One For Steps.... [Motorbike Tyres]

[apprentice87]

Hi Steps,

Now then, tis time for new tyres on my bike. The rear is a 160/60/17 but it turns out that this is not the standard size which is 150/70/17

I cannot fault how the bike handles, but i rather think i might be better off with the standard size. [the makers are not daft]

What you think?? What is the effect of fitting a bigger rear tyre, what effect does it usually have on the handling??

Also rear chains....

Read a lot about these. Now, i cannot see that an o ring chain has any advantage to it. I know people say that the lube is sealed in, and that therefore, all you have to do is have a smidgeon of oil to stop it rusting, but this is nonsense, the pins might be packed with greas and sealed, but the bushes are not, and all you are doing by having an o ring type, is you cannot remove it and wash it in petrol....

Am i right here, or talking silly....

john

 

[Andy™]

not an expert on bike tyres, but your existing may have more grip being slightly wider, even though its 18mm smaller in diameter

 

[steptoe]

ok,

wider tyres than the rim is designed for has 2 big effects,

1st , at heavy lean you will simply 'lose' grip as the shoulder is pulled tighter than it is designed to,

you wont feel it, it will just go, you will not be able to ride to the shoulder, thats how you can feel the limit[as it were]

normally as you get to the edge of the tyre your contact spot gets smaller, allowing you to feel less grip,

with wider tyres you will have a normal contact spot until the tyre reaches where the radius [across it] simply gets a lot tighter and hence it will let go,

2nd, it will cause the bike to turn slower as the centre of the tyre is much flatter than it is meant to be.

the 3rd,  is, as Andy rightly points out, different overall size means more grip, BUT, only in the centre, see above, because it is flatter in the middle it has a bigger contact patch, at the expense of less[much less] grip at lean.

another issue, perhaps not so important, but still an effect[perhaps more so on a road bike, than a race bike,]your gearing is also different, having a different profile doesnt help much either with how the tyre moves on the rim.

chains, didnt we discuss this previously?

or am I losing it again???   :C

PS, what sort of bike is it?

 

[apprentice87]

Hello!!

It is a suzuki gsf600 bandit. Just had a look in the manual, and according to it, the larger size tyre is the correct one for my year of bike [Model "sy" [Year 2000]

Soooo, now i am stuck with what are good tyres.... At the moment they are bridgestone battlax BT56R which i am perfecly happy with, apart from they do not seem to be available anymore. No idea what i should go for.. I only creep along, so i would rather something that gave longer life, over a sticky, supposed "track" type tyre that i will never get warm enough anyway, so i would be better with an ordinary type i think....

As to chains, that was for my XT600, this is a different thing. Now, the standard chain on it seems ok from the point of wear, [it is the original, bike has only done about 5000 miles] BUT you can clean it and oil it, and a few miles down the road, there willl be rusty looking stuff oozing out!!!!! This leads me to believe that a previous owner has steam cleaned it or something silly, and now the chain is full of water.

As i could do without a 14 year old rusty inside chain taking my leg off, and half the gearbox too, i thought i would change it. I was tempted to keep the old sprockets [i know!!] as they look fine, and just get a cheap chain, but new chain and old sprockets just goes WELL against the grain with me...

Is cheap chain really rubbish?? does this sound daft?? I think i will have to get a DID chain though, as that is what my chain tool does [DID hollow ended rivits]  This is the tool i got http://www.didchain.com/chainTools.html

By the way Steps, BRILLIANT tyre info!! I certainly learnt a lot!!

john

 

[Andy™]

Hello!!

It is a suzuki gsf600 bandit. Just had a look in the manual, and according to it, the larger size tyre is the correct one for my year of bike [Model "sy" [Year 2000]

they are both larger than each other... one has a bigger width, one has a bigger sidewall

 

[apprentice87]

Mine is the 160/60/ x 17

john

 

[steptoe]

there not much difference in them tbh, the second number is some sort of ratio to the width[the 1st number] , but I never was able to get my head around it,,,

but, if as Andy says, its actually 18mm , and if it was the wrong tyre, it'd be like running a 15&1/2" rim,,,  

massive difference in gearing.!!!!

but, as its the right tyre, then youre ok,

as for a good tyre with mileage,

no idea,,,,,,,, try something decent with that dual compound, harder in the middle,

or, wait til next season and get a steady supply of ex-race tyres cheap,  

look here

http://talk.electricianforum.co.uk/topic/26493-i-need-desperate-for-help/page-4

 

[Sidewinder]

The second figure is the sidewall ratio with respect to the tyre width.

On a car a standard sidewall is 80% of the width, thus carries no marking.

Anything less, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, etc. are marked on the tyre as the %age height of the tyre sidewall wrt to the tyre width, thus the "aspect ratio", therefore you can have a wider tyre that has the same rolling radius.

Does this help?

 

[steptoe]

The second figure is the sidewall ratio with respect to the tyre width.

On a car a standard sidewall is 80% of the width, thus carries no marking.

Anything less, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, etc. are marked on the tyre as the %age height of the tyre sidewall wrt to the tyre width, thus the "aspect ratio", therefore you can have a wider tyre that has the same rolling radius.

Does this help?

yep, I get that bit,

the thing is with bikes, you CAN fit a wider tyre to a narrower rim and if you adjust the sidewall height you can get the same profile on the cross-section,

quite why you would is beyond me though, it leads to all sorts of clearance issues with chains etc,

but, on saying that, way back when I raced 250s it was a common mod for some circuits, and we used to simply stanley knife away a 1/4" off the LHS to clear the chain,

such things are now banned, like cutting your own slicks,

it did though improve handling for some tracks, I still never won anywhere,     :slap

 

[sprocketflup]

I did, on standard road tyres that had already done 6 races against folks that were shoeing up new slicks every meet. :slap

<SMUG MODE OFF>

It aint the size of the dog in the fight etc

**Edit** not on the IOM thio I hasten to add, them guys are just f&%k*n nutters