MGB & GT Forum

I shifted this post on front springs on CB cars away from other, very detailed front suspension debates. My March 1972 production Tourer B should have AHH6451 springs in, but since I did not had this production date only the first road date of 1973, my garage put on my overall restoration in 1986, the slightly longer BHH1225 springs in, which according to MOSS E only came on in production year 1973 Updated elsewhere by the latest info I found in Clausagher on the how and why's for the front coils springs on CB Tourers in 1972

I found the BHH ones lifting the car somewhat higher than I was accostumed to, so I took them out one year later in 1987 and moved back to the AHH-ones ever since

Since my B always leans in on the (LHD) left side after a couple of years, I used to renew the left front spring only or swap left to right spring instead every 5 years. On the back I always renew the leaf springs at the back by 7 leaf GT types every 12 years (without swapping inbetween). Since I found bottom free space rather limited on my recent Italian summer holiday, the minimum is one new AHH spring again, but maybe I should return to these BHH ones instead. They've been lying unused now for a long time and MOSS indicates some centimeters to be gained. When following MOSS measurements I can achieve 37 cm centre hub to underside fender curve. Now I'm down to 34cm only on the driversside on the left, whilst the right one still reaches 36 cm

Any opinions here and is there any knowledge why BL changed spring types during the CB production period (I'm not interested in the why's and how's of the RB era of course)?
And wich types do other MGE members select on CB cars, strictly by date before and after 1973 or differently?



Thanx in advance...



Edited 1 time(s). Last edit at 2015-07-05 06:43 AM by Donthuis.

I'll be very interested in the responses. I have a new set of GT front springs I was going to use on a GT, but alas, I have sold the GT and have bought a 64 Tourer. I too, am wondering what that would do to the stance of the 64 roadster.

That leaves me to a similar question concerning the back leaf springs. I have a new set of BMH 7 leaf spring rears. Don mentioning he uses them on his Tourer has me wondering if they'll be OK on my 64.

Well the first item is my own question, but for the second one on back springs see below:

It is a general recipe to prevent Tourers from hanging backwards, so soon after mounting new "Tourer" 6 leaf springs. With the 7 leaf GT ones you start with a slightly forward stance (especially with the AHH coil springs at the front), but after a year or so the forward stance is hardly noticeable. And what is more important: leaning back will take many years of usage, in my case 12 years at least. For those having a luggage rack on the boot with a heavy suitcase on top I would consider GT springs almost mandatory

A side effect is that then internal friction of a 7 spring set up is somewhat higher than with 6 leafs, but is not a strong effect, because the extra one is short.
Most MG owners do not realise that one of the reasons Amstrong lever arm dampers at the back work so well, is that the spring also functions as a friction damper.

PS For those contemplating parabolic springs at the back: these have no friction damping at all and MUST be combined with strong hydraulic dampers like Koni




Edited 2 time(s). Last edit at 2015-07-05 11:07 AM by Donthuis.

No reactions from other members, so before I let this subject drop off the list to oblivion:

- trying two BHH 1225 springs at the front got me again a very high stance up front, especially at the passenger side (LHD car)
- today, I put my longest AHH6451 spring at the passenger side, but kept the BHH1225 on the driverside in place

Result: symmetrical, but lower height up front as measured with the MOSS-advised method (centre hub to underside fender) of 37 cm, the expected value for 1973 CB cars.
Strangely enough I found no ready explanation for this asymmetry, while my car log showed the different spring renewal dates, the last one being both renewed at the same time

The fact that these spring types probably differ in their spring parameters (MOSS lists 350lb for AHH and 400lb for BHH) may result in some extra rolling car movements? I wonder, because the rear leaf springs also have a strong influence on overall car equilibrium. Anyhow: my exhaust will not be scraping some nasty obstacles so soon now.
Of course I myself found the Clausagher reference on why the change from AHH to slightly longer BHH springs on CB cars during production year 1972 was made

PS This higher front position means in the future I have to re-adjust the headlamps slightly down, to satisfy MoT/APK requirements (next time is April/May 2016)



Edited 2 time(s). Last edit at 2015-07-14 09:28 AM by Donthuis.

Some insight from Paul Hunt's wonderful webste.....
http://www.mgb-stuff.org.uk/suspensiontext.htm#rideheight

Excellent material, thanks a lot. From this site I gather the spring constants of AHH and BHH springs are quite close together, much closer than MOSS specifies. So now I know why my present configuration may work fine after all.




Edited 1 time(s). Last edit at 2015-07-14 01:20 PM by Donthuis.

Usually, changes in springs are from changes in weight. Light cars would be more sensitive to accessory additions. Best guess.

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Cogito ergo sum periculoso

In my past life I always swapped out the 6 leaf spring for the 7 on tourers as I have done with my rebirth back into a MGB this past fall. The right is a little stiffer but I found they tended to hold up better. Just my 2 cents.

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jb

Too soon we get old, too late we get smart!

Odd fix for Bachelor Lean.
I ride alone a lot, weigh 225 and don't seem to need to replace springs, front or rear... ever.

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Michael J. Caputo
'79, '77, '76, '74.5 (rubber dual SU), and '73 owner. Extensive experience in 12v Audio System design and installation. Vendor of Regalia and Promotional Products since 1993. Supplier of Accessories to MOSS. Forum Member since 2009; with a warped sense of humor since birth. Publisher of the annual MGB & GT Calendar, mailed worldwide.