crankset advice please!

[novice ridgeback]

Hello, I’d like to change my crankset. It’s currently a Shimano Altus FC-M311 48/38/28. Bottom bracket is Shimano BB-UN26. Cassette is an 8 speed. Bike ridgeback tour. Would like something comparable or upgrade. Generally ride between 30-70 miles with up to 4,000ft of climbing and will be riding coast to coast in July (hopefully). Bit confused by it all tbf (maintainance novice). Like for like Altus cranksets appear to be for bottom brackets of 123mm, but I think mine might be smaller (not sure how to read BB). Part says L117R does this mean 117mm? How significant is The BB size for crankset? Cheers!

 

[Big John]

If that BB was taken off your bike and the chainset worked ok (without the inner ring's teeth chewing into the chainstay) then a 117mm is fine. The L and R simply refer to the left and right side of the bike for when you fit it. Agreed, looking on the internet it suggests a 123mm width BB but the 117 has worked fine up to now. Depending on what chainset you go for will dictate what BB you'll need. I'll leave it up to the triple chainset experts to advise a suitable upgrade but chances are you may need to buy the chainset AND a new BB.

Your bike looks ideally suited to the coast to coast you have planned. Good luck 👍

 

[Chislenko]

Just to confuse the issue my triple is on a 68-113.

 

[Cycleops]

What would be the purpose of your upgrade? Your chainset looks fine to me, apart from the fact I can't see the big ring.

You could swap it for a Shimano Hollowtech chainset which has outboard bearings but the only advantage is lighter weight. They usually come with BB. You'll need a special tool to fit.

 

[T.M.H.N.E.T]

The L-R number is the total width of the square taper, these vary. The 68 is the BB shell width on the bike

If you're changing to a more modern BB standard/crankset that will likely be Hollowtech2 - the BB you will need is 68mm shell English thread

 

[Blue Hills]

What would be the purpose of your upgrade? Your chainset looks fine to me, apart from the fact I can't see the big ring.

You could swap it for a Shimano Hollowtech chainset which has outboard bearings but the only advantage is lighter weight. They usually come with BB. You'll need a special tool to fit.

View attachment 582057

plus one to questioning the point of the upgrade, but I'd avoid at all costs going to an external BB thing, particularly on an old frame.
If I did have to replace the original crankset for whatever reason I would go for another square taper.

 

[Blue Hills]

@novice ridgeback

first, congratulations on your Ridgeback - often very good bikes.

If all is working fine I'd keep what you have got - Ridgeback know a thing or two about bikes.

Am too lazy to look up your existing crankset, so a question - can you replace the rings?
If so, just replace them when they need replacing.
If not, you will unfortunately have to dump the whole thing in time.
Then I'd head for Spa cycles and one of their square taper chainsets.

 

[novice ridgeback]

What would be the purpose of your upgrade? Your chainset looks fine to me, apart from the fact I can't see the big ring.

You could swap it for a Shimano Hollowtech chainset which has outboard bearings but the only advantage is lighter weight. They usually come with BB. You'll need a special tool to fit.

View attachment 582057

Thank you for your suggestion! The outsider chain ring is very pointy!

 

[novice ridgeback]

@novice ridgeback

first, congratulations on your Ridgeback - often very good bikes.

If all is working fine I'd keep what you have got - Ridgeback know a thing or two about bikes.

Am too lazy to look up your existing crankset, so a question - can you replace the rings?
If so, just replace them when they need replacing.
If not, you will unfortunately have to dump the whole thing in time.
Then I'd head for Spa cycles and one of their square taper chainsets.

will email spa cycles, thank you 👍

 

[Cycleops]

So what’s the plan @novice ridgeback ?

 

[novice ridgeback]

So what’s the plan @novice ridgeback ?

Pop

So what’s the plan @novice ridgeback ?

https://spacycles.co.uk/m8b17s109p2000/SPA-CYCLES-XD-2-Touring-Triple-Chainset

https://www.spacycles.co.uk/m16b254s110p3233/FIRST-COMPONENTS-Bottom-Bracket-DX-30

I’m thinking of purchasing the above BB and crankset. Just not sure whether change in BB width and parts would cause any problems for the front derailleur?

 

[novice ridgeback]

@Cycleops @Blue Hills any opinions on The implications on the derailleurs, if I swap my BB size from a 117 to 110mm? Thanks

 

[Cycleops]

Why don't you go for 117 which presumably have now?

 

[novice ridgeback]

Why don't you go for 117 which presumably have now?

the alternative crankset recommends a BB of 110.SPA CYCLES XD-2 Touring Triple Chainset

 

[Cycleops]

In that case if Spa recommend it that's what to go for.