MGB Rear Telescopic Damper Options

[niva441]

Gents

I'm looking at replacing the rear springs on my rubber bumper GT with parabolics and at the same time go to telescopic dampers. The MG Owners club catalogue lists 3 options:

Koni's fixed and oil filled £200
Spax adjustable gas filled £160
GAZ adjustable gas filled £139

There's no information on relative performance, although the Spax units are referenced in the Parabolic rear springs description. Do you have any ideas where I might find out more about their relative performance?

I'm curious why the apparently lesser featured Koni units are significantly more expensive.

Thanks

Todd

[v8bloke]

I have tried Spax and Gaz. Gaz are much better in my opinion. Spax were too hrd even on the softest setting.

[niva441]

Thanks for the information, I was a bit concerned with the GAZ units there was possibly too many adjustment steps. But if they get the right result that's great.

[alfa pint]

I had adjustable konis on my old B with parabolic springs and it worked well. Agree that the spax unit is too hard, but that's only from what I've heard and read for other people.

A B needs to be supple at the rear and stiff at the front to get the best out of it. Worth uprating your bushes while you're at it too.

[chormy]

GAZ are on offer at 89 plus PP (http://www.mgpartsuk.co.uk/prods/gaz2-mgbc-rear-telescopic-damper-conversion-kit-all-models.html)
but if your levers are ok , get the 25% uprated valves and change the oil to straight 20w bike fork oil.

If you want adjustable levers , which I use on the race MGC they are available around £100 each from states. PM me!

[alfa pint]

Except that the parabolic spring manufacturers specifically recommend gas dampers rather than lever arms with their product.

I've uprated the lever arms on my current B, rather than go down the conversion route just yet (along with a few other normal things), but it still sits on standard rear springs.

[na]

I'd contact GAZ direct, my mate did to find for his car GAZ recommended a different unit to the one fitted by the manufacturer and the MD told me mate he'd been trying to convince the manufacturer that they should use the other unit but had no joy - knowing the manufacturer I can quite believe it

don't forget to tell them that the springs are parabolic in case there there is a license agreement for a certain model of unit but possibly an alternative standard unit will be very, very similar

[niva441]

Sorry for going quiet on the thread I started, it's been a busy week culminating this morning with an odd internet problem. I had limited access to everything except my email and Pistonheads.

Thanks for all your help, this must be quite unusual for a PH thread as there is a reasonable consensus.

It looks like I'll be ordering a pair of GAZ units to match the parabolics. Next year when I rebuild the front suspension (shouldn't fall apart before then), the question should be easier as the front GAZ units should match the rear. Although as I understand it the front conversion is less beneficial than the rear.

[na]

niva441 said:

front GAZ units should match the rear.

again get advice direct from Gaz rather than what is popularly sold

it might be that GAZ say the popular units are the best suited of their range already but find out for sure for the sake of a freindly phone call - you can't expect them to put in writing that they disagree with their customers recommendations

niva441 said:

Although as I understand it the front conversion is less beneficial than the rear.

I'll leave someone with actual experience to answer that

I would say a cost effective improvement can be the next thickness up from standard fit ARB and replacing worn bushes all round will make a great difference

don't forget tyres as part of your suspension and steering, persomally I think too wide or low prife tyes spoils the feeling of the car it's ride, steering and possibly road noise

same as with the whole car the suspension needs to be kept in balance, too much or little of anything can spoil the balance and the ride, handling and road holding even braking

[niva441]

Front suspension rebuild is the plan for next year. Not sure whether I'll be using poly bushes of standard spec rubber. I'm not convinced on the benefits (apart from longevity of poly bushes).

One feature I'll definitely be keeping original is the tyre size. I think it is one of the key features that makes driving the B more involving than my current modern. In fact I specced the current daily driver with a view to the least amount of tyre width / highest profile available with a decent engine spec.

[alfa pint]

185/70x14 is pretty much the best tyre compromise. Much stiffer sidewall than normal, 4" of extra rubber sticking the car to the deck, but not so stiff as to ruin the ride and you can still stick the tail out when you want to. Standard crap tyres on a BGT I had for a bit were appalling and the car did not stop well at all.

I'm a big fan of Yokohama A drives on Bs.

[na]

Todd,
I agree with you about keeping the standard size tyre for keeping the feel of the car and its usability, that and keeping the standard steering wheel gives the steering it’s nice feel IMO

The extra sidewall of the 165/80 I think adds to the feel of the suspension and ride comfort

Modern tyres I’ve found need an extra couple of psi over the original published figures in the Driver’s Handbook (see my usual advice below)

I expect you know about tyre age and that tread depth it’s the only consideration of legacy tyres but for others a link with useful information – http://www.carbibles.com/tyre_bible.html

and on wheel/tyre sizing – http://www.kouki.co.uk/utilities/visual-tyre-size-...

I've got Super-Flex bushes front and rear on my Midget and they are 'softer' feeling than the then 2 year old yellow (fast road) urethane bushes they replaced which I originally fitted

alfa
I also agree with you that 185/70 are a good compromise, the low profile back in the day

as I'm sure you know regardless of tread depth age and lack of use can make standard tyres crap

I’ve also got Yoko A-drive on my Midget and am very pleased with them


my usual advice;
workshop manuals for repairs but better to have Driver's Handbook for prevention - (Ref: 0053) - http://www.mgocshop.co.uk/catalog/Online_Catalogue...

buy the excellent investment Driver's Handbook thoroughly read it and carry out as much as required of the 36k-mile service asap

driver the car regularly to keep it in good condition and you completely aware of its full capabilities

loads more help and advice on the MGB forums here (and I'm not on them) - http://www2.mgcars.org.uk/cgi-bin/gen5?runprog=mgb...

have this for good luck http://www.cibolas7.net/resources/cutaway.htm#

[niva441]

The car is running 175/70 tyres, I believe they are larger as it is a late GT, similar sidewall height and I've no intention of upsizing.

I changed to Kumhos when I bought it as I ordered the wrong size of Goodyears and they were available. Overall I'm pleased with their performance. Ordinarily I would shy away from Yokohama tyres because of what I expect their wear characteristics. However, given my B's mileage they are more likely to timeout than wear out, wear isn't really an issue. So I may well consider then next time.

As the B is lighter than modern cars does anyone have any recommendations for a tyre that works optimally with lower load. As I was typing this I looked on the Longstone Tyre site, but they only list the 165x14 tyre size, no 175/70 tyres listed.

[na]

niva441 said:

The car is running 175/70 tyres, I believe they are larger as it is a late GT, similar sidewall height and I've no intention of upsizing.

as far as I know tyre size would have been 165/80 on Rostyles, the low profile tyre of the time was 185/70 and obviously still remains a good fit on the wheel at least

see the tyre size guide link I posted above, 175/70 is just a bit small or big depending on which you want - not enough to worry about if the tyres are good

niva441 said:

As the B is lighter than modern cars does anyone have any recommendations for a tyre that works optimally with lower load. As I was typing this I looked on the Longstone Tyre site, but they only list the 165x14 tyre size, no 175/70 tyres listed.

as above 165/80 are what you want and see the car bibles link I posted above for load and wear rates symbols

in November RRC (rolling resistance coefficient) will be added to tyre labelling, this is for using less fuel

for your modern tyres you can experiment with putting an addition 2-4 psi (or more) over the Driver’s Handbook specification of 1970s tyres

talking of Driver’s Handbook which tells you all about your car, the specifications (including wheel and tyres sizes), how to operate the controls, the full servicing schedule and how to do the work

it’s only £8 and is a fabulous investment – would have saved you rejecting what might have been the correct size tyres

Driver's Handbook - (Ref: 0053) - http://www.mgocshop.co.uk/catalog/Online_Catalogue...

[niva441]

Ignore what I was saying about tyre sizes, they are 165/80 Kumho Power Star 958 (you've got to be impressed by that name). I must have been confused by the fitment to my old V8, similar to me getting the original order for Goodyears wrong.

[na]

yeah I know how you feel that's why I like all the information printed or written in the Driver's Handbook that way I only have to remember one thing, where I left the Driver's Handbook last

[niva441]

The handbook is conveniently on the passenger seat. But that is in the lock up, a little distance away. My memory is much more convenient, but not totally reliable.

[na]

might be cheaper and more convient and not a bad idea to have two copies one for home reference and one with the car in the glovebox - something not possible in the Spridgets