Birty Dastards Jeep Club
Tech Forum => Workshop => Topic started by: Tank on September 07, 2009, 07:31:14 PM
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Hi,as most of you know,i have a 1996 2.8 td Shogun with very large boots on.I used it a Cheapfest and one problem became very evident.......the cars inability to cope with the size of tyre on hills,so although not a jeep i have a general question. The current diff ratio is said to be 4.90,and the transfer ratio is 1.90/1 for the 2.8,so do i need to go higher or lower on the ratios to make it more usable with the 35s ?? Apparently some 2.5s have a 5.29 ratio diff and 1.92 transfer which is higher or 4.6 diff ratio for a 3.5 petrol so might be a simple way of changing gearing.Any ideas/thoughts or comments greatly accepted
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what are the original tyre size, with the converters here (http://www.birtydastards.com/frm/index.php?action=ezportal;sa=page;p=8) you can calc the optimum ratio
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Go deeeeeep with the ratios..... you can never have enough crawl ability....... some people say things can be
toooooo lowwwww. but then there's second and third??!!
Since I've gone from 2.8 ish to a 4:1 things are much better and touch wood I break less!
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ok asuming that your original tyres were 265/70R16, that equals 30.6" dia and original ratio is 4.9-1, with new tyres that are 35" to maintain original final ratio you need to gear 5.6-1
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Okay,so then if i fitted the diffs from a 2.5 which are 5.29 then i would at least be heading in the right direction then,is what you are saying guys????? Think this is the cheapest option,otherwise i would be looking at rebuilding diffs etc.Thanks so far for the input
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Okay,so then if i fitted the diffs from a 2.5 which are 5.29 then i would at least be heading in the right direction then,is what you are saying guys????? Think this is the cheapest option,otherwise i would be looking at rebuilding diffs etc.Thanks so far for the input
Yep, you are heading in the right direction and as the cost of buying and having replacement gears installed is often prohibitive it sounds like this is the only solution for you.
I swapped my 4ltr Jeep from 3.55 to 4.10 axles and I love it :icon_biggrin:
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Okay,so then if i fitted the diffs from a 2.5 which are 5.29 then i would at least be heading in the right direction then,is what you are saying guys????? Think this is the cheapest option,otherwise i would be looking at rebuilding diffs etc.Thanks so far for the input
Yep, you are heading in the right direction and as the cost of buying and having replacement gears installed is often prohibitive it sounds like this is the only solution for you.
I swapped my 4ltr Jeep from 3.55 to 4.10 axles and I love it :icon_biggrin:
Thank you for that,so really it doesnt have to be a massive difference in the ratio to make a lot of difference offroad then ?
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change the diffs, ypu'll notice the difference straight away :icon_winkle:
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Okay,so then if i fitted the diffs from a 2.5 which are 5.29 then i would at least be heading in the right direction then,is what you are saying guys????? Think this is the cheapest option,otherwise i would be looking at rebuilding diffs etc.Thanks so far for the input
Yep, you are heading in the right direction and as the cost of buying and having replacement gears installed is often prohibitive it sounds like this is the only solution for you.
I swapped my 4ltr Jeep from 3.55 to 4.10 axles and I love it :icon_biggrin:
Thank you for that,so really it doesnt have to be a massive difference in the ratio to make a lot of difference offroad then ?
Swapping from 4.90 to 5.29 is quite a small change, around 8% so maybe not as noticable as you would hope for. When I swapped from 3.55 to 4.10 that was a change of 15.5% so the difference was immediately noticeable but only in on road performance. Off-road was not so different but maybe that is because mine is an auto? on-road performance is so much livlier now.
Perhaps considering how much change you need to get back to stock gearing you might be wasting your time and money making such a small change?
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Ask a stupid question but would it not be cheaper to swap the axles for the lower ratio & slightly reduce the tyre size to compensate, not suggesting 31's but from maybe 35's to 33's ?
Cant remember whats on it but they were smurf size :003:
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Gaz,the axle ratrios i gave are from the different axles .I wasnt going to just use the diff,the bits are cheap enough to buy the complete axles and swap them over,i just wanted to know which diff ratio was the better.I wanted to keep the existing tyres if possible as they performed well on the whole
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See where your comming from matey, twas just a thought, must have accidently posted in tech by mistake :003: