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Another ball joint
smart51 - 11/6/10 at 02:52 PM

My Fiat Cinquecento lower wishbones have a built in balljoint. The donor wishbone is too heavy and too short so I need a separate ball joint. The taper is 1:10 according to figures on the internet, with a 12.6mm wide end aperture. The track rod ends have the right taper but only a 12mm diameter shank and they're a bit loose.

Does anyone know of a light duty ball joint or male rod end with this taper?


[Edited on 12-6-2010 by smart51]

austin man - 11/6/10 at 03:31 PM

try ebay for mcgillmotorsports I believe they do rose jointed Balljoints

CNHSS1 - 11/6/10 at 04:16 PM

ring and speak to Quniton Hazells tech dept. May take you a few minutes to get through to the right guys, but man are they good! tell them what you want and they will point you in the right direction

theconrodkid - 11/6/10 at 05:39 PM

http://81.246.78.74/

iank - 11/6/10 at 07:24 PM

Quinton Hazel catalogue system is available from here.

http://www9.qha.com/uk/technical/catalogues.htm

smart51 - 12/6/10 at 05:39 PM

quote:
Originally posted by theconrodkid
http://81.246.78.74/


Its a bit of a cryptic link but it has the details of almost all the ball joints they sell. Trouble is you've got to select a manufacturer, then a vehicle model, then the year, then the part to find out its size. I've done all the fiats and it was a long job.

I've found that the taper I want is 1:10 with 12.6mm at the wide end. I guess 1/2 an inch would do. Fiat don't do one. The nearest is a tie rod end with a female thread. At 140mm long. its perhaps a bit long to be unsupported.

I'm now looking for a either a ball joint with a 1:10 taper of 12.6 or 1/2" shank or a male rod end with the same taper. Any hints to let me find one in the database easier?

smart51 - 14/6/10 at 09:48 AM

For the sake of people doing searches in the future, the Sidem parts database list the BMW E28 (and others) tie rod end as having the same taper. It has an M14 male thread so can be used on suitably equipped wishbones.

MikeRJ - 14/6/10 at 11:05 AM

I know it's a light vehicle you are building, but have you done the calculations to check if an M14 thread is going to be strong enough? Don't forget the bottom wishbone takes the majority of the load under braking. Are any suspension forces going through it?

smart51 - 14/6/10 at 11:44 AM

The top wishbone takes the suspension forces. The unsprung weight on each front wheel is about 55kg with the driver on board. It is a single seater, so no passenger.

Total vehicle mass will be approaching 300kg including the driver, possibly plus some luggage. An M14 x 1.5 thread has a nominal area 58% as much as an M18 x 1.5 (a transit drag link as used in the locost. A 700kg locost with a 75kg driver and passenger on board = 850kg. 58% of that would be 493 kg. My 300kg weight would make 60% of the equivalent load.

It is not a proper calculation but it is less than a proven application. How much more braking force is on the lower wishbone than the upper one?

smart51 - 14/6/10 at 12:13 PM

A nice search on google suggests a bolt in shear has about 60% of its strength in tension. That's about 2260kg to yield for mild steel or about a 7.5g impact on one wheel. I think a 7.5 times safety factor is OK.

[Edited on 14-6-2010 by smart51]