NCM Prague - Rear wheel issue

Gleam

New Member
Region
USA
Hi, guys. Happy owner of ncm prague here. Just couple of words about myself; i am bike mechanic in the past, long time mtb enthusiast, having whole fleet of bike. wanted an entry level introduction into ebike topic, so bought prague and it is the great bike.
I d like bring to your attention certain issue, i faced just now. tried to remove rear wheel in order to fix flat tire. after unbolting, i realized that axle is deadly stuck in dropouts. took quite some time to solve. i logically deducted that axle's flat side wedged into the metal of dropout. so i tried to realign axle with wrench. applied some penetrant oil and gently hammered axle from drop outs.
visually there are traces of axle grinding into metal of the dropouts.
In my humble opinion, such issue should not arise with such a low powered motor, but i have, what i have. placed an order on torque arm and plan to install it.

another surprise was to see a lot of rubber cuttings inside of the tire and tube valve torn from the tube. rim tape was twisted over. this is often case with fat bikes, when u run them tubed at low pressure, that's why people try to run them tubeless. but i cannot say this is a common issue with conventional wheels and i m a bit concerned by this problem. so i re pumped tire to stone firm condition and look into converting wheel to tubeless, not with this tires obviously.
overall, despite of these problems (and some minor electrical glitches) it is a great bike with decent components for the price
 
Yes, the flat sides of the axle do become wedged in the dropouts. A 10mm open ended wrench will easily allow you to rotate the axle and free it for removal.
 

Papparay

Member
I've also had the same problem. I had a puncture while riding along a canal path🚣, I was about 20 miles from home when it occurred. I didn't think it a problem as I carry a spare inner tube. It became a serious issue when I couldn't remove the back wheel! 😤A passing jogger seeing my plight stopped to assist.🏃‍♂️ Even with his help the wheel would not budge. In the end we repaired the puncture with the wheel in situ using a patch.👏 A kindly lady👨‍🌾 from a cottage near by provided a bowl of water to find the leak.
On my return home I again attempted to remove the wheel. It would not budge until I gave it a couple of whacks with a hammer. ⚒️⚒️
 

Papparay

Member
I would recommend everyone check they can remove their wheels prior to setting off on their nice shiny new bikes. 🚴‍♂️😁
 

rvehock

Member
I've also had the same problem. I had a puncture while riding along a canal path🚣, I was about 20 miles from home when it occurred. I didn't think it a problem as I carry a spare inner tube. It became a serious issue when I couldn't remove the back wheel! 😤A passing jogger seeing my plight stopped to assist.🏃‍♂️ Even with his help the wheel would not budge. In the end we repaired the puncture with the wheel in situ using a patch.👏 A kindly lady👨‍🌾 from a cottage near by provided a bowl of water to find the leak.
On my return home I again attempted to remove the wheel. It would not budge until I gave it a couple of whacks with a hammer. ⚒️⚒️
I carry one of these tubes that does not require removing the rear wheel
 

Bitmugger

Active Member
Region
Canada
I carry a 5in adjustable wrench so I can get the 18mm nut, the 19mm nut and the 10mm flat on the axle to make the wheel drop out. With the wrench on the axle flats its super easy to get the wheel to drop out and I think even if you ride it a mere few km it will bind up again and the 10mm wrench will be needed.
 

Widegide

Member
Region
Canada
The Schwalbe Smart Sam tire that comes on the Moscow is quite different than the Big Ben line.