Compression damping & tyre wear?

[Toast]

Tried out my forks newly kitted with Racetech stuff at Taupo on the weekend. Stoked with them and firmly believe that they gave me the confidence to go 1.5 seconds under my previous PB with very little effort.

They were bottoming out and shagging my front tyre as I upped the pace, though, and Robert Taylor has kindly sent me a couple of syringes of oil to help prevent this problem in future, which I think will take me some way close to a good setting for me.

For now though, I’d just like a bit of help explaining the effect of some of my adjustments on the day if anyone cares to comment

First session: Back end feeling really loose under brakes. Pace: 1:40.5. Tyre wear very clean.
Second session: Add ½ turn of compression. Back end mostly planted on corner entry, overall feels good. Pace: 1:39.5 Front tyre starting to tear a very small amount.
Third session: Add another ¼ turn of compression to see how that affects braking stability, and a slight improvement was noticed. Pace: 1:38.5 Front tyre starting to chew out real bad now (pic attached, though I can say that it's worse than the photo shows, and a couple of more experienced racers said it def wasn't good)

My feeling was that adding compression would mean the forks are bottoming out for a shorter period of time and thus screwing the tyre less (even though adding the compression was for a purpose other than reducing tyre wear)

However tyre rapeage and compression damping seem directly proportional from the above, if looked at individually.

So was the tearing getting worse simply because I was getting faster and compressing the forks more? Or is it possible that the tyre is doing the work of the suspension because the compression is too slow and that caused extra wear? Or maybe just ‘cos I was getting tired and not hanging off enough later in the day?

Opinions appreciated

Cheers,

Phil

[Shaun]

Tried out my forks newly kitted with Racetech stuff at Taupo on the weekend. Stoked with them and firmly believe that they gave me the confidence to go 1.5 seconds under my previous PB with very little effort.

They were bottoming out and shagging my front tyre as I upped the pace, though, and Robert Taylor has kindly sent me a couple of syringes of oil to help prevent this problem in future, which I think will take me some way close to a good setting for me.

For now though, I’d just like a bit of help explaining the effect of some of my adjustments on the day if anyone cares to comment

First session: Back end feeling really loose under brakes. Pace: 1:40.5. Tyre wear very clean.
Second session: Add ½ turn of compression. Back end mostly planted on corner entry, overall feels good. Pace: 1:39.5 Front tyre starting to tear a very small amount.
Third session: Add another ¼ turn of compression to see how that affects braking stability, and a slight improvement was noticed. Pace: 1:38.5 Front tyre starting to chew out real bad now (pic attached, though I can say that it's worse than the photo shows, and a couple of more experienced racers said it def wasn't good)

My feeling was that adding compression would mean the forks are bottoming out for a shorter period of time and thus screwing the tyre less (even though adding the compression was for a purpose other than reducing tyre wear)

However tyre rapeage and compression damping seem directly proportional from the above, if looked at individually.

So was the tearing getting worse simply because I was getting faster and compressing the forks more? Or is it possible that the tyre is doing the work of the suspension because the compression is too slow and that caused extra wear? Or maybe just ‘cos I was getting tired and not hanging off enough later in the day?

Opinions appreciated

Cheers,

Phil



I think you should call or email Robert direct mate! Bugger all people on here know what really is the problem, or how to fix it properlly.

Let me GUESS? that you have .9 forks springs in it?

[Toast]

I think you should call or email Robert direct mate! Bugger all people on here know what really is the problem, or how to fix it properlly.

Let me GUESS? that you have .9 forks springs in it?

Robert is a very busy man and last time I called him the line was crap and I forgot to ask (my bad)

As I said, Robert has provided a future solution, but I wanted to get some opinions on whether or not my compression damping changes could have contributed to it getting worse throughout the day.

I currently have 1.0 fork spings in there

[Shaun]

Robert is a very busy man and last time I called him the line was crap and I forgot to ask (my bad)

As I said, Robert has provided a future solution, but I wanted to get some opinions on whether or not my compression damping changes could have contributed to it getting worse throughout the day.

I currently have 1.0 fork spings in there


Springs are good mate. My guess is that as the forks are running so low in the stroke, this will be over working the tire, SO PUT IN the OIL!

Once your tire has started to rip like that. you will never correct it, it is just going to get worse and worse, it is trashed really.

[Robert Taylor]

Springs are good mate. My guess is that as the forks are running so low in the stroke, this will be over working the tire, SO PUT IN the OIL!

Once your tire has started to rip like that. you will never correct it, it is just going to get worse and worse, it is trashed really.

Thanks Shaun for your input / confirmation. Appreciated. ( Springs are 1s ) As is well known if you post on a forum with such questions you will maybe get some good answers but you will also get a lot of ( Im sorry ) rubbish posted back. Thats often dangerous and counterproductive to getting a good result.

You have actually answered most of your questions.

What is happening is a combination of things. As the front end has given you the confidence to go harder and arrive at the corners later there is indeed a lot more weight transferred quickly onto the front end very quickly. That overloads the tyre and causes what you are experiencing. Taupo is also a nasty surface that often raises such issues.
Adding oil gives more air spring compression ratio in the latter stages of travel so that will effect all or a good part of the cure. Perhaps also another turn or two on the preload adjusters and inwards on the compression adjusters 1/8 to 1/4 turn. PM me with the front static sag setting you ended up with and compression and rebound settings.
We have had a new phone system put in and I got the company to rip half of it back out as it wasnt real world friendly for those working at benches rather than desks. I blew my top at the ''suit'' peddling the stuff in a way that Shaun would be proud of!

[Toast]

Springs are good mate. My guess is that as the forks are running so low in the stroke, this will be over working the tire, SO PUT IN the OIL!

Once your tire has started to rip like that. you will never correct it, it is just going to get worse and worse, it is trashed really.

Yep, I'll def. put in the oil :niceone:

Bugger, didn't realise that the tyre was screwed once that started to happen. Thanks for the advice :)

[Toast]

Thanks Shaun for your input / confirmation. Appreciated. ( Springs are 1s ) As is well known if you post on a forum with such questions you will maybe get some good answers but you will also get a lot of ( Im sorry ) rubbish posted back. Thats often dangerous and counterproductive to getting a good result.

You have actually answered most of your questions.

What is happening is a combination of things. As the front end has given you the confidence to go harder and arrive at the corners later there is indeed a lot more weight transferred quickly onto the front end very quickly. That overloads the tyre and causes what you are experiencing. Taupo is also a nasty surface that often raises such issues.
Adding oil gives more air spring compression ratio in the latter stages of travel so that will effect all or a good part of the cure. Perhaps also another turn or two on the preload adjusters and inwards on the compression adjusters 1/8 to 1/4 turn. PM me with the front static sag setting you ended up with and compression and rebound settings.
We have had a new phone system put in and I got the company to rip half of it back out as it wasnt real world friendly for those working at benches rather than desks. I blew my top at the ''suit'' peddling the stuff in a way that Shaun would be proud of!

Cheers Robert, will drop you a PM now.

Glad you're sorting out the phones! The effect they gave was shockingly bad.

[Shaun]

Thanks Shaun for your input / confirmation. Appreciated. ( Springs are 1s ) As is well known if you post on a forum with such questions you will maybe get some good answers but you will also get a lot of ( Im sorry ) rubbish posted back. Thats often dangerous and counterproductive to getting a good result.

You have actually answered most of your questions.

What is happening is a combination of things. As the front end has given you the confidence to go harder and arrive at the corners later there is indeed a lot more weight transferred quickly onto the front end very quickly. That overloads the tyre and causes what you are experiencing. Taupo is also a nasty surface that often raises such issues.
Adding oil gives more air spring compression ratio in the latter stages of travel so that will effect all or a good part of the cure. Perhaps also another turn or two on the preload adjusters and inwards on the compression adjusters 1/8 to 1/4 turn. PM me with the front static sag setting you ended up with and compression and rebound settings.
We have had a new phone system put in and I got the company to rip half of it back out as it wasnt real world friendly for those working at benches rather than desks. I blew my top at the ''suit'' peddling the stuff in a way that Shaun would be proud of!




Hope ya barked at him a few times as well:bash:

[Robert Taylor]

Cheers Robert, will drop you a PM now.

Glad you're sorting out the phones! The effect they gave was shockingly bad.

And as per the pm actually doing a sag check ( with adding preload as neccessary ) would actually be a good idea.
Thanks re your comments about the phones, I was bullied into it as a solution. My skepticism was well founded.