Uprating an RB44 to 6100 kg GVW

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Title: Uprating an RB44 to 6100 kg GVW

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snowman_tony

Rank：Regular Dodger

Score：34

Posts：9

From：United Kingdom

Register：26/10/2012 08:37:39

Date Posted：01/02/2013 10:00:31Copy HTML

What do I have to do to uprate my RB44 snowplough/gritter so I can legally fully fill the gritter? It's registered as a 'special, exempt' vehicle and required no MOT or VOSA inspection - even after conversion from the original MoD truck.The ex MOD plated weights are 2500 kg (front) and 2800 kg (rear) giving 5300 kg GVW.With the front plough lifted and the gritter fully laden the axle loads are 2850 (front) 3250 kg (rear) giving 6100 kg GVW.The tyres are 255/100 R16 which according to Michelin have up to 3400 kg capacity (per axle).The springs are nearly on the bump stops - especially the 5-leaf front spring.I have in mind to find a set of S75 springs for the rear (9 leaves instead of 7). These have a load rating of over 4000 kg, (or get 2 extra leaves made for each spring). But would S75 springs fit the RB44?The S75 front springs are the same (I think) as those on the RB44 (same 2500 kg plated axle load anyway) but I could also put extras leaves in them.But what about the loads rating for the AXLES themselves? How can I find that out and what do I have tothen do to get the whole thing 'officially' uprated? Is it anyway necessary to do that for a 'special exempt vehicle'?

Tony

Karrier Share to: #1

Rank：Ummmmmmm

Score：11828

Posts：3686

From：England

Register：02/10/2003 09:22:56

Re：Uprating an RB44 to 6100 kg GVW

Date Posted：02/02/2013 07:44:43Copy HTML

hi there you have hit the nail on the head with the axle rating, the rb44 rear axle is your point of not being able to update, the rear brakes might also be a problem as they are based on 3500kgs dodge 50's. you would need Jo change the axle and brakes to an ax9 and beef up the springs taken from a 7500kgs dodge 50. the axle you have is just not strong enough, I have upgradeed springs and axle / brakes on an RB44 for a tree surgeon,

"Nothing travels faster than the speed of light with the possible exception of bad news, which obeys its own special laws." Douglas Adams

Karrier Share to: #2

Rank：Ummmmmmm

Score：11828

Posts：3686

From：England

Register：02/10/2003 09:22:56

Re：Uprating an RB44 to 6100 kg GVW

Date Posted：02/02/2013 07:49:35Copy HTML

oh but you can only up rate to 6600 kgs unless you update the brake system to air over hydraulic and chugg on this forum knows all about this because he up rated a 4600kgs dodge 50 to 4x4 ~7500kgs so he can add to this I would think

"Nothing travels faster than the speed of light with the possible exception of bad news, which obeys its own special laws." Douglas Adams

chugg89 Share to: #3

Rank：Ummmmish

Score：1028

Posts：390

From：United Kingdom

Register：09/05/2007 09:14:22

Re：Uprating an RB44 to 6100 kg GVW

Date Posted：04/02/2013 11:25:50Copy HTML

upgrading to 6.6t spec (attaching copies of the relevant original microfische scans Greg kindly/laboriously made/uploaded to your application) might be the way to go - AX8? rear axle with bigger? drums/shoes, stronger? bearings etc., RB75 9-leaf rear springs (should fit into your hangers just fine I would think) will take some abuse (and give it back everytime you go over a bump!) although not sure how you'd achieve a plated front axle weight of over 2700kg - guess it might involve submitting design weight info to VOSA (on their VTG10) that any extra leaves added to the front end could handle the extra loading and as Karrrier says, it's the brakes again (front axle design weight of the AWD S75 with air-over-hydraulic might only be 2700kg)

it seemed like a good idea at the time

Ex_Member Share to: #4

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From：Unknown

Register：21/09/2018 12:36:07

Re：Uprating an RB44 to 6100 kg GVW

Date Posted：22/02/2013 06:58:34Copy HTML

Yes , The fact is that the MOD RB was purpose built to their requirements with no intention of anything more.
As Chugg advises, 7.5 ton Reynolds Boughton S75 was the heavyweight & designed with that weight rating.The RB 44 was designed to a spec to replace the 101" Land Rover Requirements . So its not as much of a heavyweight as it appears.

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Title: Uprating an RB44 to 6100 kg GVW
Dodge50 > Technical section > TECHNICAL	Go to subcategory：

snowman_tony
Rank：Regular Dodger Score：34 Posts：9 From：United Kingdom Register：26/10/2012 08:37:39	Date Posted：01/02/2013 10:00:31Copy HTML What do I have to do to uprate my RB44 snowplough/gritter so I can legally fully fill the gritter? It's registered as a 'special, exempt' vehicle and required no MOT or VOSA inspection - even after conversion from the original MoD truck.The ex MOD plated weights are 2500 kg (front) and 2800 kg (rear) giving 5300 kg GVW.With the front plough lifted and the gritter fully laden the axle loads are 2850 (front) 3250 kg (rear) giving 6100 kg GVW.The tyres are 255/100 R16 which according to Michelin have up to 3400 kg capacity (per axle).The springs are nearly on the bump stops - especially the 5-leaf front spring.I have in mind to find a set of S75 springs for the rear (9 leaves instead of 7). These have a load rating of over 4000 kg, (or get 2 extra leaves made for each spring). But would S75 springs fit the RB44?The S75 front springs are the same (I think) as those on the RB44 (same 2500 kg plated axle load anyway) but I could also put extras leaves in them.But what about the loads rating for the AXLES themselves? How can I find that out and what do I have tothen do to get the whole thing 'officially' uprated? Is it anyway necessary to do that for a 'special exempt vehicle'? Tony
Karrier	Share to: #1
Rank：Ummmmmmm Score：11828 Posts：3686 From：England Register：02/10/2003 09:22:56	Re：Uprating an RB44 to 6100 kg GVW Date Posted：02/02/2013 07:44:43Copy HTML hi there you have hit the nail on the head with the axle rating, the rb44 rear axle is your point of not being able to update, the rear brakes might also be a problem as they are based on 3500kgs dodge 50's. you would need Jo change the axle and brakes to an ax9 and beef up the springs taken from a 7500kgs dodge 50. the axle you have is just not strong enough, I have upgradeed springs and axle / brakes on an RB44 for a tree surgeon, "Nothing travels faster than the speed of light with the possible exception of bad news, which obeys its own special laws." Douglas Adams
Karrier	Share to: #2
Rank：Ummmmmmm Score：11828 Posts：3686 From：England Register：02/10/2003 09:22:56	Re：Uprating an RB44 to 6100 kg GVW Date Posted：02/02/2013 07:49:35Copy HTML oh but you can only up rate to 6600 kgs unless you update the brake system to air over hydraulic and chugg on this forum knows all about this because he up rated a 4600kgs dodge 50 to 4x4 ~7500kgs so he can add to this I would think "Nothing travels faster than the speed of light with the possible exception of bad news, which obeys its own special laws." Douglas Adams
chugg89	Share to: #3
Rank：Ummmmish Score：1028 Posts：390 From：United Kingdom Register：09/05/2007 09:14:22	Re：Uprating an RB44 to 6100 kg GVW Date Posted：04/02/2013 11:25:50Copy HTML upgrading to 6.6t spec (attaching copies of the relevant original microfische scans Greg kindly/laboriously made/uploaded to your application) might be the way to go - AX8? rear axle with bigger? drums/shoes, stronger? bearings etc., RB75 9-leaf rear springs (should fit into your hangers just fine I would think) will take some abuse (and give it back everytime you go over a bump!) although not sure how you'd achieve a plated front axle weight of over 2700kg - guess it might involve submitting design weight info to VOSA (on their VTG10) that any extra leaves added to the front end could handle the extra loading and as Karrrier says, it's the brakes again (front axle design weight of the AWD S75 with air-over-hydraulic might only be 2700kg) it seemed like a good idea at the time
Ex_Member	Share to: #4
Rank： Score：0 Posts：0 From：Unknown Register：21/09/2018 12:36:07	Re：Uprating an RB44 to 6100 kg GVW Date Posted：22/02/2013 06:58:34Copy HTML Yes , The fact is that the MOD RB was purpose built to their requirements with no intention of anything more. As Chugg advises, 7.5 ton Reynolds Boughton S75 was the heavyweight & designed with that weight rating.The RB 44 was designed to a spec to replace the 101" Land Rover Requirements . So its not as much of a heavyweight as it appears.