Grinding in pedals, in initial gear, only when on the bike

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Danbringbhurst

New Member
What I mean is, in the initial gear when taking off, there's a grinding vibrating that I can feel through my feet when I pedal. But the sound (which is like rubber being clipped with a fan blade) and vibration can't be duplicated when the bike is upside down and I'm rotating the pedals by hand.

Secondly, it doesn't make the sound or vibration when the wheel is spinning freely. Only when pedaling, and the moment I begin moving faster, or if move to a higher gear, the sound subsides.

Something about the bike, I discovered the kickstand was occasionally making contact with the tire, which incidentally makes the same sound, but I've made sure this is no longer happening. Additionally, and possibly related, the chain frequently slips, switching incrementally through gears, and falls off entirely around the pedals during high gears and abrupt shifts.

Thanks for any help!
 

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Location
Loch side.
Since you have your camera out and the bike nearly, please take two more photos.

I'd like to see the chain perfectly from the side on. Try and find a section where it is nice and tight and get the camera as close as possible but absolutely perpendicular to the centre point of focus.

Then snap a few shots of the front gears (chainrings). Shift the chain once or twice so that I have a clear view of both rings without the chain on them.

Also a nice close up photo like the second one, but get as much of the gear in the frame as possible.

Lastly, when you say "initial gear", is it a specific gear or just any old gear you happen to start off in?
 

Rickshaw Phil

Overconfidentii Vulgaris
Moderator
Hi and :welcome: to the site.

Looking at the photos provided it seems to me that if you are starting off in the gear shown, that is where the problem lies. Running the chain from smallest chain ring at the front to smallest sprocket at the back is a combination not usually recommended and the chain rubbing on the front derailleur is almost certainly causing the noise.

For moving off from a stand you'd be better off in the middle chainring at the front and one of the larger sprockets at the back.

Front: Small ring = low gear, slow, good for hill climbing. Middle ring = medium gear, good for all round riding. Big ring = harder work, good for fast riding/downhill.
Rear: Large sprocket = low, easy gear. small sprocket = harder, faster gear.
 
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Danbringbhurst

Danbringbhurst

New Member
The chains position is a result of me putting it on last, after it fell off. That's insane it didn't occur to me. As per the photos requested, hope these help. But the chain rings aren't very visible from any angle, really.
 

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Danbringbhurst

Danbringbhurst

New Member
And this is going to make me sound like an idiot, but I wouldn't know what you call my initial gears position. Both left and right shifters are set at their default positions, so I'd imagine it's like 1:1
 
The chain is probably rubbing on the front derailleur mechanism. You can move it outwards, by adjusting the little Phillips head screws, in the mechanism. As has been quite rightly said, try to keep the chain line straighter by using the smaller chain rings. The reason you can't replicate it with the bike upside down is because the chainset will flex outwards with you peddling, it won't flex outwards so much if you are rotating with no load on the cranks.
 

Rickshaw Phil

Overconfidentii Vulgaris
Moderator
And this is going to make me sound like an idiot, but I wouldn't know what you call my initial gears position. Both left and right shifters are set at their default positions, so I'd imagine it's like 1:1
That's just part of being a beginner and we've all been there. If you're going for 1 and 1 as your starting point that's better but will give a gear that is really low. Great on such a steep climb but on the flat the legs would be spinning away while you go nowhere.

It helps a little if you think of a triple gear on a bike as being like the gears on an old 4x4. At the back the gears are like your main gearbox and you go up and down them as the need requires. At the front this is like your transfer box. Low range (small ring) is for your serious hill climbing or off roading where you need contol at slow speed and lots of torque for getting up those gradients.
Mid range is like the 4x4's normal range. You'd stay in this most of the time for your usual every-day riding.
High range (the big ring) is like overdrive for when you're cruising at speed on the flat or downhill.

Getting back to your problem; if the chain is rubbing in gears 1 (small ring) and 1 (big sprocket) its probably a simple adjustment of the limit screws. Check the front derailleur and you'll probably see the chain touching the cage of the mechanism. There are two screws on the mech marked L and H. If it is rubbing in this combination try adjusting the L screw anti-clockwise, just quarter of a turn at a time until it doesn't rub. (oh, and do it with the bike upright: as has been said above, turning the bike upside down does affect how the gears react.
 

mjr

Comfy armchair to one person & a plank to the next
The comment about the chain being thrown off onto the pedals makes me wonder if the front mechanism is still on straight or if it's been knocked front- inwards, if the bike is of a sort where that's physically possible. I think it should be parallel to the chainrings. I can't tell from the photos.
 
Location
Loch side.
The chains position is a result of me putting it on last, after it fell off. That's insane it didn't occur to me. As per the photos requested, hope these help. But the chain rings aren't very visible from any angle, really.
Thanks for the photos. I've seen what I wanted to see.

1) Your chain is not worn.
2) The biggest two chainrings are not worn
3) The smallest chainring appears to be worn but I can't see it well enough - but I suspect that's the problem.

You say you start of in 1:1 and then feel a vibration through your feet. If 1:1 then means that you start off with the chain on the smallest ring in front and smallest ring at the back, you stand a chance of scraping the chain on the front derailer. This makes a cyclical Rrrrr-Rrrrr-Rrrrr noise with each pedalstroke but does not transmit vibration through the chain. The cycical noise corresponds with each pedal stroke on the one side. Is that it? Yes/Na?

What I suspect is happening is that you use your small chainring all the time and it has worn out. The chain then offsets slightly in the ring and the next tooth to enter the chain hits the chain's roller and slides in with a vibration. If you have a better way of showing me the small chainring with good focus I can confirm this.
 

I like Skol

A Minging Manc...
Maybe the chain is rubbing the tyre when on the small chainring and big sprocket? If the rear tyre has more tread or is a bigger size than original this can happen. Also if the front mech alignment is not great then the mech can also touch the tyre.
 

boydj

Legendary Member
Location
Paisley
For starting off, you should use the middle ring at the front and one of the larger cogs at the back. Your lowest gear is small at the front and large at the back - and you should not need anything as low as that unless you are starting off on a steep hill.
 
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