Differential Rear Ends

[Bob Sigmon]

Has anyone used a differential for their rear end?

Pros?

Cons?

[RUBICON]

Hi...I have a Comet diff. on my BSR. I looked at several....Peerless was one...I liked the look of the Comet and it is compact and a heavy duty unit...Do a search for Comet differential and start there and look at them. I had to add 2 more bearing mounts to support the axle...My axle is a 1-1/4" chromemoly kart unit that is split in the middle and has short splined stubs plug welded in....The next is sprocket mounting and lastly I welded a disk brake flange/hub on the diff carrier to give me 2 wheel braking..more details if you need...later

[elvergon]

hey bro, i would also like to see your diff. Could u post some pics? thanks

[Bob Sigmon]

Rubicon,

I was looking at the Comet Differential. I'd very much appreciate any pictures that you would care to post.

Bob Sigmon

[stool-sample]

I had a guy send me pictures to my shop addy. I will try to find it. This guy did one hell of a job! Might even be someones in here!If I can find it I will post it as well. Glenn

[RUBICON]

See If These Help

[Bob Sigmon]

Stool-sample,

I'd appreciate any pictures that you can post!


Rubicon,

Very nice! I like the chain guard! It looks like your differential is offset - what length axles did you use?

And - after mounting the brake disc on the differential, what changes did you have to make as far as the brake caliper?

Do I see a brace for a wing?

[RUBICON]

Yes there is a 30" wide curved aluminum wing.
Here is the way I installed the diff:
I ordered the Comet Diff complete with axle. I did not use the axles...only 4" of the splined ends ( the axles were too small to fit kart bearings and wheel hubs etc ). I ordered a 1-1/4" chromoly kart axle ( they are hollow). I set the diff behind the engine and alligned it so the engine sprocket alligned with the diff sprocket flange ( where the rear sprocket bolts on to the diff )...Now measure from each side of the diff to the end of your desired wheelbase. One axle will be longer than the other...Cut the chromoly axle so you have the offsets you need...The 4" long splined stub axles will slide into the hollow chromoly axle ( I did not have to bush the fit..it was perfect..if needed it can be bushed or sleeved to fit ). The finished fit is to have enough of the comet stub axles to insert in each end of the diff and the 1-1/4" chromoly axle begins exactly at the ends of the diff....The stub is held in the kart axle with a "plug weld"...( 1-1/2" from the cut end of the chrololy axle drill a 1/2" dia hole thru the side..all the way thru...then insert the stub to the proper depth and fill the 2 holes with weld ) This is the strongest weld for this tyoe of joint. It preserves the axial allignment, introduces no radial stresses due to weld, and makes welding chromoly to carbon steel a non issue...The weld area must be turned smooth in a lathe or very carefully ground so it will slide thru a kart bearing...
I had to adapt a motorcycle sprocket for mine because of the cycle front sprocket. I made a adapter ring out of 6061 aluminum and cut the center out of a cycle sprocket and made it all concentric...you can use standard Comet sprockets in a range of sizes..I think they are the same as kart sprocket chain specs....let me know if this is clear....thanks

[Bob Sigmon]

Rubicon,

That setup is very easy to follow. Relatively simple and super effective!

I'm printing this out and will definately use this when I setup my bar stool racer! I'm just starting to collect the parts. Since this is totally out of my budget range, it will take me awhile. I really want to make one, they are just too cool.

Now I just have to get more side work and make this a reality!

Do you have a picture of the racer with the wing? I bet it looks awesome.

Bob Sigmon

[Mike Bean]

Hey Rubicon,

Where did you get the heavy duty rear bearing hangers?

-mbean

[Bob Sigmon]

I second that! Those look really easy to use. I like anything that makes assembly more effecient.

[stool-sample]

Mike we stock those hangars. There maily for racing. We sell about all the accessories that go on our chassis.Glenn

[RUBICON]

The bearing hangers are available from kart shops. They are the most common style found on race karts and have 3 height adjustments. They are formed with a slight curve on the bottoms so they will weld to 1" dia round chassis tubing. I ground them flat to weld to 1" square tubing. The flanges add extra strength over the flat ones sold for use on "fun karts". Your readers might know that most kart parts fall into the catagory of racing parts ( heavy duty, billet aluminum, chromoly, anodized, precision fabricated, etc. ) or "fun kart" ( less expensive, available at even farm and home stores, zinc plated, simple made...It gives a source for all budgets...
ps: Everyone should know that racing kart shops have a selection of fabricated brackets ( corner gussets, misc mounting tabs, axle hangers, pitman steering arms, steering shaft bushings, brake caliper mounts, etc.

[DOCT.]

Where did you get the diff?

[RUBICON]

The diff was bought on-line from a parts house...just search for comet and the part number...I think SD-1 if I remember right..you will get several places to buy...shop around ...the prices vary greatly for the same thing.....

[xtman]

Im building a mini trike. My rear tires are 10 inches wide, do you think i should go with a diff? I already have trouble turning on my BSR.... If so which diff would you suggest?
Thanks

[xtman]

Yeah i will post pics! And thanks! I might go with the peerless one 1inch axle sounds good but the 38 inch lenght is a little too long! So i will jsut cut 1-2 inches of each side. And actually my uncle works for yamaha and he is getting me a complete rear end off of a quad. Im not sure which one thought but i know they come with diffs. The only problem i can think of with that rearend is the bolt pattern!

[moto1fast]

Hello, Peerless will do the job! Also most diffs from Quads use a Drive shaft and do not have a sprocket drive. There was some Kawaski LT200's and 250's three wheelers and also some of the early 300 four wheelers that had a lockin-lockout Diff with chain drive that might work great for your application! You would just have to make a adapter to fit a sprocket on to it. Good luck!