Honda CG125 Front and Rear Tyres and Changing
How to avoid falling off the bike with new Tyres
How to find the best price for Tyres
How to remove and install the wheels in the Bike
Front Disc Brake model, Front 25 psi, Solo Rear 29 psi, Passenger Rear 33 psi.
Front Drum Brake model, Front 25 psi, Solo Rear 28 psi, Passenger Rear 32 psi (40 psi for 1976 to 1984 models = 17 inch wheel).
Always test tyre pressure with a stone cold tyre (leave overnight to cool).
Stay away from garage air pumps (they can substantially over or under inflate motorcycle tyres).
Large changes in outside temperature will change pressure in tyre.
Dependant on inner tube or valve, tyre will loose air dependant on ether length of time or mileage (or speed and mileage).
A tyre (tire) will wear out, you will probably find the bike suddenly feels like its riding on ice round corners and goes round like a lorry.
In old age, the tyre can suddenly lose its strength or collapse leaving the inner tube to take the weight, this will also lead to very bad cornering.
The tyre manufacturers recommend you have 2mm of tread left in order to grip a wet road.
I have often found tyres are worn out at 2mm or just below, the tyres feel like you are riding on ice even in the dry.
But it will depend on the make and model.
Its important that the front and rear tyres are designed to work together,
mixing different makes and models is a bad idea unless the manufacturer states they are designed to work together.
Its also a good idea to change both tyres at the same time (unless the front lasts twice the mileage of a rear),
since the old tyre affects how the new tyre runs in,
also tyres go round bends differently when they are new compared to worn (you want both the front and rear tyres to go round a bend the same).
How to avoid falling off the bike with new Tyres
When you have new tyres, there is a manufacturing residue left on them and needs to be worn off.
The amount of residue and slipperiness depends on the tyre, the manufacturers advise you to run a new tyre in for 150 miles.
You must start off slowly, reduce your speed, acceleration, braking and cornering.
Slowly increase your speed, acceleration, braking and cornering during the 150 miles.
This running in time will also teach you how the new tyres corner and perform,
your old tyres at the end, are totally different, even if they are the same make and model,
since they are a different shape due to the unevenly worn parts of the tyre.
A tyre that runs in a straight line most of the time, wears more at that part than the cornering part.
The inner tubes do not need to be replaced every time you change the tyres, it depends on age,
if there is a problem the shop should tell you when they see them (they will look for cracking, stretching and other ageing things).
I have been told they can last 10 to 20 years.
I would advise you to use Michelin inner tubes, since they are noted for their quality and they do not need to be pumped up so often,
but do cost much more than the cheap ones.
I recommend the Michelin Pilot Sporty 2.75-18 Front and 90/90-18 Rear tyres (1976 to 1984 models need 2.50 (or 2.75)-18 Front 3.00-17 Rear),
they last much longer than the original Pirelli City Demon tyres (fitted to the front disc brake model) and yet are dramatically better at cornering,
rolling resistance, comfort, braking and give you more feeling of the road surface.
I advise against using a 3.00-18 rear tyre size, the bike's original tyres are 90/90-18 rear for a reason,
the tyre firms will tell you 3.00-18 is imperial and 90/90-18 is the metric equivalent, but that's not true.
The 90/90-18 can carry much more weight (do not use a 3.00-18 with a passenger unless you are both light).
The 90/90-18 is wider and lower than the 3.00-18, this effects the cornering abilities of the bike,
people who have tried the 3.00-18 report the bike is unstable going round bends (twitchy).
If you insist on having a 3.00-18 rear, a Continental ContiCity tyre might be the best?
The 90/90-18 rear is only available in Michelin Pilot Sporty, Metzeler ME22 (might not be available, check with importer) in the UK.
Pirelli do make a 90/90-18 since its in their UK catalogue and on all new Honda CG125 bikes, but the UK importer refuses to stock or order them.
3.00-18 rear is available in loads of different makes in the UK.
How to find the best price for Tyres
It's often a lot cheaper for you to give the tyre shop the wheels loose, they often charge a fortune to remove and put the wheels on to the bike.
A tyre shop will need to know which way round the wheels move when the bikes going forwards, so remember to tell them.
That's because motorcycle tyres are directional, make sure they have got the direction correct, look at both side walls of the tyre,
on one side there should be a direction arrow pointing in the direction the tyre will move when the bikes moving forwards.
If the tyre is universal fitment, it can have 2 arrows,
on one side of the tyre it will have an arrow and say front and on the other side an arrow pointing in the opposite direction and say rear.
If the tyre is being fitted to the front wheel you need the arrow that has front next to it, if it's a rear wheel you need the arrow that has rear next to it.
Shop around for the best price for the tyres, some car tyre shops will supply and fit to loose wheels and some even to the bike,
they can sometimes be substantially cheaper than a motorcycle shop.
Some motorcycle shops can even charge a fortune to fit to loose wheels, so the message is simple, shop around.
Mail order is nearly always more expensive, since you need to pay someone to fit the tyres to the wheels,
many shops (especially car shops) do not charge to fit new tyres to loose wheels if they supply them.
How to remove and install the wheels in the Bike
The Owner's Manual (you can manage without it) tells you everything except.
I found I did not have to loosen the adjuster nuts, I simply removed the rear wheel axle nut and slid the whole adjuster off the spindle and bike,
this meant I did not have to check the wheel alignment afterwards.
Both wheels have metal spacers on the wheels, some are partly inside the wheels, make sure you do not lose them.
It only takes one person to remove the wheels, I strongly advise it needs 2 people to put them back in again.
If you do not have the Owner's Manual, below are the basics.
Rear Wheel
Remove the rear brake adjuster nut at the wheel end, remove the brake rod from the brake.
There's a rear brake arm that stops the brake spinning with the wheel,
remove the small pin (you will probably damage it so buy a new one) that stops the nut from being removed at the brake end.
The small pin is called a Cotter pin, its basically a piece of metal folded in half, it goes through a hole near the end of the screw thread.
The 2 pieces that have gone though the hole are then separated and folded up and around in opposite directions around the nut.
Remove the nut and pull the arm off the brake.
If you have a fully enclosed chain, you will have to remove the chain enclosure.
Remove the rear wheel axle nut (might have a small pin to stop the nut being removed like the brake) on the right hand side of the bike.
Remove the right hand chain adjuster.
Put your foot under the wheel and remove the rear wheel axle and then remove the chain.
To reinstall the rear wheel, reverse the process, to setup the rear brake see Rear Brake in Servicing page.
Front Wheel
On the left hand side of the wheel there is a speedometer device and the cable connecting it to the instrument panel,
remove the cable at the wheel end (there's probably a screw to remove).
If you have a front drum brake, remove the brake cable.
Remove the front wheel axle nut (might have a small pin to stop the nut being removed like the rear brake) and slide the axle out (wheel will then fall out).
If you have a front disc brake, do not touch the front brake lever while the wheel is out of the bike.
When putting the front wheel back in, look at the speedometer device and the left front fork, they need to line up with each other.
The speedometer device has 2 metal pieces sticking out, the left front fork has a single piece of metal sticking out,
put the fork metal sticking out in between the 2 metal pieces of the speedometer device.
If you have a front disc brake, you will need to use the brake lever a few times before the brake works.