ebay aluminum foot pegs

[chickenStripCharlie]

Anyone buy footpegs similar to this? (Chinese eBay specials)
I have to admit, they look pretty decent. Curious how far in the threads on them go. Don't want to buy and find out there is only like 3/16" of threads holding them on.
I tried to email the eBay guy, but he just responded with the diameter of the hole (face palm).

I'm thinking of drilling out my stock mounts and bolting them up. That way they are in the exact same location, as i don't want to full "rear sets" set up.

 

[chickenStripCharlie]

So, for anyone interested, I ended up trying these. They are not bad!

On the passenger side I cut off the original peg, ground down flat and drilled through the old weld where the arrow above is pointing. This was harder than it looks. The weld area was extremely hard to drill through. Looks like the heat really hardened that spot considerably.

The thread depth on them is probably 1" or 1.25" so should have plenty of hold.

 

[chickenStripCharlie]

For the left side, I cut the peg, shaved it down to just over 8mm on the belt sander, and then threaded the piece itself.

The OEM setup has thick rubber outside and the pegs themselves are suspended in rubber , so I assume the new ones will transmit more vibrations but they look MUCH better

 

[doc_rot]

That cast piece is probably pretty soft and seems a bit spindly for this application. Have you tried jumping on the pegs?

 

[gt alex]

I have similar on the Chinese rear sets on my bike. Mine look more spindly with a built in shear point, but I can jump on them. but I am buying some thicker (probably like yours from china) with addition of a non locking folding action.
I am expecting the next week I will post a picture.

 

[chickenStripCharlie]

That cast piece is probably pretty soft and seems a bit spindly for this application. Have you tried jumping on the pegs?

Not yet. Waiting for paint on the brackets to dry. Painted them black.

But if they are strong enough to carry the stock pegs they should do ok i would think.

Granted, I did sand them down from ~10mm to ~8.3mm in order to cut the m81.25 thread I needed.

 

[chickenStripCharlie]

That cast piece is probably pretty soft and seems a bit spindly for this application. Have you tried jumping on the pegs?

I jumped once and they folded like they're made of butter lol!

I guess shaving it down 2mm did weaken it too much. Or perhaps the stock ones being suspended in rubber takes some of the shock away. Really didnt expect them to be that weak.

Heres a pic next to another stock one I have.

Back to the drawing board. Any ideas how else to make the left side work?

 

[doc_rot]

I am kinda surprised they are selling pegs with a single 8mm bolt at all. 8mm is a little too flimsy for my taste. Remember that the effective diameter of the bolt is not 8mm, the diameter of the minor threads is probably more like 6.5mm. So you really lost more like 3.5mm. I don't know what tools you have at your disposal but you could weld a 8mm bung onto the stock pivot and then use a hardened 12.9 grade stud. If the face of the peg has somethign to torque against the 8mm stud will be instead held in shear which is much stronger. Honestly if it were me I would drill and tap those pegs for a 10mm bolt.

 

[chickenStripCharlie]

I am kinda surprised they are selling pegs with a single 8mm bolt at all. 8mm is a little too flimsy for my taste. Remember that the effective diameter of the bolt is not 8mm, the diameter of the minor threads is probably more like 6.5mm. So you really lost more like 3.5mm. I don't know what tools you have at your disposal but you could weld a 8mm bung onto the stock pivot and then use a hardened 12.9 grade stud. If the face of the peg has somethign to torque against the 8mm stud will be instead held in shear which is much stronger. Honestly if it were me I would drill and tap those pegs for a 10mm bolt.

I'm having a hard time picturing what you mean .
Do you mean cut off the portion i threaded and weld a bung on there instead into which i will screw in a stud? There would only be a few threads holding the stud in that case?

The face of the peg isn't square, so i would have to have it machined in order to be able to use a nut on that side or something like that.

I'm not too concerned with stud/bolt strength as most of them are 100,000psi tensile strength. So if that translates to even 1% shear strength (it does!), its still more than enough.

 

[doc_rot]

I'm having a hard time picturing what you mean .
Do you mean cut off the portion i threaded and weld a bung on there instead into which i will screw in a stud? There would only be a few threads holding the stud in that case?

exactly. A long as you have 12mm of thread engagement you will be OK.

The face of the peg isn't square, so i would have to have it machined in order to be able to use a nut on that side or something like that.

the axis of the threaded hole is perpendicular to the end of the peg so it is square. This end of the peg needs a surface to clamp to, it will make it significantly stronger.

I'm not too concerned with stud/bolt strength as most of them are 100,000psi tensile strength. So if that translates to even 1% shear strength (it does!), its still more than enough.

Ultimate tensile strength (UTS) is used in engineering calculations to determine how much load a structural element can handle. Not to be confused with Ultimate Tensile Load (UTL) which is specific to the diameter of fastener. UTS is not a measure of how much load a individual bolt can handle, it is applicable to the material and grade of material. For example both a 20mm bolt and a 10mm bolt can have the same UTS because they are the same grade, but have very different UTL. remember this value is for "tension" instead you are putting a lateral load on the bolt which is fixed on one end so these numbers are not relevant.

What you should be concerned with the the max toque that a bolt can handle. A 12.9 grade 8mm bolt can handle 35ft lbs of tightening torque. The torque created by the lever of the footpeg with 100lbs of force is 41lbf (i'm assuming you weigh 200 lbs and footpeg is 5" long from bolt head). You will never be able to tighten the bolt enough to overcome the force from the foot-peg. Because the bolt is deflecting over and over again I suspect it will ultimately fail from stress, how long that will take I dont know, im not an engineer. However when I'm in scenarios like this I just look at what manufacturers are doing. If you can find an example of an OEM footpeg using a 8mm bolt I will eat crow.

Bottom line, its your bike, your money, and your skin. do what you think is OK.

here is a great resource if you want to do your own research.

Metric Bolts - Minimum Ultimate Tensile and Proof Loads

Minimum ultimate tensile and proof loads for metric bolts with coarse or fine threads.

www.engineeringtoolbox.com

 

[chickenStripCharlie]

exactly. A long as you have 12mm of thread engagement you will be OK.




the axis of the threaded hole is perpendicular to the end of the peg so it is square. This end of the peg needs a surface to clamp to, it will make it significantly stronger.




Ultimate tensile strength (UTS) is used in engineering calculations to determine how much load a structural element can handle. Not to be confused with Ultimate Tensile Load (UTL) which is specific to the diameter of fastener. UTS is not a measure of how much load a individual bolt can handle, it is applicable to the material and grade of material. For example both a 20mm bolt and a 10mm bolt can have the same UTS because they are the same grade, but have very different UTL. remember this value is for "tension" instead you are putting a lateral load on the bolt which is fixed on one end so these numbers are not relevant.

What you should be concerned with the the max toque that a bolt can handle. A 12.9 grade 8mm bolt can handle 35ft lbs of tightening torque. The torque created by the lever of the footpeg with 100lbs of force is 41lbf (i'm assuming you weigh 200 lbs and footpeg is 5" long from bolt head). You will never be able to tighten the bolt enough to overcome the force from the foot-peg. Because the bolt is deflecting over and over again I suspect it will ultimately fail from stress, how long that will take I dont know, im not an engineer. However when I'm in scenarios like this I just look at what manufacturers are doing. If you can find an example of an OEM footpeg using a 8mm bolt I will eat crow.

Bottom line, its your bike, your money, and your skin. do what you think is OK.

here is a great resource if you want to do your own research.

http://[URL]https://www.engineering...imum-ultimate-tensile-proof-loads-d_2026.html

[/URL]

I may just re-drill and go with 10mm. That shoudln't be too hard to do.
The end of hte peg isn't perpendicular, trust me. it's not square i checked. The holes were drilled and tapped at an angle inside, so as to make them sit slightly up/down? i don't know.

You're definitely losing me on the torque bit. 35ft lbs of tightening torque is really not that much, so for that to be the max on a 12.9 grade bolt is a bit surprising. Ok, i'll have to read up on this some more.

Thanks

 

[doc_rot]

35ftlbs is quite a bit for a 8mm bolt. Basically the force from the footpeg will pull the bolt head to zero clamping force. which means the bolt will deflect and any deflection is bad as it causes fatigue.

 

[chickenStripCharlie]

35ftlbs is quite a bit for a 8mm bolt. Basically the force from the footpeg will pull the bolt head to zero clamping force. which means the bolt will deflect and any deflection is bad as it causes fatigue.

I get what you mean with the deflection
I will go with 10mm to start, and see about an option for a bung, or perhaps an entirely different approach.

These were not expensive so not a big loss if the approach is scrapped.

Again, thank you for your feedback and time!

 

[NoRiders]

Interested in this footpeg issue as I thought through a few options including the ebay items, or similar. As luck would have it I picked up a set of ZZR600 pegs at a swapmeet that I modified to suit the Honda pillion footpeg hangers.
So maybe, you could do the same? Find and modify a set of factory pegs.

These are hung on M12 threading and the pillion guard hoop will offer more support. (I've yet to determine the final position of the peg and have left the threading over length for now) Hope this helps?

 

[chickenStripCharlie]

Interested in this footpeg issue as I thought through a few options including the ebay items, or similar. As luck would have it I picked up a set of ZZR600 pegs at a swapmeet that I modified to suit the Honda pillion footpeg hangers.
So maybe, you could do the same? Find and modify a set of factory pegs.

These are hung on M12 threading and the pillion guard hoop will offer more support. (I've yet to determine the final position of the peg and have left the threading over length for now) Hope this helps?

Yeah, i will likely scrap and go for something OEM from another application.
I was avoiding that to start because the honda mounts put the pegs 1" or so forward of the mounting points. Almost all other ones are mounted right ONTO the mounting points so the pegs would sit 1" or so back. Not necessarly a bad thing, so i will likely just pursue this option now.

Thanks!

 

[chickenStripCharlie]

Since I already had another stock left side peg, I decided to try it again to M10 this side.

So, I will run it this way until I find a good OEM alternative to swap out on both sides.

These will do for moving the bike around and some test rides. I'll swap them out by the time bike goes on the road.