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Widening the front track on a MGB

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mgb281 Philip Waterman
Taunton, Somerset, UK   GBR
For various reasons I would like to widen the front track on my MGB by two inches. I know it means new top and bottom wishbones but what I am unsure of is how it will affect the Akerman angles while turning on corners. I know Triumph used the same complete front suspension assembly on the Herald and Spitfire and the GT6? In this case the track remained the same but the wheelbase on the Herald was 91.3 inches and the Spitfire was 83 a difference of almost 9%
What I am thinking of doing in effect is similar, widening the track is similar to shortening the wheelbase. My thoughts are if Triumph got away with it why won't I
Can any of you enlightened enthusiasts tell me why it will or will not work and any remedial work I might need to do, one thought is that I may need to bend the steering arm away (?) from the wheel a little on each side.
I am also posting this question on British V8
Philip

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bills Avatar
bills Bill Spohn
W. Vancouver, , BC, Canada   CAN
You should be fine - just make sure that you check bump steer afterward. My TVR used the herald uprights and the steering tie rods needed an extender in them to minimize bump steer with the wider track (and to meet the existing steering arms). It was 2" wider track than the comparable GT6 etc.

Personally, I prefer extenders on the tie rods to bending the tie rod arms that come out of the upright!



Bill Spohn www.rhodo.citymax.com/carstuff.html
Current: 1958 MGA Twincam (race car (170 bhp)),1962 MGA Deluxe Coupe (98 bhp)
1957 Jamaican MGA (200 bhp)1965 1971 Jensen Interceptor (350 bhp)
2009 Pontiac Solstice GXP Coupe (350 bhp)
2007 BMW Z4M coupe (340 bhp)
Recent: 1969 MGC roadster (175 bhp),Jensen CV8 (375 bhp),
1969 Lamborghini Islero S (350 bhp), 1988 Fiero GT turbo (300 bhp)
North Vancouver BC

mgb281 Philip Waterman
Taunton, Somerset, UK   GBR
Thank you Bill
When I mentioned bending the steering arms it was regarding the Akerman angle, I was thinking bending the arms a little would move the intersection point closer to the centre line of the rear axle. Point taken regarding extenders anyway.
Philip

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Denis Avatar
Denis Denis Hill
Bearii, Nth Victoria, Australia   AUS
Changing the effective Akerman angle will affect "toe out on turns " which may increase tire scrub on tight turns a little. I dont think it would be a problem with that amount .
It is going to give you a "little" less toe out on turns. Denis



68 B roadster, Daffodil yellow, supercharger, Burgess SC head, SC cam, Mikuni HSR 48 carburetor and engine built for supercharging.

73 BGT V8 conversion starting with a bare shell. Built the engine "3.9L Rover" early in 2016 with high comp pistons and a few other nice bits, plus a T5 ford trans. Started on the body late 2016 and complete early 2018 Did the work myself, mechanical, body. paint etc.
Finished and going well, great to drive and quick. Now has a nice 3.07 LSD.



Edited 1 time(s). Last edit at 2018-05-09 11:28 PM by Denis.

V8MGBV8 Avatar
V8MGBV8 Carl Floyd
Kinggsport, TN, USA   USA
In reply to # 3733303 by mgb281 I know Triumph used the same complete front suspension assembly on the Herald and Spitfire and the GT6? In this case the track remained the same but the wheelbase on the Herald was 91.3 inches and the Spitfire was 83 a difference of almost 9%
What I am thinking of doing in effect is similar, widening the track is similar to shortening the wheelbase. My thoughts are if Triumph got away with it why won't I

I don't see where that is similar at all. I do think that making new A-arms one inch longer is quite do-able. May need different spring & shock rates to go with it.

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Mustangsix Gold Member Jack Collins
Orlando, FL, USA   USA
Longer lower arms are doable, but how will you extend the uppers? I would not advocate cutting and welding those.


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Jim Blackwood Avatar
Jim Blackwood * BlownMGB-V8
Gunpowder Rd, Florence, KY, USA   USA
You might either move the shock mounts out an inch or perhaps make new trunions with an additional inch of offset. Either one would accelerate the camber curve though. Not sure if that would be good or bad. I suppose you could move the lower arm mount out an inch. It'd throw off the spring alignment, but give you an excuse to make up some lighter weight spring pans maybe.

Jim

bills Avatar
bills Bill Spohn
W. Vancouver, , BC, Canada   CAN
Of course adding an inch at each side with appropriately sized rims is the other way - but can be hard on bearings. That would be easiest.

I'll have to measure the Jamaican - stock MGA frame which I converted to MGB uprights (no change in track there) plus AC Cobra wires - 6" as opposed to stock width of 4". I would bet that most of the offset is added outward so my car may be anywhere up to 4" wider track. Similarly with the coupe - added a total of 3", mostly outward.



Bill Spohn www.rhodo.citymax.com/carstuff.html
Current: 1958 MGA Twincam (race car (170 bhp)),1962 MGA Deluxe Coupe (98 bhp)
1957 Jamaican MGA (200 bhp)1965 1971 Jensen Interceptor (350 bhp)
2009 Pontiac Solstice GXP Coupe (350 bhp)
2007 BMW Z4M coupe (340 bhp)
Recent: 1969 MGC roadster (175 bhp),Jensen CV8 (375 bhp),
1969 Lamborghini Islero S (350 bhp), 1988 Fiero GT turbo (300 bhp)
North Vancouver BC

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mgb281 Philip Waterman
Taunton, Somerset, UK   GBR
Carl
This is how I see it and could very likely be wrong, the lines drawn from the steering arms in the straight ahead position should intersect in the centre of the rear axle and as you turn they should continue to intersect on that centre line, although as you turn more the intersection point moves further and further outwards. If I move the vertical link outwards one inch the intersection point in the straight ahead position will now be behind the axle and that intersection arc will move totally differently to the original. Triumph did the exact opposite they kept the whole front end the same and reduced the wheelbase by almost eight inches, the intersection point is now eight inches behind the axle. much more than I would end up with so in fact it is similar, the question was to see if any of you could see what I might do would not work.
What I should have said in the original posting was that my thoughts are a complete new front cross member, new wishbones top and bottom and coilovers, ie a homemade Fast Cars front end. Why not buy the fast cars setup? $3835 plus freight and 20% VAT when it lands in the UK is the reason and no matter how good it is, I am not in the position to spend that much. I have in the past fabricated everything from a kit car chassis and bodywork (from plans) to large steel framed farm buildings, so am happy to give it a go. I also know that I will not save 80lbs in weight. if it is successful I will have the wider track, the benefit of easily adjusting suspension height. I have a complete front cross member with suspension attached that cost me nothing I also have some old coilovers that I can use to mock up mounting points etc If it does not work I will have lost quite a few hours of my time and perhaps $75 in steel, if it is successful I will have the wider track, the benefit of easily adjusting suspension height and spring rates quite cheaply.
Philip

mgb281 Philip Waterman
Taunton, Somerset, UK   GBR
Bill
It would also be hard on my wife's arms, although our oldest son say's that she needs to get fit!
In the UK we are lucky to have quite a selection of wheels in all offsets from zero to 45mm.
I recently forgot to bid on a set of Team Dynamics Pro Race 1.2, used but unmarked 16 x 7 25mm offset and weigh less than 16.3 lbs they sold for about $150, the style is certainly not for purists though.
Philip

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bills Avatar
bills Bill Spohn
W. Vancouver, , BC, Canada   CAN
In reply to # 3733858 by mgb281 Bill
It would also be hard on my wife's arms,

Are you wanting to go with narrow rims and tires but wider track? If so, I like the idea of just creating a new wider centre section to replace the stock cross member and weld the pieces that carry the suspension to that new centre section. The tie rod extenders would work for that.

I'd add that the wider wheels on the Jamaican with 215x60 tires aren't too much effort - for me. And in my experience, building a car so that your wife can use it is often a mistake, or at least wasted effort, as they often seem to quickly lose interest leaving you with the compromises you made ostensibly for her. Guess my wife is the exception - she drove her MGC for 20 years.



Bill Spohn www.rhodo.citymax.com/carstuff.html
Current: 1958 MGA Twincam (race car (170 bhp)),1962 MGA Deluxe Coupe (98 bhp)
1957 Jamaican MGA (200 bhp)1965 1971 Jensen Interceptor (350 bhp)
2009 Pontiac Solstice GXP Coupe (350 bhp)
2007 BMW Z4M coupe (340 bhp)
Recent: 1969 MGC roadster (175 bhp),Jensen CV8 (375 bhp),
1969 Lamborghini Islero S (350 bhp), 1988 Fiero GT turbo (300 bhp)
North Vancouver BC

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fast-MG.com Gold Member Dave Headley
Cortez, 4 corners, Colorado, USA   USA
My approach to this would be to step cut the X-member on each side , widen and weld back together with appropriate reinforcements.smoking smiley


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mgb281 Philip Waterman
Taunton, Somerset, UK   GBR
Bill
Part of the reason is to mach a wider rear track and partly to end up with something better than just another lowered rubber bumper car. I have not decided on tyre size but certainly in the order of 205 section, having followed other discussions on wheel size and weight I am not wanting to add unnecessary weight. I also remember reading an article in "The Motor" magazine that was written by Alec Issignosis, where he was discussing suspension design. In the article amongst other things were the results of the times from a slalom course, all the cars were made by BL. It is no surprise to know that the Mini Cooper S was the fastest by far but second was the humble Austin 1100 and the MGB was third, Triumphs offerings trailed behind. I am not saying that I will transform the car but if a little improvement is achieved and I have been kept amused for 6 months all well and good. The idea is to construct a similar width crossmember but with one inch longer wishbones
Your wife is not an exception, mine is not quite like the preconception of a nine stone mid sixties driver either, she commutes to London each week (350 mile round trip) on some of the most congested motorway, she has driven most types of cars, her first was a Hillman Imp (rear engined small car) then a Spitfire. Then including the following Rover 3500 SD1, Various Volvos, Ferrari 360, Lotus Elise, Various Case Tractors, JCB loading Shovel and telescopic handlers of all makes. Currently her daily driver is a C class Merc. She enjoys driving and misses a manual gearbox but also enjoys the auto which is her first for thirty five years.
What we are trying to achieve is a safe to drive and reliable MGBGT with a respectable turn of speed on the straights and is fun on the bendy bits, which we are surrounded by. The reliable bit may be the hardest to achieve though!
Philip

bills Avatar
bills Bill Spohn
W. Vancouver, , BC, Canada   CAN
I owned a Sunbeam Imp and aso one Hillman Imp (RHD) that somehow made it over here to the colonies. The engines were by far the best part of the cars.

And while I am a hard core manual driver, I do understand that when you have to sit in stop and go traffic for ages, automatic makes a nice way to go. The only auto I own is a Jensen Interceptor (because the Mk 3 only came that way).



Bill Spohn www.rhodo.citymax.com/carstuff.html
Current: 1958 MGA Twincam (race car (170 bhp)),1962 MGA Deluxe Coupe (98 bhp)
1957 Jamaican MGA (200 bhp)1965 1971 Jensen Interceptor (350 bhp)
2009 Pontiac Solstice GXP Coupe (350 bhp)
2007 BMW Z4M coupe (340 bhp)
Recent: 1969 MGC roadster (175 bhp),Jensen CV8 (375 bhp),
1969 Lamborghini Islero S (350 bhp), 1988 Fiero GT turbo (300 bhp)
North Vancouver BC

Jim Blackwood Avatar
Jim Blackwood * BlownMGB-V8
Gunpowder Rd, Florence, KY, USA   USA
There is a cure for the heavy steering and it is much easier than messing with an already pretty good suspension. Mike Moore sells an electric power steering unit that goes in with just a bit of trimming of the bracket up under the dash. We've had one on the MG-Roadmaster for over a year now and it is a fantastic improvement. I'm sure your wife would love it, and the assist is adjustable. Put that on there and run whatever wheels you like.

Then a set of adjustable Armstrongs are a nice touch. I have replaced my springs with airbages which makes the height adjustable in-cockpit.

Jim

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