Tyres for dummies

[Mom]

Hello you clever lot. Can one of you please explain to us in plain english what those numbers on the side wall of tyres actually mean. I am going to assume here that everyone knows the last number relates to the rim size.

I have just changed the tyre on my bike. Old bike, never gave much thought to what if any difference (apart from improving handling) a new tyre would mean. I have dropped my bike once since the new tyre has been fitted, and did not enjoy having to get someone else to move her from where I stopped as I could not reach the ground safely :o

So, I checked today, the recommended rear tyre for my bike is 130/90/16.

A 180/90/16 has been fitted, and my feet dont reach the ground anymore :pinch:

What is the difference between 130/90 and 180/90?

Thanks in advance.

[imdying]

I don't want to sound like a Doubting Thomas, but are you sure about those numbers? That's a frightful difference!

Have a look on the rim, it'll have a number on it that's the width (it'll be in inches, so it's probably 4, 4.5, 5 etc). It's a good way to check as a certain width of tyre is designed for a certain rim width.

[slofox]

"Let's start with the first series of numbers, 130/90 16, otherwise known as the metric designation. This is the most popular nomenclature today and it's practically a standard in the automotive world.

The 130 designates the tire's width in millimeters, measured in a straight line through the tire from one edge of the tire's tread to the other. The second number, 90, is a bit trickier to understand. This represents the aspect ratio between the tire's width and its height, or how tall a tire is in relationship to its width. Simply put, the higher this number is, the taller the tire will be. In this case, the tire is 90 percent as tall as its width, or 117mm.

The last number, 16, is the tire's rim diameter expressed in inches.

The width on some tires may be expressed in inches as well, but usually the aspect ratio is left off.

The other series of numbers and letters, MT90 16, represents the same tire size, but it's expressed in an alphabetical code. M means the tire is designated for motorcycle use, T is the tire width code, 90 is the aspect ratio and 16 is the rim diameter."


Does this help?

It means your new tyre is 180mm wide. 90% of this is 162mm which is the height
Your old tyre was 130mm wide. 90% of this is 117mm also the height.

So your new tyre is 45mm higher than the old one.

I think...

[Genie]

"Let's start with the first series of numbers, 130/90 16, otherwise known as the metric designation. This is the most popular nomenclature today and it's practically a standard in the automotive world.

The 130 designates the tire's width in millimeters, measured in a straight line through the tire from one edge of the tire's tread to the other. The second number, 90, is a bit trickier to understand. This represents the aspect ratio between the tire's width and its height, or how tall a tire is in relationship to its width. Simply put, the higher this number is, the taller the tire will be. In this case, the tire is 90 percent as tall as its width, or 117mm.

The last number, 16, is the tire's rim diameter expressed in inches.

The width on some tires may be expressed in inches as well, but usually the aspect ratio is left off.

The other series of numbers and letters, MT90 16, represents the same tire size, but it's expressed in an alphabetical code. M means the tire is designated for motorcycle use, T is the tire width code, 90 is the aspect ratio and 16 is the rim diameter."



Does this help?

Hey thanks...i'd always wondered myself, I only knew the diameter one.

[doc]

the recommended rear tyre for my bike is 130/90/16.

WTF :gob: Thats the size of a Hardley tyre

[Phreak]

Bloody hell! Who fitted the 180 wide tire? Something wrong there...

[Ntoxcated]

Hi Mom!

Something doesn't sound right there. The first number is the tyre width in millimeters. The second number is the percentage of that giving sidewall height.

So, 130/90 has a sidewall height of 117mm while 180/90 give a sidewall height of 162mm. 4.5cm higher. And that is without the deformation of putting a wider tyre on a narrower rim. In fact I'm surprised a 180 will fit.

It will also take the circumference of the tyre from 201cm to 229cm which will make your speedo an additional 14% out.

Or have I got this completely wrong?

Edit: My maths must have been really slow. 4 posts while I was typing ;)

[doc]

You do realise if you take the 180 off and go back to the 130 your arse will look 50 mm smaller ?

[Mom]

Hi Mom!
Something doesn't sound right there. The first number is the tyre width in millimeters. The second number is the percentage of that giving sidewall height.
So, 130/90 has a sidewall height of 117mm while 180/90 give a sidewall height of 162mm. 4.5cm higher. And that is without the deformation of putting a wider tyre on a narrower rim. In fact I'm surprised a 180 will fit.
It will also take the circumference of the tyre from 201cm to 229cm which will make your speedo an additional 14% out.
Or have I got this completely wrong?
Edit: My maths must have been really slow. 4 posts while I was typing ;)

See this is the feedback I need. My Blue Lovely has been rendered almost too hard for me to ride, from a position of loving riding because the ride height fit. More info please.


You do realise if you take the 180 off and go back to the 130 your arse will look 50 mm smaller ?

LOL...

I hate smart arses. I am actually trying to lose weight at the moment, excercising has been challenging and productive. I have lost a couple of Kgs, but my friggen bum measures bigger :pinch: Apparently blokes love big bums :laugh:

Back on topic though. What is the the difference here? I know physically what the tyre change has meant to me. Much nicer handling, no fault corners. I am reduced to tippy toes.

What do these numbers on the side walls of your tyres mean?

[doc]

See this is the feedback I need.

What do these numbers on the side walls of your tyres mean?

I think ppl have answered your question. Maybe it's time to let Maha out of the kitchen, and ask him

[hayd3n]

have a search and find out what the correct Tyre size should be for your bike

having a bigger Tyre wont give you any better handling or grip,
it can sometimes make it worse off
i remember a old bike i had that had the incorrect Tyre size fitted, they were to wide for the rim
when ever i did a nice tight corner i would always run out of Tyre and end up having a small slide, as soon as the sidewall touched the road
a wide Tyre on a narrow rim will change the Tyre shape and the ride as-well

[Jantar]

That is dangerous. Take it back and demand the correct tyre as soon as possible. Your rims are designed for a 130 size, not a 180, that is 50 mm or 2 inches wider. Your handling will be affected, your ride height has changed, your steering geometry has changed. Overall, that is an accident waiting to happen.

[onearmedbandit]

The first number is the speed your bike can do, in mph. So before your bike could only do 130mph, now it will do 180. You should be happy with this improvement. The second number is the number of laps it should be able to do of your local track, in this case 90 (don't think you're getting shortchanged here, just because this is the same as your previous tyre, remember your bike can now go 180mph!!). The last number, generally between 16-18 is the number of wholesalers/distributors/warehouses/retailers etc who have all added their little bit on to the cost of the tyre before it makes it onto your bike.

Don't know what the others are on about...

[JMemonic]

As was said take it back ask for the correct tyre and at no cost either as Jantar said there is potential for it to be dangerous.

[Scouse]

What is the difference between 130/90 and 180/90?

Thanks in advance.50...........

[Racey Rider]

Another tyre question:

Are radials the be all and end all of everything?

Under what conditions would Cross ply or Bias Belt construction be a better option for a bike?

[Maha]

I think ppl have answered your question. Maybe it's time to let Maha out of the kitchen, and ask him


That is dangerous. Take it back and demand the correct tyre as soon as possible. Your rims are designed for a 130 size, not a 180, that is 50 mm or 2 inches wider. Your handling will be affected, your ride height has changed, your steering geometry has changed. Overall, that is an accident waiting to happen.

Crisis overted, with specs on and once the eyes have focused, I can clearly see its a 130 not a 180. A 3 can look like an 8 in some in a certain light...:facepalm:

[Ntoxcated]

So the ride height changed because the previous tyre was that bald?

[doc]

I can clearly see its a 130 not a 180. A 3 can look like an 8 in some in a certain light...:facepalm:


Still blind with rage from shoppin then. At least she lets you out of the kitchen then.

[merv]

If your bike really is meant to have a 130 width tyre I am surprised a 180 fits without clashing with the run of the chain. How close is the chain to the tyre now?

Someone has given you crap service and you need to go back an get them to sort it.

[Latte]

Different tire pressure, different manufacturer could increase height of tire.

[MSTRS]

Crisis overted, with specs on and once the eyes have focused, I can clearly see its a 130 not a 180. A 3 can look like an 8 in some in a certain light...:facepalm:

Pleased to hear that. Going up one size from recommended is not usually a big problem, but five? One would question it being possible, due to width of swingarm and run of chain.
As for 'feeling' like the bike sits higher...certainly possible.
1. There is the new depth of tread. Minimal to be sure, but noticable.
2. Different brands have differing tyre profile shape. ie. the '90' is the sidewall height (common to all) but the curve of the tread area will vary to hell. A greater curve means higher in the centre.

[Mishy]

Another tyre question:

Are radials the be all and end all of everything?

Under what conditions would Cross ply or Bias Belt construction be a better option for a bike?

When the only size available for your bike is a crossply, and that is often the case!

Radial is best - just take my word for it, but many smaller, or older bikes have a rim size that dictates the use of a Bias ply tyre (one step better than crossply)

Always fit the reccomended size (unless you have compelling information to the contrary) and if that means a crossply, then crossply it is.

You can tell what you have from the making on the tyre. 180/55ZR17 means Radial construction - the R in the description tells you that, and a "B" tells you Bias ply.
No extra letter would normally mean crossply.

There are not many sizes where you can get both radial and Bias ply, so people who deal with tyres a lot can tell you what you get from the size alone.

I hope this is useful.

[matdaymon]

Apologies for reviving an old thread,

I was looking at the specs of my tyres on my GT250 today after doing 1500km around and about the Coromandel over the Christmas/New Year period and now need to start planning for new tyres in the very near future. :violin:

I understand the first few numbers etc but mine have extras on top of these at the end; Example my Shinko brand rear tyre reads 150/70-17 M/C 69H. I Understand that its 150mm wide, 70% of that width in height and a 17inch rim, but what does the 69H mean? (I'm taking the M/C to stand for Motorcycle here). The Front's measurement (also a Shinko) is 110/70-17 M/C 54H if that means anything also.

Any light shed on my mysterious numbers would be appreciated

[cs363]

Apologies for reviving an old thread,

I was looking at the specs of my tyres on my GT250 today after doing 1500km around and about the Coromandel over the Christmas/New Year period and now need to start planning for new tyres in the very near future. :violin:

I understand the first few numbers etc but mine have extras on top of these at the end; Example my Shinko brand rear tyre reads 150/70-17 M/C 69H. I Understand that its 150mm wide, 70% of that width in height and a 17inch rim, but what does the 69H mean? (I'm taking the M/C to stand for Motorcycle here). The Front's measurement (also a Shinko) is 110/70-17 M/C 54H if that means anything also.

Any light shed on my mysterious numbers would be appreciated


Those codes relate to the load & speed rating of the tyre, 69H being 325Kg & 210km/h. 54H is 212Kg and same speed rating.
(Number being the load rating and letter being the speed rating)

[matdaymon]

Awesome, thank you very much. Gotta say after coming from a car background all the extra stuff relating to bikes is a bit confusing for my rather sluggish student brain.

I take it there is some kind of list relating to the number then and how they relate to load weights floating around somewhere or some kind of crazy algebraic formula?

[cs363]

I take it there is some kind of list relating to the number then and how they relate to load weights floating around somewhere or some kind of crazy algebraic formula?

Here you go, this will tell you most of the stuff you need to know about tyres:

[matdaymon]

Very helpful that, thanks very much