Trek 4500 / GP460 now twin belt jackshaft

Discussion in 'Rack Mounted Engines' started by DetonatorTuning, Oct 18, 2008.

  1. DetonatorTuning

    DetonatorTuning Active Member

    well i'm off and running.

    the Staton inside drive parts and wheel left for their new home today. the money is in my buisness account and taking paypal hits from parts suppliers.

    i'm going to relate and reveal as much of this build as i can without giving it completely away, i think there may be room for me and this configuration in the market place so i'll be pursuing copy right and patent (sp) paths before a full unveiling.

    i've owned and run 2 real fine pieces of MB equipment and looked very close at a few more. some of the very best configuration concepts are already being provided and more importantly protected from being used in the same fashion.

    it's going to be rack mount, have dual forward torgue straps and be very stable in the side to side aspect. that alone might be interesting to some who've had difficulty in that area.

    the upper and lower pulley centerlines are going to be the same distance thus just one size belt for both positions and a simple tensioner approach. i'm working on a belt pitch and width model not presently offered that should offer good tracking, be capable of no pedal starts and have good wear characteristics.

    the mock up / prototype atleast moves on it's own in fairly primitive material and workmanship. the first production level setup is going to have a pretty brutal life, however long it is. i fully intend to break it ,and in as many ways as i can ,so that the faults are known and delt with before anyone else gets ahold of one, if they ever do.

    i should have my new wheel, jackshaft pieces and a final configuration rack all in or built by this time next week. the pulleys may take a week longer, depends on the shops present activity.

    thanks for looking at my thread,
    Last edited: Oct 18, 2008

  2. vegaspaddy

    vegaspaddy Member

    hi steve,

    can't wait to see the finished product, if its up to the standard of your previous builds am sure the setup will be top notch....

    ME i just got my trike finished today... am so HAPPY !!!!!!!
  3. DetonatorTuning

    DetonatorTuning Active Member

    thanks VP,

    i'm not sure very many are going to be all that impressed.

    this design is super utilitarian, no cool swooping lines, no extensive area to promote neat paint.

    just a very simple, light, self aligning platform to mount choices of CC rotating engines on and drive thru a jackshaft reduction to a pulley on a disk brake hub.

    glad to hear that you got the trike all sorted, it's going to be a real nice ride !!

  4. kerf

    kerf Guest

    When you get your ducks in a row, hope for a peek.
  5. DetonatorTuning

    DetonatorTuning Active Member


    things are going almost too fast right now. it's crazy sometimes how things fall together when the "fullness of time " has arrived.

    today i blundered into a pair of VERY good disk mount wheels AND found that i can eliminate a piece of pulley mounting hardware that i tought was going to be needed and was going to add some extra expense.

    i'm old enough now to just blandly go about amassing info and sources then just let things perk like "cowboy coffee"

    i bought, rigged two working configurations of and sold the Staton inside drive to have something to ride and to keep my hands busy while i was auto-cad 3Ding my own layout and building up the mockup/ prototype.

    i have a list of "celebrities" that are going to be offered a sneak preview and asked for a "concept critique"

    stay tuned,
  6. DetonatorTuning

    DetonatorTuning Active Member

    well things are still moving along but i needed to reconfigure slightly. when i got all my pieces together in the materials I THOUGHT i wanted i realized i had OVER ENGINEERED in a couple places and would pay too great a price in weight and energy losses.

    it's OK, the main configuration is fine, just some tweeking to reduce mass/ weight and make the whole thing more compact.

  7. terrence

    terrence Member

    DT, you got the hair on my arms standing up lol. Cant wait to see a visual of your design. Keep on keep'in on. :)
  8. DetonatorTuning

    DetonatorTuning Active Member


    thanks for the interest and support.

    it's not as easy as one may think to pull this off. i'd bet Pablo, Ghost, Dax and others could tell many tales of struggle and frustration trying to do something AND bring it to market.

    if it was just a matter of satisfying myself i'd be riding it already, but the established kits are SO good that it puts the bar pretty high.

  9. DetonatorTuning

    DetonatorTuning Active Member


    it's been awhile since i updated the belt/ jackshaft build, i can now, though it's not what i nor others hoped.

    it's a workable idea though VERY painstaking to get the critical measurements to work with even custom made to order pulleys and stock HTD belts.

    this design is dead and done. all i can say is a real and heartfelt SORRY if you were amoung the people who contacted me or commented here with interest and support.

    the main problem is that every bike is just diff enough to mean that each one would have to be built on a strictly one-off basis. the current design is NOT production friendly at all.

    i've had to eat all my prototype and parts expences and turn aside from my hopes for this project.

    i am, for my own reasons, turning away from the whole single speed / engine assist arrangement and have begun work on a shifter setup using my GP460 for power. i can do this in my state as a motorized bicycle (scooter) with even fewer regulations than mopeds.

    with the gearing i've worked out, i'll have the ability to take off from a dead stop under engine power alone and accell. VERY FAST to a max of 36mph in the lowest gear. then i'll have the remaining 7 gears for speed , terrain and economy. with a theoretic topspeed of 70mph in high, though the reality may be more like 60mph. we'll see.

    i'm going to use some of my work bonus for the remaining parts i need and hope to be done by Jan. 1st.

    again, thanks to all that backed my effort to bring out another belt system with intersted support. it might be something for a later date.

    right now i really need to get riding again and in as inexpensive fashion as possible.

    i guess this means there's going to be yet another multi-page DetonatorTuning thread coming your way :shifty2:

    Last edited: Dec 4, 2008
  10. DetonatorTuning

    DetonatorTuning Active Member

    OK well..........................................................................................................

    the amount of response to my last post probably shows how comfortable and insightful you guys have become with me. i can be painfully slow with things and then at a twitch make a move or decision out of the blue.

    it seems that giving up on the belt/ jackshaft was one of those nec. times where you just need to say "that's it, i just can't reconcile this " so that your brain will disingage from the negative before you and become open to something else. somewhere on the forum is a post where i encouraged someone that if they stare at what's not working they may miss the answer right next to it. maybe I should have been listening instead of talking right then !! WHAT A BUMPKIN eh!?!

    any how, there is actual hope for this design and i have come up with a couple simple modifications that make it not just easier to assemble and mount but adaptive to more bikes.

    one of my problems was trying to do something that would work on any possible bike, presently i just can't accomplish that but there are still ALOT of bikes that this design WILL work on though there is a limiting factor.

    my Trek has those little bored ears just above and behind the rear axle (on the dropout plates ) that are usually used to mount fender stays. i drilled mine out to 1/4" and used that location as the mount point for the bottom of the rack uprights. ANY bike that has these or ANY builder that has the ability to fab something up like them on a bike that doesn't have them can CONCIEVABLY mount and use this design. i'll be looking into some alternatives here as well.

    my daughter has returned safely from Mali, Africa so there is less tension and more positive energy in the house now ,so i'm going back to work with this.

    it could be spring before i have something proven to share, but i'll be on forum daily to see what everyone else is doing, since most of my stuff isn't all that original but mostly "integrated"

    thanks for riding along....................
  11. vegaspaddy

    vegaspaddy Member

    glad to here your back on track det,even though your design will have some minor limitations it still takes alot of inspired creative work to come up with a new system.

    Keep plugging away and what the heck even if you end up with a $3000 drive train, at least you built it yourself.....
  12. DetonatorTuning

    DetonatorTuning Active Member

    yeah, about that............ ain't going to happen. i'm just not that proud. i knew from experience that it was going to much more expensive to get the first one done than any of the others, but i'm doing this on money i skim out of my lunch alowance.

    i've gotten past the bottom mounting limitation, i think.............

    i'm still at it.

  13. kerf

    kerf Guest

    I feel your pain man, budgets are a real bummer on creativity.
  14. DetonatorTuning

    DetonatorTuning Active Member

    right...... the only thing more limited than my cash right now is my time away from my day job and other things related to the direct support of and attention to my family.

    this being my hobby of sorts on top of the day job and 2 other functioning cottage industries, bike building is pretty much dead last in the priority chase. :annoyed:

    from Nov. 1st to Feb. 1st is usually pretty tough all the way around, but i'll get it done an hour and a dime at a time LOL.

  15. DetonatorTuning

    DetonatorTuning Active Member

    Trek 4500/GP460/Rackmount/Jackshaft/Freewheel crank

    this thread has been dormant since the first of the year, thought i'd up date it.

    in persuit of more experience to apply to my rackmount twin belt jackshaft i've decided to alter the rack i built slightly to drive by chain and to the cassette.

    the stuff i've learned using the shifter has given me very valuable info on ultimate gearing that has shown that my first belt ratio wouldn't have been the best possible. i hope this configuration is going to take me the rest of the way.

    i'm going to use the 5:1 tranny and jackshaft down to stacked cassette cogs on the inside of the cassette for 20.91:1 or 21.83:1 engine drive ratio (to be determined) then i'm going to have 3 cogs and the derailleur on the outside for pedal ratios.

    this is going to work because i'm going to retain the forward freewheel crank setup. that will allow the shared cassette to drive the pedal chain while under engine power but the PEDALS won't be turning, and since the crank will be freewheeling the 3/32" chain won't be experiencing any excess torque loading. the same absence of torque load at the crank freewheel will mean super durability of that part too.

    shifter experience has shown that the level of resistance in the tranny is not objectionable during pedaling so that's not a concern at this point. could all be eliminated later with a freewheel on the jackshaft. this being a centrif. clutch operation, when i drop to idle ALL drag and chain motion will be eliminated by the freewheel in the cassette.

    i have everything i need to assemble this configuration with one exception.

    i need a K910 masterlink, if any of you have or know where i can get one without having to buy another chain ?

    that's about it for now, thanks

    Last edited: Apr 28, 2009
  16. DetonatorTuning

    DetonatorTuning Active Member

    well, LBS to the recue. my guy had 2 perfect match masterlinks for the KMC K910 chain. bought them both for $1.50 total.

    BUT, when i got home i found that i was 5 full links of chain short of being able to make both my segments, sooooooooo, had to order another chain anyway. oh well, i'm waiting for a couple of cassette cogs too.

    back to work,

  17. DetonatorTuning

    DetonatorTuning Active Member

    well nuts,

    my second chain came, but the original owner of my LBS died thsi past week and the shop got understandably shaken up, so , the order my cogs were part o fdidn't get made until today.

    my cogs will be in on thursday. in the mean time i finalized the spacing of my jackshaft. the distance between the C/L's of the jackshaft and the cassette had to be dead on for the range of built in adjustment to function.

    the C/L's for both the output / jackshaft and jackshaft / cassette are both very close to 9". this was important because i'm trying to get away without added tensioners this time.

    my jackshaft brackets are at the fab'r, due back thursday too.

    when it's all here, i'll just have to bolt down the engine, assemble the jackshaft and install the chains.

  18. DetonatorTuning

    DetonatorTuning Active Member

    sorry for the extended delay in getting back to this.

    i had given my fab guy my jackshaft plates and they got messed up, so i'm going to have to alter them slightly tomorrow so that i don't have to do them all over again.

    most of everything else is taken care of and i hope to have it in atleast complete enough shape to get some pic's up over the weekend.

  19. DetonatorTuning

    DetonatorTuning Active Member

    1st pics of the basic contraption

    first 3 pics show the basic layout, the last i was hoping to show the double
    23T cassette cogs being driven by the engine chain. i have a shaft collar between the bearings inside the plates this was a planed spacing to keep the bearings seated against the inside of the plates. i will add another between the bearing and the inner jackshaft sprocket for added insurance against shaft travel.

    i have 2 functioning pedal speeds until i get another spacer then i'll have 3 though i doubt i ever use more than the smallest.

    still need to asemble the torque links, fuel line and reposition my rear lights. had hoped to ride it this weekend but it doesn't look like it right now.

    you may be able to see that when the engine is reversed to drive on the left( tranny removed at that point ) that this configuration will easily support twin belts in the place of the chains and sprockets. final drive will be to the disk brake mount.

    because of the way the rack is built and attached moving the rack forward and back provides adjustment of the final drive tension. primary loop tension is achieved by mounting the engine higher or lower over the plate in 1/32" thick washer steps.

    this rack is rock solid and completely square to the rear axle on both planes. it's configuration completely eliminates the flex and twist issues i had with belt drive in the past. when i move to belt they will be 8mm pitch and 16mm wide. sourcing is complete on the belts and cogs.


    Attached Files:

    Last edited: May 23, 2009
  20. kerf

    kerf Guest

    Looking good, should be a screamer. Looking at your setup and I don't know why but an idea struck me. A hard-tail frame, your primary gear box, a Whizzer drive ring and a frame mount for the 460. What do you think.