Factory Works C2 Carbon Fiber

[NomadRacer]

Oh man, I had no idea that was an option! Thanks brother

[GoMachV]

Note there are 2 problems with 3/16. First off you will need some 3/16 x 3/8 flanged bearings which are out there but not as common for sure. The bigger issue is that associated made the rere cva’s pretty short and I don’t know how well they would stay in the trans. I don’t remember the 1/4” ones ever being a problem but can’t say for certain on the 3/16.

[NomadRacer]

Getting the front end started today, bell cranks first. Cutting 3mm off the ends of the RPM ball cups worked out perfect for me.

[GoMachV]

There will most likely be clearance issues between the inner camber and inner steering ends. RC10’s have never been RPM friendly in those spots.

[NomadRacer]

There will most likely be clearance issues between the inner camber and inner steering ends. RC10’s have never been RPM friendly in those spots.

Getting ready to find out I have some Lunsford ball cups that may fix that problem.

[NomadRacer]

@GoMachV

Yep, RPM ball cups are not RC10 friendly

I cut off 4mm from the ends of some Lunsford 7991 4-40 ball cups and they work with no clearance problems. I only had 4 of them so did one side. Ordered some more and they should arrive about the same time as the steering servo (Savox 1251MG-BE). So, now that I'm held up on the front end, might as well move on to the shocks!

[XLR8]

Note there are 2 problems with 3/16. First off you will need some 3/16 x 3/8 flanged bearings which are out there but not as common for sure. The bigger issue is that associated made the rere cva’s pretty short and I don’t know how well they would stay in the trans. I don’t remember the 1/4” ones ever being a problem but can’t say for certain on the 3/16.

Are flanged bearings needed because there is no counterbore step in the trailing arm's bearing bore to locate the bearing? I've never actually held one of these trailing arms in my hands so just trying to understand why flanged bearings are needed.
Also, what makes B2/B3 rear wheels different from earlier RC10 wheels that also used 1/4" axles? I reckon they're both 2.2" diameter so is it the offset?

[XLR8]

@GoMachV

Yep, RPM ball cups are not RC10 friendly

I cut off 4mm from the ends of some Lunsford 7991 4-40 ball cups and they work with no clearance problems. I only had 4 of them so did one side. Ordered some more and they should arrive about the same time as the steering servo (Savox 1251MG-BE). So, now that I'm held up on the front end, might as well move on to the shocks!

C2CFlinkage.jpg

I guess that by locating the inner steering link and camber links close to the inner hinge pin this is key to controlling bump steer. I wonder if the bellcranks were a few mm shorter or if the bellcrank pivots were moved a few mm's rearward so that the inner steering link no longer collides with the camber link would this actually increase bump steer? Of the various options available for these vintage cars (there are a lot), are all bellcranks the same length?

[GoMachV]

Are flanged bearings needed because there is no counterbore step in the trailing arm's bearing bore to locate the bearing?
.....
Also, what makes B2/B3 rear wheels different from earlier RC10 wheels that also used 1/4" axles? I reckon they're both 2.2" diameter so is it the offset?

Correct, spacing and no step to hold them. Just like the original rc10 rear carriers.

B2/B3 wheels are the same offset but made for the smaller 3/16 axle.

We sell a rack bar for our ball bearing steering kits that has an extra set of holes for RPM Ball ends. I’m sure it changes the Ackerman in a negative way but the steering geometry seems fine.

[NomadRacer]

@@XLR8

Flanged bearings are a must for the trailing arms. The B2/3 retro/vintage wheels from JC Racing Products, from the pics, appear to use 3/16 x 3/8" plain bearing. Don't take my word for it though! As to offset... no idea.

I'd think if you used Factory Works/A&L steering there would be no clearance problems with the camber-steering rod ends, maybe. I wanted to use the Lunsford retro turnbuckles, hence the Worlds re-re bell cranks use. They are the same length. You could ask GoMachV about the placement of the inner camber ball stud location. I'm using his Factory Works carbon fiber shock tower.

Looks like Jeff answered much of the questions but I post my words anyway!

[XLR8]

Okay, thanks Jeff.
I have a B2 and B3 and both have 1/4" axles but they are pre-owned so maybe someone swapped out the original 3/16" axles along the way. Anyway, now I know the difference.
I think, given a choice, I would rather compromise ackerman than bump steer but that just me. I don't recall having tested different ackerman settings so I really don't fully understand its affect on handling. It's probable that I'm not a good enough driver to feel the difference anyway. I have tested with high bump steer and know first hand how much it can affect a car's handling. I remember watching vintage videos of top shelf racers bitd sitting with their cars in the pits and cycling the front suspension while sighting down the edge of the wheel and looking for bump steer (and camber rise). I approach this as a hobby not an occupation so I will tend to fixate on bump steer and pretend that I know what I'm doing.

[XLR8]

Thanks Nomad,
You've chosen the obvious solution; if RPM rod ends create interference, then use a different rod end. Hence, you're using Lunsford. It's simple! Problem solved.

[scr8p]

Some of the b2's had 1/4" axles. The b3 sport may have had them as well. i don't remember.

[XLR8]

Thanks scr8p. My B2 is the "racer" (or factory team or whatever it was called) with universals while my B3 is the sport model with dogbones. I just figured they were both original but who knows.

[NomadRacer]

Since the Lunsford Retro Turnbuckles require a 1/4" wrench I went searching on eBay for something that would be small, and cool.

Williams SUPERWRENCH ignition wrench! I got two of them for $8.50 with free shipping. What's not to like?