Outer Limits 4x4 Board

Hey all

I've been looking at a replacement rear driveshaft for the truck after i twisted it off for a second time. After looking around here at threads on the subject it seems there are some guys running 5-7mm wall tubing but they all seem to be on trail rigs or front shafts. I explained to a driveline mob in north sydney what i was after and explained that the truck gets a flogging and sits the weight on the shaft sometimes (unfortunately for now it's lower than the trailing arms.) But he still said the thickest he recommended was .125" wall thickness which is reminiscent of what the last driveline builder said when i spoke to one ages ago. Is this just because they have no idea of the kind of demands i am placing on the truck or is it just totally unfeasable to put 5mm wall tube on a road going shaft and expect it to get balanced up.

What thickness shaft do people think i could get away with and some recommendations for western sydney to get it done would be great.

I would think it comes down to three factors

1. Balancing a thick walled shaft is going to require some serious weights
2. You may hit the "law of diminishing returns" where the strength increase gained from increased wall thickness is not worth the weight.
3. Rotational inertia issues with a shaft that may be twice the weight (= approx 4 times the inertia) at potentially 3000 rpm or more and its affect on surrounding mechanical parts (bearings and UJ's).

I would think that even a slightly off balance shaft (having one or two balance weights fall off in the bush) could be a lethal hazard with the potential to rip through the floor like a knife through butter.

Give Hardie Spicer a call mate, should have a dealer somewhere near you. When i was there recently (in Newcastle branch) they had some pretty serious shafts sitting on the shelf. Should be able to make something up for ya

I know you have a real aversion to having anything Nissan on your car but when I was sponsored by Hardie Spicer I asked them about a stronger tail shaft for the GU and they said that if I was able to break that then they would replace it without any problems. Meaning that they thought it would be plenty strong enough and it was. I didn't even do a uni. But I'm not sure about the length or the flanges. It'd be easy to weld the holes and redrill on the flanges if the lengths match up. But as Nayto said, give hardie spicer a call but make sure you talk to someone that knows about our sport.

Yep, definitely give hardy spicer a call... I work for them In Vic tho. But yeah, when you call, sus out whether they know anything about 4wd's, coz I reckon if someone walked into our branch and asked for a 5mm thick walled shaft, they'd be told they are stupid and it won't be warranted, etc... simply because they don't understand the stress it has to handle in the way of being bashed etc.

But as for it being feasible, yes one can be built out of thick walled tube, but won't be able to be balanced real well if its running standard sized uni's. They have a limit to the amount of weight the uni's can handle before they can't be balanced, basically it'll be out of balance, and any amount of balance weights won't do jack!

Thanks all

I've sent an email to HS at moorebank and i'm waiting for a reply. I've outlined in the email what kind of a pizzling it gets so hopefully they'll think outside the normal automotive box.

Roughmutt - I've got no issues with using any brand of parts if it's better or more suitable. I've seen GQ/GU tailshafts and they're HEEEUGE! but i reckon it's not the diameter that's the issue but the material thickness. I'd be interested to know what the OE wall thickness is on a GU tailshaft.

The Nissan tail shafts and uni-joints are definitely strong stuff, but I don't think the tubes are 5mm or thicker.

I know of some models of 4x4 vehicles that have solid (not tube) front shafts - to allow smaller diameter to get clearance from wide auto transmission option.

For what it is worth, I have heard that having the shaft built with some oil added inside the tube helps with balance - the oil gets distributed inside to balance it, similar to the principle used with large tyres. I don't know how well it would be if the shaft is at a steep angle.

rockcrawler31 wrote: Roughmutt - I've got no issues with using any brand of parts if it's better or more suitable. I've seen GQ/GU tailshafts and they're HEEEUGE! but i reckon it's not the diameter that's the issue but the material thickness. I'd be interested to know what the OE wall thickness is on a GU tailshaft.

back in the day, HQ one tonners had a 3 1/2" HD tailshaft comnpared to 2 1/2" in sedans and ute etc. the one tonner tailshafts were often cut and shortened for sedans etc with tickled up motors

bigger diameter may play a part?

rockcrawler31 wrote:I'd be interested to know what the OE wall thickness is on a GU tailshaft.

I'm pretty sure its 95thou, so nearly 2.5mm, not real thick, but much better than the 1.6mm wall thickness that hiluxes/4runners have from factory

we have run from 1/4"wall x 2.5" id high tensile shafts for years! with std unis it took less than 5grams to balance, then change to a DC and it took ~15 grams which was mainly due to the DC being out...

you could try contacting tom woods in the USA if you don't have any luck getting a decent driveshaft made up here in Aus. they will make custom shafts to your specs.

call steve @ universal driveshafts in geebung brisbane. He does plenty of 5mm wall comp shafts for nissans and toyotas.