balancing your rims (offsetting air valve)

besides a bike wheel being completely true im wondering if rim balancing is a thing.

my thoughts are
1. that the extra weight of the air valve is offsetting the wheel balance slightly, and needs compensation.
2. that at ebike speeds an unbalaced wheel is more prevalent.

my questions are
1. does anyone balance their rim by adding a weight equal to the valve weight on their bike rims?
2. any other general thoughts on this?

There's a hole in the rim where the valve passes through, and a splice or pins on the opposite side. Both these things offset the weight of the valve.

I've never had a issue with wheel imbalance, even when there's a single good-sized wheel reflector in there. If you're using pig-heavy motorcycle wheels or tires and those parts have an imbalance, maybe it would become a problem then.

[Edited to correct a typo]

both these vids show quite high end wheels, all of which were rather out of balance (spoilers: 9g and 14g)

https://www.youtube.com/watch?v=dcgiUcbS64c

https://www.youtube.com/watch?v=UpSrrVV0XNE

also found this http://www.dnr.louisiana.gov/assets/TAD/education/ECEP/auto/d/d.htm

says that one ounce out of balance at 60mph can exert over 7.73 pounds of force
thats 28g out of balance making 3.5kg of force. (125 times more)

ive just taped two 5p peices (6.5g) on the opposite side of the rim from the valve (for testing only).....holding the bike up in the air and spining the motor, my wobbles gone from quite severe to almost un-noticable.

This may not be a massive performance gain...but i guess its also a quality of life thing.....less wobbly rides, less uneven tyre wear. better suspension performance, better cornering.

the consensus on a safe/permanent version seems to be golf club weights...once i get a few i will add them and report back.

jimmyhackers said:

says that one ounce out of balance at 60mph can exert over 7.73 pounds of force
thats 28g out of balance making 3.5kg of force.

Click to expand...

It's hard to be out of balance by an ounce if you're using bicycle wheels and not filling them with latex goo. It's also hard to reach 60 mph on a bicycle.

It's really easy to have at least 8 pounds of weight resting on each wheel, though.

Plenty of reading material here:

https://forum.slowtwitch.com/forum/Slowtwitch_Forums_C1/Triathlon_Forum_F1/Balancing_A_Bike_Wheel_To_Eliminate_High_Speed_Shakes_P2377510/

"Balancing A Bike Wheel To Eliminate High Speed Shakes"

I did balance my front wheel - but only because I could tell it needed it. When my bike was hanging (while I worked on it) the wheel obviously had a heavy side section. The wheel was very true, so I added a bit of lead wrapped around a spoke nipple.

The bike rode well before, so I'm not sure if it NEEDED to be done. I think balancing the wheel helps the tire wear more evenly though.

This is on a 16" wheel that I average 30km/hr on, so that little wheel has some rpm.

The only downside to doing this is the potential for injury if your wheel weight flies off the bike at max speed.

Colin

i do go 40 to 50+ mph some times.

even at these speeds or lower a 10g imbalance can become a resonable force.

this force has an up, down, forwards and backwards component. all of which contribute to wobble, uneven tyre wear, poor surface grip, reduced efficiency.

Chalo said:

There's a hole in the rim where the valve passes through

Click to expand...

If the hole is 8mm in diameter, and it's a double wall rim with 2mm thick walls that would work out to 0.54 grams of aluminum. I have a Schrader stem that I cut out from an old tube for other purposes, but it feels like about 15 grams, at least. I need to find my high precision scale. :lol:

well....can quite happily say my bike is perfect now. most definately worth doing.

not an hint of wobble, bike feel super smooth, cornering feels a heck of a lot more stable.

without the balance the more i leaned into a corner the less stable it felt.

https://www.ebay.co.uk/itm/380748299771 these are the weights i bought....there are chepaer available from china but i dont wanna give my money to communists, or wait 2 weeks.

if your bike does 30mph+ i would most definately suggest doing this.