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new Ashcroft ring and pinions

Tech Talk for Rover owners.

Moderator: Micka

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Posts: 97
Joined: Wed Jan 12, 2005 5:27 am

new Ashcroft ring and pinions

Post by ashtrans »

Hi Guys,

thought you might be interested to see our new range of rover ring and pinions :

http://www.ashcroft-transmissions.co.uk ... t&catId=12
Dave

www.ashcroft-transmissions.co.uk
Posts: 1559
Joined: Sun Nov 03, 2002 2:35 pm
Location: Captain Creek QLD

Post by Bush65 »

Dave,
Should be a good step up in strength over stock rover R&P.

I noticed your online ordering doesn't allow a choice between normal rear directional cut and reverse cut for the front.

What is your opinion of using the new 3.50:1 reverse cut front R&P with a stock 3.5385:1 Salisbury rear (front wheels would turn 1.1% faster)?
John
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Joined: Wed Feb 19, 2003 3:02 pm
Location: Brisbane

Post by ISUZUROVER »

Bush65 wrote:Dave,
Should be a good step up in strength over stock rover R&P.

I noticed your online ordering doesn't allow a choice between normal rear directional cut and reverse cut for the front.

What is your opinion of using the new 3.50:1 reverse cut front R&P with a stock 3.5385:1 Salisbury rear (front wheels would turn 1.1% faster)?
Just the question I wanted to ask!

Also - any idea what would the lifespan of a 3.5 be like compared to a 3.54 - for a vehicle used mainly for road/touring (what you usually call an "expedition" vehicle).
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Post by uninformed »

Bush65 wrote:Dave,
Should be a good step up in strength over stock rover R&P.

I noticed your online ordering doesn't allow a choice between normal rear directional cut and reverse cut for the front.

What is your opinion of using the new 3.50:1 reverse cut front R&P with a stock 3.5385:1 Salisbury rear (front wheels would turn 1.1% faster)?
would not the center diff take care of this? is it possible to get perfect speeds between the left and right wheel/tyre on a front or rear axle??? so would not this be the same? at only 1.1% not a hell of alot

Serg
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Joined: Wed Jan 12, 2005 5:27 am

Post by ashtrans »

Hi John,

you are right there is no separate item for front and rear but there is a 'notes' field where this can be speced,

as long as you don't have the centre diff locked for along time when on a high traction surface, ie tarmac then I can't see this being a big problem for the centre diff to take up this difference when unlocked, as mentioned it's only similar to uneven tyre wear, I once worked out the difference between 4.10 rear and a 4.11 front to be 0.75 mm difference in tyre diameter, this would be alittle more but I don't think it would be enough to cause premature wear to the centre diff,

too early to tell on the lifespan but I can't forsee much of a difference, we had the same concerns when the HD CV's came out but they are lasting OK,

in theory the teeth may wear quicker as there are less but again I doubt if this will be significant, I have seen rover diffs do 400K if you keep oil in them, maybe these will only do 350K ? don't know yet but obviously most customers will be buying these foir low milage off roading trucks,

I will know soon if they are any good, we have one customer that would blow 3.54 diffs regularly on the start line with a 4.2 Jag supercharged racer, we pegged the 3.54's and they lasted 2 races before they failed, they are now pegged with new 3.75's and new quaifes, I told him they should be good for 3 races now !
Dave

www.ashcroft-transmissions.co.uk
Posts: 190
Joined: Wed May 21, 2008 3:55 pm
Location: Coffs Harbour, NSW

Post by PacMan »

ashtrans wrote:I once worked out the difference between 4.10 rear and a 4.11 front to be 0.75 mm difference in tyre diameter
Hmm,

3.50:1 compared to 3.5385:1 is 1.1% (350/3.5385) ~ 11m on 1km.

I dont think it is a very good idea after driving a hilux of a friend with 4.1 back and 4.3 front. That is a big different from 4.1 to 4.3 but it shows what happend. It was very very hard to steer - nearly not possible with 4wd engaged.

Maybe it will work nice in 4wd with only 1.1% difference but it will give your steering a harder time, the tyres wear quicker and your drive train will bind up more.

There was a topic about it on here. Somebody had issus with a Nissan/Toyota mix. Front 4.11 and back 4.1. He could not life with it.

Hope that helps.


Thanks
Chris
Last edited by PacMan on Sat May 29, 2010 2:03 am, edited 1 time in total.
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Post by ashtrans »

Hi Chris,

does the hilux have a centre diff ?

I would not suggest running the LT230 on the road with the centre diff locked,
Dave

www.ashcroft-transmissions.co.uk
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Joined: Sun Nov 03, 2002 2:35 pm
Location: Captain Creek QLD

Post by Bush65 »

My opinion is that it wouldn't matter enough (I am tempted to try exactly what I spoke of when I have some more $$ to spare), but I wanted to get Dave's thoughts as he may have considered that situation.

On most turns, the front wheels travel around larger radius arcs than the rears. And as the difference in the ratios in this case makes the fronts turn more the problem is reduced.

The other 2 cases Chris mentioned involved the fronts turning less than the rears.
John
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Joined: Wed Aug 19, 2009 5:23 am
Location: denmark

Post by oddballrovers »

HI

I have run 4.75 reversecut in the front and 4.7 std rover in the back now for more than a year without any issues.

The truck is a series two LWT, so we have no center diff, but on the other hand we only run 4wd away from tarmac concrete and other high traction surfaces.


Kind regards

Ole
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Location: Brisbane

Post by ISUZUROVER »

Bush65 wrote:...(I am tempted to try exactly what I spoke of when I have some more $$ to spare),....
Me too - I just wish these had come out before I had built my front diff!
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Post by Ian Ashcroft »

Hi just an update on our HD ring and pinions, 3.5 (Top) compared with the stock 3.54. You will easily see the tooth profile change but we also upgraded the steel, changed the helix angle (for more tooth contact) and supply a reverse cut gear set for the front.
OOps tried to post a photo but not yet had the required 5 postings. Photo on AULRO for those who are interested. Regards Ian Ashcroft
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Joined: Sun May 11, 2008 12:30 am
Location: Manila, Philippines

Post by monmendoza »

Hi,

Will this fit a 1997 300tdi discovery? what do I have to order
aside from the R&P? I am looking at replacing my stock R&P
with 4.75 and increase tires to 33" . tia

ps. how much is shipping to the philippines and do you accept payment
via paypal? again thank you in advance. :)
Posts: 97
Joined: Wed Jan 12, 2005 5:27 am

Post by ashtrans »

this is the photo Ian was trying to post :

Image

this photo compares the stock 3.54 with our new 3.5 (28/8)ratio,

monmendoza, 4.75 may be too low with 33's, maybe 4.12 or 4.37 would be better,

next week we will have a ratio calculator on our web site, so you can put in the gearbox type, transfer case, tyre size and diff to give you the different engine RPM at any given speed for each gear in high and low ratio, should be very useful.

you can order online with our new website, we can accept visa or mastercard, we will have a neat carriage calclator on there soon but in the mean time if you would like a carriage quote just email us and I wil get a quote,
Dave

www.ashcroft-transmissions.co.uk
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