Forum

[Cranky]

Hope im not interrupting or changing the subject but is the Avon the original Chennai tyre. I ask because I have an Avon and I am in Thailand, The tyre is so hard I can run 5 psi and the bike is a 2017.

The finger nail test says it a very hard compound.

[stinkwheel]

Hope im not interrupting or changing the subject but is the Avon the original Chennai tyre. I ask because I have an Avon and I am in Thailand, The tyre is so hard I can run 5 psi and the bike is a 2017.

The finger nail test says it a very hard compound.

They generally came with an Avon Speedmaster MK2 on the front and a safety Mileage on the rear.

I wonder how old the tyre itself is? They generally have a date code on the side.

Something I've found is that the tread pattern has little to do with the grip unless you are on loose or snowy surfaces. A high silicon compound is best for winter performance on uk roads. Not good if it's icy, but then nothing much is short of studs. The Michellin Road 5 tyres I put on my VFR750 have remarkable levels of grip on cold, wet roads despite having a very "sports" orientated tread pattern. The tread on a road tyre just clears deep water to prevent hydroplaning and a bullet can't go fast enough to hydroplane so you could use slicks on one if you really wanted.

Contrary to what many think, an agressive, offroad-style tread pattern isn't actually all that good in winter. It's all about contact patch size at the end of the day. That tyre compound needs to be on the road to be of any use. An exception to this would be snow where big gaps could come in handy.

Oddly, I think the safety mileage does win in this respect somewhat due to having a comparatively large, square contact patch which tends not to come up off the road when cornering.

[windmill john]

Oddly, I think the safety mileage does win in this respect somewhat due to having a comparatively large, square contact patch which tends not to come up off the road when cornering.

That might be my rear, too wet to check! I’m assuming that the contact patch when cornering would not be that great.

It’s all down to reputation and views. If twenty people say to me that tyre sticks like glue, then I wouldn’t question it.

It’s like the views of BT45s and Tourance, never a bad word, so I trust them implicitly. Done at least 60-70,000 miles on Tourance and many thousands on BT45s.

[Wheaters]

My RAF flying training ground theory taught me that the equation for the speed at which a tyre can aquaplane is (9 x square root of P), where P = tyre pressure. Important when a runway has any standing water.

If you use 28 psi at the rear end that’s 9 x 5.3 = 47.7 mph.
26 psi = 45.9 mph.

[windmill john]

So I’ll be okay at 49.3mph....... I have the rear at 30psi.

I’d better put in 60psi

[stinkwheel]

It's significantly more complex than that, they just like to have a rough working guide for the aircraft.

Weight and contact patch size are important (makes sense, a monster truck can drive on water). Contact patch shape and cross sectional shape of the tyre are also important. Where motorcycles win is with the rounded cross section which pushes water out of the way like the bow of a boat. The front having cleared it, the rear can be square as you like.

[Wheaters]

All aircraft I can think of have rounded profile tyres.

[stinkwheel]

So out of interest, has anyone here actually aquaplaned a motorcycle?

I've had one "on the plane" because the unanticipated water was above the height of the belly-pan.

I've done three figure speeds in standing water too.