I am going on a cycling challenge and advice was to take helmet in hand luggage just in case main luggage gets lost (still cycle) but i am also taking my own pedals (SPDs) and saddle. If I include these in hand luggage will they get confiscated as weapons?

Obviously pedals are heavy metal objects that could be used to attack someone or that might be the conclusion of security!

Following the logic above I might need to take shoes with cleats in hand luggage too!

There is a list of what is and isn’t allowed. Should be on the airport website. All of the stuff you list is OK AIUI. That said some security staff do make the rules up and you can’t argue with them.

Will all depend on what side of the bed the security officer got out of!

I flew with my SPD shoes in my hand luggage, I’d forgotten that I’d stuffed my SPDs in them. They set off all sorts of alarms at the X-ray machine. Once they saw what they were, they didn’t seem so fussed about them and sent me on my way.
A mate once tried flying with a 5th element coil shock in his hand luggage, that didn’t go down so well with the customs people!

I got though Dublin airport security last year with half a dozen cable ties and my Leathermam tool in my pocket
Didn’t realise they were there until I was in departures, binned the cable ties before getting on the plane though

depends which member of security you speak to.
i carried my ice skates onto the plane coming back from canada (with the steel runners removed and placed in the hold) only to be told i could have left the runners on no problem at all, but when i asked in the uk i was told the runners had to go in the hold.

I really dont see it as an issue, no worse than a camera, as long as you can get them out and show them if they ask. Ive brought candles back from the USA as hand baggage, never been stopped yet ?

As posts above say, really depends on the mood of the security person. Have flown with all sorts of nuts, bolts, electrical bits and pieces with no problem – best approach is make sure you show them it from the off and they normally accept them.
They took my hi vis vest once though – as I could use it to impersonate airport staff once airside?? I did intend on wandering about not doing very much for a few hours so fair do’s 🙂