leading link on a Drag Bike !?

[autofetish]

Hello all My name is Will

Firstly im missing a wheel and can only go in straight lines (sorry .

Im building a Drag bike and would really appreciate some advice.


In 1986 a bike was built and then banned called Jade warrior it was fast really fast.

Since then nobody has tried this design unit now !




So after months of building im getting there. I have a chromoly steel frame a Busa engine a big big wheel and tyre

I had planned to run hub center steering from a small scooter but the more i look at it its not going to be up to the job.(brake, tyre, spinal size etc etc limitations)







I would like to build and install leading link suspension identical to what side cars run. Im think a flat top wide tyre will help stability ?

Question time.

Q. I would like to keep the front tyre small and Fat what is the common wheel size ( i see most run a 13 but do some of you run 10 inch wheels.

Q. There are a few ok webisite about leading link design but is there any good reference to measurements trail etc

Q. Any info on front axle set up bearing brakes etc

Q. Anyone live near shrewsbury i could come and have a measure up

Q. Anyone got a complete front end i can buy and stick on my bike


Advice , ideas , abuse all welcome

Many thanks Kind regards in advance

William

[G JONES]

Hi Will - you're off your head - that's quite obvious - and running a diesel doesn't help your case - but I do live near Shrewsbury - so may be able to help - I'll send my phone number by PM - whereabouts are you ? (roughly)

[ianw]

Hi Will, going for a wide front tyre goes against the reasons why drag bikes run narrow front tyres, especially the Top Fuel Dragsters.
When you launch the bike from the line, even with a wheelie bar on the back the front end goes light. The narrow front tyre helps keep direction when it comes down, if you fit a wide tyre the front will be uncontrolable & you would go into an almighty tank slapper. I can give you Pete Davis's phone number, he is the guy who started Puma Engineering , made the fastest Top Fuel Dragster engines, & some very nice frames. He could put you in touch with the Brachtvogels, Phil Brachtvogel was Britains best rider until his retirement & Frank Brachtvogel was & is a world renown dragster builder. Pete is in Crick Nothants.
Another long UK bike was drag raced quite successfully in the 60's - 70's, The Drag Waye.
https://www.google.co.uk/search?q=drag+ ... 80&bih=615
See how narrow his front tyre was. Good luck.

[ianw]

Studying your pics will, you have what is as close to a front swing arm as you could possibly get, ie, bottom loop of leading link forks. But the benefit you have is that it combines centre hub steering, very impressive. With leading link forks the wheel would"flop" from side to side plus the frame would rise & fall. Your whole front set up is a credit to you. I'd stick with your lovely front end but stick a skinny front wheel & tyre in, & a couple of steering dampers That front end would be a credit to a sidecar if the rules wern't so strict in sidecar racing.

[paul33]

I agree with Ian, if you fit leading link forks the headstock will be above and to the rear of the front wheel and will be right in your line of sight. good luck its great to see someone looking at this design again, it makes a lot of sense.

[autofetish]

Hi Will - you're off your head - that's quite obvious - and running a diesel doesn't help your case - but I do live near Shrewsbury - so may be able to help - I'll send my phone number by PM - whereabouts are you ? (roughly)

Im half way between shrewsbury and oswestry. PM received and give you a ring later many thanks
Will bring the chocolate hobnobs thank you

Studying your pics will, you have what is as close to a front swing arm as you could possibly get, ie, bottom loop of leading link forks. But the benefit you have is that it combines centre hub steering, very impressive. With leading link forks the wheel would"flop" from side to side plus the frame would rise & fall. Your whole front set up is a credit to you. I'd stick with your lovely front end but stick a skinny front wheel & tyre in, & a couple of steering dampers That front end would be a credit to a sidecar if the rules wern't so strict in sidecar racing.

Hello most of this setup has been built by ian baskerville friends with Ian King Puma racing etc etc so loads of advice there

The front swing arm set up is from a italjet dragster scooter which had a major floor in the fact the front sub axles bends due to only being supported from one side.discontinued for standard fork design. Also brakes bearing and complete design the more i look at it the more i think its all abit small. 460 bhp turbo kit 200mph etc etc ......Ideally it would run standard forks but i really want to keep everything as low as possible hence the idea of leading link from a side car set up.

Yamaha GST1000 also has hub center steering so maybe an option there with everything being abit bigger........


Narrow wheels help to stop tank slap !! Well i have never heard this before ! I can understand a large diameter wheel like most run 17 _ 18 inch would help due to size and being thin would help with aerodynamics like the dragsters run. But surly this can be compensated by steering dampers. If this was true why do aircraft not have a 22inch wheel on the front landing gear .

Do the side cars get the front wheel up and have this issue.


You comments have all been very valuable thank you

Will

[ianw]

Sorry Will, I was getting mixed up, I thought you said that you had built the bike not Ian Baskerville?
Outfit front ends can go light but they have the third wheel to compensate for when the front end gets "grip" you wont have that, that's when I forsee you having side to side whip if you use leading link forks with a wide tyre.
You could & I'm not saying it will happen, run the risk of the front end folding under which has happened on sidecars.
Yes, I know of Ian King,Top Fuel Dragster racer, he bought the name Puma Engineering from Pete Davis & the rights to build the dragster engines that Pete designed.
It sounds as though you want something " off the shelf " to fit to your bike, why cant you build your own centre hub?, if you feel you need something stronger than what you've got. Have look at any front hub on a car or van & that is the starting piont for hub centre steering.
If I was going down your route, I'd adapt a Ford Sierra front hub. When you have perfected it, you could make the hub out of alloy. In fact, there are kit car component suppliers who supply replacement Sierra hubs in aluminium.
Good luck with your quest for a leading link front end but defo don't consider a trailing link front end, that would end in tears.
PS. A Swiss sidecar rider by the name of Rolf Biland had 10inch tyres fitted to his outfit in the 70's also a British sidecar racer by the name of Andy Jackson used the same 10inch wheels. They were designed for the 6 wheel Tyrell F1 racing car.

[autofetish]

Great advice


So stick with my hub center steering and swing arm design but stick a better hub assembly on the end


Ford serra Hub i like your style but it not ideal with the large hole for the shock tube.





What is the hub off on this beast ?? is it a custom made part ?





Thinking maybe a king pin style front hub might be a good idea also

[ianw]

Hi Will, or maybe a BMC MINI alloy front hub, smaller than the Ford & lighter.
The pic of the outfit chassis maybe ??? the tubular LCR chassis that John Rae built for Ray Thomas of SRT Motorcycles???
Ray comes on here so he may confirm that.
Defo stick with the hub centre & if you can fit the new hub in your alloy bottom look, happy days.
Can you post a pic of the front suspension mechanism please Will?

[autofetish]

Mini is a good idea also looking at quad bike stuff on ebay now

its a great design just the more i look at it as the bike development the more its the weakest bit and slightly important

[ianw]

Thanks Will, after seeing your pics you have a major re design on your hands. As you say, going down the strip at 200+MPH!!!!!
I wouldn't be happy with the way the swing arm mounts to the frame, I also think you need to fabricate a new swing arm.
Swing arm is defo the easiest way to go given that you want to go in a straight line, ie no corners.
I still think I'd be looking at a BMC Mini ali hub useing the CV joint & a cut down drive shaft mounted into the side of the swing arm & useing a couple of adjustable "tie rods" arms to hold the hub / disc / caliper upright.
But that front as is is defo no good.

Another option would be a 2 sided swingarm using a mini hub but to fit it with Spherical bearings. The wheel spindle would then be mounted through the hub into both sides of the arm, again with tie rods, you would have enough side to side movement for steering.

[autofetish]

[autofetish]

[SlowPhil]

When did dragsters start using the front break?