Recent content by kielbasa

So far, so good. I found a turner who made the same-looking bolts (he modified some strong truck's engine bolts, he mentioned they're grade 10.9 steel ) and I installed them on my bike. We will see what happens, hopefully, they won't break.

Take a look at one of my previous posts where I attached two drawings with two different hinge generations. They did upgrade the hinge in the way You described, however, the drilled hole where the pin slides across the hinge (I assume) must be the same diameter at full length. Mine is not. (take...

I'm just wondering, if you look at my cross-section drawing, you'll see that the shear force is applied where two parts of the frame meet and where the bolt is thicker (cylindrical, not threaded part). Why does the bolt get cut off in the threaded part if the cylindrical part of the bolt is...

I took a shortcut. 1080MPa x 50,25mm2 = 54250 N --> (roughly equals to a mass of 5400kg)

heh, thanks. I know the calculation is rough and not so precise. But that frame support might be an important factor in reducing the stress on the hinge. And for sure, I'd not be able to calculate it more precisely by myself. But if, let's say, I use a 12.9 grade m8 cylindrical solid pin, that...

thanks. I did a quick calculation and came up with 105kg x (0.15m curb x 0.6m frame length to the hinge / 0.03m tire thickness x 0.04m bolt length) = 7875kg. That seems like a lot. However, I believe this calculation doesn't consider an important factor - the presence of the frame/hinge support...

Shouldn't it all multiplied by 'g' (gravity) ? As 'centimeters' will be reduced in the fraction, and only the 'kg' will remain.

I also tried to make an estimated calculation based on what Lnewqban wrote, but I think we cannot treat this structure as a beam supported at both ends with eccentric load since the frame has the additional hinge support that changes the load distrubution and also, it doesn't take into account...

I also made a rough sketch of the cross-section of the hinge and slid bolts. That should give You a proper idea of what the hinge looks like. What I didn't realize before, and I know now, is the fact that the shearing force is applied where the thicker cylindrical/not threaded part of the bolt...

I ride on the widest tyres possible, they were changed soon after I bought the bike. The ones I got it with were too slim, the ride was much less comfortable than it is now. But let me ask You one more thing - I realized that the thread of the bolt could be longer, there is still some space in...

It's exactly how You described it. The bolt was broken in the place where the thread meets the cylindrical section. But only the lower bolt was sheared, the upper was not. Since I've already taken out the bolt's broken part from the thread, I can't show You how it looks, but if You want to take...

Yes, I'm aware of the fact, that folding bikes are not too robust..but still thousands of people use them. It is what it is.. ;) Thanks for the explanation, but what does the 'd' stand for in the equation? is it the tyre thickness or rather the tyre/wheel diameter? BTW I didn't know that bolt...

Guys, let's not treat this thread as general advice on how I should ride a bike, please. I'd be grateful if anyone could tell me how to estimate the forces acting on the hinge bolts during the ride, under described conditions. Dropping off the curb is the only situation I can think of, that...

Hi again, Thank You for the replies however, there are few things You need to be aware of. I never thought about it this way that the bolt might be protecting the frame and is the first one to be damaged.. but... the hinge in this bike is called FBL 2 gen 1, and it has changed over the years to...

Hi, I recently bought a folding bike and it turned out over time that its weak point is the main hinge where two bolts (vertically placed) are located. I've had the lower bolt break twice during a ride, leaving a part of it stuck inside the hinge thread. It's clear that the forces applied were...