thinking about buying a kit. i wont die will I?

[nikolaou]

so i am thinking about buying a 80cc motorized bike kit to put onto my mountain bike. the topspeed is 3
40mph or approx 65kmh

i have some concerns about the safety of such a device... 65kmh is pretty damn fast and i am worried how well my mountain bike will hold up at these speeds when it is only made to withstand speeds attained by leg power.

also, how about the brakes i already have on my bike? will they really withstand these speeds? will i hqave to buy special ones?

also, should i only be driving my motorbicycle on the Road? or should i be on the sidewalk?

[Finfan]

My truck will do 100+ mph but I've never taken it that fast. Just ride sensibly. Also check out the laws where you are. You may be limited on how fast you are allowed to go. Brake wise the more the better. I have a coaster brake beach cruiser but I've added a set of hand brakes just to be sure. A bike that won't go is annoying, a bike that won't stop is dangerous!

Edit: Stay off the sidewalks! You are going too fast for the rest of the traffic there!

[Pablo]

Got news: You are going to die.

Better news: You have plenty of time to have fun on a MB before you die.

Good advice from Der Finfan. In fact, hilarious. My bike will do 40+. I did that twice. I didn't feel all that comfortable.

Helmet, gloves, shoes, pads, brain......all good items to carry. Brakes are mandatory.

[Cabinfever1977]

use the road like a bike does and keep the speed reasonable 20-30mph
and check your bike and engine often between rides.

[Earthman]

The top speed of my 24” MB is 23 MPH. I have no desire to go faster ‘cause it’s scary. However, I may make changes so I can use the gears on the back wheel and go up steeper grades, or ride slower off road. I've replaced the break cables with 2mm cables.

I too worry about the strength and reliability of bike frames – the tubing on most newer bikes is real thin for lightness. More expensive frames use butted tubing, which is thick at the joint ends and thin elsewhere along the member length (see photo). This may actually be a drawback for MBs. I’m using a cheap huffy frame, which I assume does not have butted tubing. I assume the tubing is strong enough in tension and compression, but clamping stuff to it (engine, chain tensioner, etc.) may weaken it. Also, higher speeds put higher impact loads on the joints of the frame. Bike frames do fail by joint fatigue from normal riding. In any case, bicycle frames were not designed for what we are doing to them. Use caution and inspect the frame and mounted hardware often. Finally, there must be zillions of these kits in use in China. I wonder how many bike frames have actually failed?

When I was a kid, I had an old, stripped-down, 24”, single speed Schwinn bike that I beat the crap out of for years by jumping off 8’ high hills, going up and down steps, etc. This was 20 years before there were mountain or BMX bikes. I dismounted my bike one day, and with no warning or load on it other than its own weight, the poor thing literally fell apart into a heap at my feet with me left holding nothing but the handle bars. It was like it just gave up and died. I was very sad.

[Norman]

Earthman
I have a very funny picture in my head of your misfortune with your bike. I'm sorry for your loss but it struck me funny
Norman

[spad4me]

I will say what I tell every one who rides a motorized bike .
They are your arms and legs to break.
Foolish mistake happen quick at motorized speeds.
You will need to do a lot of maintenance .
It is a lot of fun.
I ride very day.
Have fun.