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[Dennis C]

9/10 year old tyres?, your choice of course, original tyres use original advised pressure.

Tyre technology has moved on in leaps and bounds, different makes of tyre need different pressures, due to differences in tyre flexibility some makes are softer than others and consequently need higher pressures, unfortunately you can't use a broad sweeping mathematical formula for this reason.

It is best to use tyre manufacturers advised pressures, I contacted Avon for advice on all my old bikes and on modern tyres they advised approximately 50% more pressure than makers original pressure.

[Leon Novello]

This is the Workshop Manual and Owner`s Manual which came with my 2000 Bullet.

[jefrs]

Dennis C, fyi the tyres fitted to the current C5 (export) are Avon Roadriders i.e. modern euro/british spec tyres.

Leon - sorry, the pic/link is coming up, "sorry, this person moved or deleted this image".

[Leon Novello]

I`ll try a different way. I thought when I copied it that it was different.
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[Dennis C]

For information Avon recommended the following pressures for all my bikes using 325X19 front 26psi and 350X19 rear 29psi.

As so often happens we have lots of conflicting advice flying about, if in doubt consult the tyre makers, their advice will be correct.

[papasmurf]

Because my Electra X (ish) has non standard 110/80 X 19 Continental "knobblies" fitted front and rear I used the tyre manufacturers advice. 26psi front and rear.

[jefrs]

Ok but look, tyre pressures are critical for safety. Modern sports bikes are loaded roughly 1:1 front:rear so they have higher front pressures. This is probably why Avon's recommended pressures are higher, they calculate use for sports bikes, I've seen their tables.

Now the RE CGT owner's manuals says F=20/22 R=30/32 running on 100/90-18 and 130/30-18 Pirelli Sport Demon vv the C5 F=18/20 R=28/30 90/90-18 and 110/80-18 Avon Roadrider rubber.



Why is that? - our bikes have a roughly 2:3 front to rear loading, that's 20:30 or 18:29.



A bike racer can feel his tyres and knows almost instinctively when to add or remove as little as 1 psi. I'd make the world's worst bike racer but I can feel the tyres and road grip, car or bike. I've always been able to do that, dunno why. My wife who is a normal-good driver cannot, hasn't got a clue what's going on down there, most folks can't.



If the tyre pressure is too low the thing will fall off the rim. I've had that happen with a puncture and it's not funny. But if the tyre pressure is too high, you reduce the contact patch area an reduce tyre compliance to the road, you lose grip, and that's not funny neither.

Tyre pressures should be adjusted for load and speed, given.

I am probably heavier than average, like a normal solo with a small pillion then, 100kg load, 15+stone. So I increase pressures slightly. I increase pressures slightly for fast summer dry riding and reduce them for slow cold winter wet riding. If I feel the front skipping about I'll slow down, it may have too much air in it. If my wife is pillion I'll not only grab the C-spanner and raise it from #1 (I like soft suspension) to #4 but pump the rear up to 38-40psi, we're going to hit that max gross vehicle weight, not that the bike notices that, it actually seems to like it..

There is or should be (N.America rules) a maximum operating pressure embossed on the tyre, this is an absolute maximum, unlike push-bikes we do not get normal operating numbers on the tyre. If you run a mountain bike off road with competition tyres they may be as low as 12-14psi, fortunately these things have cleated beads that clip into the rim otherwise they'd fall off, it's the only way to get any grip on grass, extremely hard work on road surface; tubeless motorbike tyres cleat into the rim too. Btw you can get a thing that looks like a sparklets bulb that screws onto the valve, bangs a push bike road race tyre up to 120psi in no time; useful in the emergency kit.

Be safe Jeff.

[jefrs]

tpyo - 90/90-19 front on current C5 'export' 19-in front, 18-in rear. Oops. Modern bikes seem to have standardised on 17-in wheels.

[Scalyback]

Gaffer64, The same happened whenI asked about grease nipples... A simple 'which' gave the answer 'every'.



They are right about older tyres though, they do deteriorate, and on a motorcycle, a sudden deflation is usually a little bit more dramatic that other vehicles with more wheels.



As for pressures? well, unless you are expecting to corner whilst leaning at 45 degrees, then stick to about 18 / 28. If the bike feels ok, then fine, otherwise pop a little more in.

Bullet owners want to check their workshop manuals? It is my older cast iron bullet that is recommended at (32 / 36).

[Scalyback]

Gaffer64, Oops! I meant 32 / 36 as you have the older bullet. You can get away with a little less if the ride is hard, but I find it is about correct for my bullet Tornado.

Tornado stands proud on 32/36.

You will also find that there is no edit facility on this forum, so when you er, there is no going back.