Bearprint throttle only ride enforced by frozen gears

[bazwaldo]

Hello everyone,

This is my 1st post here apart from a recent review I posted for my Bearprint New City 505 Ebike.
As I noted in my review during extremely cold temperatures I have had problems with the gears changing down but not back-up.

Last Sunday night when commuting home after I finished work at 11pm this issue arose once more due to the very heavy frost.
Not long after starting out I noticed problems changing up from 4th gear so I stopped and sprayed WD40 into the handlebar gear change mechanism which in the past has appeared to resolve the issue.
This time it did not free up the gears which remained stuck in 1st gear.
With the peddles spinning around so quickly I had to rely entirely on the throttle and use electric power with no peddling to get me the nearly 13 miles home.

Since starting Ebike commuting back in October this felt like the coldest night I have so far experienced.
Not being able to peddle usefully contributed to my coldness and overall I have to say I did not enjoy the throttle only ride.
I really did not know where to put my feet during the ride back and having them in the mostly same position became uncomfortable. Also holding the throttle open for the whole ride home became almost painful for my right hand. The night was so cold I felt my top lip becoming numb as did my hands.
If I had been able to peddle normally I believe I would have warmed myself up to some extent.
Trying to whizz the peddles around with no friction did not work at all.

I have to say that I was pessimistic about the Bearprint's ability to get me home up some long although fairly gentle hills on electric power only but it surprised me by coping extremely well.
Compared to when I cycle normally the speed seemed much slower but I think this was because I was sitting stationary and not needing to concentrate on peddling and changing gears, etc.
After I reached home feeling frozen my cycle computer revealed that the average speed had been 15 mph and that the journey had taken 50 minutes only 5 minutes longer than if I had been peddling as well. This was after travelling to work earlier that day over nearly 14 miles.
I do not charge the battery at work.
There still seemed to be plenty of power left after reaching home so I must say that the motor and battery performance impressed me greatly.
Typically I had thought that my input was a large part of the power eating up the miles going to work but this experience has left me wondering how useful my human input has been!
I would still much rather use the bike with power assist than just throttle only though.

I do not know exactly what is causing this issue but I am guessing that the gear cable has moisture inside and this is what is freezing, I will try to lubricate the cable.

Best regards to all,
bazwaldo.

 

[theskip1]

wd40 will dry out leaving quite a heavy oil residue its really more for protecting electrical components. what you need to buy is a decent oil thats recomended for cables and gears, one thats not to heavy in this cold wheather.you cant beat 3 in one for penetrating into nooks and cranies. remember wd40 is not for oiling its more for cleaning and electrical use.

 

[bazwaldo]

I had a word with my local Cycle shop proprietor who recommended GT85.
Perhaps this would do a good job?

 

[Blew it]

Sounds like you need to slacken the gear cable a couple of 'clicks' on the rear mech. ( turn the adjuster in, clockwise )

This video will show you how.
Have fun
Bob

 

[bazwaldo]

Thanks for your post Blewit but I don't think it is an adjustment fault.
The next day which was milder the gears worked normally without any adjustments being made. It really only happens on exceptionally cold days when something is freezing.

 

[Blew it]

Okay!. To get to the bottom of this I suggest the following for a starter:

The next time we have sub-zero temperatures and the machine is stuck in a low gear, check to see if the inner cable nipple is poking out the side of the handlebar shifter instead of being seated in it's recess. If it is, then the return spring on the rear mech was unable to pull the inner cable back when you shifted up, perhaps because it is frozen as you mention. While your off the bike, grasp hold of the rear mech and pull it gently outwards, this should pull the inner cable back and at least allow you to ride home in a high gear. If the rear mech cage is already against the 'H' stop, then screw the barrel adjuster in two clicks.

Metal contracts when cold, expands when warm. I'm thinking the current adjustment may be biased towards down-shifts, alright on warmer days, but, in sub-zero temperatures the adjustment goes out just a little and prevents up-shifts. Hence my suggestion in my first reply. The long term solution involves a little more work.

The only way to be sure the gear cable is lubricated through it entire length is to remove the inner cable completely, but please make sure the mech end is not damaged or frayed, if it is, it will be nigh on impossible to refit it to the outer. I prefer to use a new inner cable for this reason. An inner gear cable is only a couple of quid, but make sure it is the 2100mm long type. Most electric bikes have a longer wheel-base than normal bikes.

To lubricate the cable I use Weldtite TF2 spray. Tie a piece of wrag around the mech end of the outer cable to prevent lubricant from reaching your disc brake rotor. Give the can a shake and fit the little tube into the spray-head. Hold the thin tube against the hole in the outer cable at the handlebar end and blast the lubricant right through to the rag at the other end, this will remove any water inside it. Spray some of the TF2 into the can's cap and use your fingers to add more TF2 to the inner cable as you thread it back through. Don't forget to thread the inner cable through the shifter first.

You can follow the video in my previous posting to set up the gears. The TF2 spray can also be used on the pivot points on the rear mech. Weldtite TF2 can usually be found in Tesco and Halfords.

Right, that will keep you busy for a while, in the meantime I'll figure out what to try next.

Happy lubing
Bob

 

[bazwaldo]

Thank you for a very informative and helpful post Blew it.
From the detail you have given you clearly know what you are talking about.
The Bicycle Tutor website you indicated is also a great resource and will help me try to get to grips with these sorts of sensible maintenance jobs.
I must admit I have no real experience of this kind of job and might prefer to pay someone else who has experience to do the work instead.
I signed up for a years maintenance plan with my local Halfords as it was at half price over Christmas, I thought that at the price it was worth a try. The youthfulness of the Halfords "technician" did not inspire confidence and I will have to find out if the plan covers this sort maintenance. They did say the bike can be brought in as often as I felt necessary - maybe monthly.
The quandary is whether the effort involved in resolving such an intermittant problem is worth it. It may be easier to perhaps use the car if weather predictions are accurate enough to avoid cycling on the few remaining winter days when extreme cold could cause the freezing gear problem to reoccur.

 

[Blew it]

Fully understood. I think choosing to use your car when the mercury heads South is a very sensible alternative to the bike. Personal contact with unyielding frozen tarmac can be a painful experience, possibly resulting in injury and at the very least, damage to the machine. The greatest danger of all, is the very real possibilty of both bike and rider sliding into the path of a lorry or bus, it's just not worth the risk.

Save the link to the 'how to' site in your favourites, you never know, one day you might just feel like having a tinker.


All the best
Bob