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Interesting tyre wear...

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Gremin View Drop Down
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    Posted: 01 Jul 2022 at 16:13
Hi,
I've noticed that the M9RR rearon my 2015 Tuono is waering in a strange way.

The "leading edge" of the grooves of the tyre is wearing more quickly so the front edge is lower than the rear edge.

I'm sure I read years ago that this was due to the rear shock rebound setting but not been able to find the article.

Any ideas?

Ta :-)


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Post Options Post Options   Thanks (1) Thanks(1)   Quote IanG Quote  Post ReplyReply Direct Link To This Post Posted: 01 Jul 2022 at 17:17
It was one of Dave Moss's vids I think,can't remember off hand if it was too much or not enough rebound though
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Post Options Post Options   Thanks (1) Thanks(1)   Quote legend88 Quote  Post ReplyReply Direct Link To This Post Posted: 01 Jul 2022 at 17:45
If the leading edge of the tread is rounding off and the trailing edge is sharp then rebound is too fast so more rebound damping needed.

I've just had my Ohlins forks rebuilt as I couldn't get any control no matter what I did. Turns out the oil was 'like water' and I was pretty much just running on the springs. It had certainly lost that amazing ride quality over bumps that attracted me to the bike on that very first test ride. Really looking forward to seeing what it's like now as I've just got them put back in the bike.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote blacklines Quote  Post ReplyReply Direct Link To This Post Posted: 04 Jul 2022 at 11:41
I could never get my head around that Dave Moss thing. Surely it's more likely to be one side wearing from throttle, the other from engine braking? If shock rebound was quick enough to react to the tiny sipes in the tyres then it must be completely un-damped. 

The sporadic wear you can see sometimes is related to too little rebound as the bike bounces on the power. But otherwise I think it's quite hard to run too little rebound as it gives less stability and can feel a little un-nerving to ride. But generally most grip is found with less rebound damping than many prefer. You might feel more stable with more, but you get less grip and work the tyres harder. But then with less you have to be smoother with the controls or scare yourself. Like letting off the brakes too abruptly when trail braking is obvious with fast rebound, but with a lot of damping it picks up and covers up your mistake.

Anyway, long story short I've looked at that picture and can't see anything wrong with the tyre. Certainly nothing that'd make me want to change damping for. How does it ride? Does it wallow and bend around corners? Does the front and rear bounce and return at a similar rate? I tend to aim for it returning as fast as possible without overshooting. Whichever end does that the slowest becomes the rate both ends want to rebound. But if you've got no bother with the bike I wouldn't change anything.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ice-mille Quote  Post ReplyReply Direct Link To This Post Posted: 05 Jul 2022 at 10:19
Air pressure?
Shake'n bake
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Post Options Post Options   Thanks (0) Thanks(0)   Quote greenman1966 Quote  Post ReplyReply Direct Link To This Post Posted: 05 Jul 2022 at 23:01
what I found with the Dave Moss vidoes is that he doesn't want to give away everything, but not enough rebound is very common on road bikes, next is tyre pressure too low, and then there is how you ride. If you coast through corners then you get the same leading edge wear too. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote IanG Quote  Post ReplyReply Direct Link To This Post Posted: 06 Jul 2022 at 19:50
Originally posted by greenman1966 greenman1966 wrote:

what I found with the Dave Moss vidoes is that he doesn't want to give away everything,

I used to belong (actually probably still do) to an online suspension forum frequented by many of the suspension pro's from around the world who wanted somewhere not manufacturer controlled to chill and discuss things, and I recall when someone mentioned Dave Moss's name it was apparent he wasn't afforded the 'adulation' from his supposed peers that his channel would suggest.

Who knows why?

Suspension is really not a black art,I think a lot of it comes with practice and an eye to detail

Originally posted by greenman1966 greenman1966 wrote:

but not enough rebound is very common on road bikes, next is tyre pressure too low, and then there is how you ride. If you coast through corners then you get the same leading edge wear too.


And the underlying cause is probably described there.  I tend to use the engine braking effect rather more than I should for instance
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Post Options Post Options   Thanks (0) Thanks(0)   Quote camngetit Quote  Post ReplyReply Direct Link To This Post Posted: 07 Jul 2022 at 23:30
I put up some pics of my tyres after a mallory trackday to ask if they looked ok or what could be done if not ,many diff answers some could of been right some poss taking the piss ,wasnt on here the ap facebook page ,i know people in the know dont like giving all their info away but a nod in the right direction would be nice 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote blacklines Quote  Post ReplyReply Direct Link To This Post Posted: 08 Jul 2022 at 10:13
Ha I lasted all of a couple weeks looking at facebook groups. Don't go on there very often and wanted to see bike stuff when I did. Had to take it off because it was mostly bollocks. 

Think final straw for me was there was a guy asking for what shock spring for a gen 1 for his weight. Loads of jokes about him needing a spring from a truck or whatever. But really I think no one really knew. Just sat there idly scrolling and making inane comments at people. At least on the forums you get people who try to give some information. Anyway, I told that guy what I use because we were a similar weight. And on the fat jokes thing, I don't think anyone who's met me would call me obese. Too skinny if anything. Just a bunch of idiots on there.

But yeah, even when people are seriously trying to help you there are a lot of conflicting opinions. Even among experts. Like ask a quick rider about your tyre wear and they'll tell you what you are doing wrong with your riding and how to change that. Ask the suspension guy in the paddock and he'll tell you what is wrong with your suspension. They're both right. Or maybe the answer is in the middle somewhere. 

Then you have middling track riders like myself with a tiny bit of suspension knowledge offering opinions too. Or even just people who've watched a few Dave Moss videos. Or just repeated what someone else on a forum has said. 

Honestly, best advice I can give is either:
a) Make a good, ongoing relationship with a suspension guy at the track and just do what they tell you to.
OR
b) Just ask the tyre guy at the track if you are seeing tearing (you don't look to be in that picture).
OR
c) Devote some time to reading books on it and trying to understand it for yourself. If you can understand the basics, then you can work through why something might be happening. If you want to go this route I'd start with watching the Traxxion Dynamics videos:

and reading the Race Tech Suspension Bible. 
Owen
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Post Options Post Options   Thanks (0) Thanks(0)   Quote wigginsjp Quote  Post ReplyReply Direct Link To This Post Posted: 08 Jul 2022 at 11:20
I agree totally with A & B for track days and racing 

For a road bike I’d just go and get it set up for my weight if I wasn’t confident myself. It’s cheap and that way the bike will be practically spot on. May find the spring weight is incorrect as most of us are heavier than the superlights the spring was designed for. I’m certainly not heavy, but every Aprilia I’ve owned has had to have an upgraded spring. Exception being the current Tuono. 

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Post Options Post Options   Thanks (0) Thanks(0)   Quote blacklines Quote  Post ReplyReply Direct Link To This Post Posted: 08 Jul 2022 at 11:55
Yeah for whatever reason I've been on a couple other bikes and had no issue with the shock. But on my bike I had to go up a couple rates to not be squatting at the rear. Then once I've done that I've had a few other people of varying weights go on my bike and find it ok. I think these bikes should have come with a 105 Nm/mm stock. Rather than 90 Nm/mm or 85 or whatever it is they come with from the factory.

EDIT: Woah sorry, just remembered you're talking 2015 Tuono here. My experience is only with a gen 1 RSV. Couldn't tell you what the shock springs are like on the V4s. For some reason on this forum I assume we're all still talking about 20 year old bikes 😂
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Post Options Post Options   Thanks (0) Thanks(0)   Quote IanG Quote  Post ReplyReply Direct Link To This Post Posted: 08 Jul 2022 at 14:55
Yep none of them fancy computery gismo's on proper bikes Wink 

LOL




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Post Options Post Options   Thanks (0) Thanks(0)   Quote camngetit Quote  Post ReplyReply Direct Link To This Post Posted: 08 Jul 2022 at 16:04
All good suggestions thanks ,i have done the suspension day ay griffs some years back and the theory side i totally get its just deciphering what the bikes doing as to what or which way wants tweeking ,i aint on the small side and have got heavier fork springs and rear spring and set all the sag up and to be fair the bike has never felt off just wanted to be sure with the tyre wear 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote blacklines Quote  Post ReplyReply Direct Link To This Post Posted: 12 Jul 2022 at 09:32
I wouldn't worry then. Can't see anything untoward in that picture.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Gremin Quote  Post ReplyReply Direct Link To This Post Posted: 17 Jul 2022 at 21:31
Hi all,

Thanks for the input. The bike handles really well.

I set it up quite stiff as that's how I prefer it. I'm 13st with my gear on and the bike doesn't wallow or bog down on the power. Also, really stable on the brakes and tracks well in corners.

The turn in isn't as sharp as my Street Triple but that's a smaller lighter bike but once it's turned in it's super stable and confidence inspiring.

Thx.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote IanG Quote  Post ReplyReply Direct Link To This Post Posted: 17 Jul 2022 at 21:50
Originally posted by blacklines blacklines wrote:

Yeah for whatever reason I've been on a couple other bikes and had no issue with the shock. But on my bike I had to go up a couple rates to not be squatting at the rear. Then once I've done that I've had a few other people of varying weights go on my bike and find it ok. I think these bikes should have come with a 105 Nm/mm stock. Rather than 90 Nm/mm or 85 or whatever it is they come with from the factory.



That was my finding on the front of my Gen2 T, now fully kitted up I guess I might have been pushing 16st+ and far from the skinny Italian the bike was probably designed for but I found I needed so much fork preload that there was zero static sag!

Definitely need a stronger spring although I'm probably getting on for 2st lighter now.  I have KTech internals and clickers to fit along with SKF seals when I strip the forks so I'll probably set that up first then look into uprated springs afterwards.

Strangely the stock Sachs rear damper seems in the ballpark spring rate wise.  Crap damping though

And then it'll probably get used twice a year like the Mille Embarrassed
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