decisions on motor bike configuration

[preventec47]

I want to do a lot of road travel and need
to be legal and as reliable as economically possible. ie need to be cheaper than store bought moped from name brand suppliers.
I am drawn to mountain bikes because of
their front ( at least) suspension and I think heavier duty brakes and frame etc that should hold up better to hitting bumps repeatedly etc.

I had five more paragraphs but had to cut them because the post was denied ? ? ?

 

[preventec47]

( rest of my post)
What I have found are inside mounted engines that either drive the front sprocket*in which case it appears the pedals have to*always spin, or drive a supplemental sprocket at the rear wheel on the side*opposite of the derailures and other sprockets. In this instance, I believe
the engine could drive the rear wheel
and the rider could coast with the
pedals. The drawback as I see it is
that the rider could not shift gears
by moving the drive chain to the
various size rear sprockets.

So does the ultimate correctly boil down
to performance and how lazy the rider
wants to be ? Is there an issue
with reliability? IE I would only want
to put the motor power to the rear sprockets if they could hold up to the
extra stress. Have the rear sprockets
been shown to be a weak link ?

 

[darwin]

Using a motor to drive a cheap cassette is not advisable, they barely hold up pedaling them.

 

[Fabian]

I want to do a lot of road travel, as reliable as economically possible. I am drawn to mountain bikes because of their front (at least) suspension and I think heavier duty brakes and frame etc that should hold up better to hitting bumps repeatedly etc.

With these parameters in mind you will need to do a bit of home engineering as well as installing the following components:


mountain bike with front suspension, fitted with a Hayes V9 nine inch front disk rotor and Avid BB7 calipers at both ends of the bike,

Sick Bike Parts shift kit, fitted with either a 4-stroke or 2-stroke engine; both engine types being reliable when set up correctly, but a 2-stroke 69cc engine produces more usable low and mid range torque than the 48cc,

Jaguar CDI,

CR Machine Manufacturing medium compression billet cylinder head,

home made, anti chain suck system that (requires some fabrication skills) is "absolutely" essential from a reliability perspective,

correctly jetted carburettor or an upgraded system using a Rock Solid Engines reed valve intake with Walbro style diaphragm carburettor,

rear wheel gear system "specifically" using an 8 speed cassette with 11-34T or ideally an 11-36T sprocket combination (and most importantly, 8 speed cassette sprocket spacing), coupled to a SRAM X7 Twistshift mechanism mounted on the left hand side,

9 speed chain driving the 8 speed cassette (an important feature to eliminate ghost shifting) and is much more tolerant of derailleur hanger misalignment, should the rear derailler suffer an impact,

high and low range gears operated by the front derailleur (using the Sick Bike Parts optional 24 tooth and 30 tooth sprockets) allowing hill climbing ability up "any" level of incline, no matter how steep it looks,

Sick Bike Parts 9 tooth and 48 tooth sprockets for the jackshaft to bottom bracket gearing ratio,

trailer to carry spare parts and extra fuel as well as food and drink and electronic equipment if on a long trip,

high power front lights, brake light, mirrors and indicators - a lot more important than most people think is necessary,

thorn proof tubes filled with slime puncture sealing compound,

optional Cane Creek Thudbuster suspension seatpost to save your backside from knocks and bumps,

optional cylinder head temperature gauge and Exhaust Gas Temperature gauge to keep an eye on what's going on inside the engine; alerting you to either a potential fuel blockage or air leaks, if the instrumentation starts to show signs that the engine is running lean, thereby preventing heat related engine failure,

optional pull start mechanism and centrifugal clutch mechanism if running a 2-stroke engine.






Once all that is done, you can do this:























and this: http://www.motoredbikes.com/showthr...e-cartage-capacity-that-amateur-s-can-t-match
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[preventec47]

In order to decide between rear cassettes or internal
rear hub gearing, has a consensus formed as to
which rear gearing type has proven to best handle
the extra stress of added motors ? Also, I was told that there were some heavy duty rear cassettes designed for tandems that were designed to be sturdier and stronger? Fabian, your setup is super impressive but I need 4 stroke and the sick bike parts website seems to imply that their jackshaft
shift kit only works with 2 stroke engines. Can anyone confirm ?

 

[Fabian]

They do 4-stroke kits: http://www.sickbikeparts.com/catalo...ucts_id=110&osCsid=fe5p29ugbe1md7ik59254l1685

If i could be given a guarantee that an internal hub would hold up to the massive amount torque being pushed through it when the bike is fitted with low range gearing, it would be on my bike tomorrow.

If i could be given a guarantee that an internal hub would still operate some of the gears even when a few of the others have smashed themselves to bits, it would be on my bike tomorrow.

As an alternative system, the Nuvinci Hub is a great design but they do not warranty the hub if it's used in a motorised application, so i am figuring that it can't take the punishment of higher torque output when used on a motored bicycle.

Although the chain and cassette and derailleur system has a lot of drawbacks, it has proven to be bullet proof when it comes to handling the extreme torque output of mega low range gearing afforded by the Sick Bike Parts shift kit and optional sprocket combinations.
Even if you do bend up a few cassette sprockets, it still allows you to get home using sprockets that are undamaged, and, if you damage a rear derailleur and hanger, it can be replaced on the spot with a spare derailleur and hanger from your tool kit.

If a hub mechanism fails 50 miles from home, you are screwed, because carrying a spare hub means carrying a complete spare (rear) wheel with hub attached - not a cost effective solution and it's not exactly a space economical solution either.

Spare chain, spare rear derailleur, spare hanger and spare rear derailleur cable are easy to pack into a small box.
Carrying a complete spare rear wheel is a logistical nightmare.

 

[bigoilbob]

A quick second to Fabian's advice, re Nuvinci hub. I have the beefier, 171 hub, with a developer's kit. Works for me, but my power is much lower and IM twisting a 20" wheel. FU run the numbers IM also at the top of my permissible torque.

The only way a NV hub should be used in powered apps with anything bigger than a 20" tire is as a jackshaft. They ARE rated for up to 1000 r/m, which is 2-3* faster than most 26" wheels ever spin. Hence, the possibility 2 transmit more power with more speed/less torque, via deployment as a jackshaft.

 

[Fabian]

I just want a Nuvinci Hub that can do the job. From what i understand the Nuvinci Hub is about as useful as female mammary glands on a bull when it comes to coping with the extreme torque being sent to the rear wheel via a Sick Bike Parts shift kit.

I just "wished"; i just "so wished" that Nuvinci would build a proper hub capable of handling the extreme torque dished out by the highest levels of twisting force that can be produced when running the highest ratio gearing provided by the optional jackshaft sprockets in the Sick Bike Parts catalogue range.

I really, really want a Nuvinci Hub that doesn't spew grease for 50 yards in every direction as it blows itself to pieces; transforming into scrap metal under a motorised bicycle configuration.
It's so frustrating when all you want is a Nuvinci Hub but are unable to use it, because it's nowhere near as tough as what it could be, or should be.

 

[KCvale]

In order to decide between rear cassettes or internal
rear hub gearing, has a consensus formed as to
which rear gearing type has proven to best handle
the extra stress of added motors ? Also, I was told that there were some heavy duty rear cassettes designed for tandems that were designed to be sturdier and stronger? Fabian, your setup is super impressive but I need 4 stroke and the sick bike parts website seems to imply that their jackshaft
shift kit only works with 2 stroke engines. Can anyone confirm ?

Yes Sick Bikes makes a nice a 4-stroke shift kit for the HS 49cc and Honda 50cc engines, a great base for the engine with all the JS mounts and the needed parts, what is important is what does the initial gear reduction and clutch work from the engine out to the drive chain output sprocket, and how it relates to the jackshaft input sprocket.

I like the HS 142F 49cc with 4G MB kit as it has everything and goes together well for direct drive and with the sickbikes 4-stroke shift kit, the rub is paying for all the duplicated and unneeded parts.

In short the SBP shift kit eliminates the need of any of the following gasbike kit parts:

Motor mount base and it's mounting hardware.
Back sprocket, chain tensioner, and all their mounting hardware.
Wider BB pedal axle, sprocket, bearing hardware, and special crank arms so the pedals don't hit the wider 4-stroke engine.

What that leaves is the SBP shift kit with just the following needed:

Engine with everything to make it run.
Cent clutch (or torque converter) transfer case.
Throttle.
Fuel system.

The rub comes when you try to price out the above and it's like $20 difference between getting the whole gasbike kit or just parts so a no brainier for me, I build a lot of bikes and a 4-stroke platform, wide pedal parts and direct drive hardware comes in handy for things like this 79cc direct drive.

As for the rear wheel gearing I find just a simple internal 3 to be perfect for anything with 2 -5HP, in short every engine has a much wider power band than a human pedaling and mor gears just make it harder to operate, for example on 7-speed shifters I only use the even numbered gears.

Hope that helps.

 

[professor]

Preventer, you got some great answers.

I ended up using some moped parts on the bike I concocted, and when one adds up the costs involved, or if you want to avoid a buckboard type ride, think about a real moped.

I have a nice Honda 90 trail that has been in my garage for decades. It is neither fish nor foul- too slow for traffic- too fast for the curb/bike lane.
So I built a motorized bike as a toy and my little jaunts around town.
It does have full suspension!
However, if I was into distance use, something more oriented for that purpose would be desired.