T-2 reduction gear

getsmarx · Post by **getsmarx** » Thu Mar 06, 2003 9:38 pm

Actually, the laydown adaptors give a Baja about a 3 inch longer wheelbase than stock. The reduction boxes are pointed back rather than down.

Charles

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http://www.c-zone.net/northgte/baja57.htm

baja1432 · Post by **baja1432** » Thu Mar 06, 2003 10:19 pm

I have ran a upright John Johnson setup with no-hop bars for 20 years now with NO hop or problems whatever. If someone wants to try it I have another J.J. setup that's never been installed.
J.R.

Guest · Post by **Guest** » Sun Mar 09, 2003 8:13 pm

No wheel hop problems in my buggy with Johnson bars. I can take some pictures next weekend if you like. Larry

Dr. Strangepork · Post by **Dr. Strangepork** » Wed Mar 12, 2003 1:54 pm

How do reduction boxes affect your top end? I would imagine that it hurts a bit. Is this somthing you would use for trail only?

Dr. Strangepork

Post by **Marc** » Wed Mar 12, 2003 2:03 pm

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Dr. Strangepork:
How do reduction boxes affect your top end? I would imagine that it hurts a bit. <HR></BLOCKQUOTE>

Yes if you're using stock-height tires. If you use the late 1.26:1 one-ton boxes with 31" tires the RPM per MPH comes out about the same. Very similar gearing to what you have with an early IRS bus "002" box that uses a 5.375 ring & pinion and no reduction gears.
The older 1.39 "half-ton" boxes would be about 10% slower at the same RPM with the same big tire. Since the rolling resistance of the big rubber is higher that 10% reduction may be welcome if you have a puny engine.

Guest · Post by **Guest** » Thu Mar 13, 2003 8:46 pm

It'll still go as fast as I want to drive it with 31" tires 75+. In a shortened dunebuggy thats enough for me. Also over 15" grond clearance at the engine.

Dr. Strangepork · Post by **Dr. Strangepork** » Fri Mar 14, 2003 8:42 am

Do you have to use reduction boxes on a swing axle? Or can you use them on IRS as well? All the pics I have found show them on swing axles.

Dr. Strangepork

Post by **Marc** » Fri Mar 14, 2003 9:00 am

I suppose it could be done (probably has been) by using a rear suspension setup similar to what some of the dragracers use, but why?

hillbilly · Post by **hillbilly** » Sat Mar 15, 2003 8:38 am

Yes it has been done.... on the west coast, (here in Canada) some one has been taking the reduction boxes and puting them on .. dont know how strong of a set up it is but the put a grease nipple on and fill the boxes up with grease.It makes the thing alot wider, so custom rims used ,to get it back. (think tornado)why ?...because it gives you awsome ground clearance.up here there is not alot of open areas alot of the good country is rough and the higher you can get it the more places you can "chew "your way up. you can use 33" tires (because of the lower gears ) and still crank 70 on the highway.

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[This message has been edited by hillbilly (edited 03-15-2003).]

getsmarx · Post by **getsmarx** » Sat Mar 15, 2003 12:58 pm

Back in the '70's, The Brasilian built VW Bus had an IRS / reduction box setup.

I saw a picture of it once on www.vintagebus.com .

I don't know how you could get your hands on those parts here in the U.S.

Charles

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http://www.c-zone.net/northgte/baja57.htm

nickg · Post by **nickg** » Tue Nov 30, 2010 7:06 pm

I saw this thread in the stickies and thought I would add this info, though it's been covered on a different forum previously.

My coworker made IRS arms with early rear reductions. So far it has survived two separate weekends at the OHV park. He had built a reduction setup about 20 years ago and it didnt' make it down the driveway before it ripped to pieces. He had a spare reduction transaxle and finally decided to do something with it... the following is a couple of weeks worth of evenings and a bit of learning about early vs. late and gears, etc. He had seen photos of the Brazilian units and it made up his mind when he was trying to decide if it could be done or not.

He cut the bearing boxes off of the back of the IRS control arms and welded on 3/4" thick square plates, and at 90' to those he added 1/2" thick plates with gussets to reinforce... he cut off the axle tubes and cut down the axles and welded type 1 cv-flange ends to the axles, and used sealed bearings on the input shafts. Since he had early, big-nut axles he cut down and re-drilled the bus drum to use as a hub for his brakes, iirc they're 914 rotors with 912 front calipers. He has a lathe and quite a bit of work was needed to keep everything true and round. iirc he had to machine some spacers to get the drum / disc combination where he wanted it in relation to the caliper. The caliper mounts were modified aftermarket units. Since he had an early transmission case it was no problem to flip the ring gear to the transmission. The boxes are filled with 90wt. The control arms were boxed in (11ga, iirc) and shock mounts were added. When measured this conversion gave him the equivalent of a 3x3 trailing arm. It does not suffer from wheel hop issues. It does have a bit of negative toe just because of how things settled out (it was all done by eye) but it's a non issue for what he uses the buggy for.

Post by **Leatherneck** » Tue Nov 30, 2010 7:11 pm

Nickg, thanks a lot for posting this setup. Lot of time and thought went into this. Nice setup.

Hebster · Post by **Hebster** » Wed Feb 11, 2015 1:00 am

Very interesting combination of IRS with redux.

I was offered awhile ago to buy this setup from a collegue who had bought a splitbeetle that had in some early stage been converted into a "snowmobile"... It had one ski upfront instead of the original frontaxle and the transmission and axles are from a -57 splitbus.
All done with Adapters and all. Bolt-on to a split bug chassis and just by replacing the nosecone for a later one it also works on later beetles...

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