Wheel/tire weight?

[olsonm3915]

Has anyone weighed their wheels and tires? I bought a Harbor Freight balancer and I am wondering how much effect a few thousandths of radial runout of the balancer shaft will have. To calculate how much imbalance weight each 0.001" of runout is equivalent to, I need to know the weight of the wheel/tire combination. I had both wheels off yesterday while I was balancing them but it didn't occur to me to weigh them at the time.

I have been using, and still will probably use, the homemade balancer found in the March 2004 issue of Motorcycle Consumer News. The drawbacks are that it is a little finicky to level and I need to use different width stretchers for front and rear wheels, but it is incredibly sensitive if set up correctly. Unfortunately my HF balancer has some runout in the shaft and the bearings have some friction which makes it difficult to get a perfect balance job.

A rough guess of 15kg for a wheel/tire and a 15" radius to the inside of the rim where the weights go, means that 0.010" of runout should equal them imbalance of adding a 10g weight.[1] I suppose it isn't necessary to know the exact weight of a real wheel/tire combination but it would be nice. I realize different tires weigh different amounts and an ABS rim probably weighs more than a non-ABS.

Putting a dial indicator on the balancer's shaft showed about 0.005" runout at one point, which according to my educated guesses would be like having a 5g weight added to the rim, not good. So I supported the shaft between two wooden blocks and applied a few taps with a rubber mallet and managed to get the runout down to about 0.002".

In my experience, anything less than half of a 7g weight (the stick on ones you buy from Dennis Kirk) is not detectable at anything up to well over freeway legal speeds. I don't know about speeds over 100 mph.

[1] 0.010in / 15in = 10g / 15000g

 

[fjrrider]

Dang Dude thats a heck of a question, wished I was smart enough to answer it!

I just use a NO-Mar tire balancer and plain ole wheel weights, works good.

Good luck with your Algebra home work!

 

[NMRoadRunner]

Thats too much brain and not enough wrist!

 

[Patriot]

"Ride On" works for me

 

[mattster31]

I can't answer that.......but what I do now is get it close with the stick on weights, on my homemade balancer. Then I pour in an ounce or two of Dyna beads. This way I figure the Dyna beads will correct any imbalances as the tire wears. It's worked great so far, as I'm about to change my Dunlop D220's out with just over 10K (the front still looks new though)

 

[old&slow]

Wow !!! and people think I'm picky,,,

I use a homemade balancer ,,, some stick on wheel weights ,,

masking tape ,,,and a 12 pack of Coors,,,

sit on a milk crate ,, spin the wheel / tire ,,, drink a beer ,,

mark light spot on tire with masking tape,, tape on a piece of wheel weight ,,

then repeat,,,

normal wheel balance usually takes about 3 or 4 beers ,,, but sometimes

it takes more,,,

Road test the bike the next day ,,,

 

[olsonm3915]

Wow !!! and people think I'm picky,,,
I use a homemade balancer ,,, some stick on wheel weights ,,

masking tape ,,,and a 12 pack of Coors,,,

I'm not picky. I just observed that with the HF balancer the wheel appeared to have its heavy spot at a completely different place compared to my known-good homemade balancer. If you "balance" the wheel using a tool that builds in 10g of imbalance, in my book that's not good. If having a wheel that is substantially out of balance doesn't matter, why waste time balancing them in the first place?

I've ordered a replacement shaft from McMaster-Carr which hopefully will have negligible runout.

 

[Zorlac]

That precision shaft looks interesting, I'm using this but I wonder if it's as precise?

 

[old&slow]

Wow !!! and people think I'm picky,,,
I use a homemade balancer ,,, some stick on wheel weights ,,

masking tape ,,,and a 12 pack of Coors,,,

I'm not picky. I just observed that with the HF balancer the wheel appeared to have its heavy spot at a completely different place compared to my known-good homemade balancer. If you "balance" the wheel using a tool that builds in 10g of imbalance, in my book that's not good. If having a wheel that is substantially out of balance doesn't matter, why waste time balancing them in the first place?

I've ordered a replacement shaft from McMaster-Carr which hopefully will have negligible runout.

OK ,, There's nothing wrong with doing a job right ... (actually, I was just poking fun)

I took my CBR into the shop one time ,, had a bit of a 55 mph shake with it ,, told the service guy I thought

I needed the head bearing checked,,, he ask who balanced the front tire ( had maybe 500 + miles on it)

I said I did,,, so he wanted to check on his computer balance machine,,

found out it was less than a .5g off ,, I asked if that was much ,,, he said it wasn't worth worrying about..

( no idea what a gram is ,, I work with lbs. ,,,oz. ,,, and grains)

after several other checks ,, he found out the head bearing needed adjusted...

And thanks for the link ,, I'm wanting to upgrade my homemade set-up ,,,

figure with a new hi-tech bike ,,maybe I should have something other than boards ,, chewing gum

and bailing wire...

and runout ,,,, is that running to the frig. for another beer while the tire is still spinning ???

( still kidding)

 

[olsonm3915]

That precision shaft looks interesting, I'm using this but I wonder if it's as precise?

I read somewhere that one of the bad things about the NoMar cones is that they are soft enough to deform if you overtighten the setscrews. But the fact that they are soft can be a good thing too, they will not get bent or nicked if you drop one on the floor. I have a feeling that once I replace the shaft of the HF balancer I will find that the cones have some runout of their own.