surreal

Interesting. I don't think Ben ever rode a bike with left-hand drive. =P Further, i don't think that fixie folk on conversions trying to go LHD are quite as innovative as Franklin or AG Bell. It should be obvious that reverse-threaded pedals on left crank-arms were invented by somebody, but I was surprised when I found out who. Torn from sheldon's page:

"Direction
The right pedal has a normal thread, but the left pedal has a left (reverse) thread.

The reason for this is not obvious: The force from bearing friction would, in fact, tend to unscrew pedals threaded in this manner. It is not the bearing friction that makes pedals unscrew themselves, but a phenomenon called "precession".

You can demonstrate this to yourself by performing a simple experiment. Hold a pencil loosely in one fist, and move the end of it in a circle. You will see that the pencil, as it rubs against the inside of your fist, rotates in the opposite direction.

Ignorant people outside the bicycle industry sometimes make the astonishing discovery that the way it has been done for 100 years is "wrong." "Look at these fools, they go to the trouble of using a left thread on one pedal, then the bozos go and put the left thread on the wrong side! Shows that bicycle designers have no idea what they are doing..."

Another popular theory of armchair engineers is that the threads are done this way so that, if the pedal bearing locks up, the pedal will unscrew itself instead of breaking the rider's ankle.

The left-threaded left pedal was not the result of armchair theorizing, it was a solution to a real problem: people's left pedals kept unscrewing! I have read that this was invented by the Wright brothers, but I am not sure of this.

Note! The precession effect doesn't substitute for screwing your pedals in good and tight. It is very important to do so. The threads (like almost all threads on a bicycle) should be lubricated with grease, or at least with oil. " https://www.sheldonbrown.com/gloss_p.html


loctite might help prevent the original problem, but it might lead to others down the road. Appropriate technology= getting the correct cranks, if you really want to do this. (But why would you really want to do this?)

You may be onto something there; the french bikes do seem to operate under a different set of rules. However, even the *french* have been using reverse-thread pedals on the left crankarms, because the forces that unscrew pedals are different from the ones that might (theoretically) mess with BB cups.

Bottom line: if you can't buy a few sugino XD bits for your super-hawt french fixie (@30bucks? maybe more with shipping?), you don't really, truly want a tricked-out LHD fix.

And, I don't blame ya. =P
-rob

Zaphod Beeblebrox 

repechage

For around town, no reason. On a steep track, I think its would be useful, like raising the bottom bracket but not. Pino Morrioni did it in 1974, very unique then. He made special left hand thread hubs and cogs. Today, maybe one of the slide on cog type hubs or the type that basically relies on 6 bolts to mount the cog, still not cheap but easier, and of course probably the use of a tandem crank set to keep the pedal threads the direction you want.

Iowegian

Hey, that's kinda cool!

Iowegian

It must be late...I'm finding this very funny!

thirdgenbird

i debated it too. my hub is splined so all i would have had to do is swith the pedal axles so the cleats would clip in correctly.

we have a tandem that has been running non tandem cranks since about 1995. a little light duty thread locker and they have never presented an issue. we just had to get three cranksets and an extra right hand pedal axle.

proantibicycle

It's a backwards picture. If you can get an old frame with a USA shell., you can get a BMX bottom bracket and pedals that are set up for left hand drive. Even some freestyle fixie bikes now come with a mid BB shell so it would be possible to set up LHD.

Here: https://fixie-factory.com/fixie-trick...E2%80%99s.html

As long as you clear the left chainstay, you should be fine. Although I am not sure why you would want to do that. Functionally it is the same.

noglider 

But the pedal threads in the cranks will be in the wrong direction.

mickey85

Just to say I did it. Of course it would functionally be the same. Why? Why not? It's an old chipped up UO-8 that I salvaged from a garage sale (wheels rusted beyond repair, broken teeth on the derailer, cracked front derailer, toasted chainrings, etc), threw some Ebay wheels and "Schwinn Approved" crankset and now have a fixed gear. 10 minutes would have it flipped around.

thirdgenbird

pedal spindles are symmetrical. you just need to put the left spindle in the right and the right in the left. (this was addressed in post #31)

Bianchigirll 

(this last quote taken out of contex to shorten post)


my post about Ben and Alex was tongue in cheek, it was intended to humorous. we all understand the mechanics and principles involved in why bikes are normally right hand drive.

Iowegian

A local brewery gives away these stickers. If you end up building your LHD bike and need a headbadge, just let me know.

thirdgenbird

perfect.

surreal

I figured it was an attempt at humor, which is why i made a comment about ol' Ben never riding a left-drive bike, and then i added the "=P" face, to signify playful hecklishness. The rest of the dissertation, however, is b/c a few other ppl who contributed to the thread do NOT know the mechanics and principles involved in why cranks are reverse-threaded on the left-side and not the right. (As for why bikes are normally right-hand drive, wellllll.... I gotta admit, i don't really understand that. I mean, since it has been the standard since almost the beginning, all the common parts relating to the pedals and freewheel mechanisms encourage continued use of the standard. But why that emerged as the standard is a mystery to me. )

-rob

cudak888 

Sorry, Rudge beat you to it:


https://www.uscoles.com/20063strprt2.html

-Kurt

surreal

???

jimmuller 

You could reverse the pedals and still keep the threads the same by threading them into the inside surface of each crank arm. Of course your power stroke would be a bit limited that way...

thirdgenbird

if you put the left spindle in the right pedal and the right spindle in the left pedal you can run LHD. thread locker will keep them from backing out. out tandem is set up this way. it works just fine.

threading is the only difference.

noglider 

The Rudge logo is a right hand. I think the left hand brewing company's logo is supposed to depict the BACK of a left hand.

Zaphod, that picture is much better.

Amesja

Back-handed complement!

surreal

Changing the spindles won't actually change anything related to the problem, which is that the pedals will back themselves out over time, unless you use loctite. I don't think I'd want to loctite my pedals, though. I think i'd buy the proper crank.

-rob

thirdgenbird

light duty thread locker works fine. our tandem has been this way for 16 years.

Amesja

Blue locktight. It'll hold the pedals in and they wont unscrew but they will still come out with standard hand tools. If locktight were around 100 years ago all pedals would be the same left for right. The problems of the last century (or the century before last) are not the same problems of today. "Because that is the way great-granddad did things" is fine until we learn better ways of doing things and then those precautions are no longer necessary.

Zaphod Beeblebrox 

I looked at that headbadge and thought to myself "Its what a left hand looks like in the mirror" for a solid 2 minutes before I read your post and realized you're correct, that would be a right hand.

Glad I could fix that OP (original Pic) up for ya

BigPolishJimmy

Damn Arborium bicycles!