triple crank with 8speed cassette

[woodbutcher]

I am seriously out of my depth on this one but can anyone tell me what the issues are likely to be if l try to run a 50 40 30 crank with an 8 speed cassette. Would l need double or triple shifters and what size chain etc etc. Forgive my ignorance but lve not tried this combination before !

 

[raleighnut]

Not a problem but you do need a triple shifter on the left, I run a few bikes with 3x7. Bear in mind you'll need at least a medium cage rear mech though or a long cage if running a wide ratio cassette.

 

[TheDoctor]

It's not that uncommon. You'll need triple shifters, yes, and the front mech should be for a triple too. 8 speed chain, and adjust the chain as normal so you can shift into the big- big combination.

 

[woodbutcher]

Thanks raleighnut and The Doctor , even one of my limited tech.expertise can understand what you say

 

[Cycleops]

All should be quite straightforward. You'll need to size your new chain but GCN have a three methods video for this on YouTube. Simplest is big ring front to big cog rear(omitting derailleur) plus two links. Make sure you buy a chain with a quick link .

 

[woodbutcher]

All should be quite straightforward. You'll need to size your new chain but GCN have a three methods video for this on YouTube. Simplest is big ring front to big cog rear(omitting derailleur) plus two links. Make sure you buy a chain with a quick link .

Will do, thanks for that !

 

[Ajax Bay]

plus two links

To be clear that's 'two' half-links of half an inch or a 'link' of one inch.

 

[mcshroom]

It's a perfectly standard set up. You need a triple front mech, triple shifter for the front (unless you are running downtubes), and a GS or SGS rear mech. At 8sp you can use either a road (medium "GS" cage), or a MTB (long "SGS" cage) rear mech. You can also use 9sp derailleurs no problem.

My tourer is 48-38-28 (or 42-32-22) with an 11-32 8sp rear. I have a 9sp sora triple front mech, an Alivio 8sp rear, and old 2300 shifters. That's worked fine for over 10,000 miles

 

[woodbutcher]

It's a perfectly standard set up. You need a triple front mech, triple shifter for the front (unless you are running downtubes), and a GS or SGS rear mech. At 8sp you can use either a road (medium "GS" cage), or a MTB (long "SGS" cage) rear mech. You can also use 9sp derailleurs no problem.

My tourer is 48-38-28 (or 42-32-22) with an 11-32 8sp rear. I have a 9sp sora triple front mech, an Alivio 8sp rear, and old 2300 shifters. That's worked fine for over 10,000 miles

To be clear that's 'two' half-links of half an inch or a 'link' of one inch.

Gotcha ! thanks.

 

[adamhearn]

As above though I wouldn't say that 50-40-30 is a common chainring size combination (closest/more 'normal' for off the shelf parts is 48-38-28). However, there's no reason those sizes would cause a problem. Quick links are chain width (aka speed) dependent; KMC's is 7/8 speed compatible.

 

[woodbutcher]

As above though I wouldn't say that 50-40-30 is a common chainring size combination (closest/more 'normal' for off the shelf parts is 48-38-28). However, there's no reason those sizes would cause a problem. Quick links are chain width (aka speed) dependent; KMC's is 7/8 speed compatible.

Its a vintage Campagnolo Centaur which l bought before l knew what l was going to do with it !

 

[Ajax Bay]

Its a vintage Campagnolo Centaur

Very nice chainset; and a good chainring combination, even if it doesn't meet @adamhearn 's valid if nit-picky definition of 'common'.
Triple chainset = triple ergo or STI (shifter). 8 speed cassette = 8 speed Campagnolo ergo and derailleur (if Campagnolo cassette) or if Shimano cassette: STI and Shimano rear derailleur.
Unless OP already has a square taper bottom bracket (for a triple), they will need one (eg UN-55) with a longish axle length (eg 113mm) to get the chain line correct with a triple.
Sheldon is well worth a read.

KMC's is 7/8 speed compatible.

KMC make 'quick links for all chain (speed) widths. Only those designed for 7/8 speed chains are 'compatible' (with an 8 speed chain which the OP's going to fit).

 

[Vantage]

I've run KMC chains on my 48-38-28 8 speed rig for the last 6 years.
In my experience, you can just fit the chain as it is straight out of the bag, no resizing and stuff. It'll run fine.

 

[woodbutcher]

Very nice chainset; and a good chainring combination, even if it doesn't meet @adamhearn 's valid if nit-picky definition of 'common'.
Triple chainset = triple ergo or STI (shifter). 8 speed cassette = 8 speed Campagnolo ergo and derailleur (if Campagnolo cassette) or if Shimano cassette: STI and Shimano rear derailleur.
Unless OP already has a square taper bottom bracket (for a triple), they will need one (eg UN-55) with a longish axle length (eg 113mm) to get the chain line correct with a triple.
Sheldon is well worth a read.

KMC make 'quick links for all chain (speed) widths. Only those designed for 7/8 speed chains are 'compatible' (with an 8 speed chain which the OP's going to fit).

Just in from a belated Burns Night French/Scots supper so best l read your info. a bit later ...on first read it looks very interesting ....thank you.

 

[woodbutcher]

Just in from a belated Burns Night French/Scots supper so best l read your info. a bit later ...on first read it looks very interesting ....thank you.

I was wondering if l could use mirage 9speed ergo shifters with the triple chainset and 8 peed campagnolo cassette , l have a campagnolo triple front derailleur . Only asking because l happen to have the mirage shifters available !