All about rearends - shopping list

[Unifoot]

Scotty at Taylor Race sent me for info. It was recommended you all are some of the brightest. Here's the deal. I'm looking to build a good but inexpensive rearend for a trike as I lost a foot in a bike crash last year. While I still ride a 2 wheeler this has become an quest. I have learned alot from these forums but I'd like some specifics, cad files (dxf. prt. dwg), parts lists, ect. which will help in my design. I know I don't have to reinvent the wheel as you people have that covered. Thanks for your help and the best of luck to all of you.

[Unifoot]

Scotty at Taylor Race sent me for info. It was recommended you all are some of the brightest. Here's the deal. I'm looking to build a good but inexpensive rearend for a trike as I lost a foot in a bike crash last year. While I still ride a 2 wheeler this has become an quest. I have learned alot from these forums but I'd like some specifics, cad files (dxf. prt. dwg), parts lists, ect. which will help in my design. I know I don't have to reinvent the wheel as you people have that covered. Thanks for your help and the best of luck to all of you.

[CMURacing - Prometheus]

i saw a trike on a cross-country drive that was a harley front end welded up to the rear frame, engine, drivetrain of a vw beetle. i'd say that's pretty cheap, and its remarkably close to what most people here would recommend i think.

[Unifoot]

Let me rephrase. I'm interested specifically in the type of drives FSAE uses. This is for a Harley driven chopper style trike. Instead of chain I'll be using a belt drive. There is one or two similar in design on the market but you are required to purchase the entire package and not just the drive assy. Just wondering, how much would you say you have $$ wise hub to hub on one of your cars. Still in need of your knowledge, if not just a basic parts list. I know you have to build these on a budget. Thanks again.

[Broderick]

When it was all said and done, I probably spent about $1800 to build the drivetrain for the Rutgers car. Its pretty strong too, it finished endurance at competition.

Ryan B.

[jdstuff]

Unifoot,

How *free* machine shop access do you have? That will make a big difference in price. We probably have about $800 into our drivetrain hub-to-hub, but I spent a LOT of time machining.

Also, so you have any type of idea on what type of diff you plan on running.....open, Torsen, LSD?? I agree with Mike, in that a VW driveline might be the cheapest route to take. Our teams in the late 90's ran a Quaife Torsen out of a VW...a bit heavy for our application, but easy and relativly cheap to impliment. I can try to dig up some pictures if you're interested.

[Akos]

I think we sent a total of around $400cdn on the rear end of the 99 Toronto car. A lot of searching around is required though.

Low cost fsae rear end shopping list:
-90 Audi qatro center diff
-2 x 90 Audi qatro center diff output stub (to the rear axle
-2 x VW GTI drive shafts, get the long ones as those can be easaly cut/welded to lenght since they are tubular
-2 x VW front hub

The drive shafts will bolt directly to the output stubs on the diff. All you have to do is machine a case for the diff and bearing carriers. To use the stock carrier on the diff you have to drill out the bolt holes to 7/16" (they are a loose 10mm, which will cause problems if you try to put torque though the bolts).

Pay carefull attention to sealing, this is probably the hardest part.

You can probably use the VW uprights as well if you fab up a bracket for an A arm where the strut bolts up.

Good luck,

Akos

[Unifoot]

This is exactly the type of info I need. Thanks & keep it coming for a bit. Type of diff?? I was told torsen but if you have 0% traction on one side you have none on the other TRUE???? So now I'm thinking LSD. Would you agree since this is street use? This is basically what I'm looking to build for a WHOLE lot less money. I can go either stock single brake or the system from the donor car. Opinions please.http://www.mysterydesigns.com/RearSuspension(largepic).htm

[Broderick]

While it is true that with a Torsen if one tire has zero friction than the diff will function as an open diff. Assuming, your not planning on a solid axle design, if your lifting a tire at any time your suspension geometry isnt optimal/correct. We've only had the problem of lifting tires during cornering on one car and that because the suspension was WAY off. Personally I think a Torsen style diff is your best bet.

Ryan B.

[scotty young Taylor Race]

I have had a couple discussions with Unifoot and I think he is looking for a Torsen set up with upper and lower A-arms and some nice uprights.I suggested he get a hold of you guys because I have seen the cool stuff a lot of you guys are doing with the diffs as well as the upright configurations.

Scotty
Taylor Race

[Agent4573]

well broderick, don't forget about this picture from competition.... i mean technically thats a problem with lifting the wheel.....http://eden.rutgers.edu/~mantegna/car.jpg

[Broderick]

thanks paul. Ill call that a bumpy lot more than anything else.

Ryan

[Unifoot]

Anyone else have a parts list and maybe some photos they can share? I would like a few to consider. This pic if I can get it done this time was my reference in an earlier post. Way to expensive that's why I'm asking for your help.
http://community.webshots.com/photo/71052604/377599479rbkHhq#

[Unifoot]

http://community.webshots.com/photo/71052604/377599479rbkHhq#

[Unifoot]

http://community.webshots.com/photo/71052604/377599479rbkHhq#

[Denny Trimble]

We build most of our drivetrain in the machine shop, and I imagine most other teams do as well. You won't find a complete off-the-shelf system, unless you go with Taylor, but you already know him http://fsae.com/groupee_common/emoticons/icon_smile.gif

[MikeWaggoner at UW]

Have you thought about building one of the reverse trikes? It seems like a conventional trike:

A) Has a pretty high Cg and a pretty narrow (zero) in the front, so if you do anything with serious performance you're gonna flip. Worrying about wheel lift etc., it sounds like you wanna drive fast. (Draw a triangle showing around the outside of the wheels. Draw the Cg shift if it's 24 inches above ground at 1.5 g's, like it would be with you sitting on top. Does it go outside the triangle? What if you hit a bump around a corner?). You can have your butt near the ground on a backwards trike.

B) It's gonna plow like a bitch. Oversteer's a lot more fun, and you could fit a really wide rear tire on an upright bike that's been modded. And the drivetrain's a lot easier to sort. Tire width on the front is limited on a bike, and the rake on a bike isn't meant to be the front geometry on a car.

C) A custom drivetrain requires a LOT of machine time. Building the front of a car can be mainly done with a welder, A tubeframe kit can be a die grinder, an oxy-ace kit, and a bench grinder for around $200.00.

Finally, with a reverse trike, when you realize you want to make it lighter and faster, swapping out the rear end with a turbo busa will be easy...

If you're more concerned with how it looks and being a cruiser, an open diff or back end from a car is probably my recommendation... The rear end of the cars represents 1,000's of hours in free machine shops and sponsor time.

/EDIT: Or.....
http://www.ratbike.org/docs/504.php

[Unifoot]

I appreciate the fact some of you are taking me seriously. I'm asking for information because I'm ignorant about THIS subject not stupid. No, I'm not and engineer but do have 25 years as a tool & die maker involved in all facets of the business including design. As engineering students I know you realize that a huge portion on your jobs will be research. This is what I'm attempting to do now. A few individuals have been kind enough to supply me with the vary info. I'm looking for. I know Scotty at Taylor had faith in you all when he recommended this site. I trust there will still be a few good suggestions and recommendation coming yet. If anybody else has a list similar to the one Akos submitted or info such as JDSTUFF and Scotty Young it would be a HUGE help and cure my ignorance. Thank you again for the information so far.

[Mechanicaldan]

I like trikes, especially tilting ones.
http://www.maxmatic.com/ttw_index.htm
http://www.maxmatic.com/Graphics/trautwein_ttw_mc.jpg

and this one I REALLY like
http://www.moebius.es/ccalleja/moto3.jpg

but to answer your question more directly, our team has paid to have our differential machined. Just the two diff halves were $900. The rest of the rear end was probably another $500.

You can brouse our picture gallery at http://sae.stuorg.iastate.edu/formula/gallery/Final-Drive

Here's a bunch of information about the Torsen differential: http://www.torsen.com/fsae/fsaefaqframes.htm Our design is based on the "old" design, but that shouldn't matter for your appication.

I believe the consensus is that you can get a Torsen differential from a salvage yard out of Audi? Just read everything on the website, and it should answer almost all your questions.

You can also try contacting these Kansas teams, as you might be able to go to their shops and look at their cars:
http://www.jayhawkmotorsports.com/portal/
http://www.ksu.edu/sae/formula/


Good luck.

[drivetrainUW-Platt]

maybe I'm just seeing things, but is that a clear drive gear????

[Broderick]

It looks like highly polished aluminum, but I could be wrong. (kinda hope I am because that would be hot)

Ryan B.

[drivetrainUW-Platt]

it is a "sprotor", down by the caliper is where I'm seeing the clear/ reflection...maybe its top secret material

[Mechanicaldan]

It is indeed a plastic sprotor in the picture.

[Unifoot]

Anyone else have list of parts they used similar to the one Akos supplied? I'm realizing I could go to the junkyard and get any old independent rearend and figure out a way to make it work but... I'm looking to you all (and your wealth of knowledge) for some insight. Some are better than others, easier to work with, less expensive, and more common or popular. I have decided I want to use a torsen lsd diff. SUGGESTIONS PLEASE???

[Denny Trimble]

Well, some Miatas have Torsens, and they're all IRS.

I hope that counts as helpful. Have fun making it into a belt-drive... http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Broderick]

as an FYI getting a torsen from a miata wont be cheap. Dont ask me how I know, but unless you find someone that doesnt know what they have, your probably looking at $300 - $400 for just the center chunk. If you find one cheaper and dont buy it I will.

Ryan B.

[Unifoot]

Here's the dealyO. I am wanting to put together the driveline for no more than $1500 - $2000 this is diff, axles, bearings, hubs, brakes, & maybe uprights. Basically hub to hub drive. The can for the diff, a-arms, trapeze for mounting the center section, I will fab. Taylors setup is around $4500 with a Quaife (just driveline). The Mystery Design rearend complete is $6800. This is why I'm trying to pick your brains. I've heard $800 -$1800 here plus fab and some machine time. $300 - $400 for a diff isn't $1000 - $2000 . Broderick, you said you spent about $1800 for the drivetrain on your Rutgers car. Mind sharing your shopping list? I'm really looking for what parts fit what (no custom splines) Would I be best buying a complete Miata or some other rearend and building from there. What say you that have been there done that : ) Still all ears here.

[Broderick]

For the Rutgers Drivetrain alot of the cost came from buying the Taylor tripods and housings (about $450) and have Moser Engineering cut the splines for the output shafts and axles. (about $450, had to overnight them the parts, so that made it alittle higher.) Actual metal stock was probably only about $250. The wheel bearing were also expensive at about $400 but they are these really small deals. The torsen itself was $375. Thats what I remember off the top of my head but it think it mite have been alittle less.
As for the Miata parts, $800 will buy you the entire driveline. Driveshaft, Torsen center (aka pumpkin) and both axles. Sometimes entire rear subframes come up on ebay for a little more but include all the suspension and brake parts too. If you pick up a rear subframe, your getting a pretty well designed piece to start with double wishbone, fully adjustable etc. Hope this helps.

Ryan B.

[Mechanicaldan]

Just thought I'd post this option if you didn't know about them.

http://www.adaptivemotorcycles.com/pg2.html

[Greg H]

No, I think this (http://www.collegehumor.com/pictures/936505/) is the only way to go.

[nathan s]

http://www.chargermotorsports.com/gallery/thumbnails.php?album=15

here are some parts that we used for our drivetrain.

In my opinion, the Miata rearend would be the best bet. You will have far less fabrication headaches, but it will be heavier.

Btw, what engine are you using? I am guessing Sportster, if it is belt drive.

[mtg]

Unifoot, check your private messages.

[Unifoot]

Thanks to those of you that offered up genuine helpful information. You know the specifics I asked for help with. I truely thought that was the nature of this forum as did Scott from Taylor Racing who recommended you all. Remember it's guys like me that will be building your ideas we should treat each other with due respect as you don't become a journeyman overnight either. Just food for thought as you venture forth into the "REAL" world. AGAIN MY DEEPEST THANKS TO THOSE WHO DESERVE IT!!! While you all are concerned with weight it's not a huge concern of mine. I ended up using parts from a 92 Supercoupe IRS. In liew of any specific design suggestions I designed my own Diff housing for the LSD from this. I'm certain someone here has some CAD drawings of a far better design but they haven't shown up yet.
http://members.tripod.com/trikekits/Choper-Trike2-copy.jpg http://fsae.com/groupee_common/emoticons/icon_eek.gif

[Agent4573]

holy shit that bike looks awesome. I would have gone with a chevy 350 instead of v-twin, but that thing still looks fucking sweet.