helicopterjim
Hero member
- Location
- near Lone Butte, BC, Canada
Tyre Pressures
- Thread starter Vince
- Start date
Andy J
Hero member
- Location
- Isle of Man
I shall be following your lead and fitting a replacement tube of the aforementioned tube type in the recently deflated front tyre of my Atlas.
helicopterjim
Hero member
- Location
- near Lone Butte, BC, Canada
I use Michelin 20W50 ........... oh wait! Which thread is this again?
Jim
Jim
Odyssey is better by far.
Paul
78jotadave
Hero member
Just my observations, sorry I have no solutions
On my 78 Jota I run Bridgestones without tubes on modified Laverda rims, it will drop about 5-8 psi if left sitting for a few weeks.
The 1200 over the same time period using tubes with Michelin drops about 3-6psi
My Mercedes E350 running low profile 245/40 x 18 Continentals will drop 8 - 10 psi in 4 weeks, PIA.
The beast is a 2002 22-foot RV running on 225/75 x 16 light truck tubeless tires that can sit for 8 -12 months without losing a pound of pressure.
Go figure, and yes I have put new valves in the bikes and the Merc with no difference observed.
On my 78 Jota I run Bridgestones without tubes on modified Laverda rims, it will drop about 5-8 psi if left sitting for a few weeks.
The 1200 over the same time period using tubes with Michelin drops about 3-6psi
My Mercedes E350 running low profile 245/40 x 18 Continentals will drop 8 - 10 psi in 4 weeks, PIA.
The beast is a 2002 22-foot RV running on 225/75 x 16 light truck tubeless tires that can sit for 8 -12 months without losing a pound of pressure.
Go figure, and yes I have put new valves in the bikes and the Merc with no difference observed.
murphus
Senior member
- Location
- Lost in the Midwest
You're likely getting leakage at the bead seat, either due to oxidization on the aluminum rim or the design of the tire. I have Michelin Pilots on my '95 BMW K75 and had to apply a thin coat of bead sealant to the rim to stop them from dropping as much as 15psi over 2 weeks.
AndyW
Hero member
isn't 40psi a bit high, Vince? No wonder your suspension always feels harsh...
TheWrongTrousers
Senior member
- Location
- South London
I don't know a lot about tyres or tubes or, anything else come to think of it. I just buy tyres from "Two Tyres" in London. They have good prices, are helpful and seem very knowledgable. I was intrigued by what Paul said about fitting only off road tubes. I attach a link to the two tyres website where the guy says that fitting super thick tubes to a road bike can cause overheating. It may be of interest.
www.twotyres.co.uk
Motorcycle Inner Tubes: Sizes, Valves and Buying Guide
Find the correct motorcycle inner tube for your tyre. Our guide explains tube sizes, valve types, thicknesses and choosing tubes for road or off-road use.
www.twotyres.co.uk
CLEMTOG
Hero member
never mind the overheating, think of the unsprung and reciprocating weight.
when I fitted 230mm stainless discs to TOG, I could not believe the difference in steering, that was the only mod done at that time, so definitave, and the weight differrence between the original 280mm cast iron rotors and the new 230mm stainless ones was not measured by me, but it cant be much, it does changes things a lot.
CLEM
when I fitted 230mm stainless discs to TOG, I could not believe the difference in steering, that was the only mod done at that time, so definitave, and the weight differrence between the original 280mm cast iron rotors and the new 230mm stainless ones was not measured by me, but it cant be much, it does changes things a lot.
CLEM
TheWrongTrousers
Senior member
- Location
- South London
Thats interesting Clem. Never would have thought of that. By which I mean the difference it would make fitting alternative discs. I reckon my discs need replacing before too much longer. It's sounds like I can look forward to more good things than just good braking.
Obviously thick tubes heat a lot more than thinner ones, that is speed dependent, but how many of us cruise at 120 mph for hours on end.I don't know a lot about tyres or tubes or, anything else come to think of it. I just buy tyres from "Two Tyres" in London. They have good prices, are helpful and seem very knowledgable. I was intrigued by what Paul said about fitting only off road tubes. I attach a link to the two tyres website where the guy says that fitting super thick tubes to a road bike can cause overheating. It may be of interest.
Motorcycle Inner Tubes: Sizes, Valves and Buying Guide
Find the correct motorcycle inner tube for your tyre. Our guide explains tube sizes, valve types, thicknesses and choosing tubes for road or off-road use.
The last time I saw 120 MPH must have been in a train.
Paul
TheWrongTrousers
Senior member
- Location
- South London
Fair point Paul. Those TGV's are quite something. It would be interesting to know at what speed a tyre overheats and how thick the tube has to be before it becomes unsafe at a given speed. If it happened at less than 120MPH and for a lesser period than 'hours on end' for instance.
.
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piranha-bro2
Hero member
- Location
- Melbourne
So you went down in diameter, Clem? That would give you less reciprocating mass due to lesser flywheel effect. But I'm wondering though if you actually went to 320mm discs? That's a much more common upgrade.
Dellortoman
Hero member
- Location
- Tasmania, Australia
Your response is a little confusing, Quentin.
Flywheel effect is the moment of inertia of the spinning disk, expressed in kg.m2
By reciprocating mass, I guess you're referring to the more common term used in suspension jargon: unsprung weight. That's normally expressed in units of mass, kg.
While both quantities are affected by mass, the moment of inertia of a spinning disk has little relevance to unsprung weight.
I'm sure you know what you're trying to say, but the message seems to have been garbled between your brain and keyboard.
Flywheel effect is the moment of inertia of the spinning disk, expressed in kg.m2
By reciprocating mass, I guess you're referring to the more common term used in suspension jargon: unsprung weight. That's normally expressed in units of mass, kg.
While both quantities are affected by mass, the moment of inertia of a spinning disk has little relevance to unsprung weight.
I'm sure you know what you're trying to say, but the message seems to have been garbled between your brain and keyboard.
piranha-bro2
Hero member
- Location
- Melbourne
Ha!! Dead right Cam. I should have said rotating mass - or maybe just left it at 'smaller dia gives reduced steering input (if weight doesn't increase)'. If you transfer all the weight from a hub to the rim you'll certainly notice an increase in steering effort but no drop in unsprung weight (reciprocating mass). I think you get the idea.
Saw a couple of Buells yesterday at the Bike Shed show...you may recall they use a single rim mounted disc. Looks funky...is there an advantage to that design? As far as I know nobody else uses it?
CLEMTOG
Hero member
rim mounted discs are easilly distorted and if the the rim itself distorts so does the disc,
230mm was a typo you numptie, far too technophobe Quentin, (overthinking or what!) for 320mm, no science here on my part, 320's are lighter by far than cast 280's and it felt great as soon as I was rolling I knew it was different.
CLEM
230mm was a typo you numptie, far too technophobe Quentin, (overthinking or what!) for 320mm, no science here on my part, 320's are lighter by far than cast 280's and it felt great as soon as I was rolling I knew it was different.
CLEM
You better not think I let that go through to the keeper, been out riding that still harsh feeling bike. 2 things, the tyres I use are Radials, Bridgestone T32 that are designed for higher pressures plus I weigh a lot so 40 psi works for me. I tried lower pressures, 34 and the bike tram tracks to an uncomfortable amount, following longantutanial road marks. My new word for the day. I am just about sick to death of playing around adjusting the new shocks on actual big rides with other people than I don't want to impact on and chasing my tail. I need to find a day and a bloody bumpy road, set the shocks up so they're hard on compression and back that off till it's just off bottoming and put it to bed. I am seriously also thinking of making inquiries with the distributor as to what spring rate was installed when I bought them. There seems to be a lot of bottoming happening with limited changes to that with compression damping adjustments, and that should not happen.
Found this..sounds like its more postive than negative Clem...
