The Roadster 100 Wheel fitted with an Avon ZV5 Tyre
Never having fitted new rubber to our wire wheels, I set out to find how best I should proceed.
At the back of my mind was the thought that the R100 is now seven years old and our low mileage cars probably results in most still running on original tyres?
Add to this the view expressed by many, that rubber is OK for say five to ten years but needs to be inspected from time to time as mileage is not the only factor – the ageing process can also deteriorate tyre wall quality and needs to be monitored particularly on a powerful car.
Against this background I decided to replace the tyres and wondered which brand to go for?
I concluded that I would stick with Avon not only to match the unused spare wheel, but Avon is also used by a knowledgeable MOG car contact who knows much more than I about these things.
So, we shall order four Avon ZV7's, the current specification.
I then looked at fitting options. Having been warned to avoid the big chains I talked with four small company fitters none of whom seemed comfortable with fitting tyres to wire wheels.
In summary the following comments were typical – “Are your wheels secured by four nuts?”, “If you tell us what to do we will follow your instructions”, “Never fitted wheels with spinners before – what is the torque setting?”, even “We wouldn’t want the wheel to overtake the car”! - I kid you not!!,
I was also told by a very technically competent MOG owner that our stainless wires have a well on the rim in the opposite position to what is normal – meaning that the tyres should be removed and fitted over the inside rim rather than the outside rim.
The Wire Wheel with Two Spoke Head Sealing Bands
(covering its two rows of Offset Spokes and its 'Clear Inside Rim' that David refers to.)
There exists a silicon protective coating over the spoke fixing points to the wheel rim – and this must not be damaged during the tyre removal or fitting process.(covering its two rows of Offset Spokes and its 'Clear Inside Rim' that David refers to.)
No one outside the Morgan dealership network that I spoke with had the spline fixing tool recommended for our wire wheels. They all employed a twin cone system to hold the wheel in place whilst balancing and adding weights – and the cone system is less stable when compared to spline balancing.
Be aware that long stem stainless Roadster valves are available from MWS if these (originals) are preferred to rubber replacements.
All of this left me convinced I would need to have the tyres fitted by a Morgan service dealership – one of whom said - “A few people will have a go at it even if they do not have the know-how and tools to do the job properly”.
Outside the dealership network and in the Birmingham area – the wire wheel specialist Paul Harris (advert in Miscellany) is also well regarded by Morgan drivers.
With winter in prospect and tyre contact with the road being little more than a palm print then new rubber properly fitted is a must!”
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Just to add in a note for R100 Cars running on the original Factory Fitted Avon ZV5's!
It appears that Avon has introduced the ZV7 tyre which has now replaced the ZV5, which no longer appears on the Avon Website Tyre List. ( Please see ZV5 & ZV7 Comparison lower down in this report ).
ZV5's are still available from some Tyre Dealers if, like Frank, you had recently changed just the Rear pair due to a puncture so would now say, need to change just the Fronts as well due to their age.
What we do not know is how long the ZV5's will remain available. therefore anyone planning to change the whole set would naturally upgrade to the ZV7 as David is intending to.
Now knowing this, and with no tyre advisories on my recent MOT, I may run them as they are for another year and then change the whole set to Zv7's then.
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Choosing the Expert Tyre Fitter - Frank's Story of Caution.
I had to have a new Rear Tyre fitted due a couple of years ago due to finding a non repairable Large Screw Puncture in the Nearside Side Wall one of the the tyres.
Living in Buckinghamshire at the time I decided to go to Motor Wheel Services (MWS ), our Morgan Wheel Supplier who is based nearby in Langley nr. Slough. They not only supply Wire Wheels for Morgans but every model of car that uses them.
They are the experts as they also completely refurbish and rebuild vintage wheels of all types therefore have a fully fitted workshop on their site.
The Green Goddess in the MWS Tyre Fitting Bay.
It was just as well that I did go to them for my new set of rears because even though they have the expert Tyre fitters and the correct fitting and balancing equipment for wire wheels, both new tyres on my rear wheels deflated overnight.
Having re inflated them both, I dashed to their workshop in the morning, where it transpired that the problem was caused by a Chap in the Indian Wheel Manufacturing Factory. (Yes, They are made in India)
The person who is responsible for painting the Silicon Rubber Seal over the Spoke Heads ( See Photo above ) had done a ' Friday Job ' on my wheels.
He had brushed on only a Very Thin Coats of Black Silicone Rubber on both wheels and these thin Spoke Seals were 'rolled over' and the seal broken as the new tyres popped into their respective Rim Wells.
This is an easily repairable problem according to MWS, which MWS also offer as part of their Classic Wheels Refurbishment Service, but the Silicone Rubber needs a minimum of 48 hours to cure.
As we were heading off to Harrogate the following day to attend the MSCC MOG being held there, MWS gave me two brand new Morgan Wheels as well. My old ones would be sent back to India.
The Wheels have been fine since then. I will probably go back to MWS again for next set of new tyres.
Question? Will the Front Wheels suffer from the same poor Silicon Rubber Band problems?
What would have happened if a non specialist Tyre Fitter had found this problem?
The MWS Wire Wheel Workshop
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Avon ZV5 & ZV7 Comparison
Our Roadster 100 Tyre Size is 205 / 55 R16 91W
Dry Grip 89%
Wet Grip 85%
Road Feedback 71%
Handling 66%
Wear 81%
Comfort 83%
Replacing the acclaimed Avon ZV5, the newly-developed ZV7 incorporates a range of advanced technologies that mean it offers a host of added features and benefits.
The distinctive tread pattern of the new Avon ZV7 is designed with large circumferential grooves that clear water quickly and efficiently to reduce aquaplaning in the wet. It features sequenced tread blocks to reduce noise generated from the road, providing a quieter driving experience.
The Avon ZV7 tread pattern also features 3D sipes, which have interlocking three dimensional points inside the sipe. The 3D sipes provide the same benefits of a traditional sipe, including helping the tyre warm up and providing enhanced wet grip, but limit the amount of flex in the tread block which helps control the amount of heat generation in the dry and keeps the tread block stable.
( Siping is the process of cutting thin slits across the surface of a tire to improve traction for driving in snowy, wet or icy conditions.
Siping can also help manage tire heat when the road is overly hot. )
Using the latest available polymer technology and advanced mixing techniques, the ZV7’s tread compound delivers excellent wet and dry grip while also reducing rolling resistance for great fuel efficiency.
This tyre replaced the Avon ZV5
For drivers who want the best combination of performance and safety.
- Large circumferential grooves clear water quickly to reduce aquaplaning
- New tread pattern featuring 3D sipes that help the tyre warm up and optimise wet grip
- New polymer technology and advanced mixing techniques provide better wet and dry grip, reducing rolling resistance and greater fuel efficiency
- Rim flange protector helps to minimise kerb damage to alloy wheels*
- New noise reducing feature - reduces noise from tyre/road interaction
- Available in a wide range of fitments from 15" to 18" rim diameters with V, W and Y speed rating
*A rim flange protector is designed to protect the flange area - not the whole wheel. Many modern wheel designs may have domed outward designs well beyond the flange.
FUEL EFFICIENCY (Rolling Resistance)
Fuel efficiency is influenced by the tyre’s rolling resistance. Lower rolling resistance means lower fuel consumption and CO2 emissions.There is a 7.5% loss of fuel economy between the best and worst class (average).
WET GRIP (Braking Performance)
Wet grip is one of the most important performance characteristics in a tyre.The effect may vary among vehicles and driving conditions, but in the case of full braking, the difference between a G and an A class for a set of four identical tyres could be up to 30% shorter braking distance (e.g. for a typical passenger car driving at 80 km/h speed this could be up to 18m shorter braking distance).
ZV7 Technical Specifications for our wheel size
TYRE MARKED SIZE
205/55R16SERVICE DESC.
91WREQD RIM
6.5SECTION WIDTH MM
214OVERALL DIAM MM
632RIM RANGE IN INCHS
5.5 - 7.5FUEL RATING
ERAIN RATING
AROAD NOISE
69dB
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