31" with stock drive terrain?

[ZookO]

I just bought my first Zook last week.  It is bone stock but I just bought a Webber Redline kit and a Rocky Road Delux spring over, I can't wait until they get here.  I was just wondering how hard is it gonna be on the zook to get down the road with some 31" all terrains?               

[zuk01]

not to bad running the stock carb with a spoa running 31`s and it does alright, let me know how the carb makes it run

[Mope]

As your next mod after that, you might consider some 4.30-4.62 diff gears, or 4.16 t-case gears. Either one would help turn the 31's.

[prowler]

i have a 1.6L 8v with a stock drivetrain on 31x12.50 boggers and its not half bad, i can use 5th gear at about 3000rpms at 60+MPH.hillclimbs can be sluggish at times but nothing you cant live with until you get gearing. i wheel mostly mud so i dont really need gearing for wheeling..can go in 4high 1st gear and can go straight throughout the rpms

[CoraZuki]

I ran 31s with the RRO SPOA and the stock drive train for about 2 years.  I could not use 5th gear any more and 50-55mph was about as fast as it could go, with no head wind.  My engine was a little wore out though.

It did fine on the trail in low, however, it was still a little underpowered. 

[ShuDuck]

I had 31" mud on a completely stock LWB with good engine. Could hold 60mph uphill, fully loaded. used 5th with little problems

[Merlin93]

...  how hard is it gonna be on the zook to get down the road with some 31" all terrains?

31's are about 14.5 % oversize, from stock 205's. If you've got an early Zuk (it sounds like you do with the carb), then your 5th gear (OD: 0.795:1) is about 9% higher than that of later Samurai's (OD: 0.865).  Combine that with the oversize tire and you'll likely NOT get a lot of use out of 5th gear any more.  A set of 4.30 R&P's would get you back to near stock and keep your speedometer about right (but 4.30's are near impossible to find). A 4.16 T-case would also get your high-range gearing back to near-stock, so you could drive in 5th again. But the later 5th OD gear might still be a good swap if you ever overhaul the tranny.
With the 4.62 R&Ps, your speedo would read a bit high (no biggie), gears 1 thru 4 would be a bit lower, but your present 5th gear would give you about the same highway gearing as later Zuks.

T-case gears are probably the easiest and cheapest, and up to about this tire size, you will likely  NOT  be breaking a lot of drivetrain parts, depending on driving style.  All three choices are reasonable, depending on what you intend to change next, after this. 

[ZookO]

Thanks for you replies. It does have 130,000 on the engine so I wasn't really expecting it to run highway speeds very well until I lowered the gear ratio. I don't plan on wheeling it a whole lot just a really cool DD. I will probably do the transfer case gears after Christmas. Is it a very difficult swap? I've been in a few trannys before.      .     

[loveofjazz]

I've been in a few trannys before.     

Let''s go with "Things I Wouldn't Say On The Zu" for $500.00, Mr. Trebek...          

[JRickey]

I wouldn't put anything less than 6.5:1 gears in the tcase.  Your starting with 31's but the lower gearing will allow for 33's barely.

[outsydthbox]

Let''s go with "Things I Wouldn't Say On The Zu" for $500.00, Mr. Trebek...          

         ....I mean...UH, "Not that there's anything wrong with it"(Seinfeld)

[outsydthbox]

         ....I mean...UH, "Not that there's anything wrong with it"(Seinfeld)

All kidding aside,  Welcome to the ZU ,  ZookO

[ZookO]

Thanks for the warm welcome  I have been a Ford tech for 3 years but I deal with mostly driveability concerns. I just didn't know if I should bribe the trans guy at the shop or if I could tackle it on my own. I do plan on going with the 6:5 gears though.

[Kermit]

I ran 31" AT's for about 6-12 months before I did the case. It was barely tolerable on road with my 100K motor. Off road, it was miserable. Any climbing required a lot of dancing with the clutch. Incidently, i have the late trans with the lower overdrive. I can use 5th but I have an early trans ready to go when I replace the crappy Advance Auto clutch (not recommended). I would like to bring the RPM's down a bit on the highway but I'm not sure if the motor can pull it. Currently, I can pull 65 on the flats at around 4200 RPM.

I finally stuck in a set of 5.14 tcase gears and have been happy ever since. Tcase gears are easy peasy if you have ever built a trans. Depending on your extended plans re: motors, tires and axles and your intentions (mud or climbing) you have several gearing options at your disposal.

Tcase gears move the torque multiplication pretty far upstream but seems to work fine with stock axles and 31-33" tires. Be careful going too low unless you are doing mostly slow moving rock crawling. A high range reduction of 16-20% seems to work well on DD stock geared zuks with 31-33's and no other gearing changes.

Axle gears are another option but you have limited choices unless you go new. You can adjust for your new wheel size really well and you can keep up your wheel speed in mud, etc. You do not gain the addl grunt for slow moving without slipping the clutch but many like this approach. If you do intend to use the Sammi as a DD, axle gears are fine but you will run into overgearing issues if you plan on a future case upgrade over 4.16, which is still marginal. This does make up for a nice balanced drivetrain as far as stress goes.

I decided to go with the tcase gears only at this point. It is doubtful that I will ever go above 33"s and might go to Toy axles (4.10) if I do. The stock axles have held up well for years until I broke one a few months ago jammed up in a rock garden.

That's my $0.02.

[Merlin93]

There used to be a great article on the Zu by Art Lilley about gears, but it has fallen off in a re-organization.  The PDF that has replaced it no longer has a useful display of the different high and low ratios available.  The data's still there, but is now undecipherable. It's at: http://www.zuwharrie.com/index2.php?option=com_content&do_pdf=1&id=15

A lot of guys with the early 5th gear ratio do like the 6.5 T-case gears for the 20% high-range reduction.   But the low range becomes VERY low.  If you stay with the 31" tire size you may not be breaking drivetrain parts very often. As noted earlier, _ALL_ the  gear reduction is in the T-case, transferring the stress to other parts of the drivetrain, from the T-case mounting arms, u-joints and back.  It might be a good idea to consider reinforcment of the stock T-case mounting arms (Petroworks does this reasonably), or replacing them entirely with an aftermarket mounting system (Trailtough or ZOR).  Good article on gearing at:  http://www.trailtough.com/index.php?view=article&catid=36%3Atechinfo&id=60%3Agears&option=com_content&Itemid=60

Chrome moly replacement rear axles are also available to handle the increased torque.