Chainring Question

[hoppym27]

I need to replace my outer chainring on my BTwin T500, its the Ounce groupset...I know its a 130BCD but can I buy any brand of that nature and install it? i.e are the boltholes in the same place whatever the brand?

 

[Globalti]

Yes as long as they are 130mm bolt circle diameter or BCD.

 

[Ajax Bay]

And the ring you procure has the correct number of bolt holes - probably 5.
Spa Cycles is the 'go to' place.

 

[tommaguzzi]

you answered your own question.
you need a chain ring which has its holes at 130 mm bcd

try these people I have used them before.




www.sjscycles.co.uk/130-bcd-5-arm/

 

[Blue Hills]

I have an unfortunate idea at the back of my head that it's not always a simple question of matching the BCD.

Or did I imagine it?

 

[boydj]

You also have to check whether it's 4-arm or 5-arm rings that you need. Older chainsets were mainly 5-arm. The newer Shimano ones are 4-arm. (Just to clarify Ajax Bay's post above).

 

[Blue Hills]

ta boyd

Isn't there another measurement which can sometimes come into play though?

 

[smutchin]

Older chainsets were mainly 5-arm. The newer Shimano ones are 4-arm.

I believe there are different designs of 4-arm as well, just to complicate things further.

 

[Tigerbiten]

I have an unfortunate idea at the back of my head that it's not always a simple question of matching the BCD.

Or did I imagine it?

Once you know the BCD then the only other question is do you need a chainring with 'ramps and pins' to help the chain climb onto it when you change gear or not.

 

[slowmotion]

One more thing you need to check is that the chainring is for the correct speed of chain.

 

[Blue Hills]

One more thing you need to check is that the chainring is for the correct speed of chain.

Isn't there a bit of leeway on that?

As in this:

https://www.spacycles.co.uk/m2b0s109p2000/SPA-CYCLES-XD-2-Touring-Triple-Chainset

Says 7, 8, or 9.

Mine's on a 9 speed build.

 

[slowmotion]

Isn't there a bit of leeway on that?

As in this:

https://www.spacycles.co.uk/m2b0s109p2000/SPA-CYCLES-XD-2-Touring-Triple-Chainset

Says 7, 8, or 9.

Mine's on a 9 speed build.

Yes, but it won't do any harm to check. Spa are really good.