HELP... Shudder / vibration thru pedals under pressure?

Grifteruk

As a total newbie to fiddling with me bike, I am struggling to locate an annoying little vibration which seems to be coming thru the pedals when I'm going uphill.

When pushing the pedals, every few pedal rotations there is a vibration which is both audible and something I can feel. I know it is not:

1. my seatpost because it's an integrated post

2. My cassette or rear wheel cos I've stripped both down and rebuilt

3. My cleats cos it happens when I'm testing on normal shoes

I can't seem to get my dura ace pedals off for some reason so it may be them but I've cleaned everythin down and it is still happening.

Any ideas anyone? Bike is only 2 months old so don't think it's any worn parts.
Cheers

Weejie54

As you say it's every few revolutions, I am wondering if it could be the chain.

Just a thought.

GavH

What kind of pedals are they? I often get a similar thing with my 105 SPD-SLs.

Monty Dog

Is it the same point on every pedal revolution - try looking at the bottom bracket / chainset.
If it happens every couple of strokes, then its likely to be the chain - check all the links e.g. stiff links or a side plate isn't sticking out and catching the jockey wheel cage. Could also the pedal spindle bearings too

John C.

At a guess you are in bottom gear and under full load. Check that your front mech is going in far enough. Your chain may be rubbing against it. the same can happen in top gear the other way round.

Grifteruk

Thanks all - I've fiddled a but and you've confirmed wot I think I suspected for a while about my chain. Not convinced it's 100% and I think I'm gonna change it.

Decided to take it out tomorrow and see if I can pin it down then back to lbs for pedal and chain fine tuning. If no joy new chain is the next stage I think

John C.

I tend to treeat chains as disposable items, use a chain checker and as soon as there is any wear chuck them and replace. ( I use cheap chains )