Square taper crank and bottom bracket: fitting to a frame
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Square taper crank and bottom bracket: fitting to a frame
I've got a White Industries square taper crank (46/30T) and their square taper bottom bracket. I want to put it on my new frame.
When I did this, the inner (30T) ring itself clears the chain stays, but the bolts that hold the inner ring on the rest of the crankset touch the frame on rotation (and I don't even have it tightened down all the way yet).
So I guess I have 3 choices:
1. Get a smaller chainring (the WI crank allows you to do this; I can go down to 26T which may be enough to get it out of the way, but maybe not).
2. Get a wider bottom bracket spindle.
3. Stick a $150 GRX crank on the thing (which is what I did on my other bike, which is why I had to buy a new frame for this crank, so that would be a demoralizing albeit expedient solution).
Option #2 seems like the most reasonable, but this is where my understanding of square taper bottom brackets is lacking. If I get one with a wider spindle, does that mean that the distance between the drive-side cup and the crank arm will be increased, or does it mean it would require a frame with a wider bottom bracket shell, and would be irrelevant to solving my problem?
Option #1 would allow me to keep my current chain-line, BB, and would have the merit of giving me an excuse to have a lower gear on my touring bike.
When I did this, the inner (30T) ring itself clears the chain stays, but the bolts that hold the inner ring on the rest of the crankset touch the frame on rotation (and I don't even have it tightened down all the way yet).
So I guess I have 3 choices:
1. Get a smaller chainring (the WI crank allows you to do this; I can go down to 26T which may be enough to get it out of the way, but maybe not).
2. Get a wider bottom bracket spindle.
3. Stick a $150 GRX crank on the thing (which is what I did on my other bike, which is why I had to buy a new frame for this crank, so that would be a demoralizing albeit expedient solution).
Option #2 seems like the most reasonable, but this is where my understanding of square taper bottom brackets is lacking. If I get one with a wider spindle, does that mean that the distance between the drive-side cup and the crank arm will be increased, or does it mean it would require a frame with a wider bottom bracket shell, and would be irrelevant to solving my problem?
Option #1 would allow me to keep my current chain-line, BB, and would have the merit of giving me an excuse to have a lower gear on my touring bike.
Last edited by Cyclist0108; 12-05-19 at 01:41 PM.
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I've got a White Industries square taper crank (46/30T) and their square taper bottom bracket. I want to put it on my new frame.
When I did this, the inner (30T) ring itself clears the chain stays, but the bolts that hold the inner ring on the rest of the crankset touch the frame on rotation (and I don't even have it tightened down all the way yet).
So I guess I have 3 choices:
1. Get a smaller chainring (the WI crank allows you to do this; I can go down to 26T which may be enough to get it out of the way, but maybe not).
2. Get a wider bottom bracket spindle.
3. Stick a $150 GRX crank on the thing (which is what I did on my other bike, which is why I had to buy a new frame for this crank, so that would be a demoralizing albeit expedient solution).
Option #2 seems like the most reasonable, but this is where my understanding of square taper bottom brackets is lacking. If I get one with a wider spindle, does that mean that the distance between the drive-side cup and the crank arm will be increased, or does it mean it would require a frame with a wider bottom bracket shell, and would be irrelevant to solving my problem?
Option #1 would allow me to keep my current chain-line, BB, and would have the merit of giving me an excuse to have a lower gear on my touring bike.
When I did this, the inner (30T) ring itself clears the chain stays, but the bolts that hold the inner ring on the rest of the crankset touch the frame on rotation (and I don't even have it tightened down all the way yet).
So I guess I have 3 choices:
1. Get a smaller chainring (the WI crank allows you to do this; I can go down to 26T which may be enough to get it out of the way, but maybe not).
2. Get a wider bottom bracket spindle.
3. Stick a $150 GRX crank on the thing (which is what I did on my other bike, which is why I had to buy a new frame for this crank, so that would be a demoralizing albeit expedient solution).
Option #2 seems like the most reasonable, but this is where my understanding of square taper bottom brackets is lacking. If I get one with a wider spindle, does that mean that the distance between the drive-side cup and the crank arm will be increased, or does it mean it would require a frame with a wider bottom bracket shell, and would be irrelevant to solving my problem?
Option #1 would allow me to keep my current chain-line, BB, and would have the merit of giving me an excuse to have a lower gear on my touring bike.
The longer spindles are always contained within a standard BB shell width bearing unit, IME. (i.e. either 68 or 70 for a road bike)
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Square taper BBs come in a variety of spindle lengths for just this purpose.
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Looks like White comes in 3 lengths, but pricey at $120+, if you could exchange......
Depends on how long your present BB is. Of course Shimano sq taper would be
80% cheaper. I had a White BB on my recumbent and it lasted ~30k miles. Bearings
seemed ok but there was a bit of slop in the axle-bearing area so I put a Shimano in.
Depends on how long your present BB is. Of course Shimano sq taper would be
80% cheaper. I had a White BB on my recumbent and it lasted ~30k miles. Bearings
seemed ok but there was a bit of slop in the axle-bearing area so I put a Shimano in.
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Is there any chance that the inner chainring is flipped around, and the chainring nuts are not able to sit in a counterbore?
I'm not super familiar with these cranks, but usually inner chainrings are counterbored so that the chainring nuts can sit flush, or close to it...
I'm not super familiar with these cranks, but usually inner chainrings are counterbored so that the chainring nuts can sit flush, or close to it...
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I have seen this suggestion in the past, but I disagree with it. Pushing the BB to one side will result in the pedal spacing being asymmetric and will effect the rider's balance on the bike - ie. one foot closer to the centre of the bike than the other. I suppose with clipless pedals you could adjust your cleats to compensate but this seems like a kludge.
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Smaller diameter chainring won't help you if the bolt heads are touching the frame, because it's the lateral width that is the problem, not the radial diameter, unless your description of the problem is wrong. A photo would help.
As someone mentioned, check that the chainring isn't flipped the wrong way. The countersink on the bolt holes on one side will reduce the head height.
If that isn't the problem, then only a spacer under the drive side cup or a longer bb will solve this proproblem. Shimano un55 is $11. However some lengths are not symmetric, usually longer on the left side, I assume to allow you to shim the drive side to adjust the chainline. Otherwise maybe Shimano cranks are designed to be symmetric when using the asymmetrical spindle
https://forum.cyclinguk.org/viewtopic.php?t=105385
As someone mentioned, check that the chainring isn't flipped the wrong way. The countersink on the bolt holes on one side will reduce the head height.
If that isn't the problem, then only a spacer under the drive side cup or a longer bb will solve this proproblem. Shimano un55 is $11. However some lengths are not symmetric, usually longer on the left side, I assume to allow you to shim the drive side to adjust the chainline. Otherwise maybe Shimano cranks are designed to be symmetric when using the asymmetrical spindle
https://forum.cyclinguk.org/viewtopic.php?t=105385
Last edited by tomtomtom123; 12-05-19 at 02:57 PM.
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You don't need a shim. You don't need to flip your chainring. You need a wider spindle. JIS spindle BB's are cheap and plentiful and come in many different widths. You could spend the bucks for the fancy White Industry one or you could get a cheap and reliable Shimano one.
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I have seen this suggestion in the past, but I disagree with it. Pushing the BB to one side will result in the pedal spacing being asymmetric and will effect the rider's balance on the bike - ie. one foot closer to the centre of the bike than the other. I suppose with clipless pedals you could adjust your cleats to compensate but this seems like a kludge.
Back when adjustable bottom brackets (both square taper and cottered) were standard, it was common for bikes to come stock with asymmetric spindles as a means of minimizing q-factor. The offsets were often huge: my '79 Fuji America is about 1cm wider on the drive side than on the non-drive side, and some bikes were even more asymmetric than that. You almost never hear this brought up as a peculiar aspect of riding vintage bikes, because people mostly didn't notice the "imbalance."
Recently I was having some trouble with the chain on my gravel bike rubbing the tire in the lowest gear (small-big). I could have moved to a longer spindle, but the q-factor was already annoyingly high. So I instead switched from a 118mm spindle to a shorter 115mm spindle, and added a 4mm spacer on the drive side:
This added 2.5mm to the drive side, while removing 5.5mm from the non-drive side, and making the spindle effectively .8cm longer on the DS than the NDS. Pedaling feels basically the same as ever.
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Thanks, everyone, for all the suggestions. It sounds like a different BB spindle is the easiest fix. I just wasn't sure that it would increase the chainline (which I guess is what I would need).
Here is a photo of the chainrings from their website. It doesn't show very clearly what is going on around back, but if you look closely, you can see the protrusion. Also, because of the unique mounting mechanism, the bolts will be moved inward with a smaller inner chainring.
My bike (loosened the crank bolt so it is no longer scraping the frame):
Here is a photo of the chainrings from their website. It doesn't show very clearly what is going on around back, but if you look closely, you can see the protrusion. Also, because of the unique mounting mechanism, the bolts will be moved inward with a smaller inner chainring.
My bike (loosened the crank bolt so it is no longer scraping the frame):
Last edited by Cyclist0108; 12-05-19 at 04:49 PM.
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That photo sure makes it look like the splay of the chainstays is the problem. I agree that a longer BB is probably the best answer.
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You might want to measure the chainline so that you can calculate what happens when you use a different length spindle. Also if you care about symmetry, you should measure the distance from the center of the frame to the outside surfaces of each arm. So you will know what happens when you change to an asymmetric Shimano spindle.
Edit- I looked in their website but they don't show the inner chainring. Is it using a standard 8 or 10mm bolt hole in a flat chainring with 12mm diameter bolt head? If so, then you might be able to use cheap $10 74mm bcd chainrings in various teeth numbers, assuming that your current inner chainring has a much bigger bcd. But if it uses some special bolt hole size or flange shape, then a standard 74mm bcd chainring might not be compatible
Edit- I looked in their website but they don't show the inner chainring. Is it using a standard 8 or 10mm bolt hole in a flat chainring with 12mm diameter bolt head? If so, then you might be able to use cheap $10 74mm bcd chainrings in various teeth numbers, assuming that your current inner chainring has a much bigger bcd. But if it uses some special bolt hole size or flange shape, then a standard 74mm bcd chainring might not be compatible
Last edited by tomtomtom123; 12-05-19 at 09:27 PM.
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IIRC, you said up thread that the crank isn't fully tightened onto the spindle. Is that correct? If so you would be best off in my opinion getting a slightly longer spindle. Or, if there is a frame builder near you they might be able to crimp the chainstay for you without damaging the entire chainstay or much of the paint.
Just be sure that whomever does the work does not do it by whacking the chainstay with a hammer. I was on a long ride in Toronto Canada when i noticed my crank was almost touching the chainstay. I stopped in at a bike shop and asked them it they could move the crank a bit to the right so that the chainring wouldn't be so close t o the chainstay. As I was just passing through Toronto I asked them if they could do it that day. They said sure. I figured they'd put a spacer between the fixed cup and the frame. Nope, they hammered t he chainstay. This is the result.
Cheers
Just be sure that whomever does the work does not do it by whacking the chainstay with a hammer. I was on a long ride in Toronto Canada when i noticed my crank was almost touching the chainstay. I stopped in at a bike shop and asked them it they could move the crank a bit to the right so that the chainring wouldn't be so close t o the chainstay. As I was just passing through Toronto I asked them if they could do it that day. They said sure. I figured they'd put a spacer between the fixed cup and the frame. Nope, they hammered t he chainstay. This is the result.
Cheers
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Cheers
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The crimp is really disturbing. It actually looks worse than it is in the photo, but what a crap design. (I was going to buy a Spork 2.0 for my other bike so I could put on front panniers, but this frame was cheaper than that fork, so I decided to go for this instead.)
Since I had a 2.5mm spacer lying around, I put that on*. The good news is it solves the crank bolt issue. The bad news is that there is not enough of the thread exposed on the adjustable (non-drive-side) cup to put the lockring on. The spindle is 113 mm, so at least I know how much to size up now if I get a new square taper BB, but my growing hatred of square taper (which is why I took this off my custom bike and put on a GRX crankset) is making me think twice.
From https://sheldonbrown.com/bbsize.html
Looking at this, I think I need 3K?
* Regarding the shim: My right heal clips my chainstay on my other bike, so shimming the BB on the drive side might actually help, all else being equal.
Since I had a 2.5mm spacer lying around, I put that on*. The good news is it solves the crank bolt issue. The bad news is that there is not enough of the thread exposed on the adjustable (non-drive-side) cup to put the lockring on. The spindle is 113 mm, so at least I know how much to size up now if I get a new square taper BB, but my growing hatred of square taper (which is why I took this off my custom bike and put on a GRX crankset) is making me think twice.
From https://sheldonbrown.com/bbsize.html
Looking at this, I think I need 3K?
* Regarding the shim: My right heal clips my chainstay on my other bike, so shimming the BB on the drive side might actually help, all else being equal.
Last edited by Cyclist0108; 12-06-19 at 10:49 AM. Reason: added footnote
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...the White Industries bottom bracket requires a lock ring ? I've never seen a sealed unit BB that needs a lockring on the non drive side. I guess maybe I don't know what we're talking about any more. The whole deal with using a spacer under the drive side lip on a sealed unit is pretty much based on the idea that the non drive side cup that holds the sealed unit in place just threads on into the BB until the tapered lip butts up against the cartridge and holds the thing in place.
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It seems to use replaceable deep groove cartridge bearings. I've never used something like this but the photo shows a locking ring on the nds cup, probably to adjust preload. If there isn't enough thread after adding a spacer, maybe he can't get the locking ring on.
You might want to measure the chainline now to see where it's at, and the distance of the crank to the center of frame to check the symmetry.
Is the chainring a standard shape? Does is have standard bolt holes? What is the BCD of the current ring? If it is large, then you might be able to replace it with a 74mm bcd ring to bring the bolts in closer to the spindle. Then you might not need the spacer.
Or ask white industries. I'm sure they get these questions frequently
You might want to measure the chainline now to see where it's at, and the distance of the crank to the center of frame to check the symmetry.
Is the chainring a standard shape? Does is have standard bolt holes? What is the BCD of the current ring? If it is large, then you might be able to replace it with a 74mm bcd ring to bring the bolts in closer to the spindle. Then you might not need the spacer.
Or ask white industries. I'm sure they get these questions frequently
Last edited by tomtomtom123; 12-06-19 at 11:41 AM.
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...the White Industries bottom bracket requires a lock ring ? I've never seen a sealed unit BB that needs a lockring on the non drive side. I guess maybe I don't know what we're talking about any more. The whole deal with using a spacer under the drive side lip on a sealed unit is pretty much based on the idea that the non drive side cup that holds the sealed unit in place just threads on into the BB until the tapered lip butts up against the cartridge and holds the thing in place.
BTW, I took this thing off of my other bike because I got sick of the NDS spontaneously tightening itself up. The lock-ring doesn't work very well. (Maybe I should chuck my $130 boutique BB and its new ceramic bearings into the trash and get the $13 Shimano special.)
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The Shimano bb is completely fixed to the drive side cup so that the nds cup is floating and doesn't need a locking ring.
There is a video if you are curious how the balls are retained
https://youtu.be/lar7mIMmTRE
There is a video if you are curious how the balls are retained
https://youtu.be/lar7mIMmTRE
Last edited by tomtomtom123; 12-06-19 at 11:55 AM.
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In case you try re-using that BB on a bike it fits, maybe try the stronger of the Loctites, for that fussy lock-ring. 🙂
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If a regular Shimano cartridge BB could be used, the 115mm UN55 would be the next logical choice. It would give approximately 1mm extra on each side.
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Last edited by Cyclist0108; 12-06-19 at 08:09 PM. Reason: :s/118/117.5/g
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They finally introduced a 30mm spindle version that you can use with 21st century BB components. (I still had to get the square taper because there wasn't enough room in the BB shell on my other bike, thanks to some Di2 wiring -- not an issue on this one.) But I have to tell you, the $150 Shimano GRX and $14 external ultegra BB I replaced this with on my other bike is an improvement over this thing.