Tonneau & Hood Fixing Points

[Malcom & Julian]

Hi All

We are looking to buy a half tonneau/hood cover for our MGB Mk1 1967. Not decided as yet on vinyl or mohair.

Being a 'newbie' having only acquired the car this summer, my question is, Are all the fixing points to the rear of the hood well always in an identical standard position when the car was manufactured or might the positions of the pop-ups changed over time.

I asked the question at Don Trimmings in Birmingham and the guy wasn't really sure hence my checking opinions on here.

Would appreciate any advice - also, Vinyl v Mohair ?

Thanks guys

[Peter Cresswell]

The answer to this is: Most likely they are all the same unless the car has been restored at some time! I have a half tonneau which came from a 1970 MGB I bought about 45 years ago, and that fits the 1969 restored car I have now.
The only way to be sure is to have the new tonneau cover fitted to the car. Don Trimming have been in business for a long time - I had a full tonneau for an MG TD made by them in 1967, so they must be doing something right! They may be able to make up a tonneau for you and fit the fastenings while you wait. Incidentally, they reckon the modern vinyl is poor quality compared to the original stuff, and although more expensive a mohair is much more durable.

[Malcom & Julian]

Thanks yet again for your advice Peter - much appreciated!
One other question, what PSI / Bar do you put into your tyres for regular running ? My tyre size is 175R/14C.
Moorland Classic Cars recommend 60psi for over-wintering in my garage.

Thanks again Peter

[Peter Cresswell]

Hi Malcolm and Julien
Sorry for what will become a long reply but there are some things to be aware of with your car at the moment and help you to make sense when you ask for recommendations on tyre pressures. The easy bit is 60psi will be fine for winter storage. Just remember to adjust the pressures when you want to start using the car again.
Now the harder bit -
My car has 5.5in Minator alloy wheels (Minilite look alikes) and so uses 185/70 x 14 tyres. The suspension is quite modified by lowering the front by 2in and rear by 1in; front springs are 600lb/in with 8.5in free length (standard car uses 9.1in and 350lb/in); front dampers have 25% uprated valves and thicker oil, rears are adjustable Spax. Front camber has been adjusted to 1deg negative using offset hole poly-bushes and the caster has been reduced from 7deg to 4deg using the B&G kit. All this helps make the most of using a radial tyre over a crossply that the car was designed for and to keep the outside tyre flat on the road during hard cornering. Tyre pressures then play an important part and the if the front tyres are set higher than the rears, that also produces more grip at the front and so makes the front grip the road better than the rear improving the feel of the car when turning into a corner. I use 26psi at the front and 23psi at the rear. However this affects the handling of the car which is very subjective whereas the standard set up of ride height, spring rates damper setting, etc., etc., was done objectively. See this thread for more explanation:
viewtopic.php?f=3&t=252&p=1166&hilit=handling#p1166
I explain all this as to show the full extent of what happens when you change or move away from the owners handbook of recommended setting. In the case of a roadster the tyres recommended were initially 520 x 14 crossplys and the pressures were 18 - 22psi all round (plus 6 psi for sustained high speeds). Sometime in the mid 1960s radials were fitted as standard and these were 155SR x 14 on steel and wire wheels for the roadster (the GT used 165SR x 14). Pressures were slightly higher as the tyre walls were softer and recommended as 20 - 21psi at the front and 24psi at the rear. These pressures were recommended until the end of production in 1980 despite huge strides being made in tyre technology. These days many people seem to use around 24 - 25psi at the front and 22 - 24 psi at the rear, which sharpens the grip at the front slightly and keeps the ride supple enough for our terrible roads these days.
If I turn now specifically to your car, you will immediately realise that the 175 x 14 tyres have moved away (quite a bit) from the manufacturers standard, so where to start determining tyre pressures that suit your style of driving. Firstly look at how the tyres are wearing. At the front if the tyres have worn more on the outside than inside then the pressure is too low. If you want to be a little more scientific try the 'Chalk Test' and this picture explains it all.
[attachment=0]Chalk test.jpg[/attachment]
You can then adjust the tyre pressures to suit your driving style and the roads you normally use, within the overall range of 20 - 27psi at the front and 24 to 30psi at the rear. I think you will settle for around 25 at the front and 23psi at the rear. Another problem with going to the 175 x 14 tyres is your speedo will under-read which strictly speaking is illegal. The MGB speedo is a bit crude anyway compared to modern cars, but if you have a satnav check the reading on a level road against the satnav reading and adjust your speed accordingly. There are also Speedometer aps you can download onto your phone which do the same job.
Sorry to take so long but hopefully you will understand the subjective nature behind the question ' what tyre pressures do you use?'
Pete

[Peter Cresswell]

Hi Malcolm and Julien,
I notice you are not too far away from me in Stone, and I don't use the hood cover I have so if you are interested let me know and I'll send you more details by PM. It is in black vinyl and is from a 1970 car. I don't have the bars that support it though as the car it came off had a foldaway hood rather than the removeable hood.

[Malcom & Julian]

Hi Pete
I sent you a PM - not sure if you received it?
Malcolm

[Peter Cresswell]

Hi Malcolm,
I've just replied to you.
Pete