Drive Shaft Help

[Kyle Kapa]

We are attempting to use a differential out of a solid axle honda ATV. I've never in my life done anything with an indepdent rear drive train. Obviously I need to get some sort of CV shafts in there while matching the internal splines on the diff, and still getting the right lenghts.

How do you guys do this?

Is there a way I can just get some small CV joints and mount them to my own custom shafts?

I'd really appreciate some help on this.

Thanks in advance.

[J. Vinella]

Originally posted by Kyle Kapa:
Is there a way I can just get some small CV joints and mount them to my own custom shafts?


Yup, that would be one solution. That is basically what we do.

There are various CV joints out there and finding the one that best fits your application is the real key.

Good luck.

[Jersey Tom]

Taylor Race engineering makes all the stuff you need... with drive shafts, CV joints, tripods, tripod housings, blah blah blah. I'm not a drivetrain guy but there's all sorts of crazy stuff that goes into that assembly.

Upside is its all premade, because.. good luck making the splines yourself.

Downside is I feel its fairly overbuilt for FSAE, and getting the shafts to length takes some tweaking. Don't even try machining their drive shafts. As far as I can determine they're thru-hardened 4340. I wouldn't touch that stuff unless it was annealed (doable), and then only on a rigid CNC lathe with CBN inserts.

[Boston]

Kyle, I think you're saying you plan on using the CVs from the ATV. You have about three options. One: Get the spline specs from Honda somehow, buy your own stock, machine it and polish it, have a company spline it, then have it heat treated. Option two: get the spline specs, pay a company like taylor race to do all the work for you. Option three: buy some shafts for the ATV, cut them in half, and extend them by welding a hollow sleeve between them. Cut the sleeve at a steep angle to increase the welded area. Some teams have reliability issues with the last route. Heat treating after welding can help. This is sometimes the easiest way for first year teams to compete.

[Kyle Kapa]

Thanks for the suggestions guys. As far as taylor or any other custom made shafts they want about $2000 for those suckers. Our budget for the whole car is only $6000.

Boston we are probably gonna go your route. Much cheaper. Byt my next question is...

How do you mount the cv's to the diff for easy on and off? Slip-yoke? Flange? ... U-Joints?


Thanks.

[Boston]

I'm assuming the CVs are driven from the differential by splines. If this is the case, you want to attach them to the differential using circlips (they should already have these).

[mtg]

When you have a splined CV housing connecting to the side gear in the diff, it is usually a detent ring type of capture (removable by yanking hard, but won't slide out during driving). The ATV CV's tend to have freakin stiff detent rings, requiring the use of a Get The F-ing CV Out Of The F-ing Diff Tool. My thoughts are that racecars need to easier to take apart....food for thought.

One thing to watch out for on the ATV drivetrain is the minor diameter of the halfshaft splines- the ATV's generally don't have as high of a shockload on the drivetrain as an FSAE car with hot slicks with a bad driver attempting a downshift.

As a baseline, the Taylor halfshafts are actually optimized really well for FSAE. I'd like to see somebody make a steel FSAE halfshaft significantly lighter that doesn't explode.

To sum all that rambling up, the ATV parts robbing can work well, as long as the minor spline diameter on the halfshafts is not too small.

[Andrew Nabb]

My suggestion for a first year team.....Find an ATV with a similar track width to the car you are planning to build and take the diff, halfshafts, CV's and Hubs. Heavy ... yes, Hidious...yes, but it will probally be the cheapest way to get something together. If you only have 6 grand, i think you have bigger things to worry about.

Another step up in the uglyness would be to use cartan joints (ie universal joints on a rear drive car driveshaft) and cut and weld up small car drivershafts (like a miata or rx7). I have seen similar things done by baja teams. Again not a good solution, not a great or light design, but it might save your very limited budget.

[Korey Morris]

Originally posted by mtg:
the use of a Get The F-ing CV Out Of The F-ing Diff Tool.

And I thought I invented that....

[mtg]

Originally posted by Korey Morris:

And I thought I invented that....

We had a whole line of F-ing tools made by the Effingham Tool Company based in Effingham, Illinois.

[Kyle Kapa]

Do they make a F-ing build a car tool?

We need one.

[drivetrainUW-Platt]

why did you start out with a solid rear if you want to go with independent? I would either take the diff to a dealer and see if they have any cv shafts you can try to fit into that piece or just use a front differential that is limited slip and already made to have cv joints, just get the whole thing, diff, housing, cv joints, half shafts and outer wheel hubs....it will all fit together and be much cheaper then talor or whoever, then just have custom half shafts made to the lengths you need.

[Kyle Kapa]

Originally posted by drivetrainUW-Platt:
why did you start out with a solid rear if you want to go with independent? I would either take the diff to a dealer and see if they have any cv shafts you can try to fit into that piece or just use a front differential that is limited slip and already made to have cv joints, just get the whole thing, diff, housing, cv joints, half shafts and outer wheel hubs....it will all fit together and be much cheaper then talor or whoever, then just have custom half shafts made to the lengths you need.

Why? Simple. MONEY!!!!

[drivetrainUW-Platt]

you can pick up everything you need from ebay used for under $500

[BStoney]

Originally posted by Jersey Tom:
Upside is its all premade, because.. good luck making the splines yourself.

Downside is I feel its fairly overbuilt for FSAE, and getting the shafts to length takes some tweaking. Don't even try machining their drive shafts. As far as I can determine they're thru-hardened 4340. I wouldn't touch that stuff unless it was annealed (doable), and then only on a rigid CNC lathe with CBN inserts.

I am curious why you think it would be terribly difficult to machine the Taylor half-shafts? Yes, they are 4340, but we cut and machine them to length and machine retaining clip grooves to retain the tripods every year with no problem on a small lathe.

Just curious if you, or others have had a problem with this...

[Wright D]

Machining the Taylor half shafts should present no problems; I have done three sets for fsae cars, and several sets for d sports. Taylor Race can also machine the half shafts to your specs if you don't have the ability, but any body that is comfortable using a lathe should have no problem cutting and grooving the half shafts.

[Chris Allbee]

I rough the Taylor axles to length on a bandsaw and then face and groove them in a small lathe using HSS tools. Entire set of axles takes about an hour at a normal pace (i.e. shootin the shit every 5 minutes for 10 minutes).

As a side note, if you do decide to use Taylor's stuff, you'll be happy with the service. They saved our ass this last week by shipping us some parts to replace the ones we ordered (incorrectly). All we had to do was give them a tracking number to prove we had shipped our stuff to them and they sent us the replacements. Seriously, I had the parts in hand less than 24 hours after I called.