Stuart’s GoldWing Blog

Correct size marking for a GL1800 front tyre. Click on the picture for a larger image

A GL1800 was fitted with Avon Venoms recently because there was a temporary stock shortage of Avon Cobras, which are now the preferred fit for a GL1800.

The owner noticed a significant deterioration in handling compared with his previous tyres, which had been Cobras.  This led to discovery that a cross ply (official terminology “bias belted”) front tyre had inadvertently been fitted while the rear one was a radial.  The tyre suppler replaced both tyres with Cobras as soon as the error was discovered.

Avon Venoms used to be made in both cross ply (for the GL1500) and radial (for the GL1800) versions.  Confusion can arise because although the rear wheels are different sizes, both bikes have the same size front tyre.

Cross ply Venoms are still made for the GL1500 but production of the radial versions stopped when the Avon Cobra was launched for the GL1800.  Any radial Venom rear tyres for GL1800s are left over stock and there are probably no Venom radial front tyres left at all.  Hence the danger of a GL1800 being re-shod with the undesirable mixture  of a Venom cross ply on the front and a Venom radial on the back.

It’s not illegal to run a cross ply tyre on the front and a radial on the rear, but it is not recommended.  It is illegal (and potentially dangerous) to run a radial front tyre with a cross ply on the rear.

The understandable mixture of venoms on a GL1800 is not likely to have happened commonly and probably not until recently, when stock of radial venoms started running out.  However if you are running a GL1800 with Venoms, it is worth checking that you have a radial front tyre.

To do this look for the size marking on the front tyre.  A radial Venom tyre will show 130/70R-18 63H, a cross ply will show 130/70B-18 63H.

So look for the letter R (rather than a B) in the size labelling.  That’s how you tell most easily that your tyre is a radial.  There will also be a “radial” marked somewhere on the tyre but this is more difficult to find.

If you find you have a cross ply Venom front tyre and you had it fitted recently as a replacement pair of tyres, contact your supplier to discuss replacing them.

The official response to my enquiries of Avon about this problem from their UK Tyre Sales Manager Graham Matcham reads as follows:

I can confirm our recommended fitments for Honda Goldwings as follows.

GL1500

Front       130/70B18 69H Venom AM41

Rear        160/80B16 81H Venom AM42

Please note that with the inclusion of the letter B in the size description these tyres are of Bias Belted construction.

GL1800

Front      130/70R18 63H Cobra AV71

Rear       180/60R16 74H Cobra AV72

Please note that with the letter R in the size description these tyres are of radial construction.

Cobra tyres have replaced the following paring of tyres which were also recommended for fitment to Honda Goldwing 1800.

Front      130/70R18 63H Venom R AM41

Rear       180/60R16 74H Venom R AM42

Although not illegal, the fitment of a Bias belted 130/70B18 to the front of a GL1800 is not recommended.

Graham Matcham

Postscript:

Last Sunday, August 23rd, our Club gathered for a ride out and we did a bit of tyre checking.  We found one pair of Venoms on a GL1800 which were a crossply/radial mix but the owner, Pete, reported no significant handling problems and was very happy with them.

The Winger who told me about this problem in the first place is an exceptionally experienced rider who has a racing background and he rides his bike hard at times – he has sufficient knowledge and experience to spot a difference in handling when other Wingers might not.

So I suppose the answer is check your tyres if they are Venoms but if you turn out to have a mismatched pair don’t panic and don’t automatically replace them; just be aware of what you are riding on and don’t ride near to any limits.  Hopefully not many of us do that anyway.

Incidentally the mismatched pair of Venoms we found had come to their owner, Pete, via a complex sequence of wheel swaps so there was no prospect of going back to the supplier to ask for a tyre change.  It all started when Frank bought a bike privately with this pair on it (almost unused) but his wife didn’t like the gold coloured powder coated wheels, indeed it was a condition of him buying the bike that he got rid of them.  He hadn’t noticed any handling problems but then he’d just switched from a GL1500 to a GL1800 so he wouldn’t have the GL1800 experience to notice any difference.

So to save Frank from the grief he was getting I swapped his gold wheels for my spare pair of standard UK wheels which still  had  decent tyres on them.  Frank was happy, so was I.  He was now running on newish matched Venoms, i.e. both were now radials.

But then another Club Member, Pete, took a fancy to the gold wheels because he was running on newish Metzlers which seemed to be causing a front wheel shimmy and his wheels were “difficult to clean”.

In a weak moment (an offer of a bottle of malt whiskey was involved ) I swapped the gold wheels for his seriously pitted, non-UK (so non-laquered) wheels and wobbly Metzlers, mainly because I was planning to get my spare set powder coated in smokey chrome anyway,  at which point they were re-shod with Avon Cobras, even though the Metzlers weren’t worn out.

So the gold wheels with the mismatched Venoms cured Pete’s front wheel wobble,  Frank’s Wife was happy withthe appearance of the standard UK wheels and Frank didn’t notice any difference switching from mismatched to matched Venoms.  Frank’s ears have also recovered and I enjoyed the whiskey.

And if anyone is looking for a slightly worn set of Metzlers which might (or might not) be the cause of a front wheel shimmy, all it would take is an offer of another bottle of Lagavulin.

Choosing and using tyres on a motorcycle is far from straightforward.