Landracing Forum

Bonneville Salt Flats Discussion => SCTA Rule Questions => Topic started by: peterdallan on January 19, 2012, 06:46:10 AM

Title: Motorcycle Ground Clearance
Post by: peterdallan on January 19, 2012, 06:46:10 AM: Hi....again

I would like my bike to sit as low as possible but as a first timer I would like advice as to what people think or know is a safe ground clearance to build to as I understand the salt is not as smooth as it might appear in films and photos.

Thanks again

Peter
Title: Re: Motorcycle Ground Clearance
Post by: Stainless1 on January 19, 2012, 09:24:17 AM: Peter, we may need more info... solid or suspension on the rear....
We ran the gsxr about 1 to 2 inches with the suspension set hard and damping at maximum. Had over 180 lbs of ballast.... 380 if you count the rider :-D
It lost a little bellypan paint when the crunchies were big
Title: Re: Motorcycle Ground Clearance
Post by: peterdallan on January 19, 2012, 09:34:10 AM: Apologies Stainless

Hard tailed frame with vintage Triumph Tele forks, so a couple of inches of movement up front. Based on a Triumph Thunderbird but lighter of course. Rider about 185 lbs

Peter
Title: Re: Motorcycle Ground Clearance
Post by: Stainless1 on January 19, 2012, 09:55:04 AM: Weight is your friend at Bonneville, be sure to bring along some bolt on ballast. Ballast = Traction
The numbers I gave you were for our partially streamlined bike. Bounce the forks rider mounted, leave yourself about an inch of clearance. The best bet is have a little adjustability, if the salt is bad you may need more clearance than when it is perfect. You can let a little or a lot of fork stick our of the tree.
Title: Re: Motorcycle Ground Clearance
Post by: peterdallan on January 19, 2012, 11:14:44 AM: Ok thanks, that makes sense, I'll try to make sure I can adjust as necessary.

Thank you

Peter
Title: Re: Motorcycle Ground Clearance
Post by: Buzz Lightbeer on January 20, 2012, 05:56:30 PM: Peter will you be at the meeting next week?
Regards
Dave
Title: Re: Motorcycle Ground Clearance
Post by: peterdallan on January 21, 2012, 05:54:35 AM: Yes I am, see you there.

Peter
Title: Re: Motorcycle Ground Clearance
Post by: bak189 on January 24, 2012, 10:05:11 AM: If he is using a early Triumph Thunderbird engine, I don't think any ballast will be needed........50hp's maybe???..............sorry
Title: Re: Motorcycle Ground Clearance
Post by: Vinsky on January 24, 2012, 03:11:25 PM: At what horsepower range do you need to start adding balast? Or at what speeds?
Title: Re: Motorcycle Ground Clearance
Post by: Nortonist 592 on January 24, 2012, 03:42:44 PM: Quote from: bak189 on January 24, 2012, 10:05:11 AM
If he is using a early Triumph Thunderbird engine, I don't think any ballast will be needed........50hp's maybe???..............sorry

I thought an early Triumph Thunderbird would be considered ballast.

Sorry. I couldn't resist. : - )
Title: Re: Motorcycle Ground Clearance
Post by: Glen on January 24, 2012, 03:56:35 PM: That's nasty Nort. :evil:
Title: Re: Motorcycle Ground Clearance
Post by: Nortonist 592 on January 24, 2012, 06:14:03 PM: Sorry Glen. It was a bit like someone handing you a $50 bill. It was irresistible.
Title: Re: Motorcycle Ground Clearance
Post by: Stainless1 on January 25, 2012, 11:00:32 AM: OK, so maybe no extra ballast will be necessary.... Our experience was at speeds above 175, might not see that with 50 hp.
Title: Re: Motorcycle Ground Clearance
Post by: 55chevr on January 25, 2012, 01:46:23 PM: 50 HP ?
Title: Re: Motorcycle Ground Clearance
Post by: Nortonist 592 on January 25, 2012, 02:10:48 PM: Early Triumph Tbird. HP in the 50s is about right if you want it to stay together.
Title: Re: Motorcycle Ground Clearance
Post by: bak189 on January 25, 2012, 07:12:10 PM: Yes,,,,we get 51hp out of the 650c.c. pre-unit Tri......65hp out of the 750c.c. Chatland kit....plan to install steel con-rods and up the comp.....so maybe 70hp if we are lucky.......you got to love these old bikes..............................
Title: Re: Motorcycle Ground Clearance
Post by: Nortonist 592 on January 25, 2012, 07:33:20 PM: Quote from: bak189 on January 25, 2012, 07:12:10 PM
you got to love these old bikes..............................

But keep an close eye on the new ones.
(http://img515.imageshack.us/img515/9475/40695036868626648130310.jpg)
By weslake (http://profile.imageshack.us/user/weslake) at 2012-01-24
Title: Re: Motorcycle Ground Clearance
Post by: oz on January 26, 2012, 01:25:21 PM: My Ballast has increased by almost 7kg since christmas, I reckon i need to get some excercise soon or my aerodynamics is gona be shot to bits and my new leathers will have to be binned!!

Oz
Title: Re: Motorcycle Ground Clearance
Post by: Peter Jack on January 26, 2012, 05:36:07 PM: Obviously just a slight material flaw. That'd get your attention going on between your legs! :-o :-o :-o

Pete