Landracing Forum
Bonneville Salt Flats Discussion => SCTA Rule Questions => Topic started by: Jon on August 24, 2012, 05:06:34 PM
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Hi
I'm pretty keen to run twin pull cable steering on my bike
I may never get to Bonneville but the Australian rules are based on SCTA rules.
The current rulebook does not allow cable and I can understand why a single cable is not allowed.
Twin pull cables can be safe and are the bassis for contol of most non commercial sized planes.
I got this pic of a bike from Speedweek this year;
(http://i178.photobucket.com/albums/w278/jonra23/B463C87B-02A3-4ADC-A4E5-5F3F98D18BC6-545-00000131848382D1.jpg)
I DO NOT want to cause any hassles for the owner of this bike and have tried to find his contact details without success.
Can anyone confirm if twin pull cable steering is now allowed for streamliner bikes under SCTA rules please.
Bumpsteer on a bike will make it pretty dangerous IMHO, this had been confirmed by the people who have been there.
Cheers
jon
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E-mail Matt Schuss or Tom Evans at the SCTA and get a definitive answer.
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Are you sure it is cable? There are no bends in the picture. Could be tie rods to other linkage.
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Rule book says direct, gear or link type only 7.H.14, pg 125.
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I'd bet there is a solid shaft in those......
~JH
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Thanks guys.
I will track down Matt's and Tom's email address and get in contact.
I'll take the wager on them being cables. ;)
Cheers
jon
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I'd bet there is a solid shaft in those......
~JH
Yeah, they appear to adjustable via heim joints, not something you'd do with cable. It would just make more work for you.
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If thats a solid link in there you'd be asking for trouble with horizontal flex between the heim & the casing mount.
Control cables come with threaded ends, you screw on what ever you want.
It will be interesting to see the out come of this question.
Sid.
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I contacted Matt and received this reply;
"We do allow a pull-pull cable steering system. There needs to be some pre-load to make sure there is no slack in the system.
We have a rule change request to fix the rulebook."
Thanks people for their assistance.
jon
P.S. Woody made contact witht he owner of the above bike, they are cables.
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Well there ya go!
It's amazing how loose our rule book can be on occasions.
Sid.
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Yes, amazing how the rules change.....10 years ago I asked if I could build our LSR sidecar using cable steering......SCTA/BNI answer: "no-way cable steering is not safe and I don't see SCTA/BNI ever approving that type of steering"..........New officials....New rules......These New Officials must have taken a look at Denis Mannings record M/C liner.....it has used cable steering for many years with great safety and great success........How times change!!!!
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Not having raced with SCTA/BNI since 2002......my question is WHO is Matt Schuss....is he one of the NEW officials.......I certainly know Tom Evans...we go way back......and I also know Van Butler......I do love New clear thinking OFFICIALS..........................
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Bak. Matt is Tom's replacement as tech head. Very knowledgeable and affable. The non BS variety of inspector.
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So go ahead and run anything illegal and we will change the rulebook later.
Really stupid. There is a process to change the rulebook.
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The guy who built the bike did a very good engineering study on how and why it would work. He did not just build it and show up! It was a vast improvement on what he had been allowed to run according to the rule book! The problem with many issues that long to be tried is how to properly evaluate it and make it "legal" based on the prior art and experience. All safety rules come from real events and the attempts of the governing body to make sure it "never" happens again. [And CYA!! :-o]
IMO I don't think he received any special treatment! He presented his reasonable case to reasonable people! Does that happen every time - probably not!
Good judgement comes from experience and experience comes from bad judgement!
It's a process - keep at it!! :cheers:
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+1 on what Woody said.
I have seen the analysis Woody mentioned, very thorough including a proper cyclical loading test of the cables.
This analysis and rule change request was not done post running the bike.
I am fortunate that someone has had the same problem I want to avoid and has done the work in front of me.
It doesn't mean I can just use some pushbike gearchange cables and I'll pass tech.
There is a process and it has and will be followed.
jon
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I know I'm very late finding this thread, but This is what I ran into while designing a HCS bike.
I looked at several different methods for setting up the steering and the method that always had the least safety and drive-ability problems was Pull-Pull cables.
As I looked closely at the rule book only Sec. 7.I.5 expressly ruled out cable control, and that was in the side-cars section.
So in order to proceed with the design of the bike I called Tom Evans in order to get his take on this very subject (Pull-Pull cables). He was clear that done properly it would be allowed.
If someone has a better method for steering HCS, I can still take a look at any suggestions, but for now I'm going with (Pull-Pull cables) using top self components, sized to do the job safely.
Rouse
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As I looked closely at the rule book only Sec. 7.I.5 expressly ruled out cable control, and that was in the side-cars section.
Streamliner 7.H.14 All steering systems shall be direct, gear or link type.
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the cable steering system is the reason why the Bub 7 does not run at scta events.
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I am early enough in the design process to choose the best steering for the bike (APS with HCS).
In looking at hard linkage, bump steer is a big issue to overcome. Cable controls solve the bump steer issues, but bring in a whole new set of potential problems that have to be addressed. As in all engineering designs there are always tradeoffs that have to be considered. I have designed and machine the axles and hubs ( out for anodize now ), how to set up the steering controls is still not settled.
There are some European bikes with HCS set up to road race using cable controls, if you read their reviews, steering control doesn't seem to be a problem with cables.
One thing is for sure at this point, the total investment to build this bike is going to be way to much, so not passing tech or having handling problems is "NOT an Option".
Rouse
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Contact the motorcycle tech committee with the details of your design in writing and get something back in writing before you proceed.
Cheers
jon
Ps. Any pics of your build?
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Thanks for the advise Jon, and Woody, I read the report and your right it makes good sense to me.
I have a few parts and pieces so far not many. Besides the hub parts done. I have the engine cases Billet Delkron, Transmission Baker Torque Box, Baker KKK Clutch and FF Primary. I also have some of the materials for the chassis. So you can see this Build is very early on in the process.
I'd post pictures, but I'm not sure how to do that yet. I'll give it a try.