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motorcycle wheel spoke adjustment

STUBBORN

Active member
Joined
Apr 21, 2021
Messages
219
What size spoke tool?
Is this in the "general manual"
which I am having trouble getting a copy of?

Honda Service Manual, bottom page 1-13
Front Wheel
front spoke qty=36, dia BC2.9, torque = 3.2 nM / 2.4 foot pounds

Honda Service Manual, middle page 1-14
Rear Wheel
rear spoke qty=36, dia BC3.2, torque = 3.7 nM / 2.7 foot pounds

What does BC2.9 or BC3.2 mean?

Both tires are 17 inch, both have brakes so perhaps the differences must be due to the rear tire having the drive sprocket?
 

dmonkey

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Joined
Jul 4, 2021
Messages
2,136
Location
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BC2.9 and BC3.2 refer to the thread size inside the nipples, which the spokes thread into. Those thread sizes are "heavier duty" ones in the bicycle world, used for cargo bicycles and trailers.
A 5.0mm spoke wrench will fit the front spoke nipples, a 5.8mm will fit the rear spoke nipples. Note that the nipples are tapered where you put a wrench on them so the correct size wrench won't slide all the way down the 4-sided nut face on the nipple, but should instead become tight on it part way down toward the rim. These are fairly unusual sizes, so if you buy a spoke wrench kit make sure it actually includes those sizes.
You shouldn't need a spoke nipple driver unless you're relacing your wheels, and even then you can get by with a flat blade screwdriver (which can even be ground down into a DIY nipple driver).
If you look at a parts diagram you'll find very little in common between the front and rear wheel assemblies other than the inner tubes and rim strips. Different tires, wheels, hubs, spokes, etc. The rear spokes and nipples are indeed beefier, just like how the OEM rear tire has a higher load index (50) than the OEM front tire (44). You may have also noticed that the OEM tires have their tread patterns in different directions, that's to match the different forces that each tire experiences - rear tire experiences more acceleration forces, front tire more braking forces.

IMO keep "if it ain't broke, don't fix it" in mind and don't fiddle with your spokes if you're not committed to understanding, taking your time, and having the equipment on hand, to properly true the wheel on a stand. It's one thing to tighten a very loose spoke for a limp-home fix, it's another to take a wheel that's fine and introduce a wobble by tightening up spokes that don't need much adjustment, if any, for thousands of miles, depending on your riding conditions.

If you are interested in that, may I recommend starting with bicycles? They can be (but aren't always) cheaper to work with and more forgiving (read: less likely to injure or kill you) if you make a mistake.
Some great resources are Sheldon Brown's page on bicycle wheelbuilding and "Professional Guide to Wheel Building" by Roger Musson. The latter is an eBook you can buy online that's also engineering porn, every formula you could need for determining spoke length for different bicycle wheel and hub sizes as well as lacing patterns, a detailed explanation of the physics behind spoked wheels, and the answers to just about any question you could have while building or tensioning and truing a wheel. It is likely what the designated "wheel builder" at your local bike shop has on hand for reference when something unusual makes its way to their stand.
 
Last edited:

STUBBORN

Active member
Joined
Apr 21, 2021
Messages
219
BC2.9 and BC3.2 refer to the thread size inside the nipples, which the spokes thread into. Those thread sizes are "heavier duty" ones in the bicycle world, used for cargo bicycles and trailers.
A 5.0mm spoke wrench will fit the front spoke nipples, a 5.8mm will fit the rear spoke nipples. Note that the nipples are tapered where you put a wrench on them so the correct size wrench won't slide all the way down the 4-sided nut face on the nipple, but should instead become tight on it part way down toward the rim. These are fairly unusual sizes, so if you buy a spoke wrench kit make sure it actually includes those sizes.
You shouldn't need a spoke nipple driver unless you're relacing your wheels, and even then you can get by with a flat blade screwdriver (which can even be ground down into a DIY nipple driver).
If you look at a parts diagram you'll find very little in common between the front and rear wheel assemblies other than the inner tubes and rim strips. Different tires, wheels, hubs, spokes, etc. The rear spokes and nipples are indeed beefier, just like how the OEM rear tire has a higher load index (50) than the OEM front tire (44). You may have also noticed that the OEM tires have their tread patterns in different directions, that's to match the different forces that each tire experiences - rear tire experiences more acceleration forces, front tire more braking forces.

IMO keep "if it ain't broke, don't fix it" in mind and don't fiddle with your spokes if you're not committed to understanding, taking your time, and having the equipment on hand, to properly true the wheel on a stand. It's one thing to tighten a very loose spoke for a limp-home fix, it's another to take a wheel that's fine and introduce a wobble by tightening up spokes that don't need much adjustment, if any, for thousands of miles, depending on your riding conditions.

If you are interested in that, may I recommend starting with bicycles? They can be (but aren't always) cheaper to work with and more forgiving (read: less likely to injure or kill you) if you make a mistake.
Some great resources are Sheldon Brown's page on bicycle wheelbuilding and "Professional Guide to Wheel Building" by Roger Musson. The latter is an eBook you can buy online that's also engineering porn, every formula you could need for determining spoke length for different bicycle wheel and hub sizes as well as lacing patterns, a detailed explanation of the physics behind spoked wheels, and the answers to just about any question you could have while building or tensioning and truing a wheel. It is likely what the designated "wheel builder" at your local bike shop has on hand for reference when something unusual makes its way to their stand.
It ain't broke, so I am gonna leave it alone.
 

SneakyDingo

Well-known member
Joined
Aug 6, 2021
Messages
1,561
As someone who used to build wheels multiple times a year, had a park tools truing stand, a full wheelbuilding kit and even the tensiometer, I am avoiding doing anything involving touching the spokes on the CT125. That's firmly in the "take it to a shop if I'm not limping home". If a spoke breaks while I'm out, that's what all the other spare spokes on the wheel are for, right?
 

Cardinal Direction

Active member
Joined
May 22, 2022
Messages
160
As someone who used to build wheels multiple times a year, had a park tools truing stand, a full wheelbuilding kit and even the tensiometer, I am avoiding doing anything involving touching the spokes on the CT125. That's firmly in the "take it to a shop if I'm not limping home". If a spoke breaks while I'm out, that's what all the other spare spokes on the wheel are for, right?

Amen
 
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