Advice sought on interchangable chain rings.

[night cycler]

I am wanting to replace my worn large chain ring-Shimano 105, 50 teeth, 11 speed, FC5800 for the identical original part.

The elderly guy that has the local cycle repair shop in the village felt that the replacement ring was quite expensive (cheapest I have found so far is £53.99).

It has been explained to me that these 11 speeds are relatively new, and apparently this reflects the price. I don't quite understand how the number of gears on the cassette effects the change ring compatibility. For example, would it be ok to fit a chain ring that was intended for a 10 speed?

 

[User6179]

I think the new 11 speed is 4 bolt instead of the usual 5 bolt system , so you are stuck with a limited choice .

 

[T4tomo]

cynics would say this isn't an accident!

spa cycles is a good place to look for stuff like chainrings if you haven't stumbled across them already online.

 

[Cycleops]

Ah, progress.

 

[night cycler]

I think the new 11 speed is 4 bolt instead of the usual 5 bolt system , so you are stuck with a limited choice .

Yes it is.

 

[night cycler]

cynics would say this isn't an accident!

spa cycles is a good place to look for stuff like chainrings if you haven't stumbled across them already online.

Thanks, I will have a look.

 

[arch684]

Tiagra 4700 10 speed is 4 bolt

 

[User6179]

Yes it is.

How many miles have you done on the crankset ?

 

[Sharky]

Are you sure it's worn out?
As you say, it's a newish product, so can't have been in use for too long and I would expect the cassettes to wear out first?

 

[User6179]

Tiagra 4700 10 speed is 4 bolt

I would bet it is the same outer ring as the 11 speed 105 but is it any cheaper ?

 

[Yellow Saddle]

I am wanting to replace my worn large chain ring-Shimano 105, 50 teeth, 11 speed, FC5800 for the identical original part.

The elderly guy that has the local cycle repair shop in the village felt that the replacement ring was quite expensive (cheapest I have found so far is £53.99).

It has been explained to me that these 11 speeds are relatively new, and apparently this reflects the price. I don't quite understand how the number of gears on the cassette effects the change ring compatibility. For example, would it be ok to fit a chain ring that was intended for a 10 speed?

Yes, it would (technically) be OK to fit a 10-speed chainring as the internal width of 10 and 11-speed chains are the same. Therefore the ring width is the same. However, that particular crank of yours is fancy. It has an 3-D structure and the chainring countours with the crank's organic shape. The chainring is hollow and therefore very complex to make and it costs a lot of money. If you were to fit another chainring on there, the shape won't match and it will look really ugly and present you with some sharp edges.

The replacement ring is a proprietary part available only from Shimano.

Good looks cost money.

Post a nice side-on photo of that chainring so we can have a look at the wear on those teeth. A big ring takes a long time to wear out.

 

[Ajax Bay]

Rose have the Tiagra FC-4700 50t chainring for less than £46 (with P&P). Could consider a complete 10sp crankset replacement (offers around £80 for Tiagra and £90 for 105).

 

[night cycler]

How many miles have you done on the crankset ?

About 2,750 miles

 

[ianrauk]

About 2,750 miles

I would say that's bugger all in the scheme of things. Certainly not enough to warrant changing it.
But as others have said, put up a picture.

 

[night cycler]

Are you sure it's worn out?
As you say, it's a newish product, so can't have been in use for too long and I would expect the cassettes to wear out first?

Guy in the indi cycle shop pointed out to me the worn area(s) I could clearly see one tooth warn down quite a bit. Knowing how the chain has been slipping, I didn't inspect further. I'm having the chain & cassete changed too. (Don't wanna be a rich man in the grave yard) The cycling does more to beat depresion than meds, so hey ho , no expense spared. I don't smoke, not had a drink for almost 6 months, single bloke etc.