Race Tyre Wear

Author
Discussion

seismic22

Original Poster:

653 posts

175 months

Monday 2nd August 2021
quotequote all
Hi, Im new to racing this year and am currently competing with the CRMC. I've just completed my 4th round of the season at Donny this weekend and want to get to the bottom of the front tyre wear, see picture below:



The tyre was brand new Saturday and that's what it looked like after quali and 4 sprint races. The tyre is an Avon AM22 Soft running approx 29 psi which is around what most of the grid seem to run (16 inch rim). I'm returning ok'ish results but I am a bib wearing novice!

So question is, is that wear normal or is there something going on? Think it's best I let you guys decide rather than me suggest what I think it is and leading you down the garden path..... Advice I've received from others on the grid is in my class the front should be lasting a lot longer than the rear but that doesn't seem to be happening...

Cheers!

Edited by seismic22 on Monday 2nd August 19:14

Steve Bass

10,329 posts

239 months

Monday 2nd August 2021
quotequote all
Suspension is set up incorrectly. Probably too slow rebound and stiff compression.
What are your settings at?

Drabbesttunic

1,308 posts

46 months

Monday 2nd August 2021
quotequote all
Hard to be Bob on but that looks like geometry tear which is too much weight on the front tyre.

Ray Luxury-Yacht

8,913 posts

222 months

Monday 2nd August 2021
quotequote all
Looks a bit like cold tearing to me. Are you using tyre warmers? And what bike is this?

seismic22

Original Poster:

653 posts

175 months

Monday 2nd August 2021
quotequote all
Bike is a 1986 Yamaha FZ600 running in a Post Classic Production Class.

All I've done setup wise since purchasing from prev owner who competed on the bike for many years is fit clip ons below the yokes, change fork oil and set sag by adding a v.small amount of preload front (using bigger spacer) and a reasonable bit on the rear. Forks are non adjustable. Currently running .90 springs but Racetech website calcs suggest I should be running at least .95 springs. I am a bit of a heavy hector at 100kg without gear on.

seismic22

Original Poster:

653 posts

175 months

Monday 2nd August 2021
quotequote all
Not using tyre warmers - not allowed.

underwhelmist

1,882 posts

140 months

Tuesday 3rd August 2021
quotequote all
Worst "I've got no chicken strips" post ever! smile

Drawweight

3,060 posts

122 months

Tuesday 3rd August 2021
quotequote all

Your weight incorporated with the move to clip ons will be adding substantially to the weight on the front of the compared to the previous owner ( who presumably was a bit lighter)

If you know your way around a bike it is fixable but you might be better throwing a few quid at a professional and get it set up for your weight front and rear.

Do it once and you probably won’t have to touch it again as opposed to constantly trying to change this and that.

Biker's Nemesis

39,582 posts

214 months

Tuesday 3rd August 2021
quotequote all
I'm 15 stone and run 10.5 front springs


Steve Bass

10,329 posts

239 months

Tuesday 3rd August 2021
quotequote all
Biker's Nemesis said:
I'm 15 stone and run 10.5 front springs
12 stone nekid and I run a mix of a 10 and a 10.5 in the front......

Rubin215

4,085 posts

162 months

Tuesday 3rd August 2021
quotequote all
Steve Bass said:
Biker's Nemesis said:
I'm 15 stone and run 10.5 front springs
12 stone nekid and I run a mix of a 10 and a 10.5 in the front......
Different spring weights?
If you listen to some folks, you should already be dead...

rofl

Edited by Rubin215 on Wednesday 4th August 00:27

Biker's Nemesis

39,582 posts

214 months

Wednesday 4th August 2021
quotequote all
Rubin215 said:
Different spring weights?
If you listen to some folks, you should already be dead...

rofl

Edited by Rubin215 on Wednesday 4th August 00:27
Now what are you laughing at Ruby. You been on the shortbread and whisky again?

Biker's Nemesis

39,582 posts

214 months

Thursday 5th August 2021
quotequote all
Come on Mr Ruby.. explain yourself Sir.

Biker's Nemesis

39,582 posts

214 months

Thursday 5th August 2021
quotequote all
Ruby!

Biker's Nemesis

39,582 posts

214 months

Saturday 7th August 2021
quotequote all
Ruby.

underwhelmist

1,882 posts

140 months

Saturday 7th August 2021
quotequote all
I don't think he's listening BN.

Out of interest, running different rate springs in each fork leg sounds a bit odd to me, not that I know anything about suspension. How did you settle on that combination?

moto_traxport

4,238 posts

227 months

Saturday 7th August 2021
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Doesn’t look entirely unusual tyre wear for that type of tyre in the classic racing paddock. Probably a combination of the whole set up - no warmers & poss too soft springs for rider weight (rear as well? - that could bring geometry tear into it as mentioned by others).

What do the tyres look like on the chaps running at the front in the same class?

underwhelmist said:
Out of interest, running different rate springs in each fork leg sounds a bit odd to me, not that I know anything about suspension. How did you settle on that combination?
Not uncommon if you want to get to spring rate half way between those available. He’s obviously fiddled enough (oh for the time & enthusiasm!) to work out he needs 10.25 so put 10.0 in one leg and 10.5 in the other. The forks are bolted to each other in the yokes and the front axle so you can ask them to do different stuff for an outcome that is a combination of the two set ups. Quite common to have compression damping in one side and rebound in the other.

It can also been seen as a back handed complement to ‘need’ heavy springs to cope with your faaaasst riding whereas lots of factors come into play - bike type & weight, rider weight, braking style (more in a straight line or more trail brake), tyre make, type & pressure blah blah blah! or Ruby Ruby Ruby! if you want.

Biker's Nemesis

39,582 posts

214 months

Saturday 7th August 2021
quotequote all
I run 10.5's in my track bike because if I run anything less the forks bottom out under braking.

seismic22

Original Poster:

653 posts

175 months

Saturday 7th August 2021
quotequote all
Drawweight said:
Your weight incorporated with the move to clip ons will be adding substantially to the weight on the front of the compared to the previous owner ( who presumably was a bit lighter)

If you know your way around a bike it is fixable but you might be better throwing a few quid at a professional and get it set up for your weight front and rear.

Do it once and you probably won’t have to touch it again as opposed to constantly trying to change this and that.
I know my way around a bike pretty well but setup for track is fairly new for me. I'm in a location where anyone who could setup the bike for me is quite a trek (outside Exeter, Devon) but I won't rule it out. Ideally I'd like to sort it myself though, if only so I can learn.

seismic22

Original Poster:

653 posts

175 months

Saturday 7th August 2021
quotequote all
moto_traxport said:
Not uncommon if you want to get to spring rate half way between those available. He’s obviously fiddled enough (oh for the time & enthusiasm!) to work out he needs 10.25 so put 10.0 in one leg and 10.5 in the other. The forks are bolted to each other in the yokes and the front axle so you can ask them to do different stuff for an outcome that is a combination of the two set ups. Quite common to have compression damping in one side and rebound in the other.

It can also been seen as a back handed complement to ‘need’ heavy springs to cope with your faaaasst riding whereas lots of factors come into play - bike type & weight, rider weight, braking style (more in a straight line or more trail brake), tyre make, type & pressure blah blah blah! or Ruby Ruby Ruby! if you want.
Cheers. I've not managed to grab a look at the tyres of the top 5 but I've seen a couple fronts on those in the mid pack and they are not quite like mine. Infact one fast chap in the top 10 but who's crashed a bit has had his front on for the last 4 rounds and his show no specific wear type.

Im fatter than prev owner, have dropped clip on below the yokes and upped the rear preload a bit to get the sag right so I'm guessing the combination of all that has overwhelmed the springs that are too soft....so I guess that's where I start....