Buckled Chainring

WesternWay

Whilst cycling in this morning, I seem to have buckled the large chainring.

This seems odd, it was pretty sudden, and is buckled by probably a couple of mm, possibly a bit more... Sufficient that I cannot get the front derailleur to anything like run smoothly.

This seems utterly bizarre, do chainrings really buckle?

George

wgwarburton

WesternWay wrote:

..., I seem to have buckled the large chainring.
.... This seems utterly bizarre, do chainrings really buckle?

It can happen, though it's rare: there shouldn't be any significant lateral force on a chainring in normal use. It's more common to bend one in a fall.

Are the "stack bolts" that hold it on to the spider tight?

Cheers,
W.

nicklouse

and is the cranks bolt(s) tight.

WesternWay

Thanks both, bolts all seem tight.... By eye it looks like the ring is buckled slightly inwards around where the crank is...

All seems odd.

George

WesternWay

Hmmm, well Evans in the city seem to have 52 or possibly 53 toothed chainrings in stock, but only Shimano 105s.... I ride a lowly Ridgeback T1 with even more lowly Alvio components.

What do you think are the chances of them interchanging nicely? I know the 105 is overkill compared to what is there already, but I just want a quick repair :-)

Rothsay

I also bent the large chainring in an inexplicale way - mostly coasting down a long hill. Miles from anywhere and in pouring rain I cannot explain it. I was on an even more lowly (and old) Raleigh. I managed to straighten it with an adjustable wrench sufficiently to get back home. I subsequently did a little more delicate bending and it now behaves perfectly.

Of course it depends on the metal the chainring is made of but it may be worth a try...

WesternWay

How bizarre, I noticed mine at the bottom of the hill at Archway, a hill which I had put no effort into due to a) inherent laziness and b) no real taste for oveertaking the roadie in front of me when I was just going to have to stop at lights at the bottom.

I bent mine back into some sort of shape and things seem "better". I have also re-adjusted the front derailleur and I /think/ that it will be better in the morning. I also took the two bigger chainrings off, cleaned them and reseated them, mainly out of blind hope :-)


Thank you everyone for your help.

wgwarburton

WesternWay wrote:

...I bent mine back into some sort of shape and things seem "better". .... I also took the two bigger chainrings off, cleaned them and reseated them, mainly out of blind hope :-) ....

If you need to come back to this:

I don't think your chainset is an "alivio". From what I can tell that's primarily an MTB groupset and the chainsets are four-bolt jobbies. I think your shifters & mechs may well be out of that stable ('cos they are easy to fit to flat-bar bikes) but your chainset is a "roadie" one (that's how it looks in the pictures of Ridgeback T1s).
To be sure of compatibility you should check the "BCD" (Bolt Circle Diameter). Assuming it is a five-bolt chainset then it'll either be a "compact" one, where the middle & outer rings mount on a 110mm BCD spider or a "standard" one with a 130mm BCD.
Put a ruler between two adjacent bolts and measure the distance between them. If it's just under 65mm then you have a 110mm BCD and if it's just over 76mm then it's 130mm.

I expect the "105" chainrings are 130mm.

Hopefully, this information will be of no use to you whatsoever... :-)

Cheers,
W.

WesternWay

WG

Thank you so much for your answer. It is mighty informative and very useful... I am sorry that I have taken so long to reply, I have been out of the office for the latter half of the week.

After putting everything back together, I set out on Weds morning, got four miles or so and snapped my chain.... ARRRRGGGGHHHHH

george

PBo

if you need to buy a replacement, check cycle surgery on holloway road too - closer to Archway than evans.