Kalkhoff speed sensor problems

[gordonmx]

Hi all. I just picked up my new Kalkhoff Impulse Ergo XXL. I had some problems with it right away: the magnet mounted on a rear wheel spoke is hitting the speed sensor placed on the frame next to the rear wheel. I took the bike right back for an adjustment. It seemed to be fixed in a short test in the parking lot. But soon after resuming my trip home I heard that "thunk thunk thunk" from the rear wheel. The problem seems to become particularly obvious at higher speed and after I've been cycling for more than a few minutes. However, once I start hearing the noises, it doesn't go away until I stop. I have checked and when I look at the clearance between the sensor and the magnet, it seems there's a sufficient gap that there should be no contact. But there is, unless something else is causing the noise.

(I didn't have time to go back for a second time today, as the mechanic had left.)

This is not the first time I've had a Kalkhoff bike. The Impulse Ergo is a replacement for an earlier 2012 Kalkhoff Agattu XXL which was declared not usable by my retailer's mechanic. The fatal issue was that the area of the frame where the rear wheel is secured had worn down, making it impossible to lock the wheel in place. This was said to be caused by having taken the rear wheel off and putting it back on too many times. One of the earliest problems I had with that bike was this same issue of the spoke magnet hitting the speed sensor.

From my experience, there are a couple of issues involved with this particular problem. There's the issue of the wheel being properly centred, then there's the question of whether the speed sensor is close enough to the spokes (or too close) - with some spacers that can be removed under the sensor. There is another problem if the magnet is too far from the sensor - the motor assistance level drops to a low level and the handlebar controls flash. I learned all this from my experience with the Agattu.

To any of you who say this is an easy fix, I should say that I've concluded that I am not able to properly install the rear wheel on Kalkhoff bikes, as I can't seem to centre the wheel, ensure sufficient chain tension, keep clear of the sensor and tighten the wheel all at the same time. (Especially as the wheel bolts tend to get stripped if over-tightened. I don't have a torque wrench, nor do I know the correct tightening specifications for the bike's bolts.)

I don't know why I keep on having this problem with Kalkhoff bikes. I also don't want to do anything that might damage the bike. Can anyone give me some tips on how this should be handled? Why would the spoke magnet only start hitting the sensor only at higher speeds and after a certain amount of time?

I look forward to any input.

Mike

 

[rsyme]

Sounds like the wheel nuts are not properly secured. I have an Impulse ergo and whenever I adjust the wheel I have to adjust the magnet position as the sensor seems really sensitive to the magnet position. It does give the check speed sensor message on every such occasion, but this goes away after about 100 yds! I haven't has any nut stripping issues - at least not yet!!!

Robbie

 

[Alan Quay]

I seem to remember others having issues with Kalkhoff rear wheel/dropouts/thread problems.

 

[tillson]

To any of you who say this is an easy fix, I should say that I've concluded that I am not able to properly install the rear wheel on Kalkhoff bikes, as I can't seem to centre the wheel, ensure sufficient chain tension, keep clear of the sensor and tighten the wheel all at the same time. (Especially as the wheel bolts tend to get stripped if over-tightened. I don't have a torque wrench, nor do I know the correct tightening specifications for the bike's bolts.)

I don't know why I keep on having this problem with Kalkhoff bikes. I also don't want to do anything that might damage the bike. Can anyone give me some tips on how this should be handled? Why would the spoke magnet only start hitting the sensor only at higher speeds and after a certain amount of time?

I look forward to any input.

Mike

The wheel may be moving in the dropouts due to not being sufficiently tight. A slight movement at the centre of the wheel will be exaggerated across its radius and may be enough to cause the sensor interference that you describe. At higher speeds the chain generally transmits more power and could be pulling the wheel out of line.

When setting the wheel, leave the chain off so that you aren't fighting the tension. Then connect / join the chain when you are happy with the alignment. A torque wrench may be a good investment for you, especially if you have damaged the frame and are worried about stripping the axle and/or wheel nuts. Lots of screws and bolts fix into aluminium on modern bikes, so it's easy to incorrectly tighten them.

 

[RobF]

I seem to remember others having issues with Kalkhoff rear wheel/dropouts/thread problems.

Yes, Alex for one.

He's not been on here since August, so may have to be put in the retired section.

My view is the Kalkhoff dropouts are designed for cassettes/derailleurs and are too spindly for hub gears.

Problem my be exacerbated by the power of the crank motor.

The dropouts on the Rose frame are beefier, and the shiny metal plate which the hub gear axle sits in is also thicker than the metal on the Kalkhoff.

 

[JohnCade]

The Kalkhoff rear wheel fixing is a problem. They seem to have finally realised that the forward sloping dropouts are not suitable for crank drives with all their extra power and have redesigned the dropouts on the latest bikes.

I had the same problem with the wheel pulling forward under load as have others, and initially I fixed it by cleaning all the contact surfaces, recutting the non rotation washer and tightening to just under the max recommended torque. OP the recommended torque is up to 45 Nm or 33 ft/ lbs in old money - you can download a manual from the Kalkhoff site.

That worked for a while and the chain didn't move. But when the time came to adjust it for wear again I saw that the dome nuts had stripped. So clearly Kalkhoff recommended max torque is too high, and yet the wheel won't stay in place if it's not that tight...

I decided at the point that with the chain needing to be adjusted for wear regularly with all the power going through it in the hilly area where I live that the alloy dropouts would be scrap in no time. So I bought a Batavus chain tensioner like this:

https://en.hollandbikeshop.com/branded-bicycle-parts/batavus-bicycle-parts/batavus-chain-tensioner/

I was a bit doubtful as to whether it would hold okay because although it's designed for non rotation washers the contact area is smooth stainless. Not the grippy N/R washer. I torqued it all up to 25 ft/lbs, well below stripping torque and it seems to be doing the job. I bought the 62 mm long one because the site as usual with online shopping gave so little detail. But the shorter one would have done I think. It makes wheel adjustment a lot easier too. But I only bought one and put it on the drive side, one on each side would make wheel adjustment even easier.

 

[tillson]

The Kalkhoff rear wheel fixing is a problem. They seem to have finally realised that the forward sloping dropouts are not suitable for crank drives with all their extra power and have redesigned the dropouts on the latest bikes.

I had the same problem with the wheel pulling forward under load as have others, and initially I fixed it by cleaning all the contact surfaces, recutting the non rotation washer and tightening to just under the max recommended torque. OP the recommended torque is up to 45 Nm or 33 ft/ lbs in old money - you can download a manual from the Kalkhoff site.

That worked for a while and the chain didn't move. But when the time came to adjust it for wear again I saw that the dome nuts had stripped. So clearly Kalkhoff recommended max torque is too high, and yet the wheel won't stay in place if it's not that tight...

I decided at the point that with the chain needing to be adjusted for wear regularly with all the power going through it in the hilly area where I live that the alloy dropouts would be scrap in no time. So I bought a Batavus chain tensioner like this:

https://en.hollandbikeshop.com/branded-bicycle-parts/batavus-bicycle-parts/batavus-chain-tensioner/

I was a bit doubtful as to whether it would hold okay because although it's designed for non rotation washers the contact area is smooth stainless. Not the grippy N/R washer. I torqued it all up to 25 ft/lbs, well below stripping torque and it seems to be doing the job. I bought the 62 mm long one because the site as usual with online shopping gave so little detail. But the shorter one would have done I think. It makes wheel adjustment a lot easier too. But I only bought one and put it on the drive side, one on each side would make wheel adjustment even easier.

View attachment 10026

John, the 45Nm torque figure comes from the Shimano data sheet, it's not a Kalkhoff derived torque value. I have heard of other people having problems with stripped threads and wheels moving in the dropouts, but I've always used a torque wrench and never had either problem on my Kalkhoff.

 

[Croxden]

So it seems another make off my winter bike list.
It'll be easier changing the weather at this rate.

 

[JohnCade]

John, the 45Nm torque figure comes from the Shimano data sheet, it's not a Kalkhoff derived torque value. I have heard of other people having problems with stripped threads and wheels moving in the dropouts, but I've always used a torque wrench and never had either problem on my Kalkhoff.

Maybe so but I took it from the Kalkhoff manual and I used my torque wrench too of course. That's how I could torque it to just below the recommended max.

I think it's a problem which started with the Impulse motor since that's a lot more powerful than the Panasonic. It's also most common with bikes used in hilly terrain where there is a lot of power going through the drive chain in a lower gear on a steep hill. When I mentioned it to the bloke in 50 Cycles the other day he knew all about the issue, and as I said they've changed the rear dropouts on the latest bikes which are more powerful still.

 

[tillson]

Maybe so but I took it from the Kalkhoff manual and I used my torque wrench too of course. That's how I could torque it to just below the recommended max.

I think it's a problem which started with the Impulse motor since that's a lot more powerful than the Panasonic. It's also most common with bikes used in hilly terrain where there is a lot of power going through the drive chain in a lower gear on a steep hill. When I mentioned it to the bloke in 50 Cycles the other day he knew all about the issue, and as I said they've changed the rear dropouts on the latest bikes which are more powerful still.

Yes that's a good point, my panasonic motor is not as powerful as the newer Impulse motor which is now fitted.

 

[gordonmx]

Dear all,

Thanks for your replies. So that's my conclusion: the rear wheel wasn't properly installed and it moved/is moving. A visual inspection showed that the rear wheel appears to be off-centre with respect to the fender - on the right side there's a lot more tire. (That's the side opposite from the speed sensor and magnet).

I can confirm that my 2015 model still has forward facing dropouts. Just like the 2012 version bike it replaces.

@JohnCade I've taken your advice and ordered a pair of the short wheel tensioners from the Holland Bike Shop. I live in a hilly area and have already experienced a bike's alloy dropouts/frame wearing out because of constant wheel movement/reinstallation and adjustment. I honestly don't know why Kalkhoff doesn't offer its own brand. t hope you're right that the short ones will fit. I see there are three variations (Batavus Chain Tensioner 62 Mm Bolt 45 Mm; Batavus Chain Tensioner 45Mm Bolt 30Mm and the Batavus Chain Tensioner Short Stainless, which the site says are made of iron.) I ordered the third kind. My bike is staying off the road until these parts arrive and are installed (to avoid multiple long trips to the bike shop). A bike shop installed a pair on my then-soon-to-be defunct Kalkhoff Agattu, so I know something like this can be fitted.

You noted how this problem (the wheel moving, the stripped bolts) seemed to start when Kalkhoff moved from a Panasonic motor to their Impulse unit. Well, imagine the effect of the even-more powerful Impulse 2.0 motor.

On the subject of torque values and torque wrenches, Kalkhoff does make the torque values available in its 2012 manual, downloadable from their site at: http://manuals.derby-cycle.com/manuals/kalkhoff/en_kalkhoff_2012_20140818_09.pdf, on page 64. The rear axle nuts are to be tightened to 30 N-m and the front ones to 25. 30 equates to 22.126864479 foot-pounds, so even less tight than you now have it. However, I don't think the bike workshop at the store where I bought my bike even uses a torque wrench.

One more thing: how on earth do you "recut the non-rotation washer"?

@RobF What's a Rose frame? That rear dropout looks pretty cool.

@tillson Thanks for your analysis. I've relayed your recommendation on how to install the wheel without fighting the tension. We'll see if that gets it right.

Once more, thanks to everyone who replied.

 

[JohnCade]

i hope the shorter ones will fit okay. I did roughly measure where my longer one sat when fitted and I think they will. I got the longer one to be sure and that one is stainless. I'm not sure about the shorter one...

These sites are useless when you need even basic information. When you can't see and handle something you need more info, but every year online in shops there is less.

I took the torque values from the later version of that pdf but the chapter on non electrical stuff is identical. On page 28 it gives the tightening torque for the dome nuts on the Nexus hub specifically as 30 Nm to 45Nm. I tightened to just under the higher number but that proved on undoing them to re adjust the wheel later to be too much for the nuts. It might be a misprint, but that's unlikely since tilson says that's the figure on the Nexus data sheet as well. The torque data sheet on the later page you refer to is a more general one.

I agree these pulls or something like them really should be fitted. They also make adjustment easy without needing to worry about fighting chain tension. Just like adjusting a motorcycle wheel. According to the latest Kalkhoff brochure they have redesigned the dropouts and beefed them up. Are your's identical to the old ones then? BTW I noticed Aldi had a cheap torque wrench for sale last week.

 

[RobF]

@RobF What's a Rose frame? That rear dropout looks pretty cool.

Rose is the brand of bike.

German, like your Kalkhoff, but family owned rather than part of a conglomerate.

They aren't doing ebikes at the minute, but if you look under 'travel trekking and city bikes' you will see similar frames.

Rose is often worth a look for parts/accessories, they reckon to keep x million lines in stock, although postage charges can make single items uneconomic for a UK buyer.

http://www.rosebikes.co.uk/

 

[JohnCade]

So it seems another make off my winter bike list.
It'll be easier changing the weather at this rate.

Just noticed this post. I don't think this problem is peculiar to Kalkhoffs. On another thread a few months ago some other people had the same problem with Bosch motored bikes. Can't remember the makes though. It's more a problem with the forward facing dropouts which are commonly fitted with hub gears and the extra power of pedelecs I think. Though single speed riders with horizontal rear facing dropouts have had similar problems.

 

[tillson]

Here is the data sheet for the Shimano Alfine 8 speed hub. It provides torque values for the rear wheel nuts. There will be a similar data sheet for your rear wheel set-up.

http://cycle.shimano-eu.com/media/techdocs/content/cycle/SI/Alfine/SGS501/37N0A-001_SG-S501-EN_v1_m56577569830638091.pdf

 

[JohnCade]

Yes the illustration and the torque numbers in the Kalkhoff manual on the wheel fitting page is lifted from this Shimano data sheet. But as I found out just under the given max of 45 Nm was too much for the nuts.....

Unless they had been over tightened before I bought the bike of course. It was only eight months old and little used but the wheels had been off to upgrade the tyres. There was no visible damage to the nut threads though.

 

[tillson]

Yes the illustration and the torque numbers in the Kalkhoff manual on the wheel fitting page is lifted from this Shimano data sheet. But as I found out just under the given max of 45 Nm was too much for the nuts.....

Unless they had been over tightened before I bought the bike of course. It was only eight months old and little used but the wheels had been off to upgrade the tyres. There was no visible damage to the nut threads though.

Over tightening is a possibility and I have to confess to having done that (set my torque wrench incorrectly). The 45 Nm figure is close to stripping the thread inside the nuts and it feels unnaturally tight to me. But the wheel holds firm. This could be dule to the lower power output of my bike as you mentioned earlier. But my guess is that some people aren't tightening them as much as they should be doing.

I don't know what the newer bikes are like, but the washers on my rear wheel are serrated and bite into the aluminium of the drop out lugs. This provides a kind of mechanical fixing in addition the the friction between nut, washer and lug.

 

[JohnCade]

When this problem surfaced I reasoned that the manufactures would not design a bike where the back wheel could not be made to stay in place. So the first thing I did was to clean everything up and make the contact surfaces as perfect as I could and refit it all according to spec. I sanded the dropout surfaces too and cut the the non rotation washer to give a good non slip contact area where the dimples had worn since I didn't have a new one to hand. I ordered a new one to fit when adjustment was needed. Torqued up to just below the recommended max it held really well, and would still be now if it hadn't needed to be adjusted for chain wear.

That's the unmentionable in the woodpile. Left alone it's all stable and the N/R washer will dig into the alloy dropouts as you say and hold with the correct torque. Even if the dome nuts might need to be replaced more often if tightened to that torque.

But with the extra power of the motor there also is a need for more regular adjustment for chain stretch - particularly if used a lot on hills - and it's that digging in by the washer in slightly different places on the alloy after adjustment which trashes the dropouts; and why I thought the pull was the best way to go to avoid wrecking them. It doesn't need to be tightened up quite that much then since the pull is holding the wheel back too. The smooth surface of the pull won't dig in and trash the drop outs progressively either.

Some others here have fitted pulley type chain tensioners so they don't need to move the axle for adjustment and so protect the dropouts that way. That works fine if the washers are seated and tightened well I should think, but it won't stop the wheel pulling forward if they aren't.

 

[gordonmx]

@JohnCade

i hope the shorter ones will fit okay. I did roughly measure where my longer one sat when fitted and I think they will. I got the longer one to be sure and that one is stainless. I'm not sure about the shorter one...

Given the delivery delay from HollandBikeShop (especially since they require a signature and I'm redirecting the package to a postal drop-off place that probably won't sign for it), and the fact that you indicated doubt about whether they'll fit, I decided to order two pairs of all four of the Batavus chain tensioners available on that online shop's site.

Batavus Chain Tensioner 62 Mm Bolt 45 Mm
Batavus Chain Tensioner 45Mm Bolt 30Mm
Batavus Chain Tensioner Short Stainless
and my latest find:
Bicycle Chain Tensioner Batavus Stainless

One of them ought to fit! Then I'll have a whole bunch of useless chain tensioners. But I don't want to have to take my bike to the workshop and leave it more often than I have to. Sucks to have a new bike off the road for so long.

I rang up the HollandBikeShop online store and complained about the lack of detail and fitting information. She conceded the point, but said the site originated as a parts site for bicycle mechanics, and has become more end-user focussed. She told me they're well into planning a new site that will feature a lot more information. And it will be more multilingual. However, she clearly ignored my not so subtle effort to get a discount.

What "later version of that pdf" are you talking about? I got the latest manual off the Kalkhoff site. There don't seem to to be any individual manuals for each type of bike.

Are you saying you don't believe the "more general" torque reading list? Even though it sounds like 30 N-m would be better than 45 N-m to avoid the bolts stripped (that happened to me a lot when I tried to tighten the bolts on without a torque wrench)? Where are we supposed to get credible torque specifications for Kalkhoff bikes?

I keep on thinking about getting a torque wrench, but my first Kalkhoff was such a nightmare that it's scared me off from doing my own maintenance. Does anyone here like the Park Tool TW-6 or is that just overpriced branding? I don't have access to an Aldi or anything similar. I'll probably have to order online.

I didn't keep a picture of the dropouts on my earlier Kalkhoff e-bike - an Agattu XXL C8. I wish I had done so, to document what can happen to the frame/dropouts from too much abuse. I can only confirm that the dropouts face the same direction, not whether the dropouts are any beefier. I'd be interested in your source on Kalkhoff having beefed up the dropouts in the 2015 models - that's apparently what I have. Where did you see that? if anyone's interested I could upload a picture of what the rear drop-outs look like.

@RobF Thanks - so that's the same company behind the Rose Versand online bike shop? Too bad they don't do electric. Thanks for taking the time to explain.

@tillson Thanks for that Shimano link. I looked for the equivalent for my bike, and found it: http://www.fallbrooktech.com/sites/default/files/videos/N360_TECH_ENGLISH_web.pdf

They suggest the rear wheel bolts be tightened to 30-40 N-m. Interesting as it's just below the 45 N-m that @JohnCade thinks stripped his bolts.

 

[JohnCade]

@JohnCade



Given the delivery delay from HollandBikeShop (especially since they require a signature and I'm redirecting the package to a postal drop-off place that probably won't sign for it), and the fact that you indicated doubt about whether they'll fit, I decided to order two pairs of all four of the Batavus chain tensioners available on that online shop's site.

Batavus Chain Tensioner 62 Mm Bolt 45 Mm
Batavus Chain Tensioner 45Mm Bolt 30Mm
Batavus Chain Tensioner Short Stainless
and my latest find:
Bicycle Chain Tensioner Batavus Stainless

One of them ought to fit! Then I'll have a whole bunch of useless chain tensioners. But I don't want to have to take my bike to the workshop and leave it more often than I have to. Sucks to have a new bike off the road for so long.

I rang up the HollandBikeShop online store and complained about the lack of detail and fitting information. She conceded the point, but said the site originated as a parts site for bicycle mechanics, and has become more end-user focussed. She told me they're well into planning a new site that will feature a lot more information. And it will be more multilingual. However, she clearly ignored my not so subtle effort to get a discount.

What "later version of that pdf" are you talking about? I got the latest manual off the Kalkhoff site. There don't seem to to be any individual manuals for each type of bike.

Are you saying you don't believe the "more general" torque reading list? Even though it sounds like 30 N-m would be better than 45 N-m to avoid the bolts stripped (that happened to me a lot when I tried to tighten the bolts on without a torque wrench)? Where are we supposed to get credible torque specifications for Kalkhoff bikes?

I keep on thinking about getting a torque wrench, but my first Kalkhoff was such a nightmare that it's scared me off from doing my own maintenance. Does anyone here like the Park Tool TW-6 or is that just overpriced branding? I don't have access to an Aldi or anything similar. I'll probably have to order online.

I didn't keep a picture of the dropouts on my earlier Kalkhoff e-bike - an Agattu XXL C8. I wish I had done so, to document what can happen to the frame/dropouts from too much abuse. I can only confirm that the dropouts face the same direction, not whether the dropouts are any beefier. I'd be interested in your source on Kalkhoff having beefed up the dropouts in the 2015 models - that's apparently what I have. Where did you see that? if anyone's interested I could upload a picture of what the rear drop-outs look like.

@RobF Thanks - so that's the same company behind the Rose Versand online bike shop? Too bad they don't do electric. Thanks for taking the time to explain.

@tillson Thanks for that Shimano link. I looked for the equivalent for my bike, and found it: http://www.fallbrooktech.com/sites/default/files/videos/N360_TECH_ENGLISH_web.pdf

They suggest the rear wheel bolts be tightened to 30-40 N-m. Interesting as it's just below the 45 N-m that @JohnCade thinks stripped his bolts.

You'll be able to sell them on to anybody else who wants a chain tug I should think. You only really need one on the drive side anyway.

The new dropouts are shown on page 8 and 9 of the Kalkhoff Highlights 2015 as well as Details of the Development Department:

http://www.kalkhoff-bikes.com/en/bike-info.html

Are you saying you don't believe the "more general" torque reading list? Even though it sounds like 30 N-m would be better than 45 N-m to avoid the bolts stripped (that happened to me a lot when I tried to tighten the bolts on without a torque wrench)? Where are we supposed to get credible torque specifications for Kalkhoff bikes?

Sometimes there are differing specs on different pages on manuals and sometimes it's a mistake. In this case the specific torque is given for the Nexus hub on the page dealing with removing the rear wheel, and a different torque in the general section. So yes I take the specific one as the best one to follow. As I wrote before it's been lifted from the Shimano spec sheet so you would expect it to be right.

I also thought it was possible that the bloke I got it from had overtightened them before I bought the bike. It's easy to do if you don't use a torque wrench.

You would not expect to strip the nuts if they were sound, if you tighten to a little under the maximum figure given in a manufacturer's manual or spec sheet....