full suspention question

redneck82

redneck82

Member
Anyone got some good ideas for spring loaded idler pully so as to put a kit on a full suspention without throwing the chain over every bump???
Im looking to make a more trail friendlt bike...
Thanks in advance!
dnut
 
It's an idea that many of us have considered. What I hear, though, is that when you put a spring loaded tensioner on you then have trouble with the chain loosening when you roll-start. It makes enough sense that I haven't yet tried it.

One day I might. But I have doubts about it working really well.
 
Yeah im looking at using a real heavy spring mounted from above with a pully on a swingarm to keep it straight...
Least thats how im gonna try it anyway...
As it stands i removed both derailers from the other side cut the chain down so the gears are fixed...
 
that was what i was thinking... i actually found a seller on ebay that has spring loaded idlers with actual sprockets rather than the vinyl wheels... like $56 or so and you get a set of 2... now the truck is finding a good frame... seems to be a bit of a pain in the ass finding a frame that is full suspension AND can accommodate the motor...
almost had one yesterday but got outbid at the last second lol
 
redneck82 said:
that was what i was thinking... i actually found a seller on ebay that has spring loaded idlers with actual sprockets rather than the vinyl wheels... like $56 or so and you get a set of 2... now the truck is finding a good frame... seems to be a bit of a pain in the ass finding a frame that is full suspension AND can accommodate the motor...
almost had one yesterday but got outbid at the last second lol
Click to expand...
I am completely lost with your situation...
You have a soft-tail bike or not?

You have a 2-stroke and want to run it direct drive with a complicated tensioner system?

The very best way to motorize a soft-tail is with a jackshaft tied to the pedal system.
The pedal system already accounts for the swing arm movement and the engine can use the pedal gears with a $200 SBP jackshaft.

2_DustinDoneRight.jpg


The trick is the rear shock not be in the center cavity of the bike like above, but most soft-tail bikes you see with a rear shock our mountain bikes with a center cavity too small for a gas engine like this bike in the build bay now.

SpecializedEpicR.jpg


In that case you go electric shifter.

SpecializedEpicMotorL.jpg


Then fill the small center cavity with lithium ion batteries.

SpecializedEpicBatteryL-1280.jpg


Pricey, but uber cool ;-}
 
well, i'm working with a minimal budget here... looking at some possible custom fabrication... but yes, ultimately i'm looking to motorize a soft tail... the ones i'm looking at are the older specialized ground control frames... i found some on ebay, but was out bid... i've got another one coming up in 2 days that i'm going to be bidding on... they are just right as far as the frame style like what you mentioned... the rear shock is mounted just behind the seat post... i don't have the cash to blow on the jack shaft and such but like i said, i found the tensioner pulley set that i think will do the trick just right... it will set it up similar to the pedal side derailer system... but will be set up on the top side of the rear support like the existing setup...
in theory it should be just enough tension without overloading the springs on a pedal start...
when and if i can get this thing going i'll def put up some pics... my goal is to make this thing more trail friendly...
 
Parts are parts.

You can buy combinations of parts that are known to work together well and give you all you need in a 'kit' form, or squander money needlessly thinking their are money saving shortcuts left.

Take it from a guy that builds a lot of shifters, you don't need to re-invent the wheel and trying to won't save you any money in the long run.
 
I've played around with this a few years back and if the suspension pivot point is not centered and between the rear sprocket and the motor's sprocket, you'll get way too much chain slack. The easiest and cheapest way is the jack shaft system.
 
redneck82 said:
Not looking to make a shift kit... just compensate for shock travel...
Click to expand...
Your pedal sprocket is aligned with the back wheel so that the back wheel travel does not effect chain tension.

In order to add a left back sprocket the motor output has to be at the same place as the pedal sprocket, hence why a jackshaft works even with no bike gears.
 
Not so much a rear derailer... but it will have the same effect... its going to be 2 spring loaded idle sprockets opposing... im fairly confident that it will work but we shall see... i actually have changed up the frame design a bit too... i found a junk full suspention frame in the woods... nothing youd want to put a motor on but i pulled the swing arm... ive got a hard tail im going to frankenstien into a dual rear shock system... its going to elongate the wheel base by roughly 6-8" but the downhill style suspension with the motor is gonna make this thing a beast...
 
KCvale said:
Your pedal sprocket is aligned with the back wheel so that the back wheel travel does not effect chain tension.

In order to add a left back sprocket the motor output has to be at the same place as the pedal sprocket, hence why a jackshaft works even with no bike gears.
Click to expand...

I just reread your thread... i missunderstood what you were saying before... ill def keep that in mind but i dont think my budget will allow... thank you tho, im gonna file that one away for future projects...
 
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