lawn mower transmission...?

[joshpit2003]

oh, I also plan on having 2 people peddal this thing if that helps.

 

[Kaptain Krunch]

Lawnmower tranny internals are all gears, with the exception of a chain for reverse. You could easily shift on the go with one if you were just pedaling, but once u add electric assist u may have problems depending on the power of the motor.

 

[joshpit2003]

thanks again for all the info.
and i'm drooling over reverse... that would be nice to have. do you have a favorite place to purchase lawn mower trannys? (and can u gimme a relative price range since that last like I posted was over-priced). I would assume I can get away w/ quite a weak tranny since it's just peddal powered (or max 3 HP electric motor)...

 

[Kaptain Krunch]

Just find a whole riding mower, i wouldnt pay more than $20 for a transaxle. i see them given away on Craigslist all the time. Or you could put an ad in the paper.

 

[joshpit2003]

i'd like to purchase something new, just for repeatability sake if I decide I want to build a second one.

 

[joshpit2003]

ok... so it's looking like this one:
The PEERLESS 700 SERIES... is going to be my best bet.

i am guessing that second output (if thats what it is) is for a brake to be attached or something? or is this a transaxle for a walk behind? (if thats the case then I would need to weld up the diff like we talked about).

5 speed w/ reverse means its actually a 4 speed + revers... right?

I've been trying to find specs for this (gear ratios) with no luck yet... If someone here happens to know the specs please post up. I'll post 'em when I find 'em.

Oh, and its looking like I cant find these new for any cheaper than 200-250 bucks... which is a bummer. Anyone have this same model lying around? Anyone used this model in a cart?
I understand it isn't the big beefy 820 series, but for what I'm doing I think it would hold up fine (pedal powered).


Thanks again everyone.
-josh

 

[joshpit2003]

found this image.. I'm not seeing how reverse works, but maybe he took that part out of the casing already. it does show me that there are two outputs and it also shows me it uses bushings/not bearings.

I'm guessing that ring gear shown must be the input...these must be a pinion on a shaft for the input that connects up to this ring gear...please correct me if i'm wrong.

 

[joshpit2003]

http://www.smallcarplans.com/manual.pdf

above is a nice assembly/disassembly manual of a variety of lawn mower trannys.
700 series on pages 15-21. Turns out there is both an in-line shift pattern version AND an "H" shift pattern version. I couldn't find any info on the gearing though!. Doh!

 

[joshpit2003]

thinking out loud here: I may be able to completely swap the gears (from output side to input side) and get a crazy over-drive transmission... or maybe I could also just run a set-up backwards... have the input be the output and plug power to the output...
hum.... i'm starting to really like this tranny.

 

[BriggsTwins]

this is a good choice for transmissions, but the swapping the gears is easier said than done, and not completly worth the time. you will be better off attaching a ratcheting sprocket so that your motor can power the trans while leaving the pedals free to spin. you still have the issue of making power reach the input from a chain....

 

[joshpit2003]

you still have the issue of making power reach the input from a chain....

I was going to fab up a sproket on the input side. I wont have to worry about a motor this first time around... I'll be sticking w/ stirctly pedal power until I finish it and yeah, some way to ratchet it would be the way to go.

i still haven't been able to find the gear ratio specs for this darn thing. I did read somewhere that there are 6 speeds out there...

anyhow, I hope those posted links/pictures can help someone else out. I'll still be on the hunt for ratios.

p.s. It seems like 1/4 of the "google" results come from this site alone. haha... I think I've read all of them. Lots of good info.

-josh!

 

[joshpit2003]

also, I've read that you need to get the model numbers that have STEEL bevel gears... which i am guessing that means there are some other, maybe hard-plastic bevel gears in some??

 

[BriggsTwins]

To my knowledge there are no plastic parts incorporated in these transmissions. if you can get your hands on a transmission you can roughly guess the ratios by turning the input and counting the turns to make one output rotation.

 

[Kaptain Krunch]

Some self propelled mower gearboxes do have plastic gears, riding mower gearboxes have all metal gears, some steel, some aluminum.

 

[joshpit2003]

maybe thats what it implied... that some of the 700 series came w/ aluminum

 

[Kaptain Krunch]

Yea, some of the 700 series did, some had steel. I have a 700 with steel gears, there very nice little transmissions, very strong, i also have an 820, which is even nice, 1" axles, needle/ball bearings all around, 3/4" input shaft...very heavy duty.

 

[joshpit2003]

yeah, from what i read the 700 sounds nice. I like that it is fairly small (at least it looks small in the pictures). Everyone seemed to have a different shipping weight, but I would guess this thing weighs in the 15 pound range... which would be much more friendly to my pedal powered kart than an 85 pound "beefy" one.

 

[Kenny_McCormic]

700 with steel input gears, reverse chain removed, and converted from grease to gear oil(add a vent) is usually what gets raced. some really good 700 variants come with needle bearings, oil seals and gear oil stock. A 500 series is the weaker 3spd cousin of the 700, that's what I'm gonna run on my "suicide trike" in a couple months.

 

[joshpit2003]

ok... i managed to throw some specs together (based on gear teeth #s)
based on model # 700-700-023

input rotations : output rotations (1)
basically how many times you need to rotate the input shaft to make one full rotation of the output shaft.


1st gear: 6.08:1
2nd gear: 5.33:1
3rd gear: 4.50:1
4th gear: 3.10:1
5th gear: 2.21:1

it actually isn't as much of a gear reduction as I thought it would be, but it still seems good.
if i did my math right that gives this tranny an over-all gear range of 275%

a good internally geared bicycle hub has an overall gear range of 350%
and I believe a typical 27 speed derailer system has a gear range of somewhere in the 500%

so I may have to double up on these bad boys (TWO 700 series trannys) if I wanted the same gear range as a derailer system...

 

[freakboy]

why u wana do all this for a pedal kart?