Hi Phil,
after ever so many flat tyres with outside laced wheels,
during the last 30 years, I am sure, that the main problem is the
difference in diameter of the two rim sides at outside laced wheels,
where the tyre edges are seating on the rims.
The reason for the smaller diameter on the spoke side
maybe is the material needed during manufacturing,
for sinking the holes for the nipples.
When the car is cornering sharply, and it is loaded heavily,
there is a gap developing between rim and tyre-edge,
and the tube is creeping into this gap.
As the wheel turns further, the tube then is squeezed
between rim and tyre, and after getting this bad treatment some
hundred times, the tube is showing cracks, looking like small cuts.
The mountains and valleys in the rim between the nipples,
and protuberant nipples are adding to the problem.
Thick-wall tubes make things better, but can't solve the problem.
Since I build up the nipple-side of the wheels with epoxy and
glassfiber-stripes to the diameter of the no-nipple-side,
I never had any more flat tyre resulting from this circumstance.
I agree that this method sounds very time consuming, and it really is,
but I was near the point to change to non original centre laced wheels,
as Abingdon did whilst producing the TA. (the same problem ??)
A big lathe, taking the 18 or 19 inch diameter wheel, helps a lot.
First clean the rim from dirt and paint, next fill the deepest valleys
with thickened epoxy, then wind a epoxy-soaked glassfibre strap
round the rim, until both sides diameters are the same.
It needs a lot of grinding (with a curved emerypaper-block),
between each layer of glassfibre, and finish the result smooth.
Renewing a spoke, still is possible.
If somebody needs more info, I could send photos off-list.
Gerhard Maier
++++++++++++++++++++++++++++++++++++++++
>>-----Original Message-----
>>From: owner-mg-mmm@autox.team.net [mailto:owner-mg-mmm@autox.team.net]On
>>Behalf Of Anderson, Phil
>>Sent: Friday, July 22, 2005 4:29 AM
>>To: mg-mmm@autox.team.net
>>Subject: Tyre tubes
>>
>>
>>Fellow listers,
>>
>>I have an inquiry about tubes. After several hundred miles on my tubes
>>and tyres (400 X 19) I have had two flats within forty miles, both on
>>rear tyres. The tubes have identical small tears (each had two tiny
>>slits about a quarter inch, close together), and I am assuming it was
>>from the rim tape wearing on the inner spokes in the rim and piercing
>>the tube. I know this can be a common problem. The tubes were Cheng Shin
>>(Taiwan) and seemed a lighter weight. I have now used a much heavier
>>tube made by Maxis (Taiwan). I renewed the tape and am hoping the
>>heavier tube will wear better.
>>
>>I am curious about the experience of others and any recommendations as
>>to tubes or dealing with the perennial spoke problem.
>>
>>Thanks much!
>>
>>Phil Anderson
>>PA1212
>>
>>P.S. Sorry about the prior transmission. I inadvertently hit send before
>>I typed anything!
>>
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