Raising the old tyre size debate, with apologies

[Angrybird]

Sorry for thrashing an old topic. I have decided on Dunlop Sportsmarts for my ZX14 and was tossing up between the 190 55s and the 190 50s. I like the idea of more tyre on the road when leaned over but by the same token I don't really want to raise my ride height by 14.5mm or up the gearing. The 180 55 would seem to have been ideal from a gearing and ride height standpoint but I had steered clear (no pun intended) of them as my tyre guy said that you need to stretch them to fit a 6 inch rim thus defeating their purposes. Then I read this, "FYI you are not 'stretching' the tire onto the rim when using a 180 on a 6" wheel." I would be most grateful if anyone can clarify this with specific regard to the Sportsmarts.

[DMNTD]

Sorry for thrashing an old topic. I have decided on Dunlop Sportsmarts for my ZX14 and was tossing up between the 190 55s and the 190 50s. I like the idea of more tyre on the road when leaned over but by the same token I don't really want to raise my ride height by 14.5mm or up the gearing. The 180 55 would seem to have been ideal from a gearing and ride height standpoint but I had steered clear (no pun intended) of them as my tyre guy said that you need to stretch them to fit a 6 inch rim thus defeating their purposes. Then I read this, "FYI you are not 'stretching' the tire onto the rim when using a 180 on a 6" wheel." I would be most grateful if anyone can clarify this with specific regard to the Sportsmarts.


Can't comment on those specific tyres with a ZX14, but I do recommend the change to a 190/55 on a ZX14....no question IMO

[Drew]

Not enough information.

Without knowing what type of riding you do it's not really possible to comment either way.

[sinfull]

between the 190 55s and the 190 50s. I like the idea of more tyre on the road when leaned over but by the same token I don't really want to raise my ride height by 14.5mm or up the gearing. Reading that, it strikes me you think that the different profiles will change your ride height by how much ?


The 180 55 would seem to have been ideal from a gearing and ride height standpoint but I had steered clear (no pun intended) of them as my tyre guy said that you need to stretch them to fit a 6 inch rim thus defeating their purposes. Then I read this, "FYI you are not 'stretching' the tire onto the rim when using a 180 on a 6" wheel." I would be most grateful if anyone can clarify this with specific regard to the Sportsmarts.

See if ya can get a picture in ya head, put palms and fingers together and then start opening your palms to 6 inches apart, now have your fingers make an even curve, then force them another 2 inches apart, the fingers are how the curvature of the tyre will look, the back of ya hands is now what the tyre walls will look like on the rim

Do you think the narrower tyre (180) will look rather flat on a wide rim ? thus losing any lean you may want in some corners ?

Can be done if ya like going in straight lines only, but the tyres differ in wall strength and there is the possibility of rolling the wall off the rim if it's on too much of an angle (backs of ya hands) more so spooning a 190 on to a 5 inch rim but hey !

The 190 is the way to go, I'd go the 55 but don't think it really makes SFA difference (ie like 5mm profile) I might be corrected on that lol

[Haggis2]

I'd be inclined to stick with standard sizes, the manufacurers surely put a lot of time into making sure they have the best possible size to bridge all uses. Just my thoughts though :yawn:

[Drew]

I'd be inclined to stick with standard sizes, the manufacurers surely put a lot of time into making sure they have the best possible size to bridge all uses. Just my thoughts though :yawn:
But, he might not ride it the way the manufacturer intended either. He might have stumpy arms and long legs, throwing the weight distribution well away from kawasaki's test models.

If you ride feisty roads heaps, get the 55. If not, get the 50.

KISS. Keep it simple, stupid.

[Angrybird]

Can't comment on those specific tyres, but I do recommend the change to a 190/55 on a ZX14....no question IMO

Thanks for that DMNTD. Being that it is a large bike I am coming back to the thought that it would benefit from the larger contact patch afforded by the 190 55s cf the 180 55s.

[slowpoke]

But, he might not ride it the way the manufacturer intended either. He might have stumpy arms and long legs, throwing the weight distribution well away from kawasaki's test models.

If you ride feisty roads heaps, get the 55. If not, get the 50.

KISS. Keep it simple, stupid.


Thanks for that DMNTD. Being that it is a large bike I am coming back to the thought that it would benefit from the larger contact patch afforded by the 190 55s cf the 180 55s.

Drew's on the money here. It's not just about contact patch, it's about the shape of the tyre and the extra agility the taller profile gives. I farkin' hate the way the 50's seem to make everything much harder work compared to the much sweeter steering 55, but each to their own.

[Angrybird]

Reading that, it strikes me you think that the different profiles will change your ride height by how much ?



See if ya can get a picture in ya head, put palms and fingers together and then start opening your palms to 6 inches apart, now have your fingers make an even curve, then force them another 2 inches apart, the fingers are how the curvature of the tyre will look, the back of ya hands is now what the tyre walls will look like on the rim

Do you think the narrower tyre (180) will look rather flat on a wide rim ? thus losing any lean you may want in some corners ?

Can be done if ya like going in straight lines only, but the tyres differ in wall strength and there is the possibility of rolling the wall off the rim if it's on too much of an angle (backs of ya hands) more so spooning a 190 on to a 5 inch rim but hey !

The 190 is the way to go, I'd go the 55 but don't think it really makes SFA difference (ie like 5mm profile) I might be corrected on that lol

Thanks sinfull. Going back to my calculator 5% of 190 (ie 55% v 50%) is 9.5mm (not 14.5mm). Even allowing for a bit of squishing of the extra rubber I still see an increased ride height of around 9mm. Hoping to find an exact measurement I emailed Dunlop NZ asking for Sportsmart diameter measurements but have heard nothing back.

On top of the static measurement tyres also get bigger when they spin (watch the top fuel dragsters) and so the ride height should increase beyond the 9mm when the bike gets up to speed. Not sure of the merits of adding sag to maintain the steering geometry.

The point you made is exactly the way I had come to see the issue of 180 v 190 tyres. The poster I quoted on the subject of "stretching" disputed this and I even found a quote from Dunlop's website which recommended (180 55s?) for 6 inch rims.

That sounded dubious to me. As you pointed out the profile of a given 180 must differ between a 5.5 and 6 inch rim. Surely they have optimised it for one or the other. Indeed when they are quoting the profile heights it must be per a given rim size therefore? But no they just bandy around numbers in the way Aiwa quoted wattage for their ghetto blasters.

I found many subjective comments in favour of both but nothing to say a 180 on a 6" rim is a categoric "no-go." Some highly technical types had actually found a way of measuring maximum theoretical lean angles. If manufacturers were to supply this info in respect of the tyre when fitted to the rims for which it was recommended that might be helpful.

[jrandom]

190/55s are sweet, and they'd make any bike nicer to ride around corners, I suspect. But if you do a lot of motorway pootling they won't last long, because they'll square that pointy middle straight down to the belt in no time flat.


If you ride feisty roads heaps, get the 55. If not, get the 50.

^ wot 'e said.

[jrandom]

Thanks sinfull. Going back to my calculator 5% of 190 (ie 55% v 50%) is 9.5mm (not 14.5mm). Even allowing for a bit of squishing of the extra rubber I still see an increased ride height of around 9mm. Hoping to find an exact measurement I emailed Dunlop NZ asking for Sportsmart diameter measurements but have heard nothing back.

Jesus H Christ, you're a bit of a fucking Poindexter, aren't you?

[Angrybird]

I'd be inclined to stick with standard sizes, the manufacturers surely put a lot of time into making sure they have the best possible size to bridge all uses. Just my thoughts though :yawn:

Hi Haggis. Good point. Somewhere in my reading a comment stood out about "strafing an offramp" as if it were the poster's justification for his heavy outlay on the latest and greatest Pirelli Supercorsas.
With all the tough talk you see in American forums you have to wonder how much of that is compensatory. How many of them are as good as the descriptions of their knee/elbow/head-dragging exploits would suggest and how many of them spend most of their riding hours droning away at freeway velocity?

I also found another comment by an authoritative sounding poster who described the standard 190 50s as crap. Got me thinking that this was a manufacturer's catchall for those who run up big numbers commuting on said freeways. America after all must be one of the biggest motorcycle consumers if not the biggest.

We live in New Zealand however where only the major centres have the luxury of straight-lining motorways. I believe that a tyre optimised for corners would therefore be more appropriate as standard fare for the New Zealand market.

[Angrybird]

Drew's on the money here. It's not just about contact patch, it's about the shape of the tyre and the extra agility the taller profile gives. I farkin' hate the way the 50's seem to make everything much harder work compared to the much sweeter steering 55, but each to their own.

Thanks slow-poke. These days I am finding my way on motorcycles closer to 200 horsepower than the featherweight 39hp RD350 I cut my teeth on in the seventies and everything has changed. Back then I would just throw it. I have memories of scraping up loose chips with my footpegs on a melting Waioeka Gorge road and couldn't see anything wrong with the picture. These days I am not so sure.

Accordingly I am taking myself back to school with a view to learning all the new rules. With my Fireblade on 190 55s I have the sense of having to fight it to really get it over in a corner and it doesn't feel natural. The Dunlop TT100s on my little Yamaha were virtual triangles and the bike was as happy on it's side as it was vertical.

I am starting to think that one of my new rules should be, "Don't blindly follow along with what the manufacturer says." I thought the 190 50s are hard work and I take your comment as validation. How it translates to the ZX is a different story. At least having a 190 50 and 190 55 I would have the option of swapping.

[Angrybird]

Jesus H Christ, you're a bit of a fucking Poindexter, aren't you?

Cheers J Random.. meet M Specific. :-)

[Angrybird]

But, he might not ride it the way the manufacturer intended either. He might have stumpy arms and long legs, throwing the weight distribution well away from kawasaki's test models.

If you ride feisty roads heaps, get the 55. If not, get the 50.

KISS. Keep it simple, stupid.

Apologies drew.. I am getting to ewe. (Saving the best to larst :-) Thanks for all your thoughts. Nope arms aren't stumpy.. my wingspan is longer than Michael Phelps. Still not long enough to allow me to sit upright on my ZX. Yep I ride feisty roads.. Can you spell Gizbun Eest Khost? :-)

[slowpoke]

Can you spell Gizbun Eest Khost? :-)

Haha, good point, hadn't noticed you're locale. Haven't ridden up there but drove it a coupla years back, never in my life have I so wished I had a bike instead. Go the 55's, it'll feel like the big girl has lost 20kg's.

[Dave-]

Thanks sinfull. Going back to my calculator 5% of 190 (ie 55% v 50%) is 9.5mm (not 14.5mm). Even allowing for a bit of squishing of the extra rubber I still see an increased ride height of around 9mm. Hoping to find an exact measurement I emailed Dunlop NZ asking for Sportsmart diameter measurements but have heard nothing back.

On top of the static measurement tyres also get bigger when they spin (watch the top fuel dragsters) and so the ride height should increase beyond the 9mm when the bike gets up to speed. Not sure of the merits of adding sag to maintain the steering geometry.

The point you made is exactly the way I had come to see the issue of 180 v 190 tyres. The poster I quoted on the subject of "stretching" disputed this and I even found a quote from Dunlop's website which recommended (180 55s?) for 6 inch rims.

That sounded dubious to me. As you pointed out the profile of a given 180 must differ between a 5.5 and 6 inch rim. Surely they have optimised it for one or the other. Indeed when they are quoting the profile heights it must be per a given rim size therefore? But no they just bandy around numbers in the way Aiwa quoted wattage for their ghetto blasters.

I found many subjective comments in favour of both but nothing to say a 180 on a 6" rim is a categoric "no-go." Some highly technical types had actually found a way of measuring maximum theoretical lean angles. If manufacturers were to supply this info in respect of the tyre when fitted to the rims for which it was recommended that might be helpful.

loving the insight here, but do you really think it's going to make much difference?

[tigertim20]

On top of the static measurement tyres also get bigger when they spin (watch the top fuel dragsters) and so the ride height should increase beyond the 9mm when the bike gets up to speed. Not sure of the merits of adding sag to maintain the steering geometry.

.

my understanding of this, as it applies to motorcycle tyres, is that you dont get this effect untill >200km/hr.

fwiw, Im in the pro 55 group too - ive toyed with profiles a bit and have found on bigger bikes it can make the steering a little kinder - noticable on particularly long rides

[Drew]

Apologies drew.. I am getting to ewe. (Saving the best to larst :-) Thanks for all your thoughts. Nope arms aren't stumpy.. my wingspan is longer than Michael Phelps. Still not long enough to allow me to sit upright on my ZX. Yep I ride feisty roads.. Can you spell Gizbun Eest Khost? :-)

In that case, 190/55r17 all the way. The 55 has a smaller contact patch when the bike is straight up and down, but more as you lean. The geometry change of the extra 9.5mm would upset a well set up race bike, but on the 14 for the road, it's just gonna tip in quicker with less effort.

[quickbuck]

The 190 is the way to go, I'd go the 55 but don't think it really makes SFA difference (ie like 5mm profile) I might be corrected on that lol

Okay, I will correct you....

The /55 and /50 refer to the PERCENTAGE of the width.
So it is 55% and 50% of 190 respectivly.
Thus 104.5mm and 90mm respectivly.

So OP had it right, 14.5mm difference in side wall height.

[Drew]

Okay, I will correct you....

The /55 and /50 refer to the PERCENTAGE of the width.
So it is 55% and 50% of 190 respectivly.
Thus 104.5mm and 90mm respectivly.

So OP had it right, 14.5mm difference in side wall height.Bad news, your math is correct, but the designation no longer means exactly as you have said. Manufacturers use that as a guide and then make the tyre whatever size they want really. There are many many tyres on the Market of varying sizes, all using the same carcas.

The exact dimension of any tyre is relative to rim fitment. All you can be sure of, is that a 55 profile of any given tyre, is taller than the 50 profile in that same model.

[quickbuck]

Bad news, your math is correct, but the designation no longer means exactly as you have said. Manufacturers use that as a guide and then make the tyre whatever size they want really. There are many many tyres on the Market of varying sizes, all using the same carcas.

The exact dimension of any tyre is relative to rim fitment. All you can be sure of, is that a 55 profile of any given tyre, is taller than the 50 profile in that same model.

Really????.... Bugger!
How dare they... they should have consulted me before making a change like that!!!!
They didn't update me via e-mail... I'm crushed.

[Drew]

Really????.... Bugger!
How dare they... they should have consulted me before making a change like that!!!!
They didn't update me via e-mail... I'm crushed.

It's rough aye, I wasn't consulted either!

Put a 190/55r17 supercorsa beside he same sized racetech, (no Poos, they haven't shared the same carcas for a fuckin decade), and the difference is huge. Makes an incredible difference on my old RF to swap from one to the other.

[quickbuck]

It's rough aye, I wasn't consulted either!

Put a 190/55r17 supercorsa beside he same sized racetech, (no Poos, they haven't shared the same carcas for a fuckin decade), and the difference is huge. Makes an incredible difference on my old RF to swap from one to the other.

Mmmmm.... That would explane it... I knew different tyres had different shape, but never realised it was because manufacturers stuffed arround with the profile number.
That would explain why we put a Shinko 100/80 on the front of an FZR250 and it looked like we put a MTB tyre in it.....

Yeah, I know.... shouldn't buy tyres where the manufacturers name starts with S....

[Drew]

Mmmmm.... That would explane it... I knew different tyres had different shape, but never realised it was because manufacturers stuffed arround with the profile number.
That would explain why we put a Shinko 100/80 on the front of an FZR250 and it looked like we put a MTB tyre in it.....

Yeah, I know.... shouldn't buy tyres where the manufacturers name starts with S....I raced the rf at the hill climb with a Shinko on the front, it was fuckin mint! The limiting factor in my times was the bridgestone 016 on the rear.

[quickbuck]

I raced the rf at the hill climb with a Shinko on the front, it was fuckin mint! The limiting factor in my times was the bridgestone 016 on the rear.

True?
To be honest I never rode on them. It was the impression they gave me really... I guess if we put a 110/80 on it, then it would have looked better, but looks aren't everything.... The turn in must have been wicked, but never got a chance to find out, sadly.

[AllanB]

Dunlop say the 180 or 190 are suitable for 5.5 or 6.0 inch rims.

Each tyre makers actual fitted widths vary a bit too - some 180's are exactly that some a few mm narrower the widest I've measured was actually 185. I must get out more .....

http://www.dunlopmotorcycle.com/tire-catalog/sport-trackday-race/sport/sportmax-q2/

[Madness]

Another vote for 190/55. Slowpoke's bang on, it'll shed 20kg off your bike in cornering performance. I'm running a Metzeler Z8 on the rear & getting good mileage on the ZX12 too, fwiw.

[Angrybird]

Haha, good point, hadn't noticed you're locale. Haven't ridden up there but drove it a coupla years back, never in my life have I so wished I had a bike instead. Go the 55's, it'll feel like the big girl has lost 20kg's.

Hey slowpoke when I told drew our roads were gnarly I wasn't joking. Just rode through the Waioeka Gorge when I brought the bike back from Whakatane (movers dropped it there as Tauranga went quiet on me) and it is covered in loose chip. Many stories of people going down there. The coast road is not conducive to letting your guard down but Morere and Matawai have some decent tracts where you can get into that sense of communing with the tarmac. Funny thing is I am so loving on just being astride a ZX14 having perved at the big Kawasaki since the mid 90s I wouldn't care if it had square tyres. It is just a beautiful machine which talks to your soul every moment you are with it.. the experience is simply profound. I did one quickish stint on a return trip to Matawai but most times I am so immersed in my "secret garden" that it would seem like a travesty not to just take your time and soak up every second of the experience. What was it that Robert Pirsig wrote? "

“To live only for some future goal is shallow. It's the sides of the mountain that sustain life, not the top.”

“The test of the machine is the satisfaction it gives you. There isn't any other test. If the machine produces tranquility it's right. If it disturbs you it's wrong until either the machine or your mind is changed.”

“We want to make good time, but for us now this is measured with the emphasis on "good" rather than on "time"....”

Actually those are a few which grabbed my attention at Goodreads. The one I was thinking of still remains in my head from when I read the book as a teenager. Something like, "Sometimes tis better to travel well than arrive.." Think the Buddha said it first in respect of the journey which is life.

[Angrybird]

loving the insight here, but do you really think it's going to make much difference?

Dave I know what you are saying and I agree. Another quote from Zen and the Art of Motorcycle Maintenance. "The cycle you are working on is a cycle called yourself." Some blokes live on chips and beer.. and Bear Grylls eats scorpion spiders when he is hungry.. does it make a difference?

[Angrybird]

Another vote for 190/55. Slowpoke's bang on, it'll shed 20kg off your bike in cornering performance. I'm running a Metzeler Z8 on the rear & getting good mileage on the ZX12 too, fwiw.

It is worth something Madness.. thanks mate. The bike came with a square 190 50 Continental sports tyre almost to the canvas and I thought it cornered quite well :-) I fitted a rear 190 55 Sportsmart last night (a job for the experts in future.. stiff carcass) so I think I am going to have to be careful when I next aim it at a bendy bit.

[Angrybird]

Dunlop say the 180 or 190 are suitable for 5.5 or 6.0 inch rims.

Each tyre makers actual fitted widths vary a bit too - some 180's are exactly that some a few mm narrower the widest I've measured was actually 185. I must get out more .....

http://www.dunlopmotorcycle.com/tire-catalog/sport-trackday-race/sport/sportmax-q2/

Brilliant AllanB. This was exactly the info I was looking for after someone referred to it in another forum. Car tyre makers always provide it so that you can match your tyres. There are fewer choices on bikes which may explain why this info comes to hand less readily.

[Angrybird]

Mmmmm.... That would explane it... I knew different tyres had different shape, but never realised it was because manufacturers stuffed arround with the profile number.
That would explain why we put a Shinko 100/80 on the front of an FZR250 and it looked like we put a MTB tyre in it.....

Yeah, I know.... shouldn't buy tyres where the manufacturers name starts with S....

I read an article by a big mileage American biker who tried Shinkos on his VF800? He was pleasantly surprised. I met a guy on the Matata straights near Whakatane who fixes bikes and did the Castrol 6 hour back in his day and he was singing the praises of one specific Shinko. Said that a friend who usually swears by Michelin 2 cts "almost" made friends with them. That it was snobbishness that limited his ability to give the cheaper brand a fair go and that half the time the way you believe your tyre will perform is the way it will perform. I agree with him. When I am an expert in an area I know all the shortcuts. I have been off bikes for close to 30 years and so I am no expert. In starting at the very bottom of the heap I am going with only the best written-up tyres and taking note of every last little comment here for what I might learn from it.

[Angrybird]

Bad news, your math is correct, but the designation no longer means exactly as you have said. Manufacturers use that as a guide and then make the tyre whatever size they want really. There are many many tyres on the Market of varying sizes, all using the same carcas.

The exact dimension of any tyre is relative to rim fitment. All you can be sure of, is that a 55 profile of any given tyre, is taller than the 50 profile in that same model.

Back in the day you could get a black or a blue one. Nowadays if you buy gourmet organic produce overseas for example it will give you every last piece of info about the producer including his shoe size. People want to know and there is a competitive edge to be gained from supplying this info. Makes me think we are still in the dark ages in terms of how manufacturers specify their tyres.

[Angrybird]

Okay, I will correct you....

The /55 and /50 refer to the PERCENTAGE of the width.
So it is 55% and 50% of 190 respectivly.
Thus 104.5mm and 90mm respectivly.

So OP had it right, 14.5mm difference in side wall height.

50% of 190 is 95 That is where I went crook in the first place.

[Angrybird]

Thanks to you experts I went for the 190 55s in Dunlop Sportsmarts. This tyre looks nothing like the 190 50 Pilot Power 2CT on my Fireblade. I have taken a rough measurement just to make sure that what I am seeing isn't imagined but the 55 Sportsmart appears way skinnier than the 50 2CT.

Side by side the Michelin looks like the Michelin man ie a big fat drag slick in comparison. In fact if there is a different in width it is not great. The 190 55 just has a more chiselled look to it. No doubt because this tyre is designed to contact the road when it is lying on it's side.

Something else I have noticed is that the Honda seems very reluctant to go into a low speed turn such as going around a roundabout in the city. The Kawasaki even with a bald old Conti Road Attack seemed more responsive and so I thought it must be because the seating position is more upright and I am putting less weight on the higher handle bars.

Actually low speed turning is a bit of a drama for me after a long period of absence from bikes and so it is something I practise at the end of our cul de sac. When I circle it on the Honda I just about use the whole road.. imagine that as a 20 cent piece. When I do "roundy-roundies" on the 14 it is as if I am only requiring 10 cents worth.

On the 190 50s chicken strips are a way of life. After riding the ZX around in ever decreasing circles I was somewhat bemused to see I had nearly used the whole tyre yet it felt as natural at that lean angle as the 190 50 shod Honda did nearly "upright."

Just by way of first impressions I am forced to conclude that the 190 55 is a tyre which is designed to go around corners.. the 190 50 for US freeways. In fact I am now convinced that my sense of the Fireblade's 190 50 fighting you is real.. it simply doesn't like being on it's side. 190 55 cf 190 50 doesn't sound like much but in reality the difference is chalk and cheese.

As for the way it affects gearing I did a quick calculation and from memory it is 3% higher. When in first gear the engine now seems more "raspy" in certain rev ranges. I wonder if it just spun through there without my noticing when the gearing was standard. Something I can live with for the moment but when bucks permit I will probably add a tooth to the rear.

[Dave-]

Something else I have noticed is that the Honda seems very reluctant to go into a low speed turn such as going around a roundabout in the city. The Kawasaki even with a bald old Conti Road Attack seemed more responsive and so I thought it must be because the seating position is more upright and I am putting less weight on the higher handle bars.

Actually low speed turning is a bit of a drama for me after a long period of absence from bikes and so it is something I practise at the end of our cul de sac. When I circle it on the Honda I just about use the whole road.. imagine that as a 20 cent piece. When I do "roundy-roundies" on the 14 it is as if I am only requiring 10 cents worth.

checked suspension?

if not, have a read of this thread:
http://www.r6-forum.com/forums/showthread.php?t=80410

Yes it's for an r6 but the process is the same, I'll assume your fireblade has fully adjustable suspension....if not do what you can and see how it goes.

also check tyre pressures too!