Suntour XCT V3 Chain Set

[hondated]

I want to increase the size of the chain ring set from the largest on my Specialised Hard Rock from 42 tooth to 48 tooth and I would like to ask if anyone knows whether a XCC Chain Set would be a straight replacement and if I will need to change the length of the BB.

Can I also ask if I can still use the existing Altus Front Changer or because I have increased the size of the chain set I need to fit another type.

 

[albion]

I have just gone the other way finding I was seldom using the 48.

If the Altus front dérailleur is an C051 you are fine. If a C050 it should work too, just not as smoothly.
For some reason I had the C050 fitted so I got an improvement in shifts.
I bought a PFF chainset and then found I had to change the bottom bracket down from 121mm.
No doubt the XCC needs around 112mm too but a way to find out is to try.
I think it is the new BB that makes it feel like a brand new bike.

 

[RecordAceFromNew]

Specialized has been making Hardrock with changes in spec throughout for nearly 20 years - unless you have the specific model code of the chainset, it is impossible to even guess what bb you have, and without that it is impossible to answer your question with any degree of certainty.

The info here seems to indicate that those Suntour chainsets (and there are different sub-models) require a 113mm JIS bb to deliver a 48mm chainline. So the necessary pieces of info are a) what specific chainset, and preferably, bb type/length you have, and b) what is the current chainline (that the front mech is presumably happy with).

Regarding the front mech it is not ideal if the front mech does not match the chainset, but depending on the model what you have might work ok.

 

[albion]

Yes I read 112.5 though I went from Suntour to Suntour!A cheap no name to a cheap but far more expensive looking XR300.

 

[hondated]

Thanks albion & RecordAceFromNew for your advice.The BB fitted is a 113mm and since posting I have ordered a XCC Chain Set. I know it only cost £20 but I still hope it does the job.
albion I can understand why you went the other way if you use the bike what it is meant for but I have hardly used it off road so I want to turn it into a fat tyred tourer. I have tried to determine what number the front mech is but I cannot see any marking on it.
RecordAceFromNew am I correct in thinking that the chain line is measured from the centre of the saddle tube.

 

[RecordAceFromNew]

Thanks albion & RecordAceFromNew for your advice.The BB fitted is a 113mm and since posting I have ordered a XCC Chain Set. I know it only cost £20 but I still hope it does the job.
albion I can understand why you went the other way if you use the bike what it is meant for but I have hardly used it off road so I want to turn it into a fat tyred tourer. I have tried to determine what number the front mech is but I cannot see any marking on it.
RecordAceFromNew am I correct in thinking that the chain line is measured from the centre of the saddle tube.

Chainline is measured from the centre of the bike, the easiest is from the centre of the seat tube near the chainset, to the centre of the middle ring for a triple, and middle of the first and second ring for a double.

If you are going to try using the existing front mech to see how it goes, you will need to move the front mech up the seat tube, by 12mm if it is correctly positioned currently. Better still follow this trying not to skip any step.

 

[RecordAceFromNew]

In case you are unaware you might need a chain longer by two or four links (again assuming the current chain is the correct length). You can check with a chain length calculator.

 

[hondated]

RecordAceFromNew apologies for not replying sooner thanks for advice again and currently working on problem