Notch in Bionx axle

`sandorszabo,
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sandorszabo,

I don't know why you think your post would be moderated because our moderators are here to help, the only reason you get moderated on this site is for inappropriate language or graphics in a post.

Now for your question.

I think the following image is the one you are talking about-

It seems to me that you can only turn the axle to vertical if you have vertical dropouts on your bike. After thinking about this a while and studying the image it seems they want to be sure the the axle is turned so it has no play in it. If the axle has any slop or play it may spin and destroy the dropout. Here is a picture that may help-

As you can see the axle wants to spin in the opposite direction of the wheel so if you make sure it is already as tight to the dropout as possible it should minimize the ability of the axle to tare out the dropout. Hopefully there will not be as much slop in the real dropout, I enlarged the slop factor so it could be seen. I would say if you turn the axle so it matches this image you should have no problems.

Chas S.
My Bicycle Pages

Well hello Everyone!

Sandorszabo, that was a good question. I've been searching around for some info on the very same thing. Chas, great diagram! I've owned an E-vox 140 with a BionX PL350 installed for about a year. It was installed by the BionX rep himself. It worked fine until not so long ago, when I started to notice some extra drag on the bike. Funny I missed it, but I found that the wheel was crooked. I straightened it out again (failing to realize the position of the axle notch) and thus, quickly became crooked again. As I have fiddled with it again and again, the axle threads and frame around them have become worn, and I haven't checked the spoke tension in a while. Finally I've got the wheel on as straight as I can get it, and the axle notch is propped up to keep everything solid from the torque.

The questions I have are as such: Has anyone had any problems keeping nuts tight on the bionx axle? Because of the weight and torque of the motor, do the spokes require semi-constant check-ups? Will these things ultimately affect the position of the wheel? And of course, any ideas on how I might rectify a crooked wheel?

Thanks everyone, glad there's a site out there for questions like these! (Of course, this is V for voltage, not B for Bionx axle nuts!)

Gus

As deep as I go, is as deep as I've dug.

The notch must be located in the six o'clock position. The torque sensing mechanism within the hub motor requires this. If the notch is rotated 90 degrees to 3 or 9 o'clock, it will not sense your pedal effort. This is not important if you only use a throttle. It is critical if you use the pedal assist modes.

In order to adjust the position you must pull the metal part with the dropout key off of the axle. This can be done with a custom puller from Bionx. All dealers should have this puller for their own use. When installing on a hybrid the dropouts are more horizontal, on a mountain bike they are more vertical. Dealers must adjust for this variation when installing Bionx kits.

You can also do this yourself with a tool from most auto parts stores. Google "3 jaw puller" look for a smaller one. The puller must be kept vertical. I have done this with a puller from Advance Auto Parts. It was slightly tricky to position the wheel and the puller, having a friend help would make it easier, but with some care it will work. Striking the center plunger bolt end with a mallet when the puller is fully tensioned also helps to loosen the part. It will come off with a sharp "pop." Then position everything on the bike. When you retighten the axle nut, the part with the key will seat itself automatically.
En szeretlek Budapest.

Hi Silentflight,

Welcome to the V-is-for-Voltage Forums!

That sounds like some very helpful advise.
Perhaps we can get one of our Collaborative Handbook gurus to add this to the Bionx Kit section.

We can use all the the helpful tips we can get here.
Your input is appreciated! Thanks

Regards,
VT-01
Moderator

Moderators are volunteer members of our community who help keep V is for Voltage Forums running smoothly, and answer support questions.

After reading the post from Silentflight I retract my previous information but it was the best I could gather from the manual. I think Bionx needs to be told their manual needs to be updated to include how this operation is accomplished.

Special thanks to Silentflight for your help.

Chas S.
My Bicycle Pages

Just in case there is any miscommunication, the tapping with a mallet should be done on the end of the central plunging bolt of the 3 jaw puller once you have already brought it to a high tension, assuming that has not already released the part. If you haven't, try a google image search for "3 jaw puller" once you see one, you'll know exactly how to use it.

The dealers need to adjust for the variation in the angle of the rear dropouts on different bikes. As described, the notch is kept vertical by loosening the piece with the key, then it is possible to freely rotate the axle within such that the notch is at the 6 o'clock position, that's all there is to it, but it's critical to making the torque sensor work. It will otherwise underestimate torque by cos(angle) where the angle is measured between a vertical line and the position of the notch. At + or - 90 degrees it essentially loses all ability to sense torque.

V Kerulet

Yes, having the notch in the correct position helps the Bionx mechansim differentiate the torque you apply through the pedals versus the bumps you hit on the road. That's what the Bionx engineer said when i asked him about it.

I have recently fitted BionX 350pl. Initially worked well but now experiencing motor going on and off every second or so on all levels of assist (but OK with accelerator). Seems this may be because notch in axle has somehow moved 60 deg away from 6 oclock. The instructions show use of special puller to pull off the 'blocker' (which fits in the dropout) but not much use if you don't have one! I was therefore very interested to read the above and the suggestion of using a 3-jaw puller instead. I have found some via Google but they are not cheap! Anyone managed to find inexpensive tool or found other way of (safely) loosening the blocker so it can be twisted back into alignment with the notch?

PS I'm located in the UK.

Steve

Thanks for your suggestions - i will look in tool stores in UK to see what I can find (we don't have the ones you mention). Also, no BionX dealer in UK (I imported mine from Nycewheels in NY). Hence the problem.

Steve

There is a good video on youtube regarding installation. http://www.youtube.com/watch?v=M5evWA1yIDk

...Bionix dealers are supplied with the ... puller. Alignment of the notch is maintained by a tapered shaft ... held in alignment by the friction of the shaft. The Bionx axle nut must be tightened with much more torque than your average bicycle ...

This pretty much nails it. I borrowed one such tool from a local BionX dealer and it really makes the job easier. You're right about getting it tight. Really tight!

I just want to add that the key needs to fit snugly into the drop-out slot. If the drop-out slot is wider than the key it will inevitably move at some point, and a few degrees is enough to make the assist and generate actions noticeably less smooth. Also, diagrams elsewhere in this thread show the "correct position" of the loose key in the slot, but realize that hitting full generation mode going down a steep hill puts significant, opposite torque on the shaft. The key can turn backwards by however much slack is in the slot. The back-and-forth action will eventually loosen the wheel.

I installed a sheet metal shim on the inside of the drop-out slot so the key won't budge.

The notch must be located in the six o'clock position. The torque sensing mechanism within the hub motor requires this. If the notch is rotated 90 degrees to 3 or 9 o'clock, it will not sense your pedal effort. This is not important if you only use a throttle. It is critical if you use the pedal assist modes.

In order to adjust the position you must pull the metal part with the dropout key off of the axle. This can be done with a custom puller from Bionx. All dealers should have this puller for their own use. When installing on a hybrid the dropouts are more horizontal, on a mountain bike they are more vertical. Dealers must adjust for this variation when installing Bionx kits.

You can also do this yourself with a tool from most auto parts stores. Google "3 jaw puller" look for a smaller one. The puller must be kept vertical. I have done this with a puller from Advance Auto Parts. It was slightly tricky to position the wheel and the puller, having a friend help would make it easier, but with some care it will work. Striking the center plunger bolt end with a mallet when the puller is fully tensioned also helps to loosen the part. It will come off with a sharp "pop." Then position everything on the bike. When you retighten the axle nut, the part with the key will seat itself automatically.
En szeretlek Budapest.

Another option that worked very well for me was a $14.00 Canadian Tire Tie Rod puller. It's the same type of puller that the Bionx one is but a little smaller.

So like me you may have to pull the wheel off first as apposed to the video showing them loosening it while still on the bike. It does make for some tricky work to stabilize the wheel as you torque on the puller which is why the video suggests leaving the wheel on the bike. However I could not get this to fit that way. Off the bike it fits like a glove.
Be very careful however as you are dealing with the threaded end on the axel and can easily damage your threads. I loosened the axle nut so that it covered the end of the axle and then put a small wrench handle in between the plunger of the puller and the nut so that the plunger would not scar the end of the nut or key on the end of the axle. It took a frightening amount of torque before the inner key let loose with some violence. All is well now but I don't want to tempt fate too often with this procedure.

Hello all,
How sensitive do you think the angle is. Is it as crude as 3 o'clock vs 6 o'clock (90 degrees)or do smaller shifts matter too. For example, if the notch is at 5.5 instead of 6 o'clock is that enough to be concerned about?

If these smaller discrepancies matter then I wonder if it could not be compensated for with code 0008 (by bumping up the assist level a little)?

It is fantastic to have a site like this so loaded down with information.

cheers,
ken

When I first took a demo ride on a BionX setup bike, the dealer had the notch misaligned... closer to 5 o'clock, I think. Although I could tell I liked the basic setup, I also thought something was strange. It didn't respond that dependably, and it would also seem to speed up going over some bumps (not a good thing). When it's off, it means that the sensor isn't seeing all the force on the chain, because the force vector is rotated. However, it does see some up/down forces, which it normally shouldn't. I'd go to some trouble to get it reasonably closely lined up.

It matters. Really matters in my opinion.

I had mine set to just slightly back of 6 o'clock and it was jerky and awkward. Now it's set to ever so slightly (almost immeasurably slightly) forward of 6 o'clock and it's way better. I think you have to set this very accurately. Once you do, crank it really tight.The torque on this motor will throw off the setting if it is not really tight.

It really does matter that it is 6'oclock. otherwise the assist happens at the wrong rotation angles when peddling. Take it to your BionX dealer and they can fix it quite quickly.

I just installed a PL350 kit on my Trek 7500 last Sunday. The dealer used the special BionX tool to loosen the
special spacer so I could rotate the motor shaft, but I installed the wheel with the bike upside down. I just
checked it last night and it was a few degrees off. I removed the wheel and popped the spacer off with a small
two jaw puller from Sears. Reinstalled the wheel and put the bike back on it's wheels and then aligned the notch
using a large screwdriver. The deal is that once you torque the axle nuts to 30 ftlbs, the spacer is now jammed
on the wheel (as it should be to keep the motor from spinning and keep the notch aligned).

If the notch is out of position it really affects the smooth operation of the assist. With the notch pointing a little back of straight down the bike was jerky and couldn't seem to decide what to do in situations where you were pushing just a little. I found the best overall performance with the notch just slightly forward of straight down. I hypothesized that this made it think it was going uphill a bit (I may be anthropomorphizing a bit too much here). Once the thing has been torqued properly the alignment nut will be rather difficult to remove. I don't have a feel for 30 ft-lb. but "really bloody tight" compared to a normal bolt-on wheel describes it.

This motor kicks quite a lot and the torque may move the notch if it's not tight. The other thing, the nut has an aggressively structured grip surface which will kind of alter the geography of the contact surface (inside the dropout) after a while. This has a positive effect of making re-alignment after removal of the wheel quite simple, but only if you had it right the first time.

I hope you enjoy the PL350. It truly is a marvel of technology. Once set it becomes a natural extension of yourself.

The dealer where I bought my PL350 system told me that the wheel nuts must be torqued to 30 foot pounds. I know that the wheel nuts on my cars call for 80 to 95 foot pounds of torque so 30 ft/lbs is not exactly what I would call "really tight".

When I use the brake, the motor feels like it's being thrown into reverse and there is a bit of a thump or "hammer action" occurring. Fortunately, I have a torque wrench and when I go to the dealer, he also uses his torque wrench to quickly check my rear wheel nuts. This back and forth "hammer action" by the motor switching back and forth from "assist" to "generation", may tend to make the nut become loose and possibly throw the notch position out of alignment. I have checked the torque and it appears to need tightening every so often. Considering how much my PL350 cost, the added expense of a torque wrench for maintenance is pretty minimal.

I have checked the torque and it appears to need tightening every so often.

Be careful that you don't over torque your system. Everytime you use the torque wrench the nut will move a little, becoming tighter (over torqued). If you want to check the torque, you must slacken the nut off first, and then re-torque. OR....

Have you every wondered why trucks and buses have those yellow fluorescent pennants all lined up and pointing to the next nut on the wheel. Well it's so you can see if a nut is loose without using the torque wrench to test (which would lead to over tightening). A loose nuts pennant would be out of alignment.

I tough this picture would make the process clearer.

On question I still have tough. Do you need to remove all nuts that are screw on the axle (3 in total) to remove the blocker with the special tool?
Is the blocker screwed in there also?!?

Just don't want to destroy the BionX ;)

Watch the youtube video that Dennis pointed out to us earlier in this thread.

http://www.youtube.com/watch?v=M5evWA1yIDk

You can see in the video how they use this puller. They did remove the locking nut on the "notch" side of the axle. The "gear cluster" side of the axle is not shown but it appears to me that the outer locking nut is loose so that they can slip the entire wheel assembly in and out of "dropout" of the bike frame.

Here is an excellent quote from "tunnsie" from earlier in this thread:

"So like me you may have to pull the wheel off first as apposed to the video showing them loosening it while still on the bike. It does make for some tricky work to stabilize the wheel as you torque on the puller which is why the video suggests leaving the wheel on the bike. However I could not get this to fit that way. Off the bike it fits like a glove.
Be very careful however as you are dealing with the threaded end on the axel and can easily damage your threads. I loosened the axle nut so that it covered the end of the axle and then put a small wrench handle in between the plunger of the puller and the nut so that the plunger would not scar the end of the nut or key on the end of the axle. It took a frightening amount of torque before the inner key let loose with some violence. All is well now but I don't want to tempt fate too often with this procedure."

I too am nervous about doing this kind of procedure for the first time. You do NOT want to damage the end of the axle. According to the BionX website, there are 3 dealers in Trois-Rivieres. I would go to one of them and see if they would show you how they do it.

Will check with a dealer in my area. Meanwhile, once you have removed the counter-couple, how do you slide it back? Just by pushing it back in?

Thanks

Claude

I find this topic very interesting, as i had the exact same questions when i first installed my BionX kit, after reading the 1 page "manual"

Interestingly enough, i found it was not really necessary to have it aligned in any specific order.
As i ride a MTB the drop out is exactly facing 6 o'clock
However the little edge that position the sensor inside the hub, was all over the place, it always changed position every time i changed the tire.
So wondering about what the manual says, it didn't make much sense, and I asked my LBS, the answer was pretty much the same it's not necessary unless you are riding a bike with a drop out that is horizontal or diagonal, then you'll need to adjust it, otherwise, there's no need to change it.

but what gets me the most is that from what the manual says, i should have been having sensor problem as you guys described, but i experience nothing of that sort, so i tend to believe more what my LBS says vs. what the manual says, as i've seen that setting point at any position you could imagine, and it has no given me any problem.

either they made new changes on the 2009 version, or that is no longer in use, and the manuals are just obsolete.

my sensors are working perfectly when pedalling on any Assist level.

I will soon post pictures of the bike.
Mine is not totally at 6 oclock (6h25) and still, everything works perfectly. So far I have save a lot of time using this BionX kit. (8min50sec instead of 14min sweating...).

I will keep you updated, experiencing the whole concept here so far.

I'm wondering about the spike tension thing altough, I'm not sure how to check that.

Claude

Andrew, for your future reference, 30 ft-lb is the torque you put on a wrench with a foot long handle and push 30 lbs, or a wrench with a 6 inch handle that you push 60 lbs, or a 2 foot long wrench (a pipe on the end of it called a "cheater') that you push 15 lbs.

I really appreciate all the effort and time that has been taken to explain this unique assemble of the servo system in the wheel. I will be getting in the mail an LP350 kit and , ofcourse, back in the hinderland of West Virginia there are no dealers. See my thread, "Good Bye Grandpa".