Universal chassis

[grumm441]

The latest installment

checking out the riding position.

7.F.12 It shall be possible to see all of the rider from either side and above.........

That tail section will need a trim

Ron's tyre problem is very interesting. The damage is exactly on the centreline and just in front of each tread groove (as the tyre rotates)............
If anyone has a favourite tyre that never gives trouble I'm sure there are people out there who'd love to hear about it.
Cheers
Dave

The problem seemed to be that all the "racing" tyres were too soft and fell to bits

G

[Hoofhearted]

Last year at World Finals I ran afoul of 7.F.12. I had built a seat with a slight curve and it was deemed illegal. I had to take a plastic quart oil bottle and fill it with water (and it was sealed and painted) to push my butt forward to clear the curve of the seat. Screwed everything up as I had exact dimensions for my fit to the fairing. Plus I ran out of time to get the Norton sorted. But it was Bonneville so it was all good!

Found a photo.


By weslake at 2009-11-08

[Stayt`ie]

sorry Bones to be hijacking ya build thread here , but you know how us bikers seam to carryon a cuppla topics in the same conversation ,,,

yeah Dave, what Greg says,,, that tyre shown was a Metzler Racetek, very soft rubber that i had been using at the drags, had 50psi in it for that run,,,, at the moment i have a Dunlop touring tyre on, but have not had an opptunity to run it hard,, am just sitting back listening to what those who have done the speeds have to say

[grumm441]

sorry Bones to be hijacking ya build thread here , but you know how us bikers seam to carryon a cuppla topics in the same conversation ,,,

yeah Dave, what Greg says,,, that tyre shown was a Metzler Racetek, very soft rubber that i had been using at the drags, had 50psi in it for that run,,,, at the moment i have a Dunlop touring tyre on, but have not had an opptunity to run it hard,, am just sitting back listening to what those who have done the speeds have to say

One of the guys who runs at Lake G is a rep for a reputable english tyre company and it is rumoured that they told him to run the sports touring tyre as it had a good hard compound in the middle where it counts
G

[Greg Watters]

I had a similar response from a dunlop tech guy , during a long phone call i found out he had been involved in the development of the new range of race tires , and he thought our using touring tires was sound practice esp if shaved, and the race rubber i was asking about in my prep for this years Bonneville was not likely to last


My new tailpiece ran foul to the same regs , took 3 towels and lots of duct tape to "square it up" .

[BONES]

I'm gunna fill the seat so it is flat. The rules here have been a little easier. Next year I hope to take the weslake to Bonneville so I
may make 2 tail setups-- speedweek and BUB. Be great if all bodies had the same rules.
Bought a chain for the 80, it's-----415. Smaller than a posty
cheers Bones

[David Leikvold]

Thanks for the tyre answers guys. My technical curiosity is now satisfied and the readers of our forum are hopefully now wiser and safer.

As for the "must be able to SEE the rider" rule, there's another part of that 7.F.12 (Partial Streamlining) rule that specifies at the top of page 116 of the 2010 SCTA rule book "It is forbidden to use any transparent material to avoid the application of these rules" so there goes my next sneaky plan The vertical shape of the front of the tail is effectively specified in the same rule on page 115 which reads "There shall be no streamlining other than a seat or tail section to the rear of the rider's body,..." so any forward curvature would ever so slightly cover a rider's bum when viewed from above. If there's no rule to the contrary (I haven't looked) the little wedge shaped gap could be filled by an addition to the rider's leathers.

Hoof, you might like to consider these ideas: rebuild the seat back fairing to include an inflatable section, pump it up for inspections and then release the pressure as you leave the start line so you sink back into the seat in a more comfortable and more secure position. You could also remake the whole body with a custom shaped fibreglass fairing that included the nose of the sidecar, went around your feet, under your knees and then joined with the rear fairing all in one relatively smooth bottom half of a teardrop shape. It probably wouldn't make much difference but you might also like to consider making aero fairings mounted on Bark Buster style brackets that covered your hands and the rest of the handlebars when viewed from the front. I hope somebody finds some of these ideas thought provoking.

Cheers
Dave

[grumm441]

Thanks for the tyre answers guys. My technical curiosity is now satisfied and the readers of our forum are hopefully now wiser and safer.

As for the "must be able to SEE the rider" rule, there's another part of that 7.F.12 (Partial Streamlining) rule that specifies at the top of page 116 of the 2010 SCTA rule book "It is forbidden to use any transparent material to avoid the application of these rules" so there goes my next sneaky plan The vertical shape of the front of the tail is effectively specified in the same rule on page 115 which reads "There shall be no streamlining other than a seat or tail section to the rear of the rider's body,..." so any forward curvature would ever so slightly cover a rider's bum when viewed from above. If there's no rule to the contrary (I haven't looked) the little wedge shaped gap could be filled by an addition to the rider's leathers.

David
Just because it's attached to the leathers doesn't make it not streamlining
"There shall be no streamlining other than a seat or tail section to the rear of the rider's body"

Hoof, you might like to consider these ideas: rebuild the seat back fairing to include an inflatable section, pump it up for inspections and then release the pressure as you leave the start line so you sink back into the seat in a more comfortable and more secure position. You could also remake the whole body with a custom shaped fibreglass fairing that included the nose of the sidecar, went around your feet, under your knees and then joined with the rear fairing all in one relatively smooth bottom half of a teardrop shape..
Cheers
Dave

A fine plan that doesn't account for the amount of photographers and officials or some one who just plain doesn't like that you are running against his or her record, out on the lake who would be very happy to point that out to the scrutineering crew after you had claimed a record. As I observed at Bonneville, you can be sitting in impound looking good for a record , when one of the tech inspectors will come up and kick you out of impound for an iffy fairing after he has been shown a digital picture of you running on the course with part of your legs hidden.

It's not about trying to find ways around the rules.
G

[Hoofhearted]

Nice plan indeed! Except for the already stated fact of photographers plus when I filled the oil bottle with water the tech people sealed it with tape and paint. Photos can get you introuble too. At the July El Mirage meet my deadman activated. Its located on the right handlebar beside the throttle. Its held in place by an alligator clip attached to my lanyard. Somehow as I shifted into fourth it popped off and killed the igniton and fuel pump. Rather than waste a good run I reached over with my left hand and held the switch on. Ran 120+. Harnick, the SCTA photographer, took this photo of me in the lights. A few days later I got an e-mail from one of the inspectors reminding me of the rule about both hands being on the bars for the duration of the run! They don't miss much!


By weslake at 2010-07-17

[David Leikvold]

OK, I'll give up on the sneaky stuff! Hoof, that's a great shot of your sidecar and it's got me thinking again. I believe it would be entirely legal and not open to argument for you to have a headrest/fairing incorporated into the body work behind your helmet to fill that hole. I also think you could gain a small aerodynamic advantage by filling the space under your knees. It would be legal if it had a panel for your legs to rest on so that nobody could argue that your legs couldn't be seen from the sides. That same structure could come up between your legs, flush with the top of the nose cone, to form a very narrow top panel that stopped about mid thigh (so you were visible from above and had no risk of becoming entangled in bodywork) and helped tidy up the airflow and deflected some of the air that now hits your helmet. As for the deadman switch, SeaDoo make a really good switch with a stretchy lanyard for their PWC range that never comes off accidentally, or maybe you could just use something as simple as a rubber band or an O ring to secure it, it would still release in an emergency but wouldn't fall off by itself.

As for the press on regardless attitude, once when I was racing my Formula Vee, the nose cone was removed at speed by the tyre of the car in front, the nose flipped up, hit my helmet and disappeared into the pack behind me. I kept going, had a great race and picked up the undamaged(!) nose on the slow down lap. At the National championships at Adelaide International Raceway in 1979 I did a sweep of the gauges on the main straight about half way through the race only to find the oil temp was maxxed out and the oil pressure well down (it was a very hot day). I considered stopping but quickly rejected that idea because the motor seemed happy enough (I always used good oil) and I'd driven half way across the country to be there. I finished 5th outright and best of the competitors who were there for the first time. As Winston Churchill liked to say, "Never surrender".

Cheers
Dave

[Hoofhearted]

Tom Evans is our head scrutineer. I think he was a consultant to God when God was making the lakebed. He knows most of the dodges. I won't say he knows them all. I ran a fiberglass primary chainguard on the Norton for years. It was'nt until the primary chain let go just before the lights and took a big chunk out of the guard that he discovered it. There is a new body rattling around in my head right now. The streamlining rules allow a lot more than I have right now. I never gave much thought to the gap under my legs. I must go think on that.

At the moment sidecars with the SCTA are a lot like red headed stepchildren. We're there and show no signs of leaving. The car guys don't know anything about sidecars and Tom has been very busy with those 250+mph Busas and their tires. So for the moment the rulebook on sidecars is pretty thin. The biggest concern is the unrestricted entry/exit rule.

The funny thing about the helmet is I don't feel a lot of wind around it. At Bonneville this year I was getting down to where I couldn't see over the nose. I watched the quarter and mile markers out the side. Maybe thats why it ran 125.715 on gas at that altitude and temp. Better aero is a priority. With winter approaching and my retirement I should have time to make something happen.

[grumm441]

Hoof
I think you're right about Tom Evans
There aint much he doesn't pick up on
I spent Bonneville speedweek at motorcycle tech yhis year and learned quite a lot from him
G

[penny]

"must be able to see the rider rule "well you can see him he's " in there " .
http://www.chevyasylum.com/lsr/bsf2010/ ... 6_jpg.html

[BONES]

This is what I am going to try and copy.
Tom Mellor. triumph T150 or 160, 750cc 180+mph. He tows down from Cannada with an old Rolls Royce.

this should help the little engine along
cheers Bones

[Stayt`ie]

Toms Trident, at full noise, at Bonneville, at sunrise, is soooooo "sweet"