125cc Motorcycle Owners Club

Honda CBF125, CBR125 and Yamaha YBR125


Tyre Pressure

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).

When is a Tyre Worn out

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.

How to mix Tyres

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).

How to avoid falling off the bike with new Tyres

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).

Tyre Makes and Models

The quality, performance and safety of the tyres you buy are critical to your safety and enjoyment.
As well as how many miles they manage and many other things.
I very highly recommend you never use a low quality brand of tyre on any motorcycle.
There have been so many reports of people using Chinese brands and falling off as a result.

Below you will find tyre information for the YBR125, CBF125 and CBR125.

Yamaha YBR125 Tyre Makes and Models

This section was last updated in July 2014.

The YBR125 (not the Custom version) original tyres are 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.

In the UK I have only been able to find tubeless tyres in the correct sizes in,
Michelin Pilot Street
Mitas / Sava MC 7
Pirelli City Demon.

The Michelin Pilot Sporty was discontinued in 2014, in my opinion and others it was the very best tyre.
I have not read about anyone comparing the Michelin Pilot Sporty to the new Michelin Pilot Street (see below).
The Pilot Sporty was marketed by Michelin as a sports tyre, the Pilot Street is not marketed as a sports tyre.

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).

Michelin Pilot Street tyre was launched on the 28th March 2013 in a Michelin press release.
The only review I have found is
People on forums with sports bike styled 125 and 250cc bikes seem to be happy with it.
Because the tyre is so new, not enough people have tried it yet, all I can assume for sure is it is not a bad tyre.
Michelin claim it is designed for high mileage and good wet performance.
It can also be used with a tube.

Mitas / Sava MC 7, I have not read about anyone who has used the tyre.
Mitas / Sava claim it is a sports tyre, but when I phoned them they claimed it uses a medium rubber compound.
It can also be used with a tube. The rear tyre is not reinforced like the others
so maximum weight (bike + rider) on the tyre is only rated at 195 kg compared to 230 kg.
Which probably means you cannot carry a passenger without overloading the tyre.

I would never want a Pirelli City Demon on a bike again, please see my Pirelli City Demon Tyre Review
(there are two different versions, one tubeless the other tube type)

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 original tyres are 3.00 - 18 Front, 3.50 - 16 Rear,
the wheels are tubeless design (even if it is not stamped in to the metal).
The rear tyre size is very unusual, especially in the tubeless design (may be impossible to obtain in tubeless),
I believe you can use a tube type tyre with an inner tube on tubeless wheels.
You may even have to fit slightly different tyres sizes, tell a tyre shop the wheels are
Front 18 inch diameter and 1.85 inch rim width.
Rear 16 inch diameter and 2.15 inch rim width.
They will then be able to check a technical manual to find what tyres will fit those wheels.
You can also ask a Yamaha dealer.

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).

Honda CBF125 and CBR125 Tyre Makes and Models

This section was last updated in July 2014.

The Continental ContiGO! from what I have read and heard appears to have poor grip,
everyone who has it seems to want a better safer tyre (especially in the wet). But they have all managed to put up with it.

The CBR125 and CBF125 use tubeless tyres.

The CBF125 original tyres are 80/100 - 17 Front, 100/90 - 17 Rear,
In the UK I could only find those exact sizes in Continental ContiGO!
But its wheels are identical (including diameter and rim width) to the CBR125 (before 2011 model),
so anything that fits it should also fit the CBF125, please see everything below about the CBR125 (before 2011 model).
Some CBF125 original tyres are the TVS brand,
they are not very good from what I have read (may be classed as bad tyres), especially in the wet.

The CBR125, 2011 model onwards has new wheels with a wider width and requires wider tyres.
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 sizes are available in many different makes and models, the Bridgestone BT45 seems to be peoples favourite.

The CBR125 (before 2011 model) and CBF125 original tyres are both very unusual 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 (before 2011 model) has been available in the UK since 2004 and sold in very high numbers.
The only tyres in the UK that are identical to the original tyre size (80/90 - 17 Front, 100/80 - 17 Rear), are

Bridgestone BT-39SS is designed for the race track,
it's very expensive, grips very well and wears out very quickly.

IRC NR73s were often supplied with the CBR125 (before 2011 model) when they were brand new.
From what I have read from many owners reports, they are definitely not a good tyre.

Continental ContiGO! is probably better than the IRC NR73s, but it is another tyre that people are not happy with.

Heidenau K66
It is available in 2 versions, normal and winter. I have not read about anyone who has tried it.

Mitas / Sava MC25. I have not read about anyone who has tried it.
Mitas / Sava claim it is a sports tyre, but when I phoned them they claimed it uses a medium rubber compound.

An alternative tyre size is 90/80 - 17 Front, 110/80 - 17 Rear.
In the UK it's available in Pirelli MT75 and Dunlop StreetSmart

Pirelli MT75, everyone seems to be very happy with its performance.
It has been around for a very long time, probably even before the year 2000.
I have read reviews of it being used on 125 and 250cc sports style bikes.
Everyone seems to be very happy with its dry and wet grip on the road.
It is a soft rubber sports tyre and can even be used on the race track.
It's not as expensive as the Bridgestone BT-39SS and is probably better on the road.

I could not find anyone who has tried the Dunlop StreetSmart, it was only released in 2013.
The press release is at http://www.dunlop.eu/dunlop_euen/mc/news/news_article.jsp?id=136501
And it is made in France.

Dunlop claim their tyres in those sizes will fit the CBR125 (before 2011 model).
Pirelli have accidently deleted the CBR125 (before 2011 model) from their tyre fitment guide,
but I have checked their technical book and also contacted Pirelli and they both confirm those sizes will fit.

The Michelin Pilot Sporty was discontinued in 2014, in my opinion and others it was the very best tyre.

Another alternative tyre size is 100/80 - 17 Front, 120/80 - 17 Rear.
Avon claim their Roadrider tyre will fit the CBR125 (before 2011 model).
Bridgestone claim their BT45 will fit the CBR125 (before 2011 model) and the CBF125.

People have fitted the BT45 to their CBR125 (before 2011 model) and their CBF125.
But I along with others are a little concerned with the size of the tyres,
they are much larger than the originals.
A good motorcycle tyre shop should be able to explain the concerns,
since many people with big motorcycles also wish to fit extra large wider tyres to their bikes.

What I do know is the Bridgestone BT45 is a very good tyre that many people very highly rate.
Due to its good grip as well as lasting a long time due to its dual compound technology (rear tyre only).
But all the reviews I have read are about the BT45 on different bikes which have wider wheels.
It has been around for a very long time, probably even before the year 2000 and is made in Japan.

Someone emailed me
He fitted Heidenau K63, 90/90 - 17 Front, 100/80 - 17 Rear after his original TVS tyres.
From the description he gives of the differences.
It sounds like the Heidenau K63 are a little better than the Continental ContiGo!.
Since people are not at all happy with the ContiGo! especially in the wet, it sounds like it is another tyre to avoid.
He did say the Heidenau tyres are a lot better than the TVS tyres
which confirms what everyone else has said about how bad the TVS tyres are.
I have checked the Heidenau specifications and the front tyre claims to need an inner tube,
the rear claims to be tubeless type.
Since the wheels are both tubeless type I would not want the expense and hassle of fitting an inner tube.

How to find the best price for Tyres

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 going forwards
(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.

How to remove and install the wheels in the Bike

See your owner's manual