I was riding my Torker LX (which I’ve had since christmas '04) along in the park when suddenly, the left pedal fell off. I took a moment to look at the parts that had failed, and found that the threads on the pedal itself appeared to have stripped off the threads inside the crank. (see the pictures below)
Because the threads were stripped so deeply, it would seem that the pedal was not loose at the time it came off - the threads gave way for no apparent reason (I have only ridden along streets and occasionally some grass w/ this unicycle - no hops, jumps, or major traumas).
Do you think this would be considered manufacturer defect? Or simply a poorly made product?
Also, does anyone know how much it would cost to repair this? I’m assuming the crank and the pedal would have to be replaced, given the extent of the thread damage. I don’t think loc-tite would hold this in very well.
This happened to my friend’s torker that he ordered off of ebay.
I think it’s a cheap product that caused the failure. We were only learning to ride on his uni and it went the same way.
The pedals are probably fine, it looks like the crank is the part that gave way. If the threads look to be intact on the pedal, you can order up some new cranks if you’d like. People always talk about nimbus x cranks as being cheap and strong. That’s an idea.
Also, nice photos! It’s much easier to tell what’s going on when good citizens as yourself post properly focused quality photos.
In fact, the one I have is also bought off of eBay (christmas present). I was just wondering if it was simply b/c it was cheap, or perhaps if it’s a problem w/ the entire line (torker, or that model - lx).
Just to be clear though, the pedals are (or were) threaded in correctly (right pedal to right crank, etc.). If I keep the pedal, I’ll have to dig out the stripped metal from the threads of the crank (I don’t mind doing that though). Thanks for the suggestion - I generally have no idea which brands to go w/ for uni stuff - I’ll start looking for some prices on that brand.
Thx for the comment on the pics, btw I take about 5 pics of the same thing just to make sure I get it focused right w/ these damn point-and-shoot cams (I’ve got an Olympus D-550Z, I’d rather have a Canon A70 though).
I doubt it is the result of putting the wrong pedal in the wrong crank (unless of course, the labels are wrong). The pedal has an R on the surface at the tip of the end of the threads, and the inside of the crank has the letters “TOP FORGED 152 D -2R”, whereas the other crank (not stripped) has the exact same, except for an L at the “-2R” part (it’s “-2L”).
Edit: To be fair, that kind of damage could also be the result of a crash. Also, cheap parts are much easier to inadvertantly damage during installation. I once cross threaded a Magura master cylinder/hose connection largely because the (plastic) threads were so soft that it was not apparent that anything was amiss untill it was too late (at least, that is my story. . .).
At any rate, the threads on the pedal are toast too, and trying to install them on a new crank is unadvisable.
Hi my names David, and I have a problem. I strip cranks.
Not being sarcastic my name is David and I strip cranks too. I’ve done two sets of torkers, my bro’s set, and most recently my KH’s, all in one year, as long as I’ve been riding semi seriously. Pedals are very finnacky in my experience. My guess is human error. My first Torker I didn’t know there was a left and a right and put them in wrong and stripped them quite easily. Second pair, the wheel got turned around in a bike shop so it was like I was constantly pedaling backwards (thank you Klaas Bill for bringing my attention to this) and it eventually worked its way out and completely stripped. My left KH I was just to rough. The threads got crossed and it stripped. I sent it to Darren and he put in a helicoil no problems since, a bit of the helicoil came off but really no issue. Recently my other one stripped and I don’t know how. I felt the tiniest wobble, then did a 28" drop (it was directly after my personal record setting rolling hop) straight to flat with no rollout, but I am pretty skinny. I heard a metallic clank and thought I hit my rim, checked it over found nothin, went to ride and there was a huge wobble in my pedal I tightened it then it popped out like after 10 metres of riding. My brothers I think he did the same screwing it in and he worked it out a little then when mine broke and I started messing around on his I really messed it up.
Personally I doubt it wa any kind of defect but it could be. You must treat the pedal/crank interface like a woman, with care and delicately. Screw (I didn’t even think that till I typed it but I won’t go there) it in by hand and very gently to make sure the threads aren’t crossed, then tighten it with a wrench as hard as you can. I have relatively limited experience but that is what I have learned. So just be careful. Your cranks are pretty inexpensive to replace so I don’t think you should worry about repairing it. Good luck.
David
Edit: Crossthreaded doesn’t mean right in left and vice versa it is when the threads are crossed like not properly aligned, so they just like grind down on each other.
Good advice, but pedal/crank threads do have a maximum torque spec. It is quite high, but not impossible to overcome and do damage. The manufacturers should be able to tell you what the proper torque spec is.
It’s easy to cross-thread the pedal threads when installing a pedal. It’s something you always need to be careful of. Cross-threading will strip the crank threads just like the picture shows.
It’s especially important to be careful with aluminum cranks because aluminum threads are softer and easier to cross-thread. It’s also important to be careful with steel cranks too cause the picture shows that steel cranks can get cross-threaded too. The results of cross-threading are not good.
Not all pedals are equal. Pedal threads for different brands of pedals are cut differently. Some are more likely to cross-thread than others. Some cranks cranks are also the same way. Some cranks are easier to cross-thread than others just due to the way the threads are cut. I have a steel crank that is difficult to thread the pedal in. Every time I put a pedal on that crank it wants to get cross-threaded.
Put some grease on the pedal threads before installing the pedals. Grease is a good thing.
Then get the threads started by hand (with your fingers, no tools) for a couple turns while being careful to make sure the threads line up. Only after you have gotten the threads started by hand for a couple turns should you reach for the pedal wrench and start tightening. Then tighten till the pedal is snug.
Yes that happend to me, so now i must carry around my tools when i ride so that it dosnt completely fall off, i used a lot of loctite and that help for a while…
Although everyone on the forum here thinks it is crossthreading, my dad informs me that it is in fact failure of the threads. He’s very experienced w/ taking apart his bike when he was a kid, as well as w/ his own unicycle (which I learned how to ride on). He’s 99% sure it’s not crossthreading - he watched me put’em in, and they are correctly paired and lined up correctly thread-to-thread. (not to be rude or anything - he’s just really sure)
Unfortunately, we assembled it at home (me, under the supervision of my dad to make sure I did it right), instead of taking it to an authorized Torker USA dealer, so the warranty is void (plus we didn’t register it w/in 30 days of purchase - guess I should’ve read that warranty when I got it).
In any case, it can’t hurt to bug Torker and see if what they’ll do. I’m betting I’ll have to pay for the repairs myself, though.
Lessons Learned:
Read the warranty soon after buying a uni.
Get your torker unicycles assembled by an authorized dealer.
Register torker unicycles w/in 30 days.
Always check how tight your pedals are before riding. (I’m not totally sure how tight mine were, they could’ve been a little loose)
In the US, it is not legal to require customers to register their products to provide warranty support, so at least that much you can ignore. But it’s probably reasonable for them to refuse to replace possibly mis-threaded cranks.
The other possibility is that the pedal was loose in the crank. Combine that with a pedal that may have had undersized threads and a crank that may have had oversized threads. That kind of combination could result in a pedal that had enough play to rip the threads out from just riding around and drooping off of curbs.
It’s not the most likely situation, but it could happen. Parts are made with tolerances. Sometimes they’re a little undersized and sometimes they’re a little oversized.
If your pedal threaded on really easily then the out of spec pedal threads or crank threads are a possibility.
I had one pedal that would never stay tight. I determined that the pedal threads were undersized and that nothing was going to make that pedal work. I threw that pedal out (it was an inexpensive cheap pedal anyways). It happens.
You should not need to Loctite the pedal threads. The only time that I can see Loctiting the pedal threads is if you do a lot of backwards riding and have problems with the pedals working loose because of the backwards riding. Other than that there is no need to Loctite the pedal threads. I’ve never Loctited the pedal threads on any of my unicycles.
If you feel the need to Loctite the pedal threads because the pedal is coming loose then it is more likely that you have an out of spec pedal that should be thrown away before it damages the crank. Don’t try to salvage it with Loctite unless you’re willing to risk a stripped crank.
After looking at the 2 photos, it appears that this was caused by overtightening. If you look at the outter part of the crank that the pedal tightens against, there is a gouge that matches up with a scrape on the picture of the pedal.
This more than likely was caused by overtightening of the pedal. In so doing, the threads would become damaged with the least damaged threads located the farthest into the crank.
that SAME think happened to me!!!
and it was correctly screwed in by finger for like a turn then by wrench
i bugged torker 'cause it was within 3 days, and they eventually got me new ones
i now have a KH '05 Freeride and made very sure to screw them in really far by hand, and i haven’t had problems after 5 days and 10+ miles of riding w/ some 2.5+ foot drops
The most likely cause of that stripping is from riding with a loose pedal.
Overtightening is unlikely unless you used a wrench with a long handle, and really cranked down on it.
Crossthreading is possible, but if you remember being accurate when putting them on, that’s probably not the problem.
Bad tolerances on the pedal and/or crank are also a possibility, and could be part of the problem. But first I would pay attention to the riding on a loose pedal thing.
This applies to Darchibald as well. If your pedal is even a little bit loose, then you do a big drop to flat, what should you expect to happen? Loose threads are very weak.
In my experience, it’s hard to notice a loose pedal until it becomes very loose. More experienced riders may notice it right away, but I’ve seen novice riders all the time cruising around on loose pedals and not aware of it. So:
For aurum78, you could try getting Torker to replace your crank, but if they say no you’ve got to believe them that it may have been you riding on a loose pedal.
For everyone, here are a few things to do with your unicycles and pedals:
Make sure your wheel is not on backwards. Most pedals and/or cranks are labeled, but not all. Look for little Ls and Rs on the cranks or pedals.
If your unicycle is old or was acquired used, make sure you have one of each, not two of the same kind. (left and right are determined from above, facing the direction of the unicycle.
If your pedals/cranks are not labeled, unscrew them some to see which way they turn. Right turns the normal way, and left is opposite (righty loosey).
Tighten all pedals. Were any of them loose?
Pay attention to pedal and crank tightness. Ride lightly, and if you’ve felt it before you know what to look for.
Properly tightened pedals seldom come loose, unless there is a defect in the threading as John Childs described.
Get a pedal wrench. I have lots of unicycles and bikes, and I do a lot of pedal-screwing. A pedal wrench is skinny enough to fit on all pedals (my trusty adjustable crescent doesn’t fit them all), and has a long handle for getting them nice and tight.
I take about 5 pics of the same thing just to make sure I get it focused right w/ these damn point-and-shoot cams (I’ve got an Olympus D-550Z, I’d rather have a Canon A70 though).