Tyre replacement

Advice required on 1969 MGB GT tyre replacement.

The existing tyres are Bridgestone SF288 165R14 on 14 x 4.5 inch 60 spoke chrome wire wheels. The date codes on the tyres are 8702 and have covered 10,000 miles in the last 22 years. I have owned the car for 30 years.

I want the keep as standard a set up as possible, the modern tyre fitment that is readily available seems to be 175/70/R14. At 175 are the tyres too wide for the 4 inch rims ?

The spare tyre and wheel has never been used, nor has it been exposed to sunlight, should this also be replaced ?

Regards

TJS

175/70x14 can be used on 4.5" wide rims, although their circumfance is a little bit shorter than that of the 165x14 tires that were used as the std. size
by the factory for your car.
With 175 section tyres there will be no rubbing but the speedo will give incorrect readings, showing a little bit a higer speed than actually driven.
You can also go for 175/80 on your rims or try 185/70. This sizesave also been used on the 4.5" rims, although the 185 section looks a bit wrong in this setup, I think.

Concerning the age of the tyres, there are different opinions around. As long as they do not show any beginning perforation on the walls, they still might be
good for some time but don't reley upon the safety they were capable for when new.
An other problem might become the handling when breaking on wet roads, as the rubber becomes harder within the years and emergency braking might
cause a critical situation to keep the car under controll or having longer stopping distances. With the spare, the same problms should to be checked too.
I just changed the old tyres of my roadster as they begun to feel slippery and the difference to the brand new ones (175/70x14) was amazing.

IMHO you should replace all five with 175/70 R14 tires. This is a good replacement size.

A suggestion: as you notes, long time, few miles. For most of us buying tires for the daily commuter wear/expected life is an issue and more = good.

Tires have a rating system (A, B, C etc) for traction, wear, and something else (i forget). For the daily commuter A or AA wear is likely more important than traction, and A wear often comes with B or even C Traction. I'd suggest this be reversed for the B...aim for as high a traction level as you can find and let the4 wear slip to lower levels. These tires will be "stickier" and the car will handle better than the low wear/high miles versions.

I

A tire that has age problems can not be determined by inspection, especially if its been stored indoors.

The materials tires are made of deteriate with age, its as simple as that.

As for fitment, ask the tire vendor/shop what the documented rim width range is for the specific make/model/size tire being considered. Also, ask what the age limit is for the make/model tire being considered. The major tire manufacturers document this info.

I have a much later version -1979 RB car- but it appears that I may have the same wire wheels as you.
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I recently replaced all tires with Sumitomo 185 70R 14's (HTR 200) and really like them. But they may be too big for your car.

The primary reason I got them was that the tires I had on there - even though they had lots of tread left - turned out to be 14 years old, and one of them disintegrated on the road!

As others have pointed out, just because a tire LOOKS GOOD does not mean much.

The Yokohama Avid 175/70/R14 tires that I used on my Rostyles for an original look worked well. Again, tires should be replaced every 7-10 years regardless of tread.

I have owned my '67 Pale Primrose Tourer for 37 years and have replaced the tires twice. The last ones were, indeed, 175/70/14 on chrome wire wheels. The speedometer and odometer, which was recently recalibrated, is dead on accurate when comparing it to a GPS unit. No problems with rubbing either. RAY

What I've been told many times by people in the tire manufacturing business is that the moment a tire is put into use, it begins to break down. Micro-fractures form in the rubber as it flexes which allows ozone and other unwanted nasties into the inner casing. Ozone especially breaks down the casing, and the bond between it and the rubber. That's why you often see old tires lose a large piece of tread or blow a sidewall clean off.

If the spare has never been used and has been in a climate controlled place then theoretically it could be safe for emergency use, but if it were me I would replace them all. The last thing you want after a flat tire is another flat tire! I carry a 155-width spare just to save room in the trunk of the B, and because the likelihood of a flat on a modern radial isn't really that great compared to days of old.

If you want to know the limits on rim size for any particular size tire/rim, check out the detailed specifications on the Tirerack.com website. Manufacturers usually specify the range of rim widths that can be used with a given tire. The same specs usually give the exact diameter (or circumference) of the tire - which varies more than you might think from manufacturer to manufacturer (even for the same nominal size).

You can use http://www.miata.net/garage/tirecalc.html to check various tire sizes. Note that the original 155R14 or 165R14 tires were 80 series. Note also that the Brits didn't change the speedo (AFAIK) depending on the 155 or 165 size - so I don't think they really expected it to be perfect anyway! :)

Thanks for the feedback, much appreciated.

I have ordered four new replacement period Michelin XAS 165 HR 14's plus tubes from Longstone in the UK. Not cheap at 129 pounds each but as it's the first new set of tyres in 22 years I cant complain. They also produce a useful summary and conversion table of European and American conversions for old to new aspect ratios, see http://www.longstonetyres.co.uk/Choose-your-rubber.php

I will keep the unused spare tyre for emergency use.

Regards

TJS

p.s; you also get a "free" poster ! http://www.longstonetyres.co.uk/Classic_Adverts.php

I bought Vredestein Sprint+ in size 165R14. They were around $80 US each. They should be available in the UK as well.