Remember to calibrate your wheels

[.....]

Just a quick reminder to properly calibrate your wheels. Some are more picky than others, but setting a 'standard' to follow when you calibrate and/or re-calibrate a wheel, is good practice.

I noted how large a difference a little calibration makes. After playing some small ball for an afternoon, I decided to toss down one of the two mtens I brought. Both mtens are nearly identical and tire pressures were the same. After riding mten (1) for about 5 minutes, I jumped on mten (2). I immediately noticed a drastic ride feel difference. My friend was with me, so we conducted a test. We each rode one for 5 mins and then quickly hopped on the other. What first seemed like one was a lot more twitchy, wound up being a simple calibration difference. Upon further trials, I determined the power delivery was similar and overall power seemed the same. The 'twitchy' wheel also was more prone to wobble. In the end, the difference was merely the 'twitchy wheel' was calibrated a tiny bit forwards. It became evident on flat ground that the slight forward tilt (rather than level) was making the wheel seem to have more power off the line but less braking ease. I can only suspect that this 'issue' would be even more apparent on a larger and more powerful wheel.

[Tawpie]

To add fuel, I discovered that bouncing up and down on an out of calibration S18 can trigger over power alarms... which makes sense. And if bouncing will over power a miscalibrated wheel, hitting a solid bump at speed could be disastrous.

[Aztek]

Any ideas how to achieve perfect leveling while calibrating?

The wheels usually don't have flat horizontal plane on top to put a bubble level on.

Edited November 29, 2021 by Aztek

[Paul A]

Perhaps spirit level on the foot plate/pedal.

Or just look at it visually.

 

[Tawpie]

3 hours ago, Aztek said:

The wheels usually don't have flat horizontal plane on top to put a bubble level on.

You can definitely use a spirit level for fore and aft leveling, but make sure it's also vertical side to side... visual alignment with something like a door frame is how I handle side-to-side. If it's tilted side-to-side when you calibrate, you'll still be off...

I always perform the calibration, then power cycle the wheel, then check fore-aft again, repeating as necessary. (be sure to set the tilt offset to zero during this process of course)

Edited November 29, 2021 by Tawpie

[Paul A]

 

[Aztek]

42 minutes ago, Paul A said:

 

16x doesn't have flat top, nor center mark, unfortunately.

The front - back leveling is easy, one can use the pedals, but left - right at the same time is not.

[Paul A]

Have never bothered using a spirit level.  Calibrated one time by looking at it.  

Side to side balancing?  Not sure if wheel is affected by that...

Wheel is self balancing in front/back direction.  Rider does the left/right balancing when riding...

Pedal scrape before over lean switch off.

[Tawpie]

42 minutes ago, Paul A said:

Side to side balancing?  Not sure if wheel is affected by that...

This is true when riding, but during calibration if it's off side-to-side the front-to-back calibration may not be 'accurate'... this is anecdotal information, it may not actually matter how it's set side-to-side but I always aim to get it level in all directions during calibration.

[Bizra6ot]

1 hour ago, Aztek said:

16x doesn't have flat top, nor center mark, unfortunately.

The front - back leveling is easy, one can use the pedals, but left - right at the same time is not.

With pillars on a stand

[Paul A]

Ok.  Maybe use a ball bearing balance toy like what SP did in his video then.  

[mrelwood]

Most wheels have a level area under the pedals. Set two identical chairs (with a hard sitting surface) facing each other 4-5” apart. Use two longitudinal pieces of any suitable material and a bubble level to help check that the inner edges of the chairs are level. Lift the EUC and place it between the chairs, tire hanging in between. Calibrate. Golden.

 

5 hours ago, Paul A said:

Side to side balancing?  Not sure if wheel is affected by that...

Wheel is self balancing in front/back direction.  Rider does the left/right balancing when riding...

The wheel however has multiple sensors providing info about the left-right balance hundreds of times per second, which the firmware also uses for providing the front-back balance.

 Ever heard of pedal dip while turning? Most wheels don’t have that, unless their left-right calibration is bad. If it is, the wheel will dip forward when turning left, and backwards when turning right (or vice verse).

And the worst thing is that people can get accustomed to just horrible dipping, and they have absolutely no clue. I almost jumped off when I tried my friend’s Nik for the first time, the dip was that bad. Left dipped forward, right dipped backwards. Calibrated properly, issue gone. Phew.

[Paul A]

Ok, left/right, dip explanation, thanks.

[.....]

13 hours ago, Aztek said:

16x doesn't have flat top, nor center mark, unfortunately.

The front - back leveling is easy, one can use the pedals, but left - right at the same time is not.

simply clamp 2 straight boards to your pedals and place the level across them in front of the tire. The longer the boards, the more accurate your front to back level wil be as well. Laying a carpenters level across the boards, will show you front/back and side to side at same time, IF your extension boards are straight and clamped at exact position on both pedals. I choose to clamp even with outside edges of the pedal, to also inrease the accuracy of side to side leveling. On my mten, 18XL and sherm nowadays, I kinda just eyeball a bubble level as its been close enough for me.

Edited November 30, 2021 by ShanesPlanet

[Seba]

On 11/29/2021 at 6:54 PM, Paul A said:

Side to side balancing?  Not sure if wheel is affected by that...

As others already mentioned, incorrect side calibration will lead to pedal dipping in turns. But there's another important thing. If wheel will lean to one side during calibration, it may simply turn off the motor during sharper turn to the other side when riding.

[Planemo]

On 11/30/2021 at 6:31 AM, ShanesPlanet said:

simply clamp 2 straight boards to your pedals and place the level across them in front of the tire.

The only problem with that idea is that many pedals aren't at the same height as each other. They might look pretty even, but it only takes a degree or so difference. The older GW wheels were notorious for having uneven pedal heights.

I think using the bottom of the hangars as @mrelwood says is probably the best option, but you still need to support them on 2 objects that are exactly the same height, as well as have a perfectly level floor of course. Even if all thats OK, you then need to use suitable wedges to get the front/back level. This is how I did my Z10 which worked OK but it was a bit of a faff.

Side to side levelling is tricky to do accurately, depending on the wheel and where you can find a flat surface. Prob why I haven't even calibrated my Sherman - too worried about making it worse

 

[Paul A]

Would it work if:

Thread a cord through a spoke hole in the wheel, tie cord, lift and suspend the wheel off the ground, upside down, calibrate when still.

Would it be balanced along all axes, albeit upside down?

Would it totally confuse the wheel when upright again?

Or

Thread a pole through handle, lift and suspend, upright, calibrate, if handle design allows it?

[yoos]

40 minutes ago, Planemo said:

suitable wedges

a simple lifehack to precisely level your stand for calibrating is to use sheets of paper. I used two old chairs (with seats removed) as a stand and magazines+individual paper sheets under the chair legs to level the wheel precisely. Note that you should start fine-tuning when the wheel is already on your leveling stand, because the wheel is heavy and its weight may un-level the stand, especially if you are working with wooden objects.

I don't know whether the calibration of an EUC slowly drifts off as you use your wheel and whether wheels have a self-correcting algorithm to counteract this. I suspect that calibration indeed is drifting and eventually it becomes so bad that you have to recalibrate. For that reason you don't need to calibrate with extreme precision - the setting won't "hold" very well anyway.

[yoos]

3 minutes ago, Paul A said:

Would it be balanced along all axes, albeit upside down?

Would it totally confuse the wheel when upright again?

Or

Thread a pole through handle, lift and suspend, upright, calibrate, if handle design allows it?

It won't work anyways.

Both approaches are bad since they silently assume that the wheel has a symmetric weight distribution and that the center mass of the EUC is exactly above the axle (in the first approach) or exactly below the handle (second approach) when the wheel is level. Afaik, most wheels satisfy neither condition. Moreover, some wheels are unbalanced sideways in terms of mass.

[Planemo]

1 hour ago, yoos said:

a simple lifehack to precisely level your stand for calibrating

It doesn't become simple when, as you say, 35kg of wheel is loaded onto your 'level' surface, constructed as it is from two relatively high wooden chairs and compressible bits of paper/magazines.

I don't understand how you can start fine-tuning when the wheel is already on because you will need to be taking your measurements from underneath the location where the hangers will be sitting. Unless you are measuring just to the side of the hanger but then you aren't accounting for the weight of the wheel. Unless I have it completely wrong and you can provide a pic of what you mean.

[Zopper]

@Planemo You don't know in advance how exactly will the support move, bend, twist and compress before putting the wheel on it. Say you use sheets of paper under some ~10 kg chair to balance it perfectly when empty. Then you put on the 35 kg wheel - and the wood of the chair bends, the paper compresses, and you have to start balancing again. So it's easier to just skip the first balancing. It won't be ideal, but it's still more precise than doing it on empty.

[Planemo]

4 minutes ago, Zopper said:

@Planemo You don't know in advance how exactly will the support move, bend, twist and compress before putting the wheel on it. Say you use sheets of paper under some ~10 kg chair to balance it perfectly when empty. Then you put on the 35 kg wheel - and the wood of the chair bends, the paper compresses, and you have to start balancing again. So it's easier to just skip the first balancing. It won't be ideal, but it's still more precise than doing it on empty.

I think I will bail out here. Either you're missing my point or I'm missing yours

Unless you can apply a 'dummy load' to the setup and level it from on top of said load, using the wheel itself is not possible as you can't get under the hangars to place whatever levelling device you are using. You can't measure from the wheel directly as there are no level surfaces to use (except maybe the top side of the hangars, but this is a very small area to get reading from, and a right pain for left/right reference).

[Zopper]

4 minutes ago, Planemo said:

I think I will bail out here. Either you're missing my point or I'm missing yours

Unless you can apply a 'dummy load' to the setup and level it from on top of said load, using the wheel itself is not possible as you can't get under the hangars to place whatever levelling device you are using. You can't measure from the wheel directly as there are no level surfaces to use (except maybe the top side of the hangars, but this is a very small area to get reading from, and a right pain for left/right reference).

I agree that you can't put the levelling device just on the spot where the L hangers are - but any balancing you did without the wheel is thrown out the moment you put the wheel on it (unless you have a really rigid setup and/or a light wheel).

You can put the levelling device next to the wheel, which is going to be off just by the deformation of the upper surface. But if you balance first and then put the wheel on, you deformed not just this surface, but the whole construction and your previous readings are further away from the real balance of the wheel than in the "balance later" approach. And I'm far more concerned about squishing the pieces of paper used to fine-tune the balance than about deforming the fairly rigid wooden chair.

After all, you can always put on something strong enough to not deform under the weight of the wheel and big enough so you can put the levelling device. But reinforcing the whole setup is going to be much harder.

[Paul A]

Maybe pre-calibrated from manufacturer to zero by default...much easier...

 

[Planemo]

I think I get you, but yeah it's still not ideal.

The only real way of doing it to make an entirely steel structure from say box section with 5mm thick steel plates top and bottom then level it using uncompressible material.

I appreciate this isn't something most people have to hand though 

Just now, Paul A said:

Maybe pre-calibrated from manufacturer to zero by default...much easier...

 

They do...but then they can drift post-purchase...