Front and Rear Tyres and Changing
See owner's manual for tyre pressures.
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 lose 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 it's 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 2 mm of tread left in order to grip a wet road.
I have often found tyres are worn out at 2 mm 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 (some designs of tyres may not show any signs even with no tread left).
In the UK the legal minimum tread depth is 1 mm.
It's 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.
It's 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).
When you have new tyres, there is a manufacturing residue left on them that
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.
Many people have dropped their bike on the first bend they come to on new
tyres since they forgot about running in the tyre.
Even experienced riders with large expensive bikes have made the same mistake,
do not make the same mistake and be very careful for the first few miles
(I keep speed below 40mph and do not lean the bike on any bend for the first 5 miles).
The quality, performance and safety of the tyres you buy are critical to
enjoyment and for passing your test (if you're in the UK).
As well as how many miles they manage and loads of other factors,
so I strongly advise you read all of my reviews on tyres (links to the reviews are in this section).
I highly recommend the Michelin Pilot Sporty tyres; see my review Michelin Pilot Sporty Tyres Review
I do not like Pirelli City Demon tyres; see my review Pirelli City Demon Tyres Review
Below you will find specific information about the YBR125, CBF125, CBR125 tyres in the relevant paragraphs.
The YBR125 (not the Custom version) uses the same tyre sizes as my reviews
above (2.75 - 18 Front, 90/90 - 18 Rear).
The Original YBR125 tyres (Chinese make) are notorious for being so bad,
people often fall off on a bend due to a bit of rain or mud.
I have only been able to find tubeless tyres in the correct size in Michelin Pilot Sporty
(can also be used with a tube), see my Michelin Pilot Sporty Tyres Review.
All other makes and models of tyres I found in the UK (and in similar sizes), are tube type only (ether the front or rear or both).
All new YBR125 wheels are tubeless type, but old ones (probably 2006 model and before) are tube type.
YBR125 tubeless wheels have "Suitable for tubeless tyres"
stamped in to the metal of one of the spokes on one side of the wheel.
If you have a 2nd hand bike, you never know if an old YBR125 wheel has been put in a newer YBR125
(due to crash damage or a very bad hole in the ground).
YBR125 Custom model, uses totally different size wheels and tyres,
I believe they have always been tubeless, even if it's not stamped in to the metal.
If your YBR125 wheels need an inner tube, I highly recommend you use a
quality branded one,
cheap unbranded / Chinese ones may cost far less but I personally would worry about the quality
(air loss or even a lethal blow out).
The inner tubes do not need to be replaced every time you change the tyres (but tyre manufacturers recommend you do),
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 by tyre fitters they have seen 10 to 20 year old inner tubes that have been used and are still fine
(that does not mean every inner tube is at that age).
CBF125 uses a different size tyre.
The original tyres are 80/100 - 17 Front, 100/90 - 17 Rear, In the UK I could only find those exact sizes in Continental Conti-Go.
But its wheels are identical (including diameter and rim width) to the CBR125 (before CBR125 2011 model),
so anything that fits a CBR125 should also fit it (please read everything below about the CBR125 and tyres).
The original tyres were probably TVS made in India,
they are not very good from what I have read (may be classed as bad tyres), especially in the wet.
The CBR125 and CBF125 use tubeless tyres.
The CBR125 (before 2011 model) and CBF125 original tyre sizes are very hard
to obtain in the UK;
they are both very odd sizes.
But both bikes have identical size wheels.
Front 17 inch diameter and 1.85 inch rim width.
Rear 17 inch diameter and 2.15 inch rim width.
The CBR125, 2011 model onwards has new wheels with a wider width and requires
Front 17 inch diameter and 2.5 inch rim width.
Rear 17 inch diameter and 3.5 inch rim width
Front Tyre 100/80 - 17
Rear Tyre 130/70 - 17
Those exact sizes can be obtained in Michelin Pilot Sporty
The CBR125 (before 2011 model) has been available in the UK since 2004 and
sold in very high numbers.
The only tyre in the UK that is identical to the original tyre size (80/90 - 17 Front, 100/80 - 17 Rear), is a Bridgestone.
Recently another make has appeared, Continental Conti-Go.
The Conti-Go is so new, not enough people have reported their experiences or how long it lasts.
What I have managed to work out, from reports from people who have ridden on the Michelin Pilot Sporty tyres as well,
is the Pilot Sporty out performs it substantially, but the Conti-Go is not a terrible tyre like many others.
The problem people found with the Bridgestone is it's incredibly expensive,
the reviews from owners on forums reported,
it really performed brilliantly, best they have ever used, but it's very expensive and wears out quickly.
A more commonly available tyre size is 90/80 - 17 Front, 110/80 - 17 Rear.
In the UK it's available in Michelin Pilot Sporty, Pirelli MT75, Dunlop D103 and Continental Conti-Go.
The only tyre I have information about is the Michelin Pilot Sporty (my
Michelin Pilot Sporty Tyres Review).
Many motorcycle shops have and do fit it to CBR125 bikes.
The owners are so delighted at the performance of the tyres;
the next time they are in the shop they often mentioned their delight.
The CBR125 owner's forum that mentioned the Bridgestone, reported they then
tried the Michelin Pilot Sporty.
The Michelin performance was nearly as good as the Bridgestone but it's much cheaper and lasts much longer (miles).
They did not like the performance of the original tyres that came with the bike.
They are all glowing about how brilliant the Michelin Pilot Sporty is.
So the shops are happy to fit the Michelin Pilot Sporty tyres and the owners
are delighted with the results.
Even Michelin was happy with it as well; the CBR125 was in their fitment chart and said the Pilot Sporty will fit.
But for some strange reason Michelin no longer state if any of their tyres
will fit the CBR125,
I expect it's a mistake by whoever wrote the latest catalogue (loads of other tyre makes, make similar errors all the time).
Continental state their 100/80 - 17 tyre will fit the CBR125 Rear,
but the technical section claims it will not fit the CBR125 rim width (same with the 110/80 - 17 rear).
Bridgestone lists the CBR125 in their fitment chart and states that no Bridgestone tyre will fit the bike.
Dunlop and Pirelli claim their tyres will fit the CBR125 (but I cannot find
what rim widths they fit).
But all makes of tyres are supposed to be standardised with each other,
meaning identical size tyres should fit the same wheels (including Diameter and Rim Width),
so if Michelin and Continental are right, Dunlop and Pirelli are wrong (so no tyres will fit the CBR125).
So after everything I have read and done, if I had a CBR125 or CBF125, I
would put the Michelin Pilot Sporty tyres on it.
It's very rare or almost unheard of to find a tyre on a 125cc bike that people are so delighted with.
I have only read vague reports about the Pirelli MT75, nobody liked them,
but it's not a terrible tyre.
Could not find anything about Dunlop.
I think every one reads and hears how incredibly good the Michelin Pilot Sporty is and so buys it.
A reminder of my review,
Michelin Pilot Sporty Tyres Review
And the size that's been fitted to the CBR125 is 90/80 - 17 Front, 110/80 - 17 Rear
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 (not always) 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.
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 needs to know which way round the wheels move when the bikes
(some wheels have the brake on the right but others are on the left).
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.
See your owner's manual