Folding Bikes - Odd noise in my new Strida - any suggestions?

I've already written to Strida UK on this, but since it's Sunday evening I thought I'd also tap the collective knowledge here.

I've had Strida 3 for a couple of weeks. At first, it was impressively quite. However, today I noticed an odd and disturbing sound.

While pedaling hard, there's now a distinct rasping noise. More noticeable on the down-stroke of my right leg than the left, but can be heard on the "power stroke" of either leg. Is louder the harder I pedal (e.g., uphill).

I have read the manual on how to stop squeaks, and will adjust/lubricate the indicated areas as soon as I can get some White Lightning or similar dry lube.

But - the noise is not quite a "squeak." Is more like somebody loudly saying "Shhhh!!" every time the crank comes round. My initial guess is it's the edge of the belt rubbing against the inside edge of either the front freewheel or the rear cog.

Any other Strida riders experienced this? Specific suggestions, areas that I might examine or adjust?

Hub brakes? Tire rubbing on fender?

I once heard a galloping noise. I put oil in the free wheel BB and it stopped. I also tightened the screws around the main gear.

My initial guess is it's the edge of the belt rubbing against the inside edge of either the front freewheel or the rear cog.

Yeah, I get that sound. It's sort of a snoring. I am under the impression the front chainring is flexing a little, messing up the alignment of the drive belt, which is now hitting the side of the grooves a little. So each tooth on the belt hits the side of the groove on the chainring and then slips down into its proper place with a little popping sound.

That's my theory. It can be rather loud and annoying, but doesn't seem to be harmful. I started getting this when the bike was a few months old; now, after almost two years, the sound comes and goes with no pattern I can discern. The fact that it may go away for a few weeks suggests I have inadvertently done something to fix it; but I have no idea what that might be. When the sound occurs, I find I can make it go away by back-pedalling a few revolutions of the crank; but this is a very temporary fix, and the sound comes back within a minute of pedalling.

While pedaling hard, there's now a distinct rasping noise. More noticeable on the down-stroke of my right leg than the left, but can be heard on the "power stroke" of either leg. Is louder the harder I pedal (e.g., uphill).

I have read the manual on how to stop squeaks, and will adjust/lubricate the indicated areas as soon as I can get some White Lightning or similar dry lube.

But - the noise is not quite a "squeak." Is more like somebody loudly saying "Shhhh!!" every time the crank comes round. My initial guess is it's the edge of the belt rubbing against the inside edge of either the front freewheel or the rear cog.

Any other Strida riders experienced this? Specific suggestions, areas that I might examine or adjust?

Do you have a sound recorder, maybe a digital camera with that function, then we could all listen?

So far, I've once had the front Allen screw, which holds the bottom tube bearing support, work loose. Tightening that fixed a similar noise.

Other than that, a bar of soap rubbed over the belt "teeth" keeps the bike nice & quiet ;-)

I've noticed belt noises in the rain, which go away in dry weather. On my bike the two halves of the bottom bracket rub together and creak when then flex, if you look down when pedalling hard you can see the chainring flex from side to side.

Do you have a sound recorder, maybe a digital camera with that function, then we could all listen?Nope, but that's an interesting thought. Wonder if I can get a microphone with a gobo on it to block wind noise, and hold it close enough to the running gear when the noise happens to get the recording.

Nah, better not even try. The noise only happens under load and I'm not coordinated enough to get the recording while trying to ride in a straight line. Maybe if I can figure out a way to get the noise while the bike is on a work stand...


I've once had the front Allen screw, which holds the bottom tube bearing support, work loose. Tightening that fixed a similar noise.Ah, THAT'S worth taking a look at, thanks!


...bar of soap rubbed over the belt "teeth" keeps the bike nice & quietTeeth? Or just the edges?

I've noticed belt noises in the rain, which go away in dry weather.My noise happens when it's dry, so it may not be the same thing.


...if you look down when pedalling hard you can see the chainring flex from side to side. I've noticed that too and wondered if it was out of true. I'll stop worrying about that now.

Well, it's good to know that my problem isn't unique. I'll try some of the sugegstions given here.

Strida UK has been quite good about replying. Their customer service rep (by email) offered to have a tech phone me. When I reminded her I am in the USA with an 8 hr time difference, she said she'd ask the tech to email me instead.

Will be interesting to see if the tech comes up with any of the same suggestions/comments made here.

I got home this evening and tried a few of the suggestions offered here. The one that thing that seems to stop the noise: Soap on the edge of the belt.

That's one thing I didn't expect would help - shows how much I know :)

A toothed belt can't slip like a v-belt, can it? Where does the noise really come from? What's sliding in a way that could make such a long rasping sound?

I had the "snoring" noise too. It happened with every revolution of the crank at the same spot, so I examined the "chainring" and noticed a slight scuffed area on one edge of the ring that the side of the belt must have been rubbing. This could have happened if the chainring hit something such as walking the bike off a high curb. I tried to clean the scuffed plastic fibers off with a utility knife, but it persisted. Then I sprayed the belt and ring with silicon spray (which rubber loves) and the noise went away.

I think it would be very difficult for the toothed belt to slip on the "chainring", but earlier Stridas had slippage at the rear sprocket. Newer Stridas have the little guide pulley at the rear which solved that problem.

The new Strida 5's have that nice, welded bottom bracket bracket that should better maintain belt tension, as well as eliminate the flex in this area. The "chainring" also is redesigned and I'm guessing is made of a stronger plastic material as seen in these photos (bottom of page): Strida 5 photos (http://www.flickr.com/photos/12948773@N00/). This is probably to address the flex in the chainring, though it looks more high-tech too.

A toothed belt can't slip like a v-belt, can it? Where does the noise really come from? What's sliding in a way that could make such a long rasping sound?
When the belt slips on a Strida, you get a popping sound as the teeth jump to the next notch on the gear.