Tyre expert opinions please

[SHELRACING]

Anyone know if I can fit a 160/17 slick to a rear 3.00 rim (safely of course) I had one fitted to a 3.5 rim and it was bloody great. Or should I stick with the 120/17 which is technically a front tyre.

The 120's heat up well on the buckets, would the 160 heat up as well or take longer ?

This is for a bucket. The theory is more tyre on the track = less chance of falling off ( yeah right )

[caspernz]

Mmmm, interesting question. Fitting a tyre too wide for the rim will in effect change the curve of the tread, so you'll end up with not being able to use all the tread. If it was me I'd get the stickiest tyre in the size that fits the rim, or at most go up one size. The 160 needs a 4.5 wide rim, so by the time you jam it onto a 3 rim, you might be able to use only about half the tread width. Hop onto any tyre manufacturers site and you'll find something to suit.

[LankyBastard]

A wider rear tyre will give you absolutely no increase in grip, as what determins grip (friction) is weight, not area.

So all a larger tyre will do for you is slow down your steering, but hey you will look awesome!

[bogan]

The theory is more tyre on the track = less chance of falling off ( yeah right )

Not a bad theory, but the deformation when fitting an oversize tyre to such a small rim may actually reduce the contact patch, especially if the tyre has a low aspect ratio. In saying that, it's buckets, so if you can get you hands on one for cheap, and give it a hoon, it may prove better than using a front tyre on the rear anyway.

[imdying]

A wider rear tyre will give you absolutely no increase in grip, as what determins grip (friction) is weight, not area.

So all a larger tyre will do for you is slow down your steering, but hey you will look awesome!

Won't a larger tyre also weigh more, which you tell us increases grip. Given it's rotational mass as well, wouldn't that make the grip increases from said larger (heavier) tyre even greater? Your logic tells me they should be mixing lead in with the rubber compounds too!

[bogan]

Your logic tells me they should be mixing lead in with the rubber compounds too!

nah, what they should really do is use a material which provides some adhesion in addition to the friction force, maybe they could even select one which provides more of this adhesion force at the hotter temperatures experienced by tyres used in motorsports. Oh, wait

[Latte]

nah, what they should really do is use a material which provides some adhesion in addition to the friction force, maybe they could even select one which provides more of this adhesion force at the hotter temperatures experienced by tyres used in motorsports. Oh, wait

Sarcasm makes learning fun

[SHELRACING]

A wider rear tyre will give you absolutely no increase in grip, as what determins grip (friction) is weight, not area.

So all a larger tyre will do for you is slow down your steering, but hey you will look awesome!

I'm no expert that's why I posed the question but...............

Surely we are looking for more surface area contact = grip which is more friction ( I think) However I can't see more weight as what we are looking for.

As we all know every manufacturer is counting grams in terms of losing weight throughout every sports bike.

Caspernz, was on the right track though. the rim may deform the tyre too much, by rounding it thusly reducing contact area.

I had a 160 slick fitted to the back of a GS500 3.5 rim). It was fantastic around manfield and Taupo. the rim didn't size seem size to deform the tyre at all.

[bogan]

The physics of it is reasonably complicated (probly why they cost so much!), but all things being equal, bigger contact patch will give you slightly more grip. But doubling the contact patch certainly won't give you double the grip. And if it gets too big, it becomes harder to keep the heat in it, and a lack of heat will lose more grip than the bigger patch would gain you.

[F5 Dave]

A 160?!?? FFS Steve that's just wrong wrong Wrong.

a 3" rim is technically too small for a 120, but you can get away with running a 120 or 115 slick or even soft road tyre. This will give you the best grip in the absence of the obsolete 105 slick it was designed for.

a 160 will be super distorted & you may have managed to bodge iit on but it was never meant to be that shape & if it felt ok it was only due to lack of speed. You will have less rubber on the ground & huooge chicken strips.

Absolutely crazy & deluded logic I am afraid.


I am in absolute disbelief.

[SHELRACING]

A 160?!?? FFS Steve that's just wrong wrong Wrong.

a 3" rim is technically too small for a 120, but you can get away with running a 120 or 115 slick or even soft road tyre. This will give you the best grip in the absence of the obsolete 105 slick it was designed for.

a 160 will be super distorted & you may have managed to bodge iit on but it was never meant to be that shape & if it felt ok it was only due to lack of speed. You will have less rubber on the ground & huooge chicken strips.

Absolutely crazy & deluded logic I am afraid.


I am in absolute disbelief.

Jesus Dave, it was just a question. If you don't ask you will never know will ya !!!

I don't have a table of rim to tyre sizes to do any comaprisons.

I fitted a 160 17 to a 3.5 rim and it was superb, and I have many witnesses at Manfield and Taupo to prove it. So my question was not totally unreasonable

To quote you

" a 3" rim is technically too small for a 120, but you can get away with running a 120 or 115 slick or even soft road tyre. This will give you the best grip in the absence of the obsolete 105 slick it was designed for. "

This was the answer I was looking for, and thanks for that.

As I said it was only a question, and it did create some discussion.