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Lengthening Herald Wheelbase


Adrian Girling
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6 hours ago, Adrian Girling said:

I've read that the herald classis tyre OD is 582mm and if I want to go to the full 680mm for my replica then 3.52 would be the exact number.  In this case, 3.69 would be within 5%

I think you may have your maths inverted. Bigger wheels make for longer gearing, as does a lower diff ratio (it's the ratio of input turns to output turns). So if you wanted to retain the Herald's 16mph/1000RPM you'd need a 4.8 diff. There was a 4.88 diff fitted to 948 Heralds but, in truth, the 4.11 is noticeably under-geared on a 13/60 and if your body is going to be lighter then you can definitely tolerate the longer legs. Many people fit the late Spitfire 3.63 diff on Heralds and don't find it too long, so if you stick with the 4.11 with your bigger wheels I think you'll be OK.

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That moderns have such wide wheels is a product of the move to MacPherson strut front, and semitrailing rear suspensions that don't suffer from excessive camber change, plus radials and radials with lower sidewall ratios, that  will not tolerate that at all.

The vehicles that have narrow 16" rims today are motorbikes!   Many in  alloy, which might not be the look you want, Adrian, but how about wire spokes?  Or, wire-look alloy??

Amazon.co.uk : Motorbike Rims

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5 minutes ago, JohnD said:

The vehicles that have narrow 16" rims today are motorbikes!   Many in  alloy, which might not be the look you want, Adrian, but how about wire spokes?  Or, wire-look alloy??

Amazon.co.uk : Motorbike Rims

Nice idea, but I'm not so keen on the prices!  I wonder if someone can make steel wheels narrower - I've seen people who can make them wider...
I think I'd prefer fairly basic looking steel wheels painted the same colour as the car

 

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3 hours ago, RobPearce said:

I think you may have your maths inverted. Bigger wheels make for longer gearing, as does a lower diff ratio (it's the ratio of input turns to output turns). So if you wanted to retain the Herald's 16mph/1000RPM you'd need a 4.8 diff. There was a 4.88 diff fitted to 948 Heralds but, in truth, the 4.11 is noticeably under-geared on a 13/60 and if your body is going to be lighter then you can definitely tolerate the longer legs. Many people fit the late Spitfire 3.63 diff on Heralds and don't find it too long, so if you stick with the 4.11 with your bigger wheels I think you'll be OK.

OMG, thanks for correcting my maths - can I do an embarrassed emoji in this forum?  Yes, the propshaft needs to rotate more often to achieve the same road speed....  and I'm liking the logic of leaving it as it is 😀
 

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Quick update, I bought the Herald on Ebay and have taken off the doors, bonnet and front bulkhead. I've lifted the whole of the rear end body and dropped it again as I've nowhere to put it!  The chassis seems to be in surrisingly good condition - that was my biggest risk.  Does anyone need these complete body panels?  They are not perfect, but not bad either.  Where necessary some good welding has been done already and I can take photos if anyone is interested.

 

 

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Where to put the body, Adrian?   In the roof!

Here's a very old pic, my first Vitesse, Old Blue, in restoration.  Two sets of pulleys in the roof beams and I lifted it off the chassis.   

NB instructions in the workshop manual.   The advice to reinforce the joint between the bulkhead and rear tube, at the sills, is a Good Idea! 

Body-off restoration.jpg

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2 hours ago, thescrapman said:

Where abouts in the country are you Adrian?

Hi, I've sent you a private message.  I've now been recommmended to hang on the the rear section and the bulkhead for a while as it's been suggested I could cut them about (make them narrower) and weld on side panels (as my project car has no doors) to be stronger than a plywood frame.  Not sure if this will work, so they may be available later

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Ah!  Convertible!    Deffo add struts across the doors before you take it off.     Essential for Spits, recommended for Heralds/Vitesse, unless they have a roof to do the same.

Once it's up, add some security lines?    Ratchet straps?   But the weak point(s) will be where it's hung, the  roof beams or whatever.   I've heard of people building  a wooden frame to support the body, wide enough to wheel the chassis in and out to work on.  Then the weight is  on the ground, as long as the frame is strong and braced.

John

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7 minutes ago, JohnD said:

Ah!  Convertible!    Deffo add struts across the doors before you take it off.    

I've heard of people building  a wooden frame to support the body, wide enough to wheel the chassis in and out to work on.

Oops, too late.  Bulkead is off, on it's side.  Lifted the back end high enough with a engine hoist to inspect under, now dropped back on chassis.  I've lifted a MX5 Unibody onto a wooden frame on casters this way - 38 x 63 timber studding is so versatile.  Thanks for the tips

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