Quick track tyre-wear question…

[Tribal Chestnut]

Had a bit of conflicting info on the cause of this, so thought I’d see if any one on here had a suggestion.

Metzler TD Slick, was run at 27 for 1.5 days, then dropped it to 25 for another day before it felt to wobbley. Did half a day at Donington beforehand.

Edit: air temp about 25 degC. Bike is a GSXR-750, L0 (no TC etc).

Is it cold tear? Hot tear as pressure was too high at first? Suspension? Bought the bike from a friend who is about 11-12 stone, I’m a bit over 14, & left on the settings he had. I do intend having it set up properly for my weight over winter, though I might firm it up a little.

Others have suggested my riding style - needing to lean the bike more, though I’m trying to keep it as upright as possible to increase the contact patch, which I thought was the right thing to do…?

I did have a very helpful chap from a quicker group drop down and follow me for a session and, aside from tidying up lines and breaking points, his suggestion on body position was that I need to get my head lower and into the corner more, so nothing massively wrong with what I was doing previously.

In hindsight I should have swapped it after day two, then I could have enjoyed all of day three.

Very grateful for any constructive advice (hence why I’ve posted here & not certain other places…).

Thanks

Edited by Tribal Chestnut on Monday 19th September 10:57

Edited by Tribal Chestnut on Monday 19th September 10:57

[Sidecar Man]

You might find this helpful.
https://lifeatlean.com/motorcycle-tyre-wear-guide/

[_Neal_]

Sidecar Man said:

You might find this helpful.
https://lifeatlean.com/motorcycle-tyre-wear-guide/

Really interesting stuff, thanks for posting that. Cold tear then by the looks of it OP, but pretty hard to tell from photo alone.

[Sidecar Man]

Yeah I would say cold tyre. Are you using warmers? What make. And have you ever checked tyre temperature?

[Steve Bass]

From the one pic posted, I'd say it's hot tear as the rips don't seem to penetrate too deeply into the carcass as they do with a classic cold tear.

Either way, check the suspension and spring settings as well as HOT tyre pressures. And if you're using warmers, make sure the rim is warm, not just the tyre surface.
And aside from warmers, it's a good idea to pop through the pits on the first session to check the tyre pressures once they're in use. Many peeps actually fail to maintain the tyre temp by riding to conservatively for the tyre type/construction etc and the tyres cool significantly from the moment the warmers come off which can cause issues.

[tafkattn]

I was going say I think it looks like hot tear too. 25-27psi may be a little on the low side if the tyre isn't being worked hard enough to keep the pressures up.

However, no expert and certainly not a fast group riding god so take what I say with a mountain of salt.

[Tribal Chestnut]

Thanks guys, feedback much appreciated. Will take a look at that link.

Suspension will be getting fiddled over winter, by someone who knows what they are doing, though it’s something I’d like/need to learn.

Wasn’t checking pressures religiously straight after each session, but did a few times and they seemed to be fairly consistent around 24-26.

The wear pattern started when I was running them higher, at about 27. Did try and stay within the guidance envelope of 25-27 when coming off the warmers.

I might invest in a tyre thermometer at some point.

[Steve Bass]

Tribal Chestnut said:

Thanks guys, feedback much appreciated. Will take a look at that link.

Suspension will be getting fiddled over winter, by someone who knows what they are doing, though it’s something I’d like/need to learn.

Wasn’t checking pressures religiously straight after each session, but did a few times and they seemed to be fairly consistent around 24-26.

The wear pattern started when I was running them higher, at about 27. Did try and stay within the guidance envelope of 25-27 when coming off the warmers.

I might invest in a tyre thermometer at some point.

The other question you need to be honest about is whether you're going fast enough out of the gates or taking a few laps to 'warm up'?? These build up laps can actually cause the tyres to lose temperature from the temps they have coming out of the warmers so throwing your calcs out.
Simple rule, come off the warmers and go flat out, no build ups, no fannying around... and make sure the pressures are spot on in the warmers, don't factor in any changes that might occur on track...

Also, check the manufacturers guidance pressures against the target track temp.... surface temp plays a big part.
Re suspension set up, it's very easy:
measure sag
adjust sag
change springs if necessary
set rebound to mid point
Rebound is FAR more important than compression.
check rebound for 'double bounce' when manually compressing suspension.
adjust as required
set compression to mid point
Ride
enjoy

Edited by Steve Bass on Tuesday 20th September 16:59

[Tribal Chestnut]

Thanks for that Steve, helpful as ever.

Generally been pretty good with pressures, but you’re right re. going slow initially and building up - don’t always do this, but maybe often enough to make a difference.

[Steve Bass]

Tribal Chestnut said:

Thanks for that Steve, helpful as ever.

Generally been pretty good with pressures, but you’re right re. going slow initially and building up - don’t always do this, but maybe often enough to make a difference.

Another thing..

Once you've scarred a tyre with hot or cold tear, it's unlikely to clean up once the damage is done. The tears can often damage so much of the surface layers across the tyre's traction loaded area it's done for and no end of fiddling with pressures will clean it up.
Simple rule of thumb, check pressures after a good time in the warmers and the rim in-between the spokes or around the valve is warm to the touch. Once the warmers are off, try to get to the track asap and once on track, get going to maintain the heat in the carcass. Remember, it's cornering at speed that puts the most heat into a carcass. Acceleration and braking are minuscule by comparison...
Some years ago we had a similar issue with the tyres cooling on a (freezing!!) cold & windy track and only by the 3rd session did we measure pressures coming in through pit lane mid session see that they were dropping significantly from the 'out of the warmer' pressure because we were seeing tyre tearing starting...
So we bumped them back up in the pitlane and it seemed to work but the actual pressures we arrived at would never have been what would have been used when in the warmers.

[Steve Bass]

Eileen K Ramirez said:

Don’t overthink this. Just simply buy a new tire, swap it, and take it easy on your corner entry speed. I’m sure there’s something to do with weight transfer, but I’m not sure what. I know that when I’m riding my bike on the track and it catches on the rear I come in too hot. I’m probably not on the throttle hard enough. So next time you’re at the track, try easing up the throttle just a bit. That’s probably the simplest fix for it.

[tafkattn]