Drive shaft lengths (again)

[Arthur 10]

Gents

 

I know it's been discussed several times, but i can't find a definite conclusion. I have some 206 drive shafts which I intend to use for my setup. They are 6 ball type C.V's, 33 mm tripods, 82 mm bearing, 25 teeth M24 nut. 

 

I will use 205 hubs (minus 1° camber) yet with an adjustable tubular arm. I intend to add 10mm to compensate for the camber of the 206 hub and about 10mm to get to 309 arms-ish camber. So to add 20 mm to the arm length and then have adjustment in the arm of about +15 to -5 mm. Stive to have about 1 to 2.5 deg camber adjustment window.  All in all I think I need drive shafts that are 209 1.9 +20mm. That's why I went for 206 shafts as I think 309 would be too short anyway. 

 

I dunno what brand mine are, but reverence is SKF though. Simply because I have the drawings. But for the love of god, how do you measure them? I see the lengths should be measured compressed all over the forums. Since I have them in bits and pieces, I can easily do that. I can measure them without the tripod spring even, but that seems to make them a bit shorter. It's easier to measure obviously without the spring but the mounted spring (yet compressed) adds some lengths. Without the spring it really bottoms out in the chamber but with compressed spring there is some 5mm left. 

 

Now the short 206 one does seem to be 590 mm, so very close to the 588 in the drawing of VKJC 4227. This seems sound. 20 mm longer then the 205 1.9 VKJC 3868, which I think would be perfect for me. 

 

But how on earth can it be that 205 are mostly said to be 600 - 840 and 309's to be 610 and 850. If that's true, that can not be the compressed length, right? 

 

Unfortunately I can't find the long shaft SKF drawing of 1.9 205. (only the 1.6 one that should be close) (VKJC 4950) (842mm)

 

1.9 shaft should be VKJC 4563 (no ABS) or VKJC 5961 (ABS) but both have no drawings. Listed as being 840 mm though. 

 

This is what is really confusing me. VKJC 3868 is listed 568 and the drawing confirms. This is contrary to the 600 - 840 info though. VKJC 4563 is however listed as being 840 which does confirm 600 - 840. 

 

So is this  VKJC 4563 listed as not compressed length or just because there is not drawing and heresay?

 

And then when I go to the long 206 shaft. VKJC 4236 is listed as being 892 mm. Quite a bit longer then 205. Not too big a deal, because I'm not afraid to shorten it. I would however want to know how much I need to shorten it before I take the car apart just to check it. 

 

The short shaft of 205 vs 206 is +20mm as both SKF drawings confirm. (perfect for me) Yet the longer shaft of 205 vs 206 is + 52 mm????

 

That got me thinking the ew engine might be placed further to the right of the car. But when I check the 406, the car I know has both UX and EW 1.8 16v, I get the same drive shafts for the UX as the EW. I can't imagine the EW in the 206 is more to the right either, because that's already quite shoehorned in the 206 I recon. Also that would mean the 206 short shaft isn't as perfect for me as I thought. Does the 206 have about 20 + 52 = 72 more track then 205?

 

Anyone have the drawings of VKJC 4563 and/or definite info on 206 shafts in a 205? 

 

 

 

 

Edited January 24 by Arthur

[welshpug 1,622]

the length of the inner stub/spline into the later larger planet gear BE differential is shorter, I don't recall by how much and whether it was both sides, though only the short shaft ever gave issue,   you also have the difference there between a staked nut on the 1.9 variant  (which is not as per oem)   and the R clipped 206 shaft.

 

the location  of the engines transversely does vary quite a bit across the platforms,   the 106/205 being a good indication of this as the track width is almost identical, but base model shafts do not swap over even though the ends are both the same.

Edited January 24 by welshpug

[Arthur 10]

58 minutes ago, welshpug said:

the length of the inner stub/spline into the later larger planet gear BE differential is shorter, I don't recall by how much and whether it was both sides, though only the short shaft ever gave issue,   you also have the difference there between a staked nut on the 1.9 variant  (which is not as per oem)   and the R clipped 206 shaft.

 

the location  of the engines transversely does vary quite a bit across the platforms,   the 106/205 being a good indication of this as the track width is almost identical, but base model shafts do not swap over even though the ends are both the same.

Year, I didn't quite grasp that diff issue. But I have a BE4r-TU gearbox, so I don't think that issue applies for me. I think all BE4's have the new diff. The engine mounts are standard as well. I have a spare BE4R-tu box as well and the shaft fit fine apparently. They seem to go in the diff perfect with the seal at the location it's intended to be.

 

So that means a TU-BE4r box is in in the same location as a BE3-XU. I.m sure of that. The under battery mount is the same as well. The pin on which the gearbox hangs in the bracket had to be placed in the same hole as the UX-BE3. That was the only thing I had to change to the gearbox mounting. And obviously an TU-BE intermediate shaft bearing bracket for the Tu. So I'm quite sure my standard is the same as GTI. I have the 1.6/diesel shafts now into base model hubs at the moment. 

 

But that would also mean a 206 shaft would be even longer should it have been designed for the older diff. That might imply I have to shorten both shafts. Not a big deal, just almost impossible to doe upfront if I can't get the actual data. The difference to the stub it actually observable when you compare the 1.6/diesel to 206. Although being the drawing of the 1.7 TUD shafts it's quite obvious. This is what you mean, correct?

 

TUD:

 

 

206

 

 

 

 

Edited January 24 by Arthur

[Tom Fenton 1,525]

To be honest the only way to reliably get it right is to dummy build. Assemble the suspension with no spring on the damper, and move through the arcs to determine the length the shaft needs to be to sit the inner tripod in the right place in the inner cup through its range of plunge.

[petert 550]

What Tom said.

[Arthur 10]

Yeah. Might indeed be best. I have a spare subframe, the 206 hubs and a spare gearbox. So I can do half a dummy build. If I can at least confirm I need to shorten the shafts, I'm happy. I'm planning to cut them of just where the hollow shaft begins. Then machine the solid part to the inner diameter of the hollow part, sleeve it over and weld it. I think that's the best way to shorten hollow shafts. 

 

In the case of a later full dummy fit, I can also wait with the final length of my arms (yet to build)(soon). I can prefab the arms on the long side and only final cut/weld them after the dummy fitment. 

 

What is the "right place"? Search for the shortest shaft-spot in the arch, then get it to bottom out and than add approx. 5 mm extra play? Something like that? When I see how much window there is. About 40 mm of play. It's hard to imagine some have 205 shafts falling out with 309 arms. Also, if you see how much better the tripod housing is, it's not a wonder these are better shafts. 33 mm tripods vs 29 is not even that a big a step imo. But the housing is also closed and the smaller types are open. 

[petert 550]

It needs to be done on the car. 
Assemble driveshaft dry, with no boots.

Assemble strut with no spring.

Fit driveshaft and place a nut loose, with a gap of 7mm to the hub face.

Whilst fully compressing the driveshaft, jack the strut through its full movement.

If the nut gets pulled in against the hub, the driveshaft is too long.

7mm is the absolute minimum. You can obviously have more, probably up to 20mm?

[Arthur 10]

32 minutes ago, petert said:

It needs to be done on the car. 
Assemble driveshaft dry, with no boots.

Assemble strut with no spring.

Fit driveshaft and place a nut loose, with a gap of 7mm to the hub face.

Whilst fully compressing the driveshaft, jack the strut through its full movement.

If the nut gets pulled in against the hub, the driveshaft is too long.

7mm is the absolute minimum. You can obviously have more, probably up to 20mm?

Noted

 

10mm seems like a nice goal as optimum then. 

[welshpug 1,622]

have you checked the 206 hub carrier dimensions VS 205?   offset of strut to balljoint pin and drive flange?

[Arthur 10]

32 minutes ago, welshpug said:

have you checked the 206 hub carrier dimensions VS 205?   offset of strut to balljoint pin and drive flange?

Sort of. I don't have a 205 hub carriers to compare one on one. I have checked the angle of of the strut to the bearing and it looks like it's indeed about 1 degree less angle ("camber") in the "hub-to-drive flange" compared to 205. Drive flange -to-pin angle seems to be the same. Not sure how to measure best. I have stainless 2" exhaust pipe to use a surrogate strut. 

 

I should be able to measure better, but I don't have a 1.9 gti carrier to compare it with. Underneath the plan. 

 

18mm (10,9) bolt serves as the pin. Cone made of CroMo and a ball joint rated at 95kN static load. By my calculations more than strong enough. I want to torque the nut at 300nM. By my calc more then enough to pre-tension the assembly well above the load it will ever have to deal with, yet low enough sot the bolt has a lot left in it before the limit. I think 12,9 was not needed because I go from 16mm to 18mm anyway. 

 

Arms will be made of 25CrMo4 30 x 2.5 pipe, welded with ChroMo tig rods as well. Just delivered this morning

 

Edited January 26 by Arthur

[Arthur 10]

Measured like this, this the angle is 89°ish degrees. De definitely not 90. So a perfect vertical stut would give negative camber. So if anyone can tell me what a 205 is. It all looks very close and similar. Can't imagine it's way off. 

 

 

 

Edited January 26 by Arthur

[petert 550]

I wouldn't stress about it, so long as you have enough adjustment in the arms. After bending a Grp A hub, I modified 306 hubs to take the Ø16mm drop pin. The 306 hubs definitely start with +ve camber. If I had my time again, I'd do it with 406 hubs. Ø30x2.5 in 4130 will be plenty strong enough. Mine are Ø28x3 CDS and didn't fail in the crash which terminated the Grp A hub. Maybe they're too strong? I would have rather bent an arm than loose the special hub.

 

Ø30 x 2.5 = 2.06 x 10^4 mm^4

Ø28 x 3 = 1.87 x 10^4 mm^4

Edited January 26 by petert

[Arthur 10]

After my answer I realized I didn’t answer the correct question. Offset from strut to flange is about 20 mm more than 205. I think worse that can happen is the track is widened more than initially intended. Your struts are clearly far from vertical but this is about 4 deg camber I guess. Offset of 206 hub will get my stut more vertical for sure but I think the angle is about right for me. About 40 to 50 more track. Think I can better do a test fit. When I only remove the arms and hub, it’s not much work anyway. The hollow axles are also 35 so maybe I can use the same pipe. Would have to calculate that. 

Edited January 27 by Arthur

[welshpug 1,622]

That explains why the 206 runs 10mm more offset than 205 without looking that wide, and the strut tops seem quite narrow!    (Ew10 timing belt is not fun)

 

Wishbone needs to be longer to retain the same strut angle as a 205, which will increase track width and driveshaft length,   not doing that might lead to odd geometry behaviour under bump.

[Arthur 10]

I did some more, better measurement. Still not perfect, but oké. 

 

The offset and difference in angle is more then I thought. It however compensates each other. I don't think geometry changes a lot. The damper would be more upright, but diagonal, from the top of the strut to the pivot point below, it's almost the same. I think diagonal is what's important, because that's the axes it all turns on. On the car the 206 shaft is to long as expected. But it looks like the hub could have fitted standard if the pin was 16mm. (it's 18)

 

I checked both hubs on the same 2 inch pipe, and both hubs on the same 10mm rod inserted in the pin bolt hole. Hard to see in the picture, but when you set both flanges up the same "camber", the pipes cross each other below 1/2 meter. And when you set it up to let the pipes cross at the imaginary strut top, the 206 has a tad more camber. But it's not nearly as big a difference as the first picture suggests. 

 

It does explain the 206 strut towers

 

Quite some difference:

 

 

Not that much difference:

 

Edited January 27 by Arthur