want to fit a steering stabilizer anyhow . Should I do that first then build the fender or will the fender stabilize itself? Thank you for any advise.

[Seldom Seen Slim]

Unh, this is partly hearsay, partly true scoop.  A steering stabilizer is required unless you're running under 125, and at those lower speeds you probably won't have much aero impact about which to worry.

The fender's help in the aero part of the equation is more from the amount of air that follows around and to the top of the tire at speed, with the fender helping shape and control that air (we're in the hearsay department now -- I'm by no means the aero expert in this forum).  There may also be some aero gains in the fact that the fender is smotther than the bare forks.

Fenders are limited by the rulebook -- can only protrude so far, can only be so distant from the tire, and so on.  Read the rulebook! to be sure.

[willieworld]

slim  just for my own information--the rule book says that no streamlining is permitted in the open motorcycle class.streamlining is defined as any devices or objects forward of the rider that has the apparent purpose of directing,limiting,or controlling airflow around the motorcycle or rider--so by that rule wouldnt a front fender be considered streamlining   thanks  willie

[Seldom Seen Slim]

I used to think a fender was streamlining -- but they are specifically exempted from being called streamlining --- so you may have the slickest thing since a soaped doorknob for your front fender (that is, fender abiding by the rules for fender) and still run and get through impound in naked bike class.  No worries there, Willie, but thanks for asking.

[willieworld]

trying to learn as much as i can about all of the classes --although the sidecar class rules are much different than modefied or special construction when it comes to streamlining    thanks   willie

[willieworld]

slim   i hate to be a pest  but could you please point out to me in the rule book where it says the front fender is exempt  thank you-------------------- willie buchta

[Ratliff]

The top of the tire is moving at twice the bike's forward speed. So even at "just" 125 mph that's 250 mph. And, yes, on a 260 mph Hayabusa that's 520 mph.

[racer x]

I am running in the Modified Partial streamline class. A fender is allowed but must not cover more than half the wheel and nothing below the centerline of the axle at the front of the wheel.I am thinking more about the sides being smooth and moving the air to the side of the front fairing.Will it even matter at 100 mph?

[Sumner]

..............................Will it even matter at 100 mph?

Sure it will matter. Look at all the effort the solar powered cars go to with aero and they don't run anywhere near 100.  Even the OEM's put a lot of effort into small things like mirrors to help their fleet mileage which is a reflection on aero.  No matter what speed you run in LSR aero is going to play a part, so why leave anything on the table?

c ya,

Sum

[willieworld]

slim  at an scta event a steering damper is required in all motorcycle classes regardless of speed ----willie


  where is that exemption for the front fender in open bike

[racer x]

This is a bad photo shop job of what I am thinking I run on the ECTA paved mile track

[Seldom Seen Slim]

Willie, there is no specific wording that says a fender is not considered part of the streamlining, but maybe I've got a note or an email from one of the M/C tech people saying so.  And whether or not I have that in print -- I know I've been approved in a naked bike class with a front fender -- repeatedly.  Sorry I can't find a specific paragraph, although you might note that fenders are described in their own paragraph (7.F.4), and not mentioned in the paragraph on streamlining.  Ask Tom Evans or Van Butler for a written response so you'll have it in print -- and if I'm wrong -- let me know so I can remove the fender before I go to Bville in a couple of weeks.  but -- I'm pretty danged sure I am correct.  About the damper - I get confused when I don't have the rulebook in front of me.  At ECTA a damper is required if a bike is running in a class with a record of 125 or above.  At SCTA you're right -- ALL bikes must have a steering damper, even production bikes that don't come stock with one.

As for you, Racer X -- from what I see, either of those fenders would be okay - as long as they cover less than 181 degrees of the front wheel.  I've seen 'em cover all the way front-to-back, and also just the front half and part of the back.  Make sure the bottom edge is above the centerline of the axle and you're okay.

[willieworld]

thanks slim   i wasnt butting heads with you --i have seen many open class  bikes  (special construction) with a front fender and set records but with the wording in rule 7.F.11 was wondering how that could be possible --i would think that a front fender would be a device or object forward of the rider that has the apparent purpose of directing,limiting,or controlling airflow around the motorcycle or rider  --i would be very happy if you or anyone  could explain it to me --awaiting the answer ---i plan on building a new bike for 09 and just want to be very sure of the rules and im building a couple of bikes for customers-willie buchta

[Seldom Seen Slim]

Willie, I'll see what I can find - and get back to you in the morning.  It's bedtime here in the Eastern time zone.  And naw, I didn't think you wre trying to butt heads -- it's a strange interpretation that the fender isn't part of the streamlining package.  See you tomorrow.

[dwarner]

"...i have seen many open class  bikes  (special construction) with a front fender and set records but with the wording in rule 7.F.11 was wondering how that could be possible..."

If you see this situation why don't you approach the person doing the impound tech and ask? Seems to me that addressing the issue at that point would be the best solution.

DW