Changing chainrings or crankset

[gmw492]

Hi all, my question as I am not clued up much on bike mechanics, can you change your ratio on the front chainrings , example 52/36 to 50/34 , do you have to buy a full crankset then re size the chain or can you change chainrings and do you have to re size the chain also ?
It would be on the Ultegra R8000 , new crank is about £175 , think I may stick with the 52/36 if it can’t be done , 50/34 better for climbing I believe
Thanks

 

[rivers]

Looks like you can change just the chainrings. However, the R8000 chainrings are £116 on wiggle

 

[Sharky]

Explore alternative rear cassettes, before you start changing chain rings. A one tooth difference at the rear is more effective than one tooth difference at the front. Have a study of the gear tables (bikecalc etc)

 

[Blue Hills]

Looks like you can change just the chainrings. However, the R8000 chainrings are £116 on wiggle

Not my patch of cycling perhaps, but how can a chainring cost that much?
(Note, am not criticising you or your post)

 

[rivers]

Not my patch of cycling perhaps, but how can a chainring cost that much?
(Note, am not criticising you or your post)

I thought the same to be honest. You might be able to get non r8000 branded compatible chain rings, but I haven't looked into it.

 

[Sharky]

Explore alternative rear cassettes, before you start changing chain rings. A one tooth difference at the rear is more effective than one tooth difference at the front. Have a study of the gear tables (bikecalc etc)

Example - a 36x 27 will give a 34.98" gear vs 34x26 will give 34.95" gear - practically the same, with just one tooth difference at the rear.
So just depends on what size cassette you currently have and what you can be found out there.

 

[si_c]

Chainrings by themselves are expensive - Ultegra and Dura-Ace more so as they are not high volume parts so their price reflects that.

My suggestion would be to look at R7000 chainrings instead of Ultegra, you should be able to get a set for under £75 (Bike Discount have them for about £55 plus shipping at the time of posting). You can use these with your Ultegra cranks with no difficulty as they are the same assymetric bolt pattern.

Don't forget if you change your chainrings then you will need to adjust the front derailleur to match the difference in height.

 

[iluvmybike]

Hi all, my question as I am not clued up much on bike mechanics, can you change your ratio on the front chainrings , example 52/36 to 50/34 , do you have to buy a full crankset then re size the chain or can you change chainrings and do you have to re size the chain also ?
It would be on the Ultegra R8000 , new crank is about £175 , think I may stick with the 52/36 if it can’t be done , 50/34 better for climbing I believe
Thanks

Yes it can be done - just done this for a friend. he was lucky enough to have another crankset on another bike and it was just a straight swap over. The front derailleur needed to be moved down a tad and the chain length adjusted. Up to you if you buy new crankset or just rings - it's often cheaper to buy the whole thing ime - but shop around

 

[12boy]

Consult a gear inch calculator before you buy anything. I like the Sheldon Brown one, but you may prefer something else. A 36 tooth chain ring and a 34 tooth sprocket, for example gives 27.9 gear inches and a 36/32 gives 29.7. As said above sprockets are much cheaper than chainrings. If you jump a lot in sprockets you may need to get a lot cage derailleur if your current one is a short cage.

 

[gmw492]

Chainrings by themselves are expensive - Ultegra and Dura-Ace more so as they are not high volume parts so their price reflects that.

My suggestion would be to look at R7000 chainrings instead of Ultegra, you should be able to get a set for under £75 (Bike Discount have them for about £55 plus shipping at the time of posting). You can use these with your Ultegra cranks with no difficulty as they are the same assymetric bolt pattern.

Don't forget if you change your chainrings then you will need to adjust the front derailleur to match the difference in height.

yes sounds easier that , will look at that option , thanks

 

[MichaelW2]

Chain rings are often paired to optimize the position iyf ramps, pins and cutout teeth. Specialities TA make matched pairs for just about anything but they may not be any cheaper than Shimano.
Chainsets have Bolt Circle Diameter BCD that limits the smallest chainring.
Smaller rings are better for climbing and for use by less powerful riders. These days super large rear sprockets are back in vogue so check out your other options.