View Full Version : Tread Wear Advice
Luckypants
09-08-12, 01:40 PM
Hello Tyre Gurus!
I would like an opinion on what is causing the stepping effect in the tread of my rear. I have run the tyre at Honda standard 42psi, with all of it's 5000 miles being two up and the last 3000 were with luggage as well. The steps have always been there on every tyre I have had on all my VFRs, including Bridgestone BT-023, Dunlop D203, Avon Storms (I and II). This tyre is a Michelin Pilot Road 3.
This time the stepping effect has been very pronounced. The steps became more pronounced and therefore an issue on Alpine hairpins fully loaded, I put that down to having to use a lot more throttle in first/second gear to keep the bike moving, but I would like some advice to cause of this so I can avoid it in the future.
The step is on the leading edge of the tread blocks at the edges of the tyre, so the rear of the tread block wears down while the front edge seems to roll over itself to form a little burr. While riding the tyre feels like it is squirming and wriggling a bit when leaned over and hard on the gas, but does not slide.
Some pics to help
http://i174.photobucket.com/albums/w111/luckypants_photos/Random%20biking%20photos/IMAG0359.jpg
http://i174.photobucket.com/albums/w111/luckypants_photos/Random%20biking%20photos/IMAG0355.jpg
http://i174.photobucket.com/albums/w111/luckypants_photos/Random%20biking%20photos/IMAG0357.jpg
http://i174.photobucket.com/albums/w111/luckypants_photos/Random%20biking%20photos/IMAG0358.jpg
Discuss please.
yorkie_chris
09-08-12, 02:53 PM
What shock is that? How does rebound feel?
Its made worse by the fact you were loaded.
The load is made worse by under damping
This causes the tyre to squat out of shape.
Look what thry have to put up with .
Shearing loads ,high temprature and diffrences in expansion of the tyre carcase
http://www.youtube.com/watch?v=xLbxcYVEPYc&feature=related
Is that Dave Moss Unsprung: Tire Wear?.
Cant see youtube at work(fierwall)
Luckypants
09-08-12, 03:33 PM
What shock is that? How does rebound feel?
It is the standard VFR shock. Has pre-load and rebound damping adjustment only. It was set with enough pre-load to ride level with pillion and two 12KG panniers. Rebound damping not changed.
Rebound feels like suspension, it goes up and down Chris :) I'm not good enough to feel nuances of damping, but I'll say it felt a pogo at times. Gunning it out of hairpins in 1st or second made the bike feel a bit squirmy, but cannot say if it was the tyre or suspension. To me it felt like tyre.
Wow that was illegal thousands of miles ago. That is more bald than me!
Seriously, it may be a very soft compound tyre. Try a different make next time. Great grip, poor wear.
Regards
H
AndyBrad
09-08-12, 09:00 PM
My guess is its been overloaded when cold
Sent from my GT-I9300 using Tapatalk 2
Mikey10
09-08-12, 10:09 PM
No expert but they way its worn look like a tread pattern fault.
So who ever designed the pattern has'nt taken into acount the tyre compund and wear rate to allow the tread pattern to not wear like that.
Im most likely talking utter rubbish but from the way its worn, following the tread pattern it seems like that may be a cause.
No expert but they way its worn look like a tread pattern fault.
So who ever designed the pattern has'nt taken into acount the tyre compund and wear rate to allow the tread pattern to not wear like that.
Im most likely talking utter rubbish but from the way its worn, following the tread pattern it seems like that may be a cause.
Rebound Rebound Rebound :smt096
Luckypants
10-08-12, 08:43 AM
Wow that was illegal thousands of miles ago. That is more bald than me!
Seriously, it may be a very soft compound tyre. Try a different make next time. Great grip, poor wear.
No it went 'illegal' (it not actually) on the ride up from Dover, so literally wore it out a few miles ago. :rolleyes: It is a Michelin Pilot Road 3, not a soft tyre by today's standards. It is a sports touring tyre and that's exactly what I was doing :D You will note I stated I had these steps on every tyre I've ever fitted to the VFRs I've owned, but I have updated the OP to make that clearer.
No expert but they way its worn look like a tread pattern fault.
So who ever designed the pattern has'nt taken into acount the tyre compund and wear rate to allow the tread pattern to not wear like that.
Im most likely talking utter rubbish but from the way its worn, following the tread pattern it seems like that may be a cause.I really don't think that Michelin wouldn't take tread compound and wear rates into account when designing their tread patterns.
Just get a new shock that you can adjust.
Get it propely sey up for you and you save mony in the end by not scrubbing tyres out
Luckypants
10-08-12, 08:52 AM
Rebound Rebound Rebound :smt096
OK that may be fair comment. I watched the video and some of what he said suggested it may be rebound damping. BUT you need to come up with some more facts for me :D
Just get a new shock that you can adjust.
Get it propely sey up for you and you save mony in the end by not scrubbing tyres out
Let me say that I have seen this stepping effect on both my VFRs and all tyres fitted to them. My previous VFR had Maxton suspension that was set up by them for my weight, riding type and riding style. I still saw steps in the tread (but not this bad), so did Maxton set it up with too little rebound?
As to my current bike and this particular tyre, I had a load of pre-load on to support the load on the bike, but the load on the bike is also damping the rebound surely? It never felt like the bike was trying to kick us out of the saddle by rebounding too fast?
So please can you or anyone else explain why more rebound is needed when loaded up?
PS That tyre has done 5000 miles, so not really wearing out too fast (but more would be better)
Problem with set up is you can't cover all basses.
One day its hot one days its cooler.so oil flows diffrent gas pressure etc and how your ridding it.
You say the stepping is less Thats a good thing.Its wight transfer allways pushing the hoop into the tarmack.
My RSV does it but in part ist due to having the damper preload low (I'm short) so have my compresion too high the suspension is allways at the end of its travle when i come out of a corner if i cant get on the gas.
This" As to my current bike and this particular tyre, I had a load of pre-load on to support the load on the bike, but the load on the bike is also damping the rebound surely? It never felt like the bike was trying to kick us out of the saddle by rebounding too fast?"
The suspension is at the bottom of its travle, so more rebound won't let it recover .The more rebound you put in the worse it gets.(left compresion same)yes i know this sound wrong .But I went the wrong way on mine and got a big shake .Thats was just rebound i adusted(seperate compresion on mine) same road ,vastly diffrent out come.
Mike,
Damping adjustment is quite a personal thing. I am of the opinion that a little more rebound damping might help in this case though.
When the suspension's being loaded how fast it returns is down to rebound damping. Too little and the tyre is over-worked as the load goes on-off-on-off as the suspension compresses, rebounds and is quickly forced back to where it should be instead of settling where it's needed. This heats the tyre up and also makes it squirm, causing uneven wear. Too much rebound damping and the shock doesn't recover fast enough, leaving your suspension packing down and bottoming out on corner exits robbing you of grip.
Your current suspension is adjustable for rebound damping, I would suggest finding out what it's set to at the moment (count clicks/turns until fully in) you can then set it back exactly where it is if you don't like any changes.
Now go in a "chunk" from where you are now (technical term). Not all the way in, but enough that you'll notice, don't bother moving it in by a click at a time. Go for a ride as it is, then if it were say 11 clicks out from fully in I'd set it to about 5 clicks from in and go for a ride. I'm certain you'll feel a difference. Go back and forward by smaller increments until it feels as nice as it can.
This will cost you about an hour or so of riding on roads you enjoy, carrying a screwdriver. The weather this weekend looks good, and if you don't like any of the settings you can just pop it back to where it was :)
Jambo
Luckypants
10-08-12, 09:24 AM
Thank you Jambo, that is useful advice. I'll take that on board next time we are out.
My own belief is that the extreme stepping I have seen with this tyre is due to the weight on the bike on our European trip. What to do about it so it doesn't happen again is what I want from this thread. I don't know if this was tyre pressure or damping or just too much right hand when that loaded up.
So far the opinion seems to be rebound damping.
Are tyre pressures anything to do with this type of wear?
We had a 200 sx do a very similar thing.
We tried tyre pressure upping it and it lost grip.
Only after getting silvia engineering involved did we get the right dampers .
For two up trying a tyre with a different load index would be a good plan.
Just be carefull with big step changes on the damping ,as I said made my rsv very unstable .(too much rebound so it bottomed )
Its rewarding when you get it get just right though.
not trying to be funny but another thing is may be your riding habit.
do you crack the throttle open out of corners or wind it on?
do you carry throttle in the corner e.g. keep the throttle steady till the apex?
do you close the throttle on entry then crack it open on exit?
do you close the throttle coast and wind the throttle on threw the corner?
how is the wear on the front tyre?
Luckypants
10-08-12, 04:26 PM
Hi Bib
My cornering style is..
Slow down for the corner, by closing throttle/down gears, brakes if needed.
Tip in on gentle acceleration/neutral power
keep gentle acceleration/neutral power on through corner until corner opens or exit is spied
Wind the throttle on from spotting corner opening up / exit to required amount of gas...
I try to be smooth.
Bluepete
10-08-12, 06:19 PM
Mike, you need to slow down.
I haven't got a clue about why you're lunching tyres from a boingy bits point of view, but you are very fast, you use a lot of counter steer into corners and carry the speed through before firing off again, still on the shoulder of the tyre. Lots of stress through the softest part of a dual or triple compound tyre,
I'd have thought that would stress any tyre!
Then again, I'd rather you didn't slow down, Wales wouldn't be the same again ;)
Glad you had a great Euro tour pal!
Pete ;)
reduce your compression by 1/2-3/4 turn and up your rebound by 1/4-1/2 turn and see how that goes.
http://i49.tinypic.com/2v2v7mx.jpg
i'm no way a guru with suspension but from what i can work out the section marked in red is from to much compression (its tearing the edge as you get on the throttle out the corner due to the tyre pushing into the tarmac) and the section in green is from to little rebound (tyre is skipping as its loosing grip due to it rebounding to fast).
but i'll let someone who knows better than me confirm it.
Luckypants
10-08-12, 08:41 PM
Well Bib lots of folks are pointing the finger at rebound and as that is the only adjustment I have I'll be looking at that. There was lots of pre-load on due to luggage and pillion so rebound may be the culprit.
Pete, love you too x x x
Sent from my phone.
Luckypants
03-09-12, 11:42 AM
It was suggested to me that I email Michelin technical folks about this, so I did. The upshot was they asked to examine the tyre. They told me that the stepping on the outside was most likely caused by poor rebound damping, but that there was also evidence of the tyre overheating.
So I checked the rebound setting on my bog basic VFR standard shock and yes, someone prior to my ownership has turned down the rebound damping below 'standard' yet I had more preload on to compensate for the weight. Result was very little rebound for the amount of 'spring' in the rear. My bad for not checking this. So I have turned up rebound 'a lot' but still have about the same left if this proves to be not enough. It is up more than 50% over standard. Took it out for a brisk ride and the rear felt more planted and 'firm' with no squirming. There is a caveat to this, I was scrubbing in a new tyre so not giving it full beans. Subsequent short rides show the bike to more stable.
Michelin reckoned the overheating was caused by flex due to the weight being carried. The PR3 rear in 180/55R17 comes in two formats, standard and the 'B-type'. The 'B-type' has an extra sidewall ply and is recommended for regular pillion and luggage carrying. That is exactly the type of riding I am doing. However, my tyre fitter had put on a standard tyre as the B-type was not available when the tyre was fitted. So the tyre itself was too squiggly but is now replaced with a b-type rear so that should be cured. They also suggested adding some pressure to cope with the extra weight. I had a read around this subject and it seems the tyre should increase in pressure around 10% from cold to working temps. This worked out that I put in 2 psi extra and it goes up by the 10% when ridden with pillion in my normal manner.
Seems that there were a number of things not quite right, sorted now hopefully and I'll keep a close eye on the tyre over it's life.
Great technical description. I'm sure someone will find this useful in future.
Dicky Ticker
03-09-12, 04:51 PM
As I have said before in former posts tyres are very dependent on the use they are intended for and when applied to something different have these sort of results.
Example My ST with luggage and full fuel tank is fairly heavy and was squirming all over the place with Corsa111 due to them being sports orientated where as a set of Mich Pilot Road seems like riding on rails. Side wall flex can be compensated to a degree by increasing the tyre pressure but in the end it is the intended application that the rider puts on the tyre that matters. Identical bikes with different tyres can be miles apart on handling due to tyre selection.
speedyandypandy
03-09-12, 05:40 PM
Stepping like yours is normally caused by one of two things on the rear, sometimes both at the same time.
1. suspension which your problem where
2. people using too much enginebreaking to slow down
Stepping on front is breaks or suspension.
Also one thing to remember is that countersteering saves tyre wear, people just 'dropping' it in have higher wear rate.
Giving it a large helping of right hand might have some barring on said patterns , heat include ;)
yorkie_chris
04-09-12, 08:04 AM
It was suggested to me that I email Michelin technical folks about this, so I did. The upshot was they asked to examine the tyre. They told me that the stepping on the outside was most likely caused by poor rebound damping, but that there was also evidence of the tyre overheating.
So I checked the rebound setting on my bog basic VFR standard shock and yes, someone prior to my ownership has turned down the rebound damping below 'standard' yet I had more preload on to compensate for the weight. Result was very little rebound for the amount of 'spring' in the rear. My bad for not checking this. So I have turned up rebound 'a lot' but still have about the same left if this proves to be not enough. It is up more than 50% over standard. Took it out for a brisk ride and the rear felt more planted and 'firm' with no squirming. There is a caveat to this, I was scrubbing in a new tyre so not giving it full beans. Subsequent short rides show the bike to more stable.
Michelin reckoned the overheating was caused by flex due to the weight being carried. The PR3 rear in 180/55R17 comes in two formats, standard and the 'B-type'. The 'B-type' has an extra sidewall ply and is recommended for regular pillion and luggage carrying. That is exactly the type of riding I am doing. However, my tyre fitter had put on a standard tyre as the B-type was not available when the tyre was fitted. So the tyre itself was too squiggly but is now replaced with a b-type rear so that should be cured. They also suggested adding some pressure to cope with the extra weight. I had a read around this subject and it seems the tyre should increase in pressure around 10% from cold to working temps. This worked out that I put in 2 psi extra and it goes up by the 10% when ridden with pillion in my normal manner.
Seems that there were a number of things not quite right, sorted now hopefully and I'll keep a close eye on the tyre over it's life.
a) I told you so :-P
b) Why increase pressure AND stiffness of tyre... try them at same pressures first now you got heavier carcass, IMO.
TheRamJam
04-09-12, 09:06 AM
As other folk have mentioned already try adjusting both rebound and compression settings first though instead of messing with tyre pressures. Try to have rebound balanced front and rear so the whole bike moves as one. For example if you push down the bike front and rear at the same time the bike rebounds at the same rate front and rear!
The Dave Moss videos are quite good and have used his video's to set up my suspension. Have a look at his On The Throttle website.
I have even made up a little excel document that automatically calculates the amount of SAG i need and also record the number of clicks for Rebound, Low Speed Compression, and High Speed Compression.
If you ride 2 up regularly and the bikes always loaded up i'd suggest maybe a stiffer rear spring and adjust your rebound and compression damping accordingly.
The ball park is around 5 to 10mm of static SAG on your shock and forks. When fully loaded ie rider, pillion, luggage etc you want around 30 to 40mm of SAG in your shock and forks.
Once you've got that dialled in, go ahead and remeasure your static SAG figure again. If the value is greater than 10mm then it may be best to buy a slightly harder spring, if its less than 5mm you need a slightly softer spring!
yorkie_chris
04-09-12, 09:11 AM
Don't bother getting too fancy about sag, the "right" numbers aren't from God or anything. Preload and ride height are all settings to get the ride height and chassis angles to behave how you want in various dynamic ways in the corners.
Luckypants
04-09-12, 09:18 AM
As other folk have mentioned already try adjusting both rebound and compression settings first though instead of messing with tyre pressures. I only have rebound adjustment. I'm following the advice of a tyre specialist from Michelin.
If you ride 2 up regularly and the bikes always loaded up i'd suggest maybe a stiffer rear spring and adjust your rebound and compression damping accordingly. I do most of my riding two up and I know the standard spring is not really up to it, but money supply is limited. I've started looking at Maxton/Nitron/Ohlins replacement shocks and fork upgrade to get best ride possible, but for the moment I'll have to stick with what I've got. :(
Thanks for the advice.
Dicky Ticker
04-09-12, 09:30 AM
If it isn't to personal a question taking the combination of rider,passenger and luggage how much weight in total are you loading on the bike?
Example Sprint ST max carrying capacity is 217kgs [Two fairly hefty people and luggage plus dont forget approx a kilo for every litre of fuel]
Myself and luggage plus a full tank of fuel comes to approx 140kgs.
If you are exceeding the max capacity no matter what you do with the current suspension you are going to induce odd tyre wear.
Tyres themselves also have a "Load" capacity making your tyre selection even more critical
Luckypants
04-09-12, 10:06 AM
Max payload is 195KG with a full tank. So two of us in gear plus the luggage is about 188kg. We are close to the limit but not over it.
As mentioned when I resurrected the thread, for this use I should have the 'B' rear fitted, which was not available when I fitted the original tyre. I now have the correct tyre for the load (although the A and B tyres both have same load rating).
barwel1992
04-09-12, 11:50 AM
I get that with my front tyre , don't like the feel with any other settings though so might see if it changes with the next tyre
careful with that axe eugene
to much rebound and your going to pack the rear down which = bad
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