GNG second trials build

[Denisesewa]

Interesting, I have always thought you could build a frame out of fiberglass, it is pretty strong stuff, what do you think? It works for boats! You should do it!

I have researched bike frames people have made at home with carbon fiber, usualy with a high density foam core with a carbon fiber skin, they dont seem to last but I think that is due to not using a heated centrifuge for curing, Hand layup has its limitatations, I have made kite surfing boards using a vacume bagging method which works well, also made a hydrofoil kiteboard which eventualy broke the foil section when I hit a sand bar at speed, the stresses on that board were pretty high and it held up fine till I killed it. There is no limit to what can be made at home with carbon/fiberglass, I did the entire interior of my ratrod with it along with many other things over the years, here are some examples, If you browse my photobucket account you'll see many more.
Hand made Canoe with ballistic nylon / epoxy skin ( boat wieghs 12 pounds)

Foil board

Kayak paddle

Parts for my ratrod, armrests, door panels, light housing, fenders ect.

 

[Whiplash]

Love the bug!! I want to do a street bug Soooo bad! Here's my baby still under construction on the front but close!

 

[Cyclebutt]

Got any finish photos of this second build? Would love to have a look. BTW, are those hookworm tires on your Cannondale? If so, are they worth the price? I'm having difficulty pulling the trigger on those things so I'm looking for some "real world" testimonial. Thanks!

 

[Denisesewa]

Got any finish photos of this second build? Would love to have a look. BTW, are those hookworm tires on your Cannondale? If so, are they worth the price? I'm having difficulty pulling the trigger on those things so I'm looking for some "real world" testimonial. Thanks!

I ditched the super-v as I didnt like the geometry, It rode fine and looked ok but riding charictaristics were too old school for me, I ended up building another hardtail ( not finished )


The hookworms are great urban assult type tires, I've used them on several bikes, they roll well and grip well on good concrete or pavement but off road they pretty much lose their charm , unless you really just stick to street riding and skate parks with clean hard surfaces I wouldnt recomend them, hitting loose stuff in a turn will leave you having a conversation with the concrete in less than a heartbeat.

 

[speedmd]

Hi Denise

Great build. I am hoping you can find a suitable/ reasonable pure trials bike for your next one so we can see what you can do with it.

 

[Denisesewa]

Unfortunatly pure trials bikes are at a premium , I sold my Echo ( same as in your middle pictue ) last year and a Limey , both are really nice trials bikes but I'm getting old and healing isnt as much fun as it used to be. its tough to alter what I consider the nicest looking bikes out there.

My Echo


My Limey

 

[speedmd]

Hi Denise

I hear you on the cost. I just would like to see a bridge between the motor sport and the pedal version in a high grade build. Not suggesting for you to be the tester in chief, but more to move the whole thing up a notch now that you have shown your great work. I doubt you will loose money on it with the grade builds your doing. I hear you on the getting hurt thing. If I was still into this, I would be cutting tubes and welding right now.

The hard tails have their advantages, but bringing these up to 40 and 50 pounds with motor and batteries may require a bit of suspension. Fat tires definitely, but a few inches of good stiff suspension may be all that is needed. Not sure how light it can be made and still be strong enough for real duty.

Big advantages in the extra short chain stays and the high / rearward position of the BB. Like the way the top and down tubes come together on your white one toward the head. Frames are so low that you could mount motor above and still have plenty of room for adding a seat, for when you get lazy. Electric motors are perfect for trials.

Best wishes

 

[Cyclebutt]

Thanks for the update and info, Denise. Bike on!

 

[spinningmagnets]

I don't know the brand of this seat, but...I could fab one of these. The benefit would be it is still easy to remove for "no seat" trials riding, and it pops right on for the street...all the while allowing a motor or large battery to be mounted above the trials bikes' low top tube.

 

[Denisesewa]

I don't know the brand of this seat, but...I could fab one of these. The benefit would be it is still easy to remove for "no seat" trials riding, and it pops right on for the street...all the while allowing a motor or large battery to be mounted above the trials bikes' low top tube.

Thats a " Softride" TT bike, I sold mine a couple months ago and now have 2 Zipp's , 1 is setup single speed and the other with gears, although the softride seat boom could be used it would take alot of moding any frame except a softride and the Geometry of those bikes is too old school for me ( they made a mountain bike version), the booms are built with hi density foam ( divincell) with an elastomer sandwitched longitudenaly ( boy is my spelling suffering today) and then laminated with carbon fiber, it would be a tough build to get it right.
Anyway, The Planet-x " jackflash" I used in the first build is a great trials bike although not as cool looking as a modern trials bike and I dont mind pulling the seat when its time to get serious, its also a very good trail bike which is what I do most nowadays.

 

[Denisesewa]

This is the uglier of my two zipp's, Full carbon frame, forks and seat pod,

 

[Mitch3514]

I would really like to do this cross over moto/ cycle trials electric build, i even have a trials bicycle available for use. However sorting the correct geometry with suspension is whats holding me back.
i was initially thinking of adding a pivot to the bottom tube where it connects to the BB and then adding a shock/spring to the upper which would give a suspension like action pivoting from the bottom bracket like this:

[youtube]oMP7TW1ZZp8[/youtube]

however as i am aware trials riders land with the rear wheel locked which completely changes this geometry giving this affect:

[youtube]ujVzPHUIuAI[/youtube]

basically this renders the suspension in this setup useless and i would imagine actually makes balancing after a drop off even harder as you would tilt back..

im not much of a suspension/geom expert with this stuff but could anyone here suggest a suspension mod setup for a trials frame that would actually benefit the design? i agree adding the weight due to electrics would make the ride pretty shit without any suspension at all however..

 

[Denisesewa]

I have both my current bikes setup hardtail , I dont miss rear suspension at all however front suspension is key and "good " front suspension makes a world of differance, I am running rockshox Boxxer's on both bikes, When I had the super -V up and running the rear suspension sucks up all the energy your body puts into moving the bike unless I had the rebound adjustment set at zero, then I could use the rebound of the shock to help move the bike, this is a bit unpredictable , unlike a trials motorcycle there is no clutch to use in combination with the suspension to " Launch" the bike.
I find it easier and more predictable with the hardtail, I am using a 24x3.00 downhill tire on the rear which I can run a very low pressure which adds some "give" to the rear. These bikes are actually super light considering they are powered.

 

[speedmd]

Hi Mitch

Welcome to the topic. Nice diagrams.

Coming from a early gasser days, I can relate a bit. Don't think the power is close yet, but do think just a few inches of travel will help loads. It would need to be very stiff and just the right balance between absorption and rebound. I just got a older giant FS mtn bike that I have been playing with, sorting it out for a road bike/ super moto style ebike. It has two rear suspension travel settings, and the shorter travel setting is much much better at power transfer. Has a tight spring and snugged up It will hop nicely on the rear wheel with my weight (much less than the previous owner). Tight is good. Much better than the DH bike I have been playing with for a possible build. Something like 2- 4 inches of travel may be best at this weight class. Even possibly polymer bushings.

I think the pivot will need to stay in line with the chain drive line to keep it from acting weird under power. The rear suspension is there mostly for hitting stuff the rear wheel runs into and not for hopping / dropping when bike is vertical. Only way to do both would be a severe compromise in travel direction.

Hi Denise.

Love the look of the old zipp. All it needs is a set of tri spokes painted to match to finish it off.

 

[melodious]

Carbon fiber really is the key way into marine products. Am I wrong?

That needs a jet.