Tyre wave pattern

[Gixxer 4 ever]

Can anyone help with this.
I have a 190 50 17 Diablo on a 1996 GSX-R 750V. If you sit on the floor behind the bike you see a wave pattern on the side of the tyres. Not chicken strips. The tyre is heavily scuffed to the very edge but there is a wave pattern around the edge of the tyre where the chicken strips could be.
They start at the out side edge of the tyre and move in to the tyre 3 mm over a distance of 27 mm. Then they tapper off back to the edge of the tyre and again that distance is 27 mm. Then there is a gap of 40 mm with normal scuffing from the road and then the next wave starts the same as the one described. This is even and travels completely around the tyre.
Same on the right hand side but the wave is only 2mm deep. Could the difference be due to road camber?
But my question is...does anyone know why this pattern has developed? It is only there after very hard throttle use out of corners. Could it be the tyre pressure is to soft? I run it at 38 psi cold. No pillion. Is the tyre crimping under load and hence the pattern?
The last tyre was a pilot sport and it did the same.
Any ideas?

[Two Smoker]

any chance of a photo???

[onearmedbandit]

Someone with the correct knowledge will be able to confirm this but after talking to a fellow member here it was pointed out to me that the tyre pressures my have been too low. Same thing happened on my 750 under hard throttle out of corners.

Just setup a temp. seat bump for the thou so over the next few nights I'll be trying to see if that does as well!! Better be careful with that right hand out of corners though!

[Gixxer 4 ever]

any chance of a photo???

I will get the cam tomorrow and see if I can get pic's. Thanks for the help so far people.

[Motu]

Cupping - check out the front tyre of a road ridden dirt bike with knobs,they all do it.

[Gixxer 4 ever]

Cupping - check out the front tyre of a road ridden dirt bike with knobs,they all do it.
Cool That would happen because of the movement in the knobs so there for it would indicate the tyre pressure is to low. Might have a play with it and see what comes up.

[Gixxer 4 ever]

any chance of a photo???
Now you strike me as someone that knows a bit about bikes, so what would you think it could be. I tried to photograph it tonight but hard to get so will put it out in the sun tomorrow.
What pressure would you expect to run a rear, one up at? cold

[Sensei]

I use 36-38 cold on the rear & 34-36 cold in the front , have used these for over 20 years on the road & have find them to be excellent .

[R1madness]

It is a simple suspension adjustment problem combined with an incorrect tyre size. Sounds like you need some more rear preload. Is it squatting a lot at the rear under hard acceleration? Oh yea try the 180 as well because i think you are running on 5.5inch rear rim and the 190 is designed for a 6inch rim. You will get more rubber on the road with the right size tyre for the rim. The pressure sounds ok.

[Gixxer 4 ever]

any chance of a photo???

Here it is

[Gixxer 4 ever]

It is a simple suspension adjustment problem combined with an incorrect tyre size. Sounds like you need some more rear preload. Is it squatting a lot at the rear under hard acceleration? Oh yea try the 180 as well because i think you are running on 5.5inch rear rim and the 190 is designed for a 6inch rim. You will get more rubber on the road with the right size tyre for the rim. The pressure sounds ok.

Thanks for the reply.
It sits down and pulls the weight off the front under load, that's for sure. I road in the 7000 plus rev rang on the weekend when this happened and it really sits down and feels good. I will try a bit harder preload. Could well help but it never bogs down just sits down and gives you that "give me more" feeling I can do this. Good idea thanks

The bike is designed for the 190. Everything I have read said they are made for the 190 and I am sure the 180 will have far less tyre on the road than this 190 at any point in a corner. Could be wrong but I will stick to the 190.

Thanks for your help R1:yeah:

[TwoSeven]

It is a simple suspension adjustment problem combined with an incorrect tyre size. Sounds like you need some more rear preload. Is it squatting a lot at the rear under hard acceleration? Oh yea try the 180 as well because i think you are running on 5.5inch rear rim and the 190 is designed for a 6inch rim. You will get more rubber on the road with the right size tyre for the rim. The pressure sounds ok.

That doesnt at all sound right.

Can you explain the logic further ? - the math would be good :)

How does preload affect uneven tire wear ?

How does a bike squat under acceleration ?

[Two Smoker]

Ive got the same problem on my ZXR400... This is due to the rear shock being too soft, and as R1Madness suggested, try upping the preload by 1/2 a turn on the rear shock see how it goes then...

[Gixxer 4 ever]

That doesnt at all sound right.

Can you explain the logic further ? - the math would be good :)

How does preload affect uneven tire wear ?

How does a bike squat under acceleration ?

When I go into a corner, on a piece of road I know, I can keep the reves up and as I open the throttle just before the apex the front unloads the weight and that give the bike a real feeling of sitting the back down. But it is not an unstable or bounce it is a firmness that really gives you a good sling shot out of the corners. So I would describe it as "squatting". As long as the power stays on the rear unloads nice and evenly as you get out of the corner.
I am no racer and would only be a mid rang rider so I can only describe things as I see them. Or in this case feel them. I was interested to know why this Patten had developed and if someone suggests something that sounds like it might work I am happy to play with it and see. All part of the learning. If by tweaking the rear shock I get a better ride or foot print I am happy to try it.
Can't do any maths but I will soon know if the pattern disappears.

[Gixxer 4 ever]

Ive got the same problem on my ZXR400... This is due to the rear shock being too soft, and as R1Madness suggested, try upping the preload by 1/2 a turn on the rear shock see how it goes then...

Thanks for the tip. I will try it over the weekend and report back. :2thumbsup

[Gixxer 4 ever]

That doesnt at all sound right.

Can you explain the logic further ? - the math would be good :)

How does preload affect uneven tire wear ?

How does a bike squat under acceleration ?

Any ideas on why this happens? Sounds like I am not the only one that has it. I am pleased about that.:spudflip: :yeah:

[DEATH_INC.]

Torque reaction on the chain/ sprockets causes the rear to lift (under accel),weight transfer causes squat,must be real soft if it's squatting.
Try (as ts said) more preload AND more compression damping.Check static sag,should be about 5mm(no rider) or just keep going 'till the squat dissapears.
Stick with the 190.
Get rid of the diabolical and get a real tyre :Pokey:
These bikes love a 15mm or so raise in rear ride height too, done with a 5mm (or thereabouts) spacer on top of the shock.

[Gixxer 4 ever]

Torque reaction on the chain/ sprockets causes the rear to lift (under accel),weight transfer causes squat,must be real soft if it's squatting.
Try (as ts said) more preload AND more compression damping.Check static sag,should be about 5mm(no rider) or just keep going 'till the squat dissapears.
Stick with the 190.
Get rid of the diabolical and get a real tyre :Pokey:
These bikes love a 15mm or so raise in rear ride height too, done with a 5mm (or thereabouts) spacer on top of the shock.

Wow. The fact that I am 110 kg and 6' 1" might be part of the problem. I will play with the preload and check the sag. This bike is firm to ride so I will take the adjustments a few clicks at a time. Looking forward to it.

And pray tell, what is a real tyre Death? Remember the pilot sport did the same thing.

Lifting rear ride......The bolt looks long enough so not to hard to do. This would push more weight to the front wouldn't it?

Thanks for your time Death. Roll on da weekend.

[R1madness]

TWOSEVEN - What doesn't sound right? 5.5inch rims are designed for 180 tyres except for the single type of one that was fitted to the bike from new by the manufactures. This tyre is specially designed to the bike manufactures specifications. (eg TL1000s metzeller fronts) ALso it would have been a JAPANESE 190 which when measured on the rim and compared to a european 190 of the same brand and model would be a completely different size.
Now if you try to squeeze a euro 190 onto a 5.5 rim you deform the carcase. Grab a new 190 and squeeze it in so the outside of the beads are 5.5 inches apart. Look at the trye. now let the beads out by 1/2 an inch. What a difference.
Dont believe me? Try it and see for yourself
All to often i see people with the wrong size tyres on and all they do is complain about the handling. It turns in too slow, it runs wide, its pushing the front blah blah blah.
Yea up the preload by heaps add a click or 2 of compression and rebound and go for a ride. Raise the ride height as well but the biggest difference you can make is to go back to the CORRECT tyre sizes.

[sugilite]

Is your wheel in straight in the swingarm?
The factory alignment marks are not always accurate, if it is a screw and lock nut adjustment, count the threads on the adjuster each side to be sure.

[Gixxer 4 ever]

TWOSEVEN - What doesn't sound right? 5.5inch rims are designed for 180 tyres except for the single type of one that was fitted to the bike from new by the manufactures. This tyre is specially designed to the bike manufactures specifications. (eg TL1000s metzeller fronts) ALso it would have been a JAPANESE 190 which when measured on the rim and compared to a european 190 of the same brand and model would be a completely different size.
Now if you try to squeeze a euro 190 onto a 5.5 rim you deform the carcase. Grab a new 190 and squeeze it in so the outside of the beads are 5.5 inches apart. Look at the trye. now let the beads out by 1/2 an inch. What a difference.
Dont believe me? Try it and see for yourself
All to often i see people with the wrong size tyres on and all they do is complain about the handling. It turns in too slow, it runs wide, its pushing the front blah blah blah.
Yea up the preload by heaps add a click or 2 of compression and rebound and go for a ride. Raise the ride height as well but the biggest difference you can make is to go back to the CORRECT tyre sizes.

Hmmm. you could have a point. I was unaware of the difference in the size. And I can imagine a 1/2 inch would seriously change the shape. I have had a look at the rim and along with the usual stuff cast in to it, it has the number 9/6 on one spoke. This would be to show year of manufacture and the other spoke has /6. Size? So when I take this tyre off I will measure the rim.
The bike handles really well. It corners and rides as I would expect it to.
This bike was Craig Sheriffs race bike in the 96-97 street season and as far as I can find out it was running these rims and the 190 tyre. But all you say is good information so I will keep it and do some research. The manual specs say 190 as does the swing arm but I understand what you are saying. This thread was not so much a handling setup question as a what is this? But I think Death and TS have hit on something. I measured the sag and it is 15mm. Far to much. So I will play with the setup and see how that changes it. After I have been to Paeroa this tyre should be stuffed so I will take it off and measure the rim.
I assume from the inside of where the tyre bead?
Thanks R1

[Gixxer 4 ever]

Try (as ts said) more preload AND more compression damping.Check static sag,should be about 5mm(no rider) or just keep going 'till the squat dissapears.
Stick with the 190.
.
Sag = 15mm. That is I take the weight off the shock and Mrs gixxer 4 ever marks a board. Let the bike sit down and the difference is 15mm. So I should have checked this stuff before posting here. Anyway I will do as you have advised and see what happens. As above I am happy with the way the bike rides but it will be interesting after a bit of time spent on setup. I last set it up 35,000km ago :Oops:
I will look at the 5mm lift when I take the rear tyre off.

[Gixxer 4 ever]

Is your wheel in straight in the swingarm?
The factory alignment marks are not always accurate, if it is a screw and lock nut adjustment, count the threads on the adjuster each side to be sure.
good point but I did check that before I asked. That's what I did when I noted one side wave was deeper than the other.:2thumbsup

[R1madness]

Ahhh now the truth comes out. If its Craigs old bike (and i have no reason to doubt it) then he may have had a 6 inch rim on the rear. It will be stamped on it somewhere MT6.00x17 or 5.50x17 or something like that. If it is a 6.00 then the 190 will be fine. If you cant find the markings then measure them as you described. Up the preload for sure. 25mm with the rider is a good start. You are a bit bigger than the average 750 rider so i would suspect you will need to run less than 5mm static (without the rider) or go for a heavier spring (extra cash but will help). You are headed in the right direction.

[Gixxer 4 ever]

Man that's one way to reduce your productivity. Start shagging around with the bike setup in work time.
I have reset the sag. Around 4.8 5.2. it appears not to be an exact science.
Tweaked up the rebound as well.
It feels so different. I will play with it for a while and see what happens. Even if the wave pattern stays the retuning of the suspension has made a big difference. I have a feeling Mrs Gixxer 4 ever will have somthin to say as the shock comes up threw her back.
Set the rebound on the front a click harder as well.
I know this is not the way to sort out what made the pattern but I am sure the bike will feel a heap better now. Raining so I can't go out and play.
Will post here after the weekend.

[Gixxer 4 ever]

Ahhh now the truth comes out. If its Craigs old bike (and i have no reason to doubt it) then he may have had a 6 inch rim on the rear. It will be stamped on it somewhere MT6.00x17 or 5.50x17 or something like that. If it is a 6.00 then the 190 will be fine. If you cant find the markings then measure them as you described. Up the preload for sure. 25mm with the rider is a good start. You are a bit bigger than the average 750 rider so i would suspect you will need to run less than 5mm static (without the rider) or go for a heavier spring (extra cash but will help). You are headed in the right direction.


Found this on it J17XMT 6.00. So that's good.
See above for adjustments made today.
Yep it is the one. When it went on the market on TradeMe I asked if it had been raced and Ed, the current owner at that time, had been told it had but had no details. So I got the frame number and stuff and checked it on the reg papers and found Suzuki NZ owned it for the first part of it's life. Then I sent mail to them and asked and Mike Wink from Zuki sent me details on what they knew. Unfortunately Craig dropped it big time at Ruapuna and bent the steering dampener mount and indented the top of the frame on the right hand side. it was recertified and continued on the track till the end of the season. It was then sold and setup for the road.
I found the photographer in Christchurch that did the work for Zuki NZ and wrote to him to get some pic's. He said he had them and would dig them out if I would send some money. Never heard back from him. Which is a shame. I could ask here in the general area cos someone is bound to have been racing at that time and have a shot of it.
Looking forward to getting out and having a ride with it setup like this.

[Two Smoker]

Bloody remembered last night (ask Chloe hehehe) to up the compression dampening ASWELL... but Death has already added that...

[Gixxer 4 ever]

Bloody remembered last night (ask Chloe hehehe) to up the compression dampening ASWELL... but Death has already added that...
hahaha as we do. Usually at 3.20 in the morning :wacko: and then can't get back to sleep.
Thanks for all the help. I am sure this is the answer and it should be great after a bit of playing and tweaking.
It is great to have a place to ask and have people that can answer based on experience.:not:
KB rocks.....:headbang: ......

[R1madness]

Good man. You are now in control. Doing the suspension adjustments will cure the wave pattern. It may take a bit of time to clean it up but keep fiddling.
Mrs GSXR will like the extra confidence in the bike mid corner and 2 up the adjustments will not make too much of a difference for comfort.
Fiddle fiddle dude. It will teach you heaps.

[R1madness]

Oh yea the photographers name is Euan Cameron and his email is euan@cameronphoto.co.nz Good luck tracking down a photo or 2.

[Gixxer 4 ever]

Oh yea the photographers name is Euan Cameron and his email is euan@cameronphoto.co.nz Good luck tracking down a photo or 2.
Thank you for the name and Email. You the man...:yeah: ...Do you know Euan? I will send him mail now.

[R1madness]

Know him thru racing bikes. He is a decent guy but a little busy. If ya are nice to him he will look a bit harder. His pics are top quality and worth the price he charges.

[Gixxer 4 ever]

Know him thru racing bikes. He is a decent guy but a little busy. If ya are nice to him he will look a bit harder. His pics are top quality and worth the price he charges.
Cool. I will hunt for his race number over the weekend, for that year, and see what I can find. I have sent Euan mail.

[slob]

I've got a GSX-R750T ('96) with a 180 section Metzler Sportec M1 on the rear. Last time I was at Pukekohe on a trackday, I noticed the same pattern forming on my tyre. I'd say it was due to a combination of having the wrong suspension setup (damping was low - on road settings) and tyre pressure (released too much air in my haste to get on the track).

Basically, if your tyres are wallowing around while you're leaned over, you will get that pattern.

[TwoSeven]

So why wouldnt it be an incorrect tire pressure then ?

[slob]

So why wouldnt it be an incorrect tire pressure then ?

If the suspension isn't damping the spring action, then I imagine the tyre will be bouncing around excessively, thus forming the wavy wear pattern I imagine..

[DEATH_INC.]

A couple of things....
All the srad 750's run a 6" rear ,hence the 190.
Don't run the rebound too stiff,it'll pack down and make it real harsh feeling.....run it as light as you feel comfortable with.....alternately don't make the compression too light,it needs to be as firm as poss while still feeling compliant....

[Gixxer 4 ever]

Holy shit...............What a difference......I had to drop the rebound back a bit but what a ride.......
One more question.......I know I have asked enough but this advice has made this bike ride so much better, and I loved it before. Anyway I recon the front is less stable. That is it appears to lift a lot more under power. A bit off putting to start with when coming out of corners or opening the throttle to pass cars. She always unloaded the front but it lifted it twice in the first 3 ks as we headed up the Wairoa road. Why?
F#uk I love this bike:love:
Will report after the weekend when I have had a chance to play some more.
Thanks people:clap: :clap:

[Gixxer 4 ever]

TWOSEVEN - What doesn't sound right? 5.5inch rims are designed for 180 tyres except for the single type of one that was fitted to the bike from new by the manufactures. .
I had a look at a mates Black bird today and what you said is correct. It has a 5.5" rim.
Amazing what you learn when people share information. Thanks R1

[Brian d marge]

Can I ask what wieght you are and if the bike has a standard shock ( as in unmodified)

Stephen

[R1madness]

Holy shit...............What a difference......I had to drop the rebound back a bit but what a ride.......
One more question.......I know I have asked enough but this advice has made this bike ride so much better, and I loved it before. Anyway I recon the front is less stable. That is it appears to lift a lot more under power. A bit off putting to start with when coming out of corners or opening the throttle to pass cars. She always unloaded the front but it lifted it twice in the first 3 ks as we headed up the Wairoa road. Why?
F#uk I love this bike:love:
Will report after the weekend when I have had a chance to play some more.
Thanks people:clap: :clap:

Take a couple o clicks o rebound off the front (to allow the forks to extend a little quicker under acceleration) and take off 4 clicks o compression from the rear (to allow it to squat just a little). Just fiddle fiddle. Adjust one setting at a time and see the effect. SO many people are too nervous to play with their suspension settings and dont realise that they probibly have it all wrong anyway. Just keep playing mate.

[DEATH_INC.]

I'd suspect it's because the rear no longer squats that the c.o.g. is higher and that's why the wheelies.....like r1 sez, just experiment a little at a time,you can always go back. keep a written record of what you've done and what it does.

[Gixxer 4 ever]

Can I ask what wieght you are and if the bike has a standard shock ( as in unmodified)

Stephen
Hi Stephen. It is standard. I will check for the 5mm lift when I have this tyre off next. A mate added an 8mm lift to his Black Bird and it has made a massive difference to the turn in. 8 mm at the shock = 20mm at the back of the swing arm. So he told me. I have not done the maths but the tyre is now on the ground when he has the centre stand down.
I am 110 kg's and 6 1. I know I am a bit big for the 750 but I saw this bike on TradeMe and just wanted it. So I got it. I like the fact it had some history and Mary loved the colour. I have no problems keeping up with the big bikes and we tour from time to time on it. Pillion seat is very comfy for a sports bike.We have done a few trips to Auckland and Welly town and many places in between.

[Brian d marge]

I know that feeling about just wanting bikes ...Every bike I see I want !
Anyway suspension set up , I fel that the original problem is tyre squirm , wether caused by, supension or Tyre pressure I dont know.

What I would do is set the bike up for your wieght.
1 check the sags ( if you are not sure how to do this correctly I can send you document which explain in easy language ...as I am a bit slow so needed it in simple terms )
The sags will tell you if springs are to soft or hard ( I suspect to soft )

At this point if you dont correct the spring rate all other changes just mask the inherent problem,

Set clickers to the factory settings , or the middle

NOW go riding and as others have said change only ONE thing at a time and note the effect
( if you need a list of causes and effects again PM me )

make the changes untill the bike feel nice and holds the line through a bumpy sweeper

The most likely reason why its tending to wheely is you have jacked up the preload so as the bike accelarates and the wieght is transferred to the rear...... the shock is trying to extend but is being squashed by the wieght transfer by adding more preload you have given the shock more advantage ie empowered the shock to extend which will tend to lift the bike ie tend to wheely

That was a crap explaination try this... wieght transfer -( energy in spring + added preload given by preload ) equals wheely rate !

If that makes sence then cool , if not Pm me and I will scan a diagram with the maths which would probably make more sence!!

Finally when all that is done Then you go and start with adding /subtracting tyre pressures . clicker adjustments ..to see if the tyre wear pattern grows bigger or smaller

and when you get to rossis level and can constantly hold the same line through a turn all the above rubbish become Kawooshial ( sorry I am watching monty pythons life of brian on web tv while typing this and they are up to the Bigus Dickus scene ,,,thats a classic scene)

Anyways good luck

Stephen

[Gixxer 4 ever]

I know that feeling about just wanting bikes ...Every bike I see I want !
Anyways good luck

Stephen

Everything you say sounds good. I am working on the one click thing and I think I have it close to as good as I can get it. It appears the wave pattern has gone. I need a longer hard ride to see but it all feels good.
I like the lift in the front. I can dial it out, as you say, but I am enjoying it at the moment. Added value on a harder ride. I am just a boy at hart. When I say it lifts the front we are not doing the big wheelie thing just up off a little and the throttle controls it nicely.Thanks for your time and info.
Roll on tomorrow. Hope I have enough tyre to get to Paeroa and back :eek5:

[Brian d marge]

Everything you say sounds good. I am working on the one click thing and I think I have it close to as good as I can get it. It appears the wave pattern has gone. I need a longer hard ride to see but it all feels good.
I like the lift in the front. I can dial it out, as you say, but I am enjoying it at the moment. Added value on a harder ride. I am just a boy at hart. When I say it lifts the front we are not doing the big wheelie thing just up off a little and the throttle controls it nicely.Thanks for your time and info.
Roll on tomorrow. Hope I have enough tyre to get to Paeroa and back :eek5:

and that at the end of the day is what its all about ,,enjoying it .... The reason why I like MX ,,,I can go nuts ...and the boys in Blue cant do squat!!!!

Stephen

[Gixxer 4 ever]

It has been a fantastic learning experience. I think I have set it up as well as I can.
The wave has gone from the right and is very small on the left. The reason for this is answered by Sugilite. The left hand side of the adjustment is 0ne turn further out than the right. I counted it the night I posted here but there you go. I got it wrong.:doh: Will fix it tomorrow.
Well spotted Sug.
I have one more tip for people who go out and pursue this interest. Warm up the tyres before you get to excited about carving up the corners.:eyepoke: Believe me it helps. Try and get on a track to do it.
I have had a ball. Learnt so much and the ride is so good now. I can say the bike will out corner my nerves. So I guess I should move to the track if I want to continue this. However after today I think I should just ride and enjoy what I have learnt. Today's ride cut a shit load of rubber off the rear and the bike rode like a dream. I have not come across the shingle or the oil on the road in the last 4 days so I have had a great time but time to slow it down.:nono:

Many thanks people for taking the time. This has renewed my interest in the bike. It is so pleasing to improve the ride and the response of the bike and spend no money. Getting the most out of what I paid for in the first place.


Anyway thanks all. :2thumbsup
Think a call to Cycle treads is on the cards soon.

[Morepower]

Such A lot of theory , the reality is;

The Tyre wear was cause you go too fast:rolleyes:
now all this fooling arounds just going to make you faster ! :argh:
I wont be able to keep up :crybaby:

I better get to setting up the TL

Ha Ha Dave

[Gixxer 4 ever]

Such A lot of theory ,
Yea but it worked.





I wont be able to keep up :crybaby:

You have that wrong Dave, I might be able to keep you in sight. That TL, with you in the saddle, is one hard arse speed machine.


Ha Ha Dave[/QUOTE]

Anyway as I am now an older gentleman I will slow to a more appropriate speed for my age.............




not






bring on Paeroa....

[Morepower]

Today's ride cut a shit load of rubber off the rear and the bike rode like a dream. .

It doesnt hurt to live 100 metres or so from the best Motorcycling Road in Hawkes Bay :eek:

Talk to you later in the week , do you feel like a warm up on Thursday ???

[Gixxer 4 ever]

It doesnt hurt to live 100 metres or so from the best Motorcycling Road in Hawkes Bay :eek:

Talk to you later in the week , do you feel like a warm up on Thursday ???

Ummmm sorry no, better get the work done. I might not be able to keep up with you all. Better to be thought a fool than prove it.:eek:
I will send mail later in the week.

[sugilite]

It has been a fantastic learning experience. I think I have set it up as well as I can.

Cool, glad to hear you got it sorted....
Thats what I love about motorcycling, you never stop learning, as a rider or a mechanic!