Race Crank Balance
Posted: Fri Dec 07, 2018 3:57 pm
How close are racecranks normally balanced? 1% over/under-10% over-under?
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Race Crank Balance
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Re: Race Crank Balance
Posted: Fri Dec 07, 2018 4:19 pm
Normally? Depends on the opinion of the guy building it.
Re: Race Crank Balance
Posted: Fri Dec 07, 2018 7:27 pm
The pro teams order lot's of them at once (because of long lead time) in bob-weight steps of about 20 grams.
They rarely balance them beyond that.
Still never heard of a good reason for overbalance.
Re: Race Crank Balance
Posted: Sat Dec 08, 2018 12:34 am
Because 99% of engine building is opinion.
Re: Race Crank Balance
Posted: Sat Dec 08, 2018 7:12 am
more like best guess. 
Re: Race Crank Balance
Posted: Sat Dec 08, 2018 9:15 am
Or, to put it as a %, if the bobweight is 1500 grams then 20/1500=0.0133 or 1.3% so they can get within +/- 0.67%.SchmidtMotorWorks wrote: ↑Fri Dec 07, 2018 7:27 pmThe pro teams order lot's of them at once (because of long lead time) in bob-weight steps of about 20 grams.
They rarely balance them beyond that.
Still never heard of a good reason for overbalance.
Re: Race Crank Balance
Posted: Sat Dec 08, 2018 9:21 pm
But, in crankshaft engine balancing that opinion is normally based upon RPM range to be run;
not whether it is to be designated "Race" or not.
Re: Race Crank Balance
Posted: Sat Dec 08, 2018 11:01 pm
People seldom defend a "best guess" to the death.
Re: Race Crank Balance
Posted: Sun Dec 09, 2018 6:53 am
There is that.