3 x 6 crankset question
03-31-21, 09:11 AM
#1
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3 x 6 crankset question
I'm a casual plonker and need to replace my current crankset. Having some difficulty locating 3 x 6s that appear any better made than my current (press fit/welded rings). What is the down side to installing a 3x7 or -8 with my 6 gear freewheel?
03-31-21, 09:26 AM
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You need to look at whether the freewheel will fit. It might not fit between the frame.
You may need a new derailleur.
You may need a longer chain.
You may need a new derailleur.
You may need a longer chain.
03-31-21, 10:33 AM
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Not enough information given. Start with make and model of your current bicycle, and year if known. Then make and model of your crankset, if known. Also, number of teeth on each of the three chainrings. Type of interface appears to be tapered square spindle.
Now, what is your budget for the replacement?
After you've removed your crankset, then you can measure your existing spindle. If you want to re-use the bottom bracket bearing and spindle, then this measurement will tell you whether any particular replacement crankset will be compatible. Full replacement of the bottom bracket bearing/spindle plus crank becomes an economic/availability decision based on what you have now.
Please provide the requested information.
Now, what is your budget for the replacement?
After you've removed your crankset, then you can measure your existing spindle. If you want to re-use the bottom bracket bearing and spindle, then this measurement will tell you whether any particular replacement crankset will be compatible. Full replacement of the bottom bracket bearing/spindle plus crank becomes an economic/availability decision based on what you have now.
Please provide the requested information.
03-31-21, 10:38 AM
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If you're only replacing the crankset of a 3x6 drivetrain, with a new triple, there really shouldn't be any triple crankset that won't work. You may also need to replace the bottom bracket, but if your existing crankset is square taper, any square taper, triple crank, should work just fine. You may need to verify taper standards and spindle length, are the only things I can think of that might go wrong?
03-31-21, 10:45 AM
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I just don’t see the point of your question. It sounds like recovering wants to replace the crank on an existing drivetrain.
No, recovering won’t need a new derailer or a chain or to see if the freewheel will fit in the frame. I’m assuming that recovering has a 6 speed drivetrain already.
You haven’t said why you want to replace it but, assuming that you are replacing an old crank with a newer, better crank, the “speed” won’t matter. I’d suggest looking for used at this point because triples have become rare and the ones offered are often not much better than the riveted (not welded) rings you have.
You haven’t said why you want to replace it but, assuming that you are replacing an old crank with a newer, better crank, the “speed” won’t matter. I’d suggest looking for used at this point because triples have become rare and the ones offered are often not much better than the riveted (not welded) rings you have.
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03-31-21, 12:29 PM
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03-31-21, 05:51 PM
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As said a 6s rear drive will work just fine with 6/7/8 and even most 9s cranksets. Assuming BSA threaded square taper bottom bracket what you have to pay attention to is BB spindle length and chainline. The crankset chosen determines what BB spindle length you will need. If you're lucky your existing BB is "close enough" to give a decent chainline and not interfere with stays. Or you buy a $15 Shimano UN 26 bottom bracket with the spindle length your new crank requires. Likely may need to do some adjustment on your FD
03-31-21, 07:15 PM
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When I swapped out my 3X Chain rings on my MTB I reused the BB (sq taper) and had to shim out the FD to get the proper chainline, but it wasn't a big deal. I could have replaced the BB and avoided the shimming, but the one in it was less than a year old and in good nick. My new 3X had taller gears so I did have to add a couple links to the chain also. Not sure what recovering is actually trying to do though.
04-01-21, 08:19 AM
#12
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The OP wasn’t specific as to why the current crankset needed to be replaced other than wanting one that would “appear any better made” than the OEM one. Is the current crankset damaged? Does it not function properly? That reason would definitely be a factor, IMHO, in the decision to put any effort into this project. I too, would need more info RE: the bike’s make, model and age before spending time, effort and/or money on this project.
Last edited by sovende; 04-01-21 at 08:24 AM.
04-01-21, 09:18 AM
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A lot to unpack here.
While bike value is not the driving force, it does lead to a woulda-shoulda situation depending on the cost.
I would guess your bike is either inexpensive, older, or both.
You can go from a 2x to a 3x and it doesn’t matter if the crankset is designed for 6,7, or 8 speed.
With that change, you might need a new front derailleur for the wider chainring range, or you might get by with what you have.
You can go from a 6 speed to 7 speed freewheel without issue, except if you are running 6 speed index shifters and not friction. Which might mean new shifters.
There is a snowball effect depending on what you have, and no one here knows exactly what you have.
Upgrading always “sounds” like a good idea until one thing leads to another and then you should have just bought another bike, even a used or inexpensive one.
John
While bike value is not the driving force, it does lead to a woulda-shoulda situation depending on the cost.
I would guess your bike is either inexpensive, older, or both.
You can go from a 2x to a 3x and it doesn’t matter if the crankset is designed for 6,7, or 8 speed.
With that change, you might need a new front derailleur for the wider chainring range, or you might get by with what you have.
You can go from a 6 speed to 7 speed freewheel without issue, except if you are running 6 speed index shifters and not friction. Which might mean new shifters.
There is a snowball effect depending on what you have, and no one here knows exactly what you have.
Upgrading always “sounds” like a good idea until one thing leads to another and then you should have just bought another bike, even a used or inexpensive one.
John
04-02-21, 10:41 AM
#14
Senior Member
A lot to unpack here.
While bike value is not the driving force, it does lead to a woulda-shoulda situation depending on the cost.
I would guess your bike is either inexpensive, older, or both.
You can go from a 2x to a 3x and it doesn’t matter if the crankset is designed for 6,7, or 8 speed.
With that change, you might need a new front derailleur for the wider chainring range, or you might get by with what you have.
You can go from a 6 speed to 7 speed freewheel without issue, except if you are running 6 speed index shifters and not friction. Which might mean new shifters.
There is a snowball effect depending on what you have, and no one here knows exactly what you have.
Upgrading always “sounds” like a good idea until one thing leads to another and then you should have just bought another bike, even a used or inexpensive one.
John
While bike value is not the driving force, it does lead to a woulda-shoulda situation depending on the cost.
I would guess your bike is either inexpensive, older, or both.
You can go from a 2x to a 3x and it doesn’t matter if the crankset is designed for 6,7, or 8 speed.
With that change, you might need a new front derailleur for the wider chainring range, or you might get by with what you have.
You can go from a 6 speed to 7 speed freewheel without issue, except if you are running 6 speed index shifters and not friction. Which might mean new shifters.
There is a snowball effect depending on what you have, and no one here knows exactly what you have.
Upgrading always “sounds” like a good idea until one thing leads to another and then you should have just bought another bike, even a used or inexpensive one.
John
but you said it better 
!
