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Ifs 101

I thought the rules specifically state NO IFS in the 4800 class. In 4500 it says no independent suspension unless using factory farm and attachment points.
 
"Thanks for posting. What did you see as being wrong with the factory knuckle geometry?" Nothing wrong. I wanted to use uniball bearing for my control arms, and I could build them to suit my needs.
"I thought the rules specifically state NO IFS in the 4800 class. In 4500 it says no independent suspension unless using factory farm and attachment points." KOH was a one time thing for me. This car will only be racing east coast, Line Mountain, and Canada. Not a 4800 car anymore.
 
OCM said:
. Narrow track width = short half shafts = limited travel and steering. 82 inches to outsides of the tires about 14 inches of wheel travel and about 35-38 deg of steering is all that I have to keep the cvs safe.
Couple of cad pics, everything in 2d just to see it before I built it.
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all things considered for what is arguably about as budget as you can get, that is pretty dang good. be nice for more steering angle, but that is why god invented cutting brakes :grinpimp:
 
The closest I have to cutting bakes is separate front and rear break pedals. Spools front and rear. I wish that I had an ARB in the front now but I used what I had from the old front axle. With limited steering angle and a spool in the front this thing is terrible for tight muddy woods racing, tree sliders help a lot!
 
OCM said:
The closest I have to cutting bakes is separate front and rear break pedals. Spools front and rear. I wish that I had an ARB in the front now but I used what I had from the old front axle. With limited steering angle and a spool in the front this thing is terrible for tight muddy woods racing, tree sliders help a lot!
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Is that a “d60” sized bell? You are not too far off of the 43 degree absolute max angle, if so
 
I don't think the bell on the chev ifs kits is d60 size, a bit smaller maybe. 43 deg is not much with ifs. Some of the steering angle is used up with the suspension travel, that dosen't happen with a straight axle.
 
I think the older pre 12 ifs was 33 spline outter stub. Newer ones are bigger and 36 spline,(with a bigger unit bearing as well). The late model kit chev kit is 36 spline otter stub. As for the mid shaft is should be 35 spline at both ends and the inner cv is a 934, plunging with the 35 spline star thingy. Those parts are available in different splines for the same 934 cv joint. It has been a couple of year since I built these but I think all this info is accurate. The kit comes with an adaptor to bolt the 934 cv joint to the stock chev diff flange. I skipped the adaptor because the 934 joint bolt directly to the currie inner stubs.
 
OCM said:
I think the older pre 12 ifs was 33 spline outter stub. Newer ones are bigger and 36 spline,(with a bigger unit bearing as well). The late model kit chev kit is 36 spline otter stub. As for the mid shaft is should be 35 spline at both ends and the inner cv is a 934, plunging with the 35 spline star thingy. Those parts are available in different splines for the same 934 cv joint. It has been a couple of year since I built these but I think all this info is accurate. The kit comes with an adaptor to bolt the 934 cv joint to the stock chev diff flange. I skipped the adaptor because the 934 joint bolt directly to the currie inner stubs.
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Correct. Not trying to sound like an ass, but what is your point?
 
In the link for the talk with RCV it said the inner spline on the middle shaft was 33 spline. I was just saying that everything but the outer stub shaft was the standard 35 spline, also pointing out the difference between the early and late model chev stuff. I spent a lot of time looking for that info before and was just trying to keep it clear on here if someone else need it. When I did this, I was all over the internet trying to make sure the parts that I picked would match up.
 
OCM said:
In the link for the talk with RCV it said the inner spline on the middle shaft was 33 spline.
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The guy I spoke to on the phone was very specific about the shaft spline where it enters the inner 934 joint being 33-splines. I asked multiple times if he was certain because it didn't really make sense to me that they would make a shaft with 2 different splines when they could easily make it 1. So we have a discrepancy. BUT I suspected he may have been wrong because the spline at the differential is 33. My thoughts were that he was just looking in his catalog or something and misinterpreting the carrier spline as the inner CV spline. So if you're saying your inner CV spline is absolutely 35 then my inclination is to believe you over the guy I spoke to because 35 there makes more sense to my mind.
 
That 33 spline shows up a lot. There was a class of 4x4 desert truck long ago and they where using the chev front diff stuff. I think that is why it is common. On most sites that sell the cvs, you have a choice of different splines for the same joint, they just change the center star piece. i think they are listed on the RCV site in the cv parts section. Hope that clears it up a bit more.
 
Ocm
Would you have info on Chevy 12+ ? Unit bearing size versus 05 up super duty ?
also the spline diameter of the 36 spline stub
paul
 
Bearing size is very close to the same but not rebuildable like the ford one. 36 spline is about 1.56". I looked at using the ford bearing but then I would have had to buy all the parts from RCV separate, not a kit like the chev setup and it would be much more expensive. Also, the chev kit can be bought with custom length mid shaft to fit lifted chev trucks or in my case the length I needed for my setup.
 
EBPaul said:
Ocm
Would you have info on Chevy 12+ ? Unit bearing size versus 05 up super duty ?
also the spline diameter of the 36 spline stub
paul
Click to expand...

Overall dia. of the Chevy 36-spline stub shaft is 1.57".

Side-by-side pics of the two UB's, Chevy on left. The Ford is beefier with bigger bearings and up to 2.78" axle shaft. potential:

fordvchevy1.JPG - Click image for larger version Name: fordvchevy1.JPG Views: 0 Size: 529.4 KB ID: 286139
 
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I had the older ford bearing, not the 05+ bearing. Here is a pic of the late model chev one, same as the one above.

IMG-0801.jpg
 
The bearing is bigger than the older chev but not as big as the ford.
 
This in depth analysis of these GM diff components is really intriguing, there's a lot more strength in these components than I would have otherwise guessed. Makes these outers and some replacement parts more and more interesting for the budget IFS setup. That scaled 3d print is awesome too. I feel like I've seen people use the acetone vapor technique even for PLA smoothing, but haven't experimented myself yet.

Ben, I knew you were doing some amazing stuff but I am awestruck by the scale of the task you've taken on, and how everything has turned out!

I have some concepts I'd like to put into action for IFS stuff, but want to see how feasible it is in CAD before bringing the discussion here. I really enjoy how this is still a subject that still doesn't have a "one size fits all" answer so people are still experimenting and innovating, I think there is still a ton of room to grow.
 
OCM. Thanks for the picture of your front drive shaft. If you were to run a low pinion front would that have allowed you to lower the motor some? That is where I am gong even though on the wrong side of the teeth. 9". Maybe the transfer case stays flatter for you? Looks legit!
 
Is there a chart somewhere that lists the achievable angularity for different ball and spacer combinations, Isdtbower ?
 
Tech Tim said:
You can also have custom hi-mis spacers made. We had to do that on a couple IFS designs to get what we wanted.
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One of your bearing stack ideas in #573. Modified slightly for key and update. TMR requested the actual bearings as they have found differences in center widths among manufacturers and wanted these perfect. Awesome. Clearances that are "air tight."
 
Isdtbower. I had to tilt the motor/drivetrain up the get the high pinion in there and clear the oil pan, a low pinion wouldn't need that. In my case, I already had the high pinion and it helped my rear driveshaft angle.
As far as bearings, my lower ca uses a vertical bolt. I used a EMF large weld in joint that was modified to about 30 deg misalignment. It uses a one piece ball/misalignment. I think it is a strong enough design to hold the weight of the vehicle and is rebuildable and grease able. My upper is a normal com bearing in a cup. My bump hits a pad on the top of the knuckle and the limit strap is attached to the knuckle as well. The upper bearing only takes side loads.
 
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OCM said:
I don't think the bell on the chev ifs kits is d60 size, a bit smaller maybe. 43 deg is not much with ifs. Some of the steering angle is used up with the suspension travel, that dosen't happen with a straight axle.
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I understand that, but was making the comment on behalf of the budget-minded followers and maybe as a reminder for yourself; that your design didn’t leave much on the table.
 
The plate that hold the unit bearing is 1". Bottom plate under the lower control arm bearing is 1/2. Sides of the 1" plate is 3/8. Everything else is 1/4. All crs.
They are kind of heavy and maybe a bit over built but they shouldn't bend or fail. I tend to hit things doing fast woods racing.
 
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