105 compact chainrings fitting and which...

D@VE

I need to replace my chain and chainrings also cassette my first question is can i remove
the 34t without removing the crank?(105 hollowtech ll)as i don't have the tools to do this.

I'm running 50t/34t and 12-25 at the back would i be able to run a 12-27 or would that not work.
What i mean is will 12t to 34t make the chain to slack or 50t to 27t to tight?(does that make sense?)

I think I'm going to get a kmc chain but one last question is it a good idea to get say a TA or Stronglight chainring or just get Shimano?

Thanks for any help.

markos1963

Yes you can remove the chainrings without taking off the cranks, just undo the bolts and rotate the chainrings a few degrees and then carefully slide off along the crank arm(remove pedal first to make it easier)

But why? I have a 105 crankset that is over 4 years old and is showing no signs of wear. In fact I have an old Raliegh Record Sprint thats still going strong on it's 25yo Sugino crankset.

34/12 and 50/27 are ratios you wouldn't use(or shouldn't) and are irrelevant to the set up. Probably ok with same number of links as before but try it with one more to start with to see how it goes(you can eaily take one out, not so easy the other way round)

rocksteadyeddie

No you can't. You need to take the chainset off. It is a pretty easy job - not like the old day with crank extractors etc. A 5mmm allen key (IIRC) and you can use a big screwdriver/chissel if you don't have the tensioning screw tool. Then just ease it off. Shouldn't take more than 2 minutes.

markos1963

Rocksteadyeddie wrote:

No you can't. You need to take the chainset off. It is a pretty easy job - not like the old day with crank extractors etc. A 5mmm allen key (IIRC) and you can use a big screwdriver/chissel if you don't have the tensioning screw tool. Then just ease it off. Shouldn't take more than 2 minutes.

Errr yes you can, I have done it many times as I run a 36t for some events and need to swap over with the 34. Unless you have misread the Op and are thinking about if you can remove inner ring without taking off the outer?

D@VE

Thanks markos1963

markos1963 wrote:

But why? I have a 105 crankset that is over 4 years old and is showing no signs of wear. In fact I have an old Raliegh Record Sprint thats still going strong on it's 25yo Sugino crankset.

To be honest it's my fault it's been fine for a couple of years but i joined a club last year and i should of changed the chain earlier (been putting a new one on each year) having done a lot more miles stretching the chain causing the damage :oops:
The big ring looks ok but the small ring is definitely no good.

So if i keep on top of cleaning and swapping the chain regularly,every thing should be ok.
I've read you should measure the chain with a ruler but from where to where and how much stretch is to much?

Thanks again.

markos1963

Yes, clean and relube regulary and there should be no problems. Like you I change my chain yearly regardless and have had no problems, I have even managed to get 5000 miles out of my 105 cassette. Not a big fan of the measuring of chains, I feel that it's something thought up by manufacturers to sell more chains/cassettes. I go by the performance of the shift to decide when to change things over.

P_Tucker

Rocksteadyeddie wrote:

No you can't. You need to take the chainset off. It is a pretty easy job - not like the old day with crank extractors etc. A 5mmm allen key (IIRC) and you can use a big screwdriver/chissel if you don't have the tensioning screw tool. Then just ease it off. Shouldn't take more than 2 minutes.

No, really you can.

Pinner

Yup you should be able to take the chain ring off without taking off the crank, I have done it heaps on my own bikes.
My own 105 bike has over 20,000km on it with the original chain rings still, it just got its 4th chain (chains lasted over 6000km each, and I wouldn't clean them for that whole time) and just got its first new cassette! yup 20,000km out of one cassette, both the frame and the wheels of the bike were fatigued to death and had been replaced by the time the cassette wore out, I would call that durability from the drive train, Wouldn't use anything else for a training bike.

nmcgann

D@VE wrote:

....
So if i keep on top of cleaning and swapping the chain regularly,every thing should be ok.
I've read you should measure the chain with a ruler but from where to where and how much stretch is to much?

Thanks again.

Measure a 12" length (I measure from the edge of a rivet) and when it has stretched to 12+1/16" replace the chain.

See http://www.sheldonbrown.com/chains.html for lots of detail.