4 inch narrowed beam questions

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scull

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Hi Guys. I have managed to purchase an unused 4 inch adjustable narrowed beam with fitted leaves and centre-pin for my 1971 early bay. I want a lowered look but not weed scraping. Questions: Can I fit my original torsion bars and hubs (disc brakes) or will I need to fit dropped spindles to avoid strainng the steering geometry to far. Also, I am assuming I will need to use x2 adjustable tie rods due to the shorter distance caused by the narrowed beam?? Also concerned about the lower shock mount and whether it will be misaligned using my orginal stock spindles/hubs. Looking forward to your replies and any helpful advice here. Thank you.
 

Moseley

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Hi, we’re running a similar setup and are as low as I’d comfortably like to be to get most of the places we want to go! We have about 1” to 1.5” of tyre travel before it would touch the wheel arch to give you an idea of the height (or check out photos in the gallery).

The steering geometry is unaffected when comparing standard spindles to dropped spindles; all that changes is the location of where the stub is welded to the assembly. What does change though, is the height of the front end (most dropped spindles lower a further 3.5” from standard). What you do need to consider is the angle of the ball joints on the trailing arms, and this is dependent on how low you want to go. My tuppence - when running a 4” narrowed beam it will look very odd if you’re at a height which means you can get away with standard spindles, so I would personally factor in a set of dropped spindles, and then use the beam adjusters to tweak the height where you want it. Again, if you look at my gallery pics, we’ve got standard arches, the beam is set close to as low as it will go (with dropped spindles) and I am using Gaz coilovers to stiffen the suspension, which also raises it slightly from it’s static position.

Something else worth mentioning, you will need to run narrowed lower trailing arms on a 4” narrowed beam so that the shock mount doesn’t hit the beam end plate.

Adjustable and shortened tie rods are required - standard ones are too long.
 

milfredo

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Hi, we’re running a similar setup and are as low as I’d comfortably like to be to get most of the places we want to go! We have about 1” to 1.5” of tyre travel before it would touch the wheel arch to give you an idea of the height (or check out photos in the gallery).

The steering geometry is unaffected when comparing standard spindles to dropped spindles; all that changes is the location of where the stub is welded to the assembly. What does change though, is the height of the front end (most dropped spindles lower a further 3.5” from standard). What you do need to consider is the angle of the ball joints on the trailing arms, and this is dependent on how low you want to go. My tuppence - when running a 4” narrowed beam it will look very odd if you’re at a height which means you can get away with standard spindles, so I would personally factor in a set of dropped spindles, and then use the beam adjusters to tweak the height where you want it. Again, if you look at my gallery pics, we’ve got standard arches, the beam is set close to as low as it will go (with dropped spindles) and I am using Gaz coilovers to stiffen the suspension, which also raises it slightly from it’s static position.

Something else worth mentioning, you will need to run narrowed lower trailing arms on a 4” narrowed beam so that the shock mount doesn’t hit the beam end plate.

Adjustable and shortened tie rods are required - standard ones are too long.
Can I ask what front tyres you are running? I have a almost identical setup but mine were rubbing like bastard on the bumpy roads to Stamford hall. Mine are 175 55 R15 but I was thinking some 165 50 R15 would be better.
 

Moseley

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Can I ask what front tyres you are running? I have a almost identical setup but mine were rubbing like bastard on the bumpy roads to Stamford hall. Mine are 175 55 R15 but I was thinking some 165 50 R15 would be better.
We’re running a 155/60 R15, and that is on a 4.5” width wheel.
 

mcvw

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I've got a pair of 165/50's (that I ran on the front of my bus - dropped spindles and a 4" narrowed beam - on Flat 4 Enkei's). I won't be putting the wheels back on the bus so I could get the tyres taken off the wheels and you can make an offer if they're of use to you?
 

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naskeet

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185/80 R14 => 2047•0 mm external-circumference

195/70 R15 => 2054•6 mm external-circumference [0•4% larger than 185/80 R14]

185/65 R16 => 2032•2 mm external-circumference [0•7% smaller than 185/80 R14]

185/65 R16 => 2073•1 mm external-circumference [1•3% larger than 185/80 R14]


175/55 R15 => 1801•7 mm external-circumference [12•0% smaller than 185/80 R14]

165/50 R15 => 1715•3 mm external-circumference [16•2% smaller than 185/80 R14]

155/60 R15 => 1781•2 mm external-circumference [13•0% smaller than 185/80 R14]

To put these percentage figures in context, keep in mind that the external circumference of tyres typically decreases by approximately 2%, as a result of the tread wearing down from an as-new tread-depth of 7~8 mm to an absolute minimum legal tread-depth of 1•6 mm

The maximum legal tolerance for speedometers is ZERO per cent – 0% less than the actual speed and up to 10% higher than the actual speed, so on average, when tyres of factory-standard, external-circumference are fitted (e.g. 185/80 R14 or 195/70 R15), speedometers might normally be expected to read about 5% higher than the actual speed.

Unless you folks have had your speedometers recalibrated, then using either 165/50 R15, 155/60 R15 or 175/55 R15 would probably give speed readings of circa 21•2%, 18•0% & 17•0% in excess of the actual speed; which is well over the legal limit!

If you have also increased or decreased the external-circumference of the rear tyres, then this will change the overall effective engine gearing (akin to changing the transaxle’s final-drive ratio). Reducing the tyre’s external circumference will generally improve hill-climbing and acceleration capabilities, but on a vehicle that was already either optimally-geared or under-geared for that engine, will reduce the greatest attainable actual maximum speed; something that isn’t particularly great (i.e. 65~68 mph on a level road with no headwind) for a 1968~79 VW Type 2 with a factory-standard, 50 horsepower, VW 1600 Type 1 Beetle style air-cooled engine.

Keep in mind that narrowing the front track (an almost inevitable consequence of substituting a 4 inch = 101•6 mm narrower front-suspension beam), will increase the tendency for a vehicle to exhibit over-steer, which is a characteristic one would most wish to avoid with a rear-engined, rear-wheel-drive vehicle like the 1968~79 VW Type 2.

There is an added complication that changing to wheels of a different wheel-offset and/or changing to tyres of a different external-radius (recall that circumference = 2 x 3•14159 x radius) changes the steering-offset (aka scrub-radius), which can also adversely affect the steering characteristics re over-steer and/or under-steer under various driving conditions.

Also keep in mind that the front & rear tyres of a 1968~79 VW Type 2 should have at least half the front-suspension’s (i.e. front-axle’s) & rear-suspension’s (i.e. rear-axle’s) maximum load limits of 1010 kg & 1300 kg respectively; corresponding to absolute-minimum load-indeces of 85 & 93 respectively; although I would not wish to risk such low load ratings, given the effective weight transfer under braking and/or cornering! All too often, I have seen 1968~79 VW Type 2s, with substitute wheels or even factory-standard wheels, fitted with tyres of wholly inadequate load ratings; some of which were marketed by well-known wheel & tyre factors for the 1968~79 VW Type 2.

Even if one had front & rear tyres of at least 85 & 93 load indeces respectively, there is no guarantee that a motor-insurance company would not declare one’s insurance policy null & void in the event of an “accident” involving one of these radically-modified vehicles. In this case, you would personally be liable to pay all claims against you!

If one has non-standard front and/or rear wheel & tyre combinations, then consider what type of spare wheel & tyre combination would be appropriate for both the front and rear, keeping in mind the potential problems of interference with the wheel arches or suspension and the need to have tyres of the same external radius on the same axle.

Many people just keep a factory-standard, 5 x 14 inch or 5½ x 14 inch steel wheel with 185/80 R14C tyre as the spare, but in many cases this would be inappropriate for either the front or rear, for a variety of reasons. Would one need to carry two separate spare wheels for the front and rear!?! If a wheel and/or tyre is severely damaged, then use of tyre sealant would be inadequate, inappropriate and unsafe, so having a suitable spare wheel & tyre is essential; especially for a long-obsolete vehicle, for which obtaining a replacement wheel might be very difficult at short notice; involving considerable incidental expense if travelling far from home.

On any vehicle, it is the progressive compression of the springs, rather than dampers, which absorbs the impact-shock of encountering bumps, potholes, drain-covers, road-debris and other perturbations. The purpose of suspension-dampers (inappropriately named “shock absorbers”), is to damp out the spring-oscillation arising from their absorption of the shock. Together they maximise ride comfort and ensure that the tyres remain in contact with the road.

Radically increasing spring stiffness and limiting suspension travel, can seriously compromise both ride comfort (important to minimise driver fatigue) and road holding. If one seeks to reduce body roll when negotiating bends, it would be better to substitute a stiffer front anti-roll bar and retro-fit a rear anti-roll bar of appropriate stiffness, rather than increase the stiffness of the suspension’s torsion bars. When designing Lotus sports cars, it was Colin Chapman’s philosophy to use soft springs & firm damping, together with anti-roll bars of appropriate torsional stiffness to minimise body roll; something I have done with my 1974 Triumph Toledo 1300 “HL Special”.

One should be very cautious about deviating from the factory-standard specifications for the brakes, suspension, wheels and/or tyres, any of which could all too easily adversely affect the safety and performance of the vehicle, as well as voiding one’s motor-insurance policy and/or failing to comply with the “Motor-Vehicle Construction & Use Regulations”.
 

milfredo

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I've got a pair of 165/50's (that I ran on the front of my bus - dropped spindles and a 4" narrowed beam - on Flat 4 Enkei's). I won't be putting the wheels back on the bus so I could get the tyres taken off the wheels and you can make an offer if they're of use to you?
How worn/ condition are they and what kind of price? Also, I am north London, not too sure how logistics would work?
 

mcvw

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How worn/ condition are they and what kind of price? Also, I am north London, not too sure how logistics would work?
Both tyres are Bridgestone Potenzas and are in very good condition (bit dusty, but no cuts, repairs or curbing). I could get the tyres to the workshop where my bus is - Sunbury on Thames, middx if that's of use?
 

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milfredo

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Both tyres are Bridgestone Potenzas and are in very good condition (bit dusty, but no cuts, repairs or curbing). I could get the tyres to the workshop where my bus is - Sunbury on Thames, middx if that's of use?
Look great, I’m taking the kids to Coral reef in Bracknell for swimming on Saturday around 1130 should be done by 13:00. I could continue down the M3 past the M25 on the way home to collect? It might be hard to call an exact time now will you be at the workshop?
 

naskeet

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To satisfy my curiosity, I did an Internet search for Bridgestone Potenza 165/50 R15 tyres and came up with the following extremely disturbing two results, indicating that this tyre specification has a load index of 73, corresponding to a maximum load rating of only 365 kg at the prescribed inflation pressure, which should be embossed on the sidewall somewhere. If inflated to a lower air pressure the actual load rating would be reduced to less than 365 kg.

https://tirepressure.org/metric-tire-load-inflation-chart

In the USA, the published load rating of passenger-car tyres have to be de-rated by at least 10%, when used on commercial-vans or light-trucks.

https://www.tyres.net/bridgestone-p...4618?msclkid=9a86fdfbd14d11ecb70ac761d8aa7088

https://www.roundtriptyres.co.uk/br...html?msclkid=9a86d8cbd14d11ec9a716a1242510f3c

Even at a load rating of 365 kg, this is only 72•3% (i.e. less than three quarters) of the 505 kg absolute minimum load rating that would be required for the front tyres of a 1968~79 VW Type 2! The all-round factory-fitted tyres on a 1968~79 VW Type 2, would typically have had a minimum load index of 95, corresponding to a maximum load rating of 690 kg.

The vital question that needs to be asked, is whether you have informed your vehicle insurers of the following, in addition to any other non-factory-standard features of the vehicle:
  • Substitution of dropped spindles
  • Substitution of 4 inch narrower suspension beam
  • Substitution of non-standard, narrower than standard wheels
  • Substitution of non-standard tyres having a maximum load rating less than factory-standard
Unless they have been informed of these deviations from the factory-standard specifications, the insurers would be quite within their legal rights to declare your insurance policy null & void, on the failure to disclose ALL relevant information, which would be in breach of contract. Hence, if you were involved in a road-traffic incident, your vehicle would only be worth scrap value and assuming you survived the incident, you might have to pay to have it removed; plus your unlimited third-party liability for property damage, injuries & deaths.

Having illegal tyres on your vehicle can result in a fine of up to £2500 and 3 penalty points per illegal tyre. To avoid fines, penalty points and to ensure safety you must make sure all your tyres are within the UK regulations.

https://www.extremetyres.com/tyre-guides/uk-tyre-laws/

Even my relatively lightweight, four-door, 1974 Triumph Toledo 1300 “HL Special” [kerb weight = 875 kg | maximum laden weight = 1240 kg] with 5½ x 13 inch Triumph Dolomite Sprint wheels, has Firestone S211, 185/70 R13 85 T tyres of 85 load index, corresponding to a maximum load rating of 515 kg. In the future, I intend to replace the 5½ x 13 inch Triumph Dolomite Sprint wheels with 185/70 R15 85 T Firestone S211 tyres on my 1974 Triumph Toledo 1300 “HL Special”, with 5½ x 15 inch MG 2000 Maestro wheels, for which the normal tyre choice would be 185/55 R15, that would typically have a load index of 81, corresponding to a maximum load rating of 462 kg.

These are normal passenger-car tyres without extra reinforcement, as specified for the 185 SR14 Heavy-Duty (i.e. Reinforced) radial tyres, listed in the 1973 VW Type 2 official owner’s handbook. In general, a tyre’s load rating increases with both tyre section-width and tyre aspect-ratio, so choosing an ordinary passenger-car tyre, of narrow section-width and especially-low aspect ratio, was inevitably problematical!

Having discovered that these Bridgestone Potenza 165/50 R15 tyres are wholly unsuitable for a 1968~79 VW Type 2 on just the basis of its very low load rating alone, I also investigated the other tyre sizes that were mentioned as follows, which can be checked against the table of load indeces from 60 to 114, which correspond to maximum load ratings of 250 kg to 1180 kg, it seemed prudent to also investigate the load ratings of the other inappropriate passenger-car tyre sizes that various people had mentioned in this topic thread:

Tyre Load Index Tables / Charts

https://www.extremetyres.com/tyre-guides/tyre-load-index-table

https://worldtirereview.com/tire-lo...Load Index Chart Load, 103 47 more rows

https://tirepressure.org/tire-load-index-chart

https://tirepressure.org/metric-tire-load-inflation-chart

https://www.gov.uk/guidance/mot-ins...al-vehicles/appendix-b-tyre-load-index-tables

https://www.gov.uk/guidance/mot-ins...al-vehicles/appendix-b-tyre-load-index-tables

175/55 R15 – Load Index & Inflation Pressure

https://tirepressure.org/metric-tire-load-inflation-chart#175/55R15

165/50 R15 – Load Index & Inflation Pressure

No information listed

155/60 R15 – Load Index & Inflation Pressure

No information listed

Search for standard tyres, plus “Reinforced” and “Extra Load” tyres

175/55 R15 – typically of load index 77 [much too low]

https://www.oponeo.co.uk/tyre-finde...m_term=175 55 r15 tyres&utm_content=175/55R15

There is a GT Radial FE1 City 175/55R15 81T XL extra-load tyre at Asda Tyres of load index 81 [better but still too low]

https://www.asdatyres.co.uk/175-55-15

165/50 R15 – none listed at Oponeo , only one at Asda Tyres and two at Tyre Leader of load index 72 or 73 [much too low]

https://www.asdatyres.co.uk/165-50-15

https://www.tyreleader.co.uk/car-tyres-165-50-15/

https://www.mytyres.co.uk/search?pr...Types=OFF&width=165&profile=50&size=15&season=

155/60 R15 – typically of load index 74 [much too low]

https://www.oponeo.co.uk/tyre-finder/s=3/summer,winter,all-season/t=3/car,van,4x4/r=1/155-60-r15

There is a GT Radial FE1 City 155/60 R15 78T XL extra-load tyre at My Tyres of load index 78 [better but still too low]

https://www.mytyres.co.uk/search?pr...Types=OFF&width=155&profile=60&size=15&season=
 

Gjb4212

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If you go for 185’s then the load rating goes to 85/88
 

naskeet

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I have yet to find a definitive reference for the United Kingdom, but I am aware that in Australia, there are restrictions regarding DIY changes in a vehicle’s wheel-track (i.e. distance between ground-level tyre-tread centres of opposite wheels on the same axle) from the factory-standard specification, owing to suspension modifications and/or substitution of wheels having a different wheel-offset. There, the wheel-track must NOT be decreased at all, but may be increased by a maximum of 25 mm.

Many years ago, I recall reading some material in the United Kingdom, which stated that if a vehicle’s wheel-track was altered by more than 20 mm, this would result in one’s motor insurance policy being declared null & void! This is something which it would be advisable to clarify with one’s insurers.

According to the official Volkswagen owner’s handbook for my 1973 model-year [manufactured in late-August or early-September 1972] VW 1600 Type 2 Westfalia Continental motor-caravan (based upon a Kombi Type 23-517], the front & rear wheel-track are 1395 mm & 1455 mm for the front & rear respectively. My various Haynes and Robert Bentley workshop manuals, suggest that the wheel-track specifications for 1968~70 & 1971~72 VW Type 2s might be slightly different.

J. H. Haynes & D. H. Stead, “VW Transporter 1600 Owner’s Workshop Manual – All Transporter based models 1968 to 1972 – 1584 cc (96•7 cu. in)”, J. H. Haynes and Company Limited, 1974, ISBN 0-900550-82-1.

Front wheel-track [with drum brakes] = 1384 mm

Front wheel-track [with disc brakes] = 1386 mm

Rear wheel-track = 1426 mm

J. H. Haynes & K. F. Kinchin, “VW Transporter 1700/1800 Owner’s Workshop Manual – All Transporter based models 1972 to 1974 – 1679 cc (103 cu. in) & 1795 cc (110 cu. in)”, J. H. Haynes and Company Limited, 1975, ISBN 85696-226-0.

Front wheel-track = 1395 mm

Rear wheel-track = not specified

Volkswagen of America, “Volkswagen Official Service Manual Type 2 – Station Wagon / Bus 1968~1979”, 4th Edition, 1979, Robert Bentley Publishers, ISBN 0-8376-0094-4.

Front wheel-track = 1395 mm

Rear wheel-track = not specified

I previously mentioned the need to comply with what I described as the “Motor-Vehicle Construction & Use Regulations”, which would be invoked in any legal prosecutions. Anyone involved in modifying vehicles from the factory-standard specifications, would be well advised to properly acquaint themselves with the various appropriate regulations (e.g. Road Vehicles Lighting Regulations 1989 and later amendments), at least some of which should be listed in your current, up-to-date copy of the Highway Code, that can now be accessed on-line.

https://www.gov.uk/guidance/the-highway-code

http://www.highwaycodeuk.co.uk/

The Road Vehicles Lighting Regulations 1989, UK Statutory Instruments 1989, No. 1796

http://www.legislation.gov.uk/uksi/1989/1796/contents/made

The fact of having been issued with an MOT Pass Certificate, does not indicate compliance with the various regulations, because this is not a part of the MOT Inspector’s remit. It is you as the owner, not an MOT Inspector, who is responsible for ensuring that your vehicle complies with these regulations, for which a Voluntary IVA Inspection might appropriate!

https://www.gov.uk/transport/vehicle-manufacturing-and-modification

https://www.gov.uk/vehicle-approval

The 1968~79 VW Type 2 effectively has “plated weights” by virtue of the fact that behind the right-hand front seat (or possibly elsewhere) there is or should be, an embossed aluminium identification plate, riveted to the bodywork, giving details in German, of the vehicle-type number, chassis number, exhaust heat-exchanger reference and front & rear axles’ maximum load limits, which dependent upon vehicle model (e.g. Kombi or Microbus etc) are typically 1010 kg for the front (i.e. vorn in German) and 1270 kg for the rear (i.e. hinten in German)), so under the provisions of The Road Vehicles (Construction and Use) Regulations 1986, any tyres fitted to the vehicle must be capable of supporting those maximum axle weights, at the appropriate tyre inflation pressures; irrespective of the loads that are actually carried by that vehicle when in service.

The Road Vehicles (Construction and Use) Regulations 1986

http://www.legislation.gov.uk/uksi/1986/1078/contents/made

UK Statutory Instruments1986, No. 1078, PART IIC

http://www.legislation.gov.uk/uksi/1986/1078/part/II/chapter/C/made

Tyre Loads and Speed Ratings

25.—(1) This regulation applies—

(a) to a goods vehicle first used before 1st April 1987 in respect of which a plating certificate has been issued;

(2) Each axle of a vehicle to which this regulation applies solely by virtue of paragraph 1(a) shall be equipped with tyres which, as respects strength, are designed and maintained adequately to support the maximum axle weight for that axle.

Condition and maintenance of tyres

27.—(1) Save as provided in paragraphs (2), (3) and (4), a wheeled motor vehicle or trailer a wheel of which is fitted with a pneumatic tyre shall not be used on a road, if—

the tyre is unsuitable having regard to the use to which the motor vehicle or trailer is being put or to the types of tyres fitted to its other wheels;
 
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