rocklobster

Interesting to hear real life experience's of these box's rather then "it should be ok with this box"!. Funkyjimny, in your experience you think a 4:1 box with 215/80/15 tyres is a good option? Ive got 215/75/15's on mine so i surpose it will be similar in performance to the above mentioned? I only ask as i will be using a trailer at some point in the future. Not a big trailer, but it would be nice to improve the gearing for that as well as off road. Iam also considering getting some AT tyres so i could always get a differnt size if i get them.

Nobby

where can i get a 4.1 do rob at offroadarmouy do them so 5.1 and 6.5.1 are just a offroading box then i take it haha will a 4.1 be nice with 31" when i go to them in the future eny one had the gear set that go in your std tbox
so at 50mph in 5th gear with 6.5.1 tbox with 215 80 15 tyres what rpm will i be at sorry just got a bit of coin that needs to be spent on the jimny but want to spend it on the right one THANKS GUYS

Cheapest option is a Rockwatt made 4:1 box using 410 and 413 innards. Rockwatt supplies all the mounting brackets/rockbuckets, speedo adaptors etc.
Next option is new gearsets fitted into SJ transfer cases,Rob Storr does these in 4:1, 5:1,6:1, and 8:1 ratio's along with all the mounting hardware, speedo adaptor, rockbucket protection etc.
ORA advertise a 6.5:1 fully built box with all the mounting hardware, I cant see a 4:1 offering, maybe Rob will be along in a mo.

With 215/75/15's I wouldnt have more than a 4:1 which restricts your choice a little.
I find that with my 32" tyres and 6:1 box I can do 70mph.... but i'm doing 7000 revs so on road speed is a little undergeared and maybe a 5:1 would be a better choice for my tyres.

Some info from Rob Storr's site that may be useful to show the difference between gearsets:
www.rsmfg.co.uk
Reduction Ratio % Reduction Price

4:1 Works great with tyres up to 30” 12% High - 83% Low £375.00

5:1 Well suited for 31” & 32” 21% High - 128% Low £475.00


6:1 The only great gear set designed for 33” 24% High - 170% Low £525.00


8:1 King of the rocks, makes you lower than a
Snakes belly 24% High - 260% Low £625.00

I think these prices are for the box only, not the mounting kit !

Just been on Rob Storr's site, not the best website in the world by a long shot, thankfully he's much better at making gears !
If you are looking around www.rsmfg.co.uk then look for the little 'next page' button in the bottom right and you'll find the link to the kit prices. Note that Rob Storr modifies your propshafts on an exchange service where other people use some SJ parts instead.

Gary

I have a rocklobster 4.1 with BF mud KM@ 31-10.5-15.

With 5th gear on road i have 3700rpm with 100km and 4000rpm with 110km measurment made with gps.

So if you try with 215-80-15 you will have -20 km from my measurments.

Off road the 4.1 with the 31'' is very very good.

Dont forget , yes we want the 4L to be as much shorter can be but to get to the 4x4 area(greenlaning)

you will have to drive on road first.

For tire until 225-75-15 a mini rocklobster is the best option.

For 215-75-15 a 413 stock t-case is the best. I used to have my car with this combination at first and

never had any problem.

suzuki jimny fella, if you get one let me know how you get on. I know when people are looking for low ratio gear boxes for the Jimny, Rob Storr's name crops up every time. I would be particularly interested in how much it all cost .
Just out of interest, what would people say is the best tyres size for the 4:1 box in terms of road driving? Looks as if 215/80/15 is a good size, according to funkyjimny .

Nobby