GameboyRMH
GameboyRMH MegaDork
1/1/18 1:57 p.m.

I've been working out budgets for different wheel & suspension options for my Corolla, and doing a rear pushrod conversion to make room for 15x9s is actually not looking like a terrible idea. Considering the difficulty of sourcing a bunch of oddball bearings with which to fabricate bellcranks (and the engineering effort of choosing the right ones), I'm wondering if any are available off the shelf. I've searched around a bit but haven't found any yet.

I'm looking for a fairly large bellcrank that will let me put the coilover at a 60~90deg angle to the pushrod at a 1:1 slightly progressive rate.  The one on the front of a NASA/Elan NP01 might work:

Side note: How common are steel turnbuckle bodies? I'd have to weld a tab for a sway bar link to one.

Apexcarver
Apexcarver PowerDork
1/1/18 2:03 p.m.

Going to be looking into similar soon-ish, looked at all at whats on the back of sportbikes?  Would need a bit of additional research that they have the load capacity, but you might be able to get some there.

 

Please share your results.  Will be looking to pushrod/bellcrank to use motorcycle shocks on miata front and rear subframes on a ~1300lb car myself, so I will be looking for slightly different motion ratios.   I know there is a wealth of information on the Locost USA forums that might at least get you started.  Search out the threads on using motorcycle shocks.   (also see if Loosecannon on here can reply, hes done them on his build)

GameboyRMH
GameboyRMH MegaDork
1/1/18 2:07 p.m.

Load-wise the sportbike bellcranks should be enough for my car (though not by a large margin), but they all seem to come in oddball motion ratios.

Apexcarver
Apexcarver PowerDork
1/1/18 2:10 p.m.

In reply to GameboyRMH :

do you already have shocks/springs selected?  if not, you can easily design around that. 

GameboyRMH
GameboyRMH MegaDork
1/1/18 2:13 p.m.

Yeah I'll be reusing the current coilovers. They're longer and heavier than they need to be in a pushrod-actuated position, but I don't have the budget for anything else.

Apexcarver
Apexcarver PowerDork
1/1/18 2:18 p.m.

gotcha, well, still might be worth diving around and seeing if there is some obscure bike that uses a 1:1 ratio.

 

I am hoping to use motorcycle shocks all around on my build to keep costs down and performance up. challenge is doing it and having enough overall travel (as loosecannon has run into on his rear)

 

If you find a really good cross reference, please share!

GameboyRMH
GameboyRMH MegaDork
1/1/18 3:28 p.m.

I've been Google image searching motorcycle bellcranks for a good half hour, still haven't found anything close to 1:1, other than a costly reproduction part for a 1910s Harley that doesn't come with bearings.

I'm also pretty confident now that the only non-motorcycle ones that may be available off the shelf would be replacement parts for purpose-built race cars.

Fabricating is starting to look like a decent option. A small car's wheel bearing could work for the point where the bellcrank mounts to the chassis. For the other two points I could use common generic race car spherical bearings.

44Dwarf
44Dwarf UltraDork
1/1/18 4:28 p.m.

Well hopefully 4th times a charm...somedays i hate computers...

With two of AA-202-A2 and some tubing you could make your own

https://www.aa-mfg.com/

Knurled.
Knurled. MegaDork
1/1/18 4:29 p.m.

Ladder bars come to mind, but the motion ratio would be  WAY off of 1:1.

GameboyRMH
GameboyRMH MegaDork
1/1/18 4:39 p.m.
44Dwarf said:

Well hopefully 4th times a charm...somedays i hate computers...

With two of AA-202-A2 and some tubing you could make your own

https://www.aa-mfg.com/

I would need something like this, but not exactly like this. I figure I'd cut mounts off of some scrap stock shocks, slot the upper hole for camber adjustment, then weld in a threaded rod for one end of the turnbuckle.

Knurled.
Knurled. MegaDork
1/1/18 4:50 p.m.

I wonder now if you bought a ladder bar and cut the long leg and hypoteneuse off and welded it back on so that it is not only shorter, but the rod end gets loaded along its axis instead of perpendicular to it?

 

OTOH I have no idea how expensive ladder bar kits are.  And most of the ones I have seen do not use rod ends, they use clevises (?) for strength.  They figure the duty cycle and range of travel is low enough that pivoting on a Nyloc'd 3/4" bolt is sufficient.

GameboyRMH
GameboyRMH MegaDork
1/1/18 5:18 p.m.

Ladder bar kits are basically just a couple of bars with rod ends and mounts, from what I can find...doesn't look like it would save a lot of fab work to modify one.

I wouldn't risk just riding on a bolt unless it's only for short-term use, the range of motion is low but suspension pieces are moving a little bit all the time, with hundreds or even thousands of pounds of force going through them.

Edit: Looks like bigger clevis joints still use bushings or bearings in them.

2GRX7
2GRX7 New Reader
1/1/18 8:29 p.m.
GameboyRMH said:

I've been working out budgets for different wheel & suspension options for my Corolla, and doing a rear pushrod conversion to make room for 15x9s is actually not looking like a terrible idea. Considering the difficulty of sourcing a bunch of oddball bearings with which to fabricate bellcranks (and the engineering effort of choosing the right ones), I'm wondering if any are available off the shelf. I've searched around a bit but haven't found any yet.

I'm looking for a fairly large bellcrank that will let me put the coilover at a 60~90deg angle to the pushrod at a 1:1 slightly progressive rate.  The one on the front of a NASA/Elan NP01 might work:

Side note: How common are steel turnbuckle bodies? I'd have to weld a tab for a sway bar link to one.

Is this what you're looking for...

http://www.haasauto.com/home.php?cat=343

http://www.haasauto.com/home.php?cat=339

pm'ed you.

 

freetors
freetors New Reader
1/1/18 10:59 p.m.

Build your own? I built these mainly out of sheet steel.

loosecannon
loosecannon Dork
1/1/18 11:11 p.m.

Build ones that work out of steel and when you're sure they are perfect, get them recreated out of aluminum. That's what I did.

GameboyRMH
GameboyRMH MegaDork
1/2/18 7:57 a.m.

I don't have money for CNC'd ones...not even the NP01 parts when new, it turns out (but thanks for finding them, 2GRX7). If I fabricate my own I'd have to settle for steel.

I've been thinking it might make sense to connect the sway bar links directly to the bellcranks. I already have super-long Camry links I can use to move the connection point completely above the tire, if I have extra tabs coming off the bellcranks alongside where the pushrod connects, that means I could lower the whole bellcrank setup in the car close to trunk floor level, something like this E30 that had the same conversion done for the same reason:

That also means I could have multiple mounting holes for an adjustable motion ratio, and since I wouldn't have to modify the turnbuckles I could use off-the-shelf aluminum ones to save weight.

Edit: Looks like Pit Stop USA has all the rods & ends at decent prices:

https://pitstopusa.com/c-131713-chassis-suspension-suspension-tubes.html

chaparral
chaparral Dork
1/2/18 9:21 a.m.

Bellcranks are all over the place on jetliners. If anyone lives near an aircraft boneyard, they may be able to score a part that was lightened until further reduction cost >$1000/lb. McDonnell Douglas was probably the best at this.

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