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Pacific Cycles BSO's are engineered by idiots.

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Pacific Cycles BSO's are engineered by idiots.

Old 01-19-19, 03:10 PM
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JonBailey
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Pacific Cycles BSO's are engineered by idiots.

My "Schwinn" Discover has the pedals threaded incorrectly. It has the reverse thread on the left-hand side and the normal thread on the (right-hand) drive side when the threads should be vice-versa.

Discover is a good name for my bike because I have discovered the hard way how much different this "Schwinn" branded thing is from the Schwinn of old. I put new pedals on the other day and the one on the left unscrewed as I was pedaling down the bikeway. I had to use the 15 mm wrench I had to tighten it back up. My heart desires a Cannondale Quick 6 hybrid in the future but my budget sense says otherwise. I hope Cannondale engineers are smarter than that

I thought about switching the crank arms from one side to the other so the correct pedal threads would be on correct sides but the young "bike mechanic" at my local "bicycle project" shop assures me that can't be done.

I put oil on the pedal threads to inhibit rust which may cause them to not stay snug in place. If this pedal unwinding continues to be an issue I will cement the threads with blue Lock-Tite. I still want to see if I can't flip-flop crank arms first.

It pays NOT to "Discover" a China-made Schwinn-branded bike these days.

PS - Avoid Discover Card (Discover Bank, Salt Lake City, UT, Mormon-based scam artists) too like the plague. My lawyer is now suing them for $10,000 for violating the federal Fair Credit Reporting Act against me. I will gladly settle for $5 grand and then buy my dream Cannondale.

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Old 01-19-19, 03:18 PM
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Originally Posted by JonBailey View Post
My "Schwinn" Discover has the pedals threaded incorrectly. It has the reverse thread on the left-hand side and the normal thread on the (right-hand) drive side when the threads should be vice-versa.
I think you have it backwards.

For pedals, it should be Right-Right, Left-Left.
Bottom Brackets are the opposite (for most modern ones), Right-Left, and Left-Right.

It seems counter-intuitive for the pedals, but apparently precession is worse of an issue than simply unscrewing due to friction.
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Old 01-19-19, 03:44 PM
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Originally Posted by CliffordK View Post
I think you have it backwards.

For pedals, it should be Right-Right, Left-Left.
Bottom Brackets are the opposite (for most modern ones), Right-Left, and Left-Right.

It seems counter-intuitive for the pedals, but apparently precession is worse of an issue than simply unscrewing due to friction.
Presession? Is that like planetary gear system? So the force the bearings impart to the axle surface want to force the axles to turn right on the RH side? Vice-versa for the left?
Do bearings act like a planetary gear system, counter-rotating between the other gears? Maybe that's what my intuition missed. But what caused that Wally-World pedal to come undone on the left is still a physics mystery to me. If they were to have solid bushings in the pedals instead of rolling bearings, my intuition might otherwise prove correct. I must have forgotten about the counter rotation of bearings when I tried to make my forensic analysis.

If you were to tape or weld the RH hand pedal to its axle so they were as one unit and pedal forward, it would want to unscrew at the arm threads assuming it was right-hand thread. Same for the left.

The young buck at the bike shop said the trouble was that I had Bell pedals from Wally-World with screw-in adapters: my crank arms are 9/16ths. He then sold me a pair of new generic platform pedals sans adapters for $4.16 that somebody had donated to the shop. Still the same type of threading, left-left, right-right. He put grease on the threads and torked them down with a pedal wrench. So, far they haven't loosened up after two miles but I have a wrench in my tool kit just in case. Intuitively, ball bearing drag would seem to want to unscrew the axle studs from the crank arms while pedaling forward. The Bell kid's pedals I tried earlier unscrewed right where the stud screws into the arm, not where the adapter screws into the pedal. That adapter-to-pedal connection had blue factory Loctite on it by the way. There was no Loctite going from adapter to arm: just lubricant.

The $7 kid's pedals with two sets of adapters, the other is 1/2", go back to Walmart today along with that handlebar bag I bought that didn't work.

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Old 01-19-19, 03:47 PM
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You have found what you lose when least cost is your main priority...

after over 100 years the engineering is long settled in bicycles. now the engineering is focused on the automated machines that make the bicycle parts..


Suppose by Now, the visualization of mechanical logic is off the SAT tests...
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Old 01-19-19, 03:54 PM
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You also don't understand "precession" and how it applies to ball bearing. Yes, the correct pedal threading is right side-right handed threads, left side-left handed threads. If you were indeed to weld the pedal to it's axle then the correct threading would unscrew them, but they are not a solid unit, they have a ball bearing separating them, and it's precession applies a small torque in the opposite direction and keeps the pedals tight.

The "young buck" at the bike shop gave you the correct pedals and, assuming their bearings are at least adequate, they will stay in place.
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Old 01-19-19, 04:04 PM
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There are a few explanations out there about Precession and bicycle pedals.

https://www.purecycles.com/blogs/bic...t-it-all-means
https://blog.everydayscientist.com/?p=2655



I think the idea is that if the pedal gets slightly loose on the crank arm, then the action of pedaling will naturally tighten it (I.E. keep it tight).

That is, if your pedal bearings don't completely lock up due to cheap quality pedals.

Even though the pedal to crankset interface has long been standardized, there are still issues with the pedal internals that usually aren't reverse threaded, and over time, one side will tend to loosen until it is too loose, and if cup & cone, the other side will tend to tighten until it is too tight.

I'm surprised your mechanic didn't explain precession.
Perhaps you can go back and talk to him.
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Old 01-19-19, 04:25 PM
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Originally Posted by HillRider View Post
You also don't understand "precession" and how it applies to ball bearing. Yes, the correct pedal threading is right side-right handed threads, left side-left handed threads. If you were indeed to weld the pedal to it's axle then the correct threading would unscrew them, but they are not a solid unit, they have a ball bearing separating them, and it's precession applies a small torque in the opposite direction and keeps the pedals tight.

The "young buck" at the bike shop gave you the correct pedals and, assuming their bearings are at least adequate, they will stay in place.
Yes, I do understand that ball or roller bearings (I used to be a car and truck mechanic by trade and have observed Timken bearings rolling inside their races moving in opposite directions) are supposed to rotate about their axes in the opposite direction of the surfaces they are bearing against. I never have heard of PRECESSION before.

My bad: I overlooked the theory of bearing operation when I made a premature conclusion earlier about alleged "incorrect" threading at the factory.

I did also notice that cheap left pedal was gritty when I turned the axle while the right cheap pedal turned smoother and it was the one in fact that didn't come unwound. That grittiness is probably the culprit that loosened the left one on the ride the other day.

If the bearings get gummy, rusty or freeze then the precession theory you speak of won't hold and then my earlier intuition would prove correct.

It now seems clear to me that engineers specified pedal threading ASSUMING bearings were in good working order and functioning properly.

My pedal unscrewing issue wasn't due to incorrect threading after all but rather crappy bearings so it seems now that I have given how bearings are supposed to work some thought.

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Old 01-19-19, 04:33 PM
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Next bike purchase go to a proper bike shop and get a better bicycle..
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Old 01-19-19, 04:34 PM
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Originally Posted by JonBailey View Post
It now seems clear to me that engineers specified pedal threading ASSUMING bearings were in good working order and functioning properly.

My pedal unscrewing issue wasn't due to incorrect threading after all but rather crappy bearings so it seems now that I have given how bearings are supposed to work some thought.
In the last 20 years or so, the cheap pedals have been cheapened significantly.

You can still find pedals with metal bodies, but most of the low-end pedals have plastic bodies. I have no idea how they're expected to work as precision systems.

And, all new cheap bearings begin "gritty". I bought a Mongoose Massif for a project, and found some of the cones had actually simply been painted. Needless to say the paint wears off quickly, and contaminates the grease.

Go to a bike shop and look at some of their, say $30 to $50 pedals, and they should spin perfectly smoothly.
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Old 01-19-19, 04:34 PM
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Originally Posted by fietsbob View Post
Next bike purchase go to a proper bike shop and get a better bicycle..
Occasionally, he hits the nail right on the head.
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Old 01-19-19, 04:48 PM
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Originally Posted by CliffordK View Post
In the last 20 years or so, the cheap pedals have been cheapened significantly.

You can still find pedals with metal bodies, but most of the low-end pedals have plastic bodies. I have no idea how they're expected to work as precision systems.

And, all new cheap bearings begin "gritty". I bought a Mongoose Massif for a project, and found some of the cones had actually simply been painted. Needless to say the paint wears off quickly, and contaminates the grease.

Go to a bike shop and look at some of their, say $30 to $50 pedals, and they should spin perfectly smoothly.
Most laymen don't think of "lowly" bicycle pedals as something that might require the sophistication of an Apollo moon rocket.
They expect the things to turn with their feet and make the bike go and not fall off or stop the bike if they turn them the opposite
way with a coaster brake. That's it.

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Old 01-19-19, 05:00 PM
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Originally Posted by JonBailey View Post
Most laymen don't think of "lowly" bicycle pedals as something that might require the sophistication of an Apollo moon rocket.
They expect the things to turn with their feet and make the bike go and not fall off or stop the bike if they turn them the opposite
way with a coaster brake. That's it.
True, and the bearings probably don't have to be maintained to the same tolerances of a 10,000 RPM precision machine in a 24/7 industrial application.

But, sloppy construction can cause other problems, as you've discovered. Pedals unscrewing.

In about 45 years of riding road bikes, I don't think I've ever had a pedal unscrew.
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Old 01-19-19, 05:30 PM
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Originally Posted by CliffordK View Post
True, and the bearings probably don't have to be maintained to the same tolerances of a 10,000 RPM precision machine in a 24/7 industrial application.

But, sloppy construction can cause other problems, as you've discovered. Pedals unscrewing.

In about 45 years of riding road bikes, I don't think I've ever had a pedal unscrew.
I've got blue Loctite as backup. Used it for years to keep the spinning blade on my 3,000-RPM oscillating fan on: works like magic.

At what age did you first start riding road bikes?

When I replaced the stocker pedals, one was on so tight I needed to hit the wrench with a hammer to break it loose. The other came off much easier.

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Old 01-19-19, 05:31 PM
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Originally Posted by JonBailey View Post
My "Schwinn" Discover has the pedals threaded incorrectly. It has the reverse thread on the left-hand side and the normal thread on the (right-hand) drive side when the threads should be vice-versa.

Discover is a good name for my bike because I have discovered the hard way how much different this "Schwinn" branded thing is from the Schwinn of old. I put new pedals on the other day and the one on the left unscrewed as I was pedaling down the bikeway. I had to use the 15 mm wrench I had to tighten it back up. My heart desires a Cannondale Quick 6 hybrid in the future but my budget sense says otherwise. I hope Cannondale engineers are smarter than that

I thought about switching the crank arms from one side to the other so the correct pedal threads would be on correct sides but the young "bike mechanic" at my local "bicycle project" shop assures me that can't be done.

I put oil on the pedal threads to inhibit rust which may cause them to not stay snug in place. If this pedal unwinding continues to be an issue I will cement the threads with blue Lock-Tite. I still want to see if I can't flip-flop crank arms first.

It pays NOT to "Discover" a China-made Schwinn-branded bike these days.

PS - Avoid Discover Card (Discover Bank, Salt Lake City, UT, Mormon-based scam artists) too like the plague. My lawyer is now suing them for $10,000 for violating the federal Fair Credit Reporting Act against me. I will gladly settle for $5 grand and then buy my dream Cannondale.
I could be misunderstanding your post...But I think that the threading you have described in your first paragraph is standard. You might be suffering from user error.

Even if this isn’t user error, you should not be surprised. Your posts seem to mostly be complaints related to the fact that you bought a ****ty bike.
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Old 01-19-19, 05:51 PM
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I bought a bike for £80 in England when I was there for a few months. Within the first km of the shop, a pedal unscrewed, and I came down hard on the top tube. Fortunately, I already had 3 kids.

Unfortunately, you get what you pay for.

Another weird thing: It had Dunlop valves:

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Old 01-19-19, 07:32 PM
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Originally Posted by Koyote View Post


I could be misunderstanding your post...But I think that the threading you have described in your first paragraph is standard. You might be suffering from user error.

Even if this isnít user error, you should not be surprised. Your posts seem to mostly be complaints related to the fact that you bought a ****ty bike.
Ditto on that one.
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Old 01-19-19, 07:35 PM
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Maybe the engineers engineered the product for the people that would buy it.
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Old 01-19-19, 07:45 PM
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Tandems often have the front crankset reversed. I think there are people who have tried using standard cranks, and absolutely must loctite their pedals in place.
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Old 01-19-19, 10:09 PM
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Originally Posted by CliffordK View Post
Tandems often have the front crankset reversed. I think there are people who have tried using standard cranks, and absolutely must loctite their pedals in place.
While I would never use a wrong threaded crank on a customers bike I run a tandem set up with just that. The pedals are Speedplay Xs. I do keep the pedals pretty tight and make sure that the bodies spin freely. But I don't use a thread locker compound and in about 20 years haven't had a pedal loosen. I consider this to be one of those "don't do as I do but do as I say" moments. Andy
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Old 01-20-19, 12:16 AM
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RE Tandems

Originally Posted by CliffordK View Post
Tandems often have the front crankset reversed. I think there are people who have tried using standard cranks, and absolutely must loctite their pedals in place.
Cross over drive they look like they're back wards , but the pedal threading is done relative to their position... R & L ..


Left side has 2 chainrings , so front and back people both power the back wheel ...

( Florian Schlumpf , for example.. in his mountain and speed drive gearbox cranks uses same arms , pedal thread is different )

likewise on unicycles..








....





.....

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Old 01-20-19, 01:48 AM
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Wait, so the left side pedal is tightened clockwise?
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Old 01-20-19, 02:42 AM
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Mr. Bailey, are the college girls at Jacksons near Albertsons/Bronco Stadium still as baffling and confidently unattainable walking past the taco place next door?

Assuming the I think Del Taco is still there, been maybe three years.

Enquiring cyclists want to know.

The wonders of Foo await. For whatever reason.

Meh. I'm old.
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Old 01-20-19, 02:47 AM
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Originally Posted by Gecko77 View Post
Wait, so the left side pedal is tightened clockwise?
If they were threaded the same or the opposite way you would unscrew them. They are what they is so you keep them on.

(Loctite, Egad,)
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Old 01-20-19, 03:05 AM
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Originally Posted by Rollfast View Post
If they were threaded the same or the opposite way you would unscrew them. They are what they is so you keep them on.

(Loctite, Egad,)
So if the non-drive left side pedal, pedals counter clockwise, but the bolt is
threaded to fit clockwise, the pedal would unscrew over time? If so, I think I found the answer to my own post.
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Old 01-20-19, 06:02 AM
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Originally Posted by JonBailey View Post
Presession? Is that like planetary gear system? So the force the bearings impart to the axle surface want to force the axles to turn right on the RH side? Vice-versa for the left?
Do bearings act like a planetary gear system, counter-rotating between the other gears? Maybe that's what my intuition missed....:

If you were to tape or weld the RH hand pedal to its axle so they were as one unit and pedal forward, it would want to unscrew at the arm threads assuming it was right-hand thread. Same for the left...:. Intuitively, ball bearing drag would seem to want to unscrew the axle studs from the crank arms while pedaling forward.
The reason for crank threading is NOT the bearings, not even with any planetary gear action.
In any healthy pedal, bearing friction is too low to overcome even very minor torque, regardless of for how long it’s applied.
The threaded end of the pedal axle, is by definition smaller in diameter than the crank arm hole. If you stick a pin in a slightly larger hole, and roll it along the inside, the pin will turn. Pedals are threaded to use this turning motion to draw them tighter. Have another look at that animation CliffordK posted.
If pedal axles had a conical seat against the crank arm - like lug nuts - they wouldn’t need to use the reversed thread. Properly torqued, they’d stay on because they would no longer be able to wiggle and roll.
Why pedals despite this do manage to come off occasionally, I have no firm opinion about.
Maybe there is a threshold value where too little torque and/or poor production tolerances can cause a pedal to basically rattle loose.

Last edited by dabac; 01-22-19 at 04:12 AM.
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