Chain slipping after shimano 105 front derai lleur adjustment

Doors1575

Hi all.
This is my first post. I have just put on a new chain and cassette on my cx bike. Although all was previously running fine the chain was stretched and the cassette had done 4000 mile. The bike hadnt been used for about 3 weeks and had picked up a lot of salt and rain through the winter which is i think why when I went to shift the front derailleur nothing happened. SO not to worry , I just used it on small chainring till I got home. After some front derailleur cable adjustment all seemed fine, with the derailleur shifting smoothly. As soon as I started to pedal on the road the chain slipped like buggery on the big ring, not being able to put any pressure on whatsoever. All is absolutely fine on small chairing. The derailleur looks to be set up ok so why is chain slipping? Surely the big cog can't need replacing as I thought if that was the case it would just slip slightly at first under load. Anybody have any ideas?
Cheers Ian.

cgfw201

Could well be the big ring needs replacing. If chain and cassette are new, and the big ring is worn then it might skip.

4000 miles can be enough for this depending on how clean the chain was kept previously. If it was often running with crap in the drivechain then it can erode faster than usual, and it only needs a slight bit of wear to cause the skipping, annoyingly.

Could be something else mind.

cooldad

IF it was fine until you fiddled, it's probably due to the fiddling.

vimfuego

My bet is the chainring is worn & needs replacing too. Mileage looks low for that TBH but as above, depends on how clean you keep things & how often you use the big ring. If you're on it a lot & mash away then that might explain it.

I have a 1X on my commuter & the chainring needed replacement last time I changed the chain - only had about 4,000 miles in it too (which is way less than any of my road bikes have done before a replacement was needed) but as it's obviously always in the same ring, then mileage isn't shared between the chainrings & so it's bound to need replacing sooner. I would add that I keep mine pretty clean (bike related OCD me) so it's entirely possible that yours is worn too. Do the teeth look a bit shark-finny?

That and SRAM chainrings are made of cheese ;-)

diamonddog

cooldad wrote:

IF it was fine until you fiddled, it's probably due to the fiddling.

^This. the derailleur was probably sticking due to the salt and dirt build up and it just needed cleaning not fiddling with.

Doors1575

Thanks for the replies. Will probably just buy a new chainring. Hear is a picture of mine at the moment. Can anyone tell me if it looks worn..
How do I attach a picture??

webboo

In the 30 plus years of cycling I have never had to replace a big chain ring as a result it being worn out.

Riding High

Agree with Webboo, it is unlikely the chainring is the problem but not impossible!!

The chainring would be the last thing to replace and I would first check your chain for stretch which requires a tool to measure the links, you may find that you're chain is stretched and needs replacing. If this is the case then most people would recommend replacing the chain and the rear cassette and if you do that and still have issues then it could be your chainring!!!

Hope this helps........

cooldad

I would clean, lube and make sure everything is adjusted properly before buying random stuff.

diamonddog

100% This^^

Doors1575

It's a brand new chain and cassette but 4000 plus mile chainring...

Doors1575

Thanks all for the advice. It WAS just the chainring. Replaced it and all is fine