crawl ratio

[308LUX]

anyone wanna sell me a marks heavy duty, cheap

its got an awesome first gear ratio 5.15:1

[redzook]

Ok my Sierra is

3.6 x 6 x 4.1 = 88.6:1

to factor in tyre size if you divide by the size of your tyres in my case 34" I get a figure of 2.6. This figure then gives us a figure to compare different vehicles with different tyres sizes

So Hypolux with 120:1 and 37s has a figure of 3.2

amd Nick with 220:1 and 38s (thats right tyre size isn't it) = 5.8

Whereas Dumbdunce with 48:1 and say a 35" tyre = 1.4

I'd reckon that between about 2.3 - 3 would be a good usable figure anything above would be a dedicated rockcrawler

mine would be 2.6589032258064516129032258064516

[2car]

I guess we could take grimbo's equation and multiply it by your peak engine torque, then divide by the weight of the vehicle to try to "standardize" things across engine capacities/gearing/vehicle weights.

It would give actual torque put to the road per kg weight.

2.25 x 323nm = 726.75 / 1950kg = 0.37

Dude, you have inches and metres in the same equation. It's doing my head in.

[Wendle]

I guess we could take grimbo's equation and multiply it by your peak engine torque, then divide by the weight of the vehicle to try to "standardize" things across engine capacities/gearing/vehicle weights.

It would give actual torque put to the road per kg weight.

2.25 x 323nm = 726.75 / 1950kg = 0.37

Dude, you have inches and metres in the same equation. It's doing my head in.

that's what he asked for! ....I think?

[dumbdunce]

it doesn't matter, it's just making a comparitive figure

[MissDrew]

As I said before I have around 90 to 1 but I decided today that I am deffently going to put a marlin in my lux very soon so that will make it around 210 to 1

[Strange Rover]

My rangie drive train with 4.1 diffs and 42in tyres would crawl better than POS setup with his dual transfers and 4 cyl motor and 39in tyres.

I think my crawl ratio was 55:1 and it was better than POS 90:1 for crawling over, say , 2ft vertical rocks.

For overall crawling ability I think the motor plays a much bigger part and you need to look at the torque figgers around the engine idle revs and not peak torque IMO.

Tyre size doesent really matter IMO cause a bigger tyre will crawl over vertical obstacles much easier than a small tyre so the gearing effect of big tyres doesent really matter.


Im at about 100:1 and my second it at 50:1. I would probably be better off with less crawl ratio (say 80:1 first and 40:1 second) cause my motor easily pushes the 50:1 second and if it was 40:1 I would get a bit more wheel speed.

Overall crawl ratio is good but people really need to look at their throttling gearing where you need wheelspeed cause low crawl ratios will only get you over the easy stuff more easily (less stalling and less riding the clutch). IMO a big crawl ratio wont make you rig any more capable, it will just be easier to drive and good for posing. When it comes to the hard stuff crawl ratio means nothing.

Sam

[Bitsamissin]

Nothing at the moment
Was 3.92x1.925x4.875 = 37:1

Would have been (but may still be) 3.92x2.85x5.29 = 59:1

[HSV Rangie]

What I now have:

ZF 4 speed auto Lt230 T/Case.
2.4795x3.32x4.3= 35.39-1 x 2 70.39 / 33 = 2.145.

Next change:
2.4795 x 4.316 x 4.3 = 46-1 x 2 = 92-1 / 35 = 2.629.

(x 2 for torque converter.)

Have around 400 nm torque at 1200 rpm.

Performs adequetly.
Michael.

[Liam]

3.652x 6.129x 5.89= 132 to 1
tyres are 35.5 so gives 3.71 overall ( then add nitrous)

[bj on roids]

My old rig:

4.89 x 1.963 x 4.11 R (4.10 F) = 39.453~

divide that by grimbos tyre height in inches thing = 0.940 It was a strong motor

My new car is the ultimate crawler, slowest EVARRR:

2.54 x 4.7 x 4.10 = 48.946

divide again by 42 = a healthy 1.166 whatever the fawk that means. Certainly feels better than my last one.

You idiots at 100:1 are missing out on the seat of your pants thrill and the chance to get your wheelspeed up!

Crawlin aint gettin it awwwn!

[MissDrew]

Just to add to this

In some ways I agree with what Sam has said about crawl ratios, having super low low dosen`t make your rig any better, having some where around 70:1 to 100:1 does that.

I`m NOT putting in a second T case so that I can have the extra low ratio of 210:1. I am putting the second T case in so that I can have the opion of standard low range as well as the low range I have now of 90:1. Getting the final crawl of 210:1 is just a bonus, because I allready have the rockhoppers, so I might as well put them back in

[Strange Rover]

Yea - its good to have the options of dual transfers with different gears in each. There would have to be a gear thats perfect for every situation.

Had A bit of a play with BJ rig today with the lexus v8, auto and 48:1 and all I can say is farwkin incredible. Feels very, very good. Nice and controlled on the vertical stuff (like ramping it on the forklift) and plenty of acceleration and wheel speed when you stand on it.

Think I might have to go auto with the mogrover.

Heres the ramping pic - not bad for something without any lockers.

Sam

[hypo]

Just to add to this

In some ways I agree with what Sam has said about crawl ratios, having super low low dosen`t make your rig any better, having some where around 70:1 to 100:1 does that.

I`m NOT putting in a second T case so that I can have the extra low ratio of 210:1. I am putting the second T case in so that I can have the opion of standard low range as well as the low range I have now of 90:1. Getting the final crawl of 210:1 is just a bonus, because I allready have the rockhoppers, so I might as well put them back in

u wil only b able to get standard low if u run a twin stick in the rear case so that u can put the front case in low range(standard) and the rear case in high and use the second stick 2 select front wheel drive, this is probly the best way 2 use a dual case i reackon as im gunnd set mine up that way

[MissDrew]

When running 2 transfers with low range gears in 1 you run the gears in the rear case.

To select standard low you have front case in low and the rear case in high range 4WD.

To select the low range I have now, run front case in high range and rear case in low range.

To have low low run both cases in low range.

For 2WD standard low range just run front case in low range and the rear case in 2WD.

The only opion you can`t get unless hubs are in free is 2WD with the low range I have now or low low 2WD.

Having 2 cases one with low range gears will give me 15 4WD low range gear opions to choose from. 3 4WD low range reverse gears. 5 2WD low range gears.

[MissDrew]

And I shore even with a twin stick in a hilux case that you CAN`T get front wheel drive only.

Doing a twin stick on a hilux case will only give you the opion of low range 2WD over the standard selections.

[hypo]

When running 2 transfers with low range gears in 1 you run the gears in the rear case.

To select standard low you have front case in low and the rear case in high range 4WD.

To select the low range I have now, run front case in high range and rear case in low range.

To have low low run both cases in low range.

For 2WD standard low range just run front case in low range and the rear case in 2WD.

The only opion you can`t get unless hubs are in free is 2WD with the low range I have now or low low 2WD.

Having 2 cases one with low range gears will give me 15 4WD low range gear opions to choose from. 3 4WD low range reverse gears. 5 2WD low range gears.

shit i must still be pissed from last nite u r right u dunno wot i was thinkin wen i posted

[hypo]

And I shore even with a twin stick in a hilux case that you CAN`T get front wheel drive only.

Doing a twin stick on a hilux case will only give you the opion of low range 2WD over the standard selections.

i know that u cant get only front wheel drive on a twin stick i was thinking bout 2 few things wen i posted

[MissDrew]

GGGGGG I love it when I`m wright, even better when its twice in a row

[hypo]

GGGGGG I love it when I`m wright, even better when its twice in a row

heheh ueah i wish i could delete my post now fark i cant even beleive i rote

[NICK]

you CAN`T get front wheel drive only.

I BEG to differ


NICK

[MissDrew]

Not with a hilux case.

[RUFF]

Not with a hilux case.

It is possible to get FWD only while still running hilux T-cases.


And putting your front case in low and your rear case in high is asking for trouble. You wont get away with doing this many times. Especially if you go V8.

[RUFF]

Currently im running 3.93 x 2.28 x 2.28 x 4.88= 99.69:1

When my rig is back on the road i will be at 83.76:1 with 4.1 diff gears.

I dont see any reason to go any lower with a V8. You are only going to wheelspin any lower. Even at 99.69 and the stock 22R 2.4ltr i was running 1st gear was too low.

83.7 will be plenty to idle around and will allow enough wheelspeed to get on it when i need.

[OVERKILL ENG]

Mine is 114:1 I don't think you need much lower than that.
SAM

[Beastmavster]

Just to add to this

In some ways I agree with what Sam has said about crawl ratios, having super low low dosen`t make your rig any better, having some where around 70:1 to 100:1 does that.

I`m NOT putting in a second T case so that I can have the extra low ratio of 210:1. I am putting the second T case in so that I can have the opion of standard low range as well as the low range I have now of 90:1. Getting the final crawl of 210:1 is just a bonus, because I allready have the rockhoppers, so I might as well put them back in

Think I said something similar in another thread.... it isnt the fact that you can get ultra low by dual transfer, its the extra options that matter. You can gear as low as you want,..... in the end too short is every bit as much of a problem as too tall.

having 20 forward gear options would be really nice on the Vitara.....

[hypo]

Not with a hilux case.

It is possible to get FWD only while still running hilux T-cases.


And putting your front case in low and your rear case in high is asking for trouble. You wont get away with doing this many times. Especially if you go V8.

y will running the front in low and the rear in high have a different effect on the rear case than running the front in low and the rear in low ??? the rear case is still getting feed the extra reduction and torque ??

i dont understand ??

[Strange Rover]

y will running the front in low and the rear in high have a different effect on the rear case than running the front in low and the rear in low ??? the rear case is still getting feed the extra reduction and torque ??

i dont understand ??

Still gets the same torque multiplication. But when you are in double low first gear you are generally just ideling around and you dont have the wheelspeed to generate much traction so you dont really load up anything in the second case. When you shift second or third double low to get a bit of wheel speed then you loose all the torque multiplication in the gearbox so again the transfers dont see much torque.

If you have the front in low and the rear high you will generally be in first gear (max torque gear) and will probably be getting it good (otherwise why are you in first low high) with heaps of throttle. So you got heaps of torque, max torque going into the second case (1st gear low range), heaps of wheelspeed to get traction. So the second case has the best chance to be broken.

If you had the same overall gearing with both in low and say 3 or 4th in the main gearbox then the input of the second case sees a much lower torque.

Sam

[MissDrew]

But the high range gears in the cases are bigger and stronger then the low range section.

I don`t see this as being a problem.

[beebee]

For a hilux application, I cannot see why everyone recommends duals. If you look at my attachments, you'll see that with the aid of a 4.7 gearset, you get a wide selection of ratios.