Hub dimensioning
Hub dimensioning
(OP)
So, having a car with combined rotor/hub (an '85 fiero), I'm looking to upgrade the brakes and might have to manufacture new hubs or at least modify the existing rotor/hub. What do I need to know in order to avoid making huge (dangerous) mistakes? How do I approximate the forces on the hub?





RE: Hub dimensioning
Rod
RE: Hub dimensioning
RE: Hub dimensioning
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Hub dimensioning
RE: Hub dimensioning
Yes, roughly.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Hub dimensioning
The whole front end is taken off another GM car, so you might just look for what that was and see what options those cars had over the years. You may also want to consider a spindle swap from a midsize.
But increasing the front brake forces will just make that heavy rear end want to go around it even more!
RE: Hub dimensioning
I have done the exact thing you speak of, but for other applications. Hubs have been designed. manufactured, and are running.
Gary King P.E.
RE: Hub dimensioning
How many g's should I be calculating for?
With a mid-engined car, would locking the rear wheels be preferred over locking the fronts? From what I've read it's generally preferred to lock up the front brakes, but then most cars are front engined so maybe that will be a factor as well?
RE: Hub dimensioning
For what?
"With a mid-engined car, would locking the rear wheels be preferred over locking the fronts? From what I've read it's generally preferred to lock up the front brakes, but then most cars are front engined so maybe that will be a factor as well?"
Lock the front's first.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Hub dimensioning
For what?"
for heavy braking (in an emergency situation or on the track). A rough estimation is that the fiero pulls about 1g braking from 100-0 (stopping distance about 40m and I was assuming an average speed of 50kph, which is probably way off). To be on the safe side of things, I would be calculating for a bit more, but how much?
RE: Hub dimensioning
But, this pales into insignificance when compared witht he force that is generated when you hit a pothole or kerb.
So it rather depends which bit you are designing. The calliper and rotor will only see the braking load, the rest of the spindle and suspension will se pothole and kerbing loads.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Hub dimensioning
next thing then is to find out what material is likely to have been used for these rotors...
RE: Hub dimensioning
The UTS is ~35-45ksi
The yield is nonexistant (or only a small bit less than UTS)
The Modulus is ~29,000ksi
Nick
I love materials science!
RE: Hub dimensioning
What literature would you recommend me to look for?
RE: Hub dimensioning
Curb-weight * 1.5 * 1.2 results in a moment of 7202Nm.
Will continue this thought a bit later...