Chain pulley accident

clay830

Member
Jan 29, 2017
55
0
6
Illinois
Today I was cruising around on my motorized bike and the chain pulley came loose and went into my bike spokes. It tore up my chain and broke 4-5 spokes. Do I need those spokes or can I remove them and go without them?
 
Last edited:

Chaz

Well-Known Member
Jun 3, 2012
1,004
69
48
Vancouver, British Columbia
I hope you weren't injured badly. Remember my advice on the first page of your smaller sprocket thread?

Your question above tells me you are in no way ready to go fast.

I don't mean to rag on you at all, I am just hoping you build a solid bike that you can ride safely. Take your time, enlarge your knowledge base and proceed in stages.

and one more yes to the need for all of your spokes.
 

Cylon

Member
Jun 26, 2015
346
9
18
Maine
Today I was cruising around on my motorized bike and the chain pulley came loose and went into my bike spokes. It tore up my chain and broke 4-5 spokes. Do I need those spokes or can I remove them and go without them?
Spokes are $2 each at most bike shops, get those and a wheel truing tool. You can try to ride it with missing spokes. I've done it before because I was riding on a trail and 3 snapped so I pulled them out and tried to continue home because I didn't want to walk the whole way lol. It didn't work out, the torque from the motor causes the wheel to warp then the weight from the bike and your body will taco the wheel resulting in more money spent. If i remember right I made it about 75 feet before the rim was FUBAR and I had to carry it home. Bad day.
 

clay830

Member
Jan 29, 2017
55
0
6
Illinois
I hope you weren't injured badly. Remember my advice on the first page of your smaller sprocket thread?

Your question above tells me you are in no way ready to go fast.

I don't mean to rag on you at all, I am just hoping you build a solid bike that you can ride safely. Take your time, enlarge your knowledge base and proceed in stages.

and one more yes to the need for all of your spokes.
On my bike I have both front and back hand brakes. I used a 300+ dollar raleigh bike. I knew the tensioner wasnt tight enough (because I was using a stripped screw that wouldnt tighten at all) and I decided to risk it and ride any way. Now I am out a chain and more than half my rear wheel bike spokes (I went and actually counted and found out most broke), and also time and money. Next time im going to buy lock nuts on the tensioner. Anyway I didnt get injured at all. Surprisingly.:-||
 
Last edited:
Nov 27, 2013
143
4
18
earth
www.Frankenbikes.com
IMO - stuff breaks in this hobby

The more you do it the more you can judge the severity and "get home-ness" of whatever is happening. - F'rinstance i ride with a few tools to hopeful handle emergent situations. That is one of my favorite parts.

but stopping once (or before) something is busted often saves a PIA repair. And you will get better with practice.


this spoke thing is pretty bad, and the motor exerts more than enough force to further damage this wheel.

Finally, let me impart the wisdom of my favorite auto shop teacher:
Do your brakes first! - his message, safety first. don't ride the bike until it is complete.
 
Nov 27, 2013
143
4
18
earth
www.Frankenbikes.com
IMO - stuff breaks in this hobby

The more you do it the more you can judge the severity and "get home-ness" of whatever is happening. - F'rinstance i ride with a few tools to hopeful handle emergent situations. That is one of my favorite parts of doing this.

but stopping once (or before) something is busted often saves a PIA repair. And you will get better with practice.


this spoke thing is pretty bad, and the motor exerts more than enough force to further damage this wheel.

Finally, let me impart the wisdom of my favorite auto shop teacher:
Do your brakes first! - his message, safety first. don't ride the bike until it is complete.
 

buba

Member
Jul 2, 2010
914
6
16
los angeles
very very very lucky you did not get seriously hurt or worse...anyone riding with fenders and sloppy tensioners- no proper braking and a few other such things has a death wish!!! and it may happen!!!
 

Chaz

Well-Known Member
Jun 3, 2012
1,004
69
48
Vancouver, British Columbia
Glad to hear you weren't badly hurt. You dodged a bullet there. I think Cylon posted a link to the best design for a spring tensioner.

One thing to remember is that a new chain will "stretch" which will contribute to possibly jamming the chain up in the drive sprocket cover.

If you can get the tensioner welded then that would be great.

I think the weak point in the stock tensioner is that it is prone to being pulled into the spokes. To make things easier for the tensioner I always que up the motor to the downstroke when I start up.

The best tensioner design, in my opinion is the arc tensioner available at Custom Motored Bikes.

Ideally, you would have no tensioner at all if you can get your chain length perfect.
 

clay830

Member
Jan 29, 2017
55
0
6
Illinois
Glad to hear you weren't badly hurt. You dodged a bullet there. I think Cylon posted a link to the best design for a spring tensioner.

One thing to remember is that a new chain will "stretch" which will contribute to possibly jamming the chain up in the drive sprocket cover.

If you can get the tensioner welded then that would be great.

I think the weak point in the stock tensioner is that it is prone to being pulled into the spokes. To make things easier for the tensioner I always que up the motor to the downstroke when I start up.

The best tensioner design, in my opinion is the arc tensioner available at Custom Motored Bikes.

Ideally, you would have no tensioner at all if you can get your chain length perfect.
Do you use a tensioner?
 

Nashville Kat

Well-Known Member
Apr 20, 2009
1,497
48
48
Jacksonville, Florida
A very typical problem with the tensioner- probably the most common fail-

If you broke a lot of spokes, your best solution might be a new wheel- if it's a typical 26 alloy rim those are usually easy to find on craigslist- even if you have to buy some $20 old bike.

Don't ride the old wheel without replacing the spokes- you'll just have more problems and could fall and get hurt.

Lose the tensioner if you can- a smaller rear sprocket gives more frame clearance- you can match the chains with 1/2 links-easier installed on the pedal chain- but yes, the chains do stretch over time. I have run matched chains with no tensioner or incidents and few adjustments for many years

you could also set the motor chain and hang a derailleur on the pedal side to tension that side, which works well. So if you get a new wheel, you might get a threaded freewheel and put a multi-speed cog on the pedal side- you can get a cheap three or five or six cog on ebay and have easier gears to pedal or for some pedal assist accelerating.

A single speed freewheel is under five dollars from China, but for just a bit more, get one that has slots for a removal tool.
 
Last edited: