PDA

View Full Version : Suspension-- Tire wear issue


Drew13
08-20-2008, 08:16 AM
Hey guys, I read the thread in this section on sending the forks out and I may do that. Defan told me that the stock suspension isnt cutting it. The bike should hold its line in the turn but mine wants to run wide and I'm forcing it to hold. Which results in a front tire like this: (one day on the tire)

http://photos.imageevent.com/drew231506/gsxr600/websize/IMG_3515.JPG

What do you guys think? Could it have been tire pressure instead? I don't know much about suspension and I've only ridden my stock bike so I wouldn't even know what to look for. Except I can't be buying a new tire every track day.

How difficult is it to remove your forks? I can take my wheels off now, which is pretty sweet. :lol: Any idea on turnaround when you send them out? I guess I'll shoot them an email as well.

GUess the track from the tire and pic??
http://photos.imageevent.com/drew231506/gsxr600/websize/shenny%208.18.08.JPG

lateapex
08-20-2008, 09:10 AM
Follow what DeFran said and get the fork done. Removing the forks is no big deal, they slide out of the upper and lower triple clamps. Just mark the location of the handlebars so you can put them back in the same spot, use whiteout or a white tire pen and draw a line on the bar clamp and the upper triple. Ther may be other minor stiff that needs to be removed but it's a easy job. The hard part is looking at the bike with no forks on it :-)

This time of year the suspension guys are not as busy as in the spring so the turnaround time should be quick.

IrocRob
08-20-2008, 09:54 AM
Definately get the forks done. I rebuilt my own with RaceTech springs
and an Ohlins valve kit and it is well worth the money. While the bike is
apart you may as well get the rear shock rebuilt also, if you haven't
already upgraded that.

Turn around time should be pretty quick if they have all the required
parts in house, the actual work takes just a few hours to complete.

Chris
08-20-2008, 10:24 AM
Are you using tire warmers? Are you chopping the throttle while in the turn or at neutral throttle? Might be pushing the front trying to enter to fast.Slow in fast out.

ronaldo9
08-20-2008, 10:58 AM
Drew, Troy (Landshark) shimmed my rear shock and flushed the forks and that helped me dramatically at Beaver Run bc I had the same problem. Maybe try that before sending your forks out. Nevertheless I hear its a great thing to do to get suspension work done. I'm still on my stock 600 as well.

Cakes206
08-20-2008, 10:58 AM
Was the stock suspension ever set to your weight to begin with? Our suspensions are pretty damn good out of the box. What psi were you running?

carl_g
08-20-2008, 01:18 PM
If you are running wide in the turns the back end is squatting forcing the bike to be like a chopper and not want to turn. You might want to check the ride height and preload on the rear shock first

Jake
08-20-2008, 01:56 PM
Defan told me that the stock suspension isnt cutting it. I didn't see that one coming. :ohmygod:

Drew13
08-20-2008, 05:04 PM
Are you using tire warmers? Are you chopping the throttle while in the turn or at neutral throttle? Might be pushing the front trying to enter to fast.Slow in fast out.

I am not using tire warmers, I just take it easy a couple of laps. I def don't chop the throttle while in the turn. As far as entering to fast...I can't answer that. You going to be at Shennandoah Aug 30/31? Maybe you can check me out?

Was the stock suspension ever set to your weight to begin with? Our suspensions are pretty damn good out of the box. What psi were you running?

Yep Cakes, did it myself. Turned out I didn't have to touch a thing...measured out perfect. :huh: But again the key words are "did it myself" My PSIs: I started the day 29/29 cold. Was around 32 hot...and tried taking a little bit out before last session.

Originally Posted by drew231506
Defan told me that the stock suspension isnt cutting it.

I didn't see that one coming.

It was sorta funny that my buddy's rear was wearing funny and Defan told him "It's a CBR problem, needs a new shock." Then I went over and he said, "It's a gixxer problem...." But I'm sure he's good at what he does and I may go that route.

Hmmmm...guess I should pick something...

Jake
08-20-2008, 05:37 PM
It was sorta funny that my buddy's rear was wearing funny and Defan told him "It's a CBR problem, needs a new shock." Then I went over and he said, "It's a gixxer problem...." But I'm sure he's good at what he does and I may go that route.


I would suggest going to Washington Cycle Works first.

JimRBlue
08-20-2008, 06:57 PM
I would suggest going to Washington Cycle Works first.


I would suggest the same..

High_Revs_17
08-20-2008, 08:28 PM
+3...WCW's very proactive with "bike problems".

I would suggest the same..

Chris
08-20-2008, 08:58 PM
I'll be at beaver for the sunday and I'll be at summit for the ccs races.I can help you set the stock suspenion up.I was going fast on stock suspenion and my tires didnt look like that and im a big guy..lol I had the same problem with my old gixxer and it was me not the bike.I was entering to fast and coasting through the corner off the gas causing all of the weight on the front wheel.Once i learned about neutral throttle it all went away.

brianfults51
08-20-2008, 09:11 PM
my tire did the same thing, but it was only on the left side. now if you were at shenandoa the left side of the front takes a beating. i think that my tire was to hot on the left side. maybe a little more air would help us both. this only happened to me when i really started pushing it really hard. i was at 31, 31 hot, i will try 31,32 next time. try air preasure frist befor spending time and money on shocks, just my 2 cents

Drew13
08-20-2008, 10:13 PM
I found this little blurb on the WERA site...maybe I'll try a little higher pressure next time. "At Miller we had to run the front Pro's at 35-36psi hot to get them to stay together, rears we ran anywhere from 27-30psi hot depending on the track temp"

Drew13
08-25-2008, 08:29 PM
Saw this posted on this site. The second one is my tire!! So it says:

SHOCK SPRING TEAR
When the shock spring is too soft or too hard, the tire carcass is put under extreme duress to the point where the tire shreds and melts. This can be determined by measuring sag to see if the target number cannot be reached firstly, without considerably adding preload to the spring or secondly, if all the preload is off the spring.

Now what does that mean? haha.

http://www.feelthetrack.com/Art/tire-wear.jpg

RCM78
08-26-2008, 11:45 AM
http://www.sportrider.com/tech/146_0308_geek/index.html

CORNBREAD
08-26-2008, 12:47 PM
The link rcm provided is a great resource.

WCW will always get my business. Not only are they knowledgable but great guys as well.

FDNYDANO18
08-26-2008, 12:47 PM
Saw this posted on this site. The second one is my tire!! So it says:

SHOCK SPRING TEAR
When the shock spring is too soft or too hard, the tire carcass is put under extreme duress to the point where the tire shreds and melts. This can be determined by measuring sag to see if the target number cannot be reached firstly, without considerably adding preload to the spring or secondly, if all the preload is off the spring.

Now what does that mean? haha.

http://www.feelthetrack.com/Art/tire-wear.jpg

It means.... see if you have the correct rate/strength spring to properly set sag.... if you are not able to properly set sag with the spring you have then all the rest of the adjustments count for nothing. Setting sag is the starting point. If your spring is wrong your tire becomes your suspension and the tire ends up looking like yours.

Trackdaze
08-26-2008, 03:23 PM
Hey guys, I read the thread in this section on sending the forks out and I may do that. Defan told me that the stock suspension isnt cutting it. The bike should hold its line in the turn but mine wants to run wide and I'm forcing it to hold. Which results in a front tire like this: (one day on the tire)

http://photos.imageevent.com/drew231506/gsxr600/websize/IMG_3515.JPG

What do you guys think? Could it have been tire pressure instead? I don't know much about suspension and I've only ridden my stock bike so I wouldn't even know what to look for. Except I can't be buying a new tire every track day.

How difficult is it to remove your forks? I can take my wheels off now, which is pretty sweet. :lol: Any idea on turnaround when you send them out? I guess I'll shoot them an email as well.

GUess the track from the tire and pic??
http://photos.imageevent.com/drew231506/gsxr600/websize/shenny%208.18.08.JPG

To me, that looks more like hot tear than spring tear. But I would still check sag front and back as well as have someone with knowledge like Dafan look at the suspension.

But I would bet that is hot tear MORE than spring tear.

Drew13
08-26-2008, 11:07 PM
Okay I had suspension set up by Rick at RNR Cycles, he was nearby and fit me in today. He said my suspension was set up to firm but the spring would be decent for my weight. He set the sag with 35mm front 36mm rear...seems like a lot to me if i remember correctly. Ill prolly redo it with a buddy to double check after doing some research. He also changed the fork oil. I went for a short ride tonight and i think i noticed a difference...it felt taller and a bit more nimble...but who the hell knows I may be making that up.

I'm a little nervous my suspension is going to be all jacked up now.

I'm going to try to flip that tire for this weekend to see what kind of wear I will get out of it. Should be interesting...

RCM78
08-27-2008, 07:39 AM
35mm up front is the norm. 36mm out back is more then usual. 25-30 is the norm.

Drew13
08-27-2008, 09:03 AM
To me, that looks more like hot tear than spring tear. But I would still check sag front and back as well as have someone with knowledge like Dafan look at the suspension.

But I would bet that is hot tear MORE than spring tear.

Yea you could be right. I'll keep a better eye on tire pressure this time as well.

Cakes206
08-27-2008, 10:34 AM
What were your sag #'s to start off with before it got changed to 35mm-f and 36mm-r? Thats opposite of what you'd ultimately want to accomplish. They way they put it now the front end is sitting higher than the rear, which might feel "nimble" on the street(because the front is up higher changing CoG) but won't want to turn at higher speeds.

Drew13
08-28-2008, 10:33 AM
I'm going to redo the sag and double check what he did. It feels squishy, I think I'm going to set it between 25-30mm to start and do what you said Cakes.

SO has anyone flipped a front Supercorsa Pro?? I just had the one pictured flipped since I'll be at Shenny this weekend again. They also put these Dyna Beads into the tire to balance it?? I'll have to do some research...not real thrilled they did that.

Jake
08-28-2008, 11:13 AM
I've ridden with a front SC pro flipped. No big deal.

lateapex
08-28-2008, 12:19 PM
I've ridden with a front SC pro flipped. No big deal.

Do it all the time, no problem.

Trackdaze
08-28-2008, 01:06 PM
You also have a rebound issue

You will notice the leading edge of the sipe is high while the trailing edge is chamfered also you see how the hot tear below each sipe is a bit cleaner. The tire is skipping over each sipe.

acronut
08-28-2008, 01:45 PM
If you're to far to go see Ron at WCW at least give him a call. He can probably give you the best place to start. (908) 835-0043

Drew13
08-28-2008, 11:36 PM
If you're to far to go see Ron at WCW at least give him a call. He can probably give you the best place to start. (908) 835-0043

Ok I will if it continues.


The rider sag is set for 36mm Front/ 24mm Rear, that should be fine. I'm now leaning more towards the hot tear than the spring tear. I have tire warmers for this weekend and I'll be checking the pressure. I'll let you know the results...

Thanks for the help!

Cakes206
08-29-2008, 07:24 AM
Ok I will if it continues.


The rider sag is set for 36mm Front/ 24mm Rear, that should be fine. I'm now leaning more towards the hot tear than the spring tear. I have tire warmers for this weekend and I'll be checking the pressure. I'll let you know the results...

Thanks for the help!
With that 24mm do you have enough static sag? I happen to be on the phone with Ron for something else, he was sayin about a 7mm spread between f/r is about average.

pillaka
09-02-2008, 12:06 AM
Check your tire pressures when you come right off the track, you're aiming for a hot pressure of 32 front 29 rear. I usually well check my pressures when the warmers are at there peak temp, but once I come off the track the pressure will go up 1 - 3 psi. Additionally you'll have to check continuously throughout the day.

To quote your "The bike should hold its line in the turn but mine wants to run wide and I'm forcing it to hold" - thats why the tire is getting ripped up, you can mess with the suspension but is there a way you can alter your riding to use it to your advantage? Turning in earlier, then getting on the gas sooner? What about trailer braking a little harder to compress the front end more to keep a steeper rake angle? When does the bike fell like it running wide, entry, mid corner, or exit?

Trackdaze
09-02-2008, 03:53 PM
Check your tire pressures when you come right off the track, you're aiming for a hot pressure of 32 front 29 rear. I usually well check my pressures when the warmers are at there peak temp, but once I come off the track the pressure will go up 1 - 3 psi. Additionally you'll have to check continuously throughout the day.

To quote your "The bike should hold its line in the turn but mine wants to run wide and I'm forcing it to hold" - thats why the tire is getting ripped up, you can mess with the suspension but is there a way you can alter your riding to use it to your advantage? Turning in earlier, then getting on the gas sooner? What about trailer braking a little harder to compress the front end more to keep a steeper rake angle? When does the bike fell like it running wide, entry, mid corner, or exit?


Trailer braking? My trailer doesn't even have brakes :roflmao:

J/K

Drew13
09-02-2008, 05:16 PM
Days 1 & 2 Shenandoah: (try to make it short)

tire warmers tire pressure 31 front, 29 rear hot all day. Ignored the first session then went out the second session and it felt terrible again. (disclaimer- there is a possibility this is all in my head and there is also a possibility that lack of skill is a contributing factor) The front end felt really light coming out of corners and was wobbling sometimes. I couldnt steer it and it would push wide hard. When I came in, I had the sag measured and the front was 46mm somehow. So we turned the preload all the way stiff and got it down to 35mm in front. It did feel better and I trusted it more and ran my best time of 26.6.

The front tire looked terrible again...maybe worse than before. I'm not sure how it passed tech. It slipped once and that was it for my confidence, so I spent most of the day waiting for Glen to check the suspension. He asked if i had been at Lightning with a front like that, i hadn't been. After a little chuckle at how bad it was set up he fixed it for me, I didn't get much feedback on what he did, looked like he tightened up the dampening and compression. He said your suspension wasn't working and now it is. I went out again for 1.5 sessions but ran only 80% cause of the tire. I didn't notice anything significant...but i was more concerned with the tire. Nobody was around to mount a new one.

Enjoying the process...

Drew13
09-02-2008, 05:27 PM
So uhhhhh....through all of this I may have left out a minuscule detail that could hold the answer. Here's the short story...was at Beaverun...rear tire failed tech on the second day...they had no tires...except a 190 supercorsa pro. So I know a 190 tire can fit, but does it change the geometry of the bike such that one would need to adjust the suspension? Maybe it puts a little more weight on the front? Or no?

I'm also going to talk with CTR Suspensions for fun this weekend at the CCS races.

ronaldo9
09-02-2008, 06:01 PM
Yes i used a 190 rear on my old 750 and it made the bike harder to turn but you could get on the gas earlier and harder when ur leaned over. It does affect the geometry since your ride height has increased.

Trackdaze
09-03-2008, 03:55 PM
The front end felt really light coming out of corners and was wobbling sometimes. I couldnt steer it and it would push wide hard.

That sounds like the rear shock is "packing in"

It sounds like you really need to have someone look it all over. Sometimes we get so focused on one area of the bike (forks in this case) and ignore the other end.

Ifthe shock is packing in, you will have a feeling of the front end being light, it willpush wide, and it will cause head shake. All three things that you describe.

FDNYDANO18
09-03-2008, 07:38 PM
So uhhhhh....through all of this I may have left out a minuscule detail that could hold the answer. Here's the short story...was at Beaverun...rear tire failed tech on the second day...they had no tires...except a 190 supercorsa pro. So I know a 190 tire can fit, but does it change the geometry of the bike such that one would need to adjust the suspension? Maybe it puts a little more weight on the front? Or no?

I'm also going to talk with CTR Suspensions for fun this weekend at the CCS races.

Pretty important detail..... changes the suspension ratio front to rear plenty... always needs to be adjusted.

best of luck

Drew13
09-03-2008, 08:39 PM
Pretty important detail..... changes the suspension ratio front to rear plenty... always needs to be adjusted.

best of luck

Yea........

Learned a lot about suspension along the way though. :roll:

Cakes206
09-03-2008, 10:11 PM
As stated above, give Ron at WCW a call tomorrow. Explain the situation, and where you're from...see if he can give any insight over the phone. Tell him you're with sportbikeaddicts.

RCM78
09-03-2008, 10:31 PM
If the bike is running wide at the exit your rear shock is squatting too much.
Add some compression to the rear shock until it feels better. You might need aftermarket suspension to get it right.

Trackdaze
09-04-2008, 09:27 AM
If the bike is running wide at the exit your rear shock is squatting too much.
Add some compression to the rear shock until it feels better. You might need aftermarket suspension to get it right.


Or the rebound could be too slow which could also cause packing.

carl_g
09-04-2008, 10:19 AM
If the bike is running wide at the exit your rear shock is squatting too much.
Add some compression to the rear shock until it feels better. You might need aftermarket suspension to get it right.

Hey at least someone agrees with me. :ride:
http://sportbikeaddicts.com/forums/showpost.php?p=89525&postcount=7

pillaka
09-11-2008, 11:07 PM
If the bike is running wide at the exit your rear shock is squatting too much.
Add some compression to the rear shock until it feels better. You might need aftermarket suspension to get it right.

Just give it more gas

FDNYDANO18
10-14-2008, 02:47 PM
Just give it more gas

I did that..... and now I need a new rear tire after 2 days :moocow: :nopity: :nopity:

Jake
10-14-2008, 09:00 PM
lol just saw looked at the first pic again. It looks familiar -
http://img.photobucket.com/albums/v190/Zakath/tires.jpg

That's my front tire and Mario's rear tire from one day at Bogie.

Drew13
10-16-2008, 08:15 AM
Geeez. My rear has never looked that bad. Front looks familiar. I think a lot of it must depend on the track too.

Jake
10-16-2008, 11:48 AM
Geeez. My rear has never looked that bad. Front looks familiar. I think a lot of it must depend on the track too.

Yea, the only time I've ever had that happen is at bogie, and it happens when I use the blue compound that TPM sells. I managed to get a green front the last time at bogie and for the last two days it held up much better.

oh yea and it only happened on the right side

MarioB
10-16-2008, 02:10 PM
Oh yeah, I remember that day all too well. Some much for once set of tires lasting me through the weekend. I hope new suspesnsion work will help me get more life out of these tires.

FDNYDANO18
10-21-2008, 09:45 PM
Stock shock 2 days on tire.......
http://i92.photobucket.com/albums/l3/FDNYDANO18/IMG_1417.jpg

http://i92.photobucket.com/albums/l3/FDNYDANO18/IMG_1418.jpg




After-market shock 2 days on tire

http://i92.photobucket.com/albums/l3/FDNYDANO18/IMG_1423.jpg


http://i92.photobucket.com/albums/l3/FDNYDANO18/IMG_1422.jpg

landshark
10-23-2008, 10:03 AM
What track and what temps outside plus the tire pressures?

FDNYDANO18
10-23-2008, 11:45 AM
First set was at NJMP Lightning 75*f 30psi hot

Second set NJMP Thunderbolt 62*f 28.5psi hot

rear tires obviously : :) :

pillaka
10-23-2008, 08:03 PM
looks like that elka is working pretty good for ya!

FDNYDANO18
10-24-2008, 10:29 AM
Yep... dropped 3 seconds a lap average... still slow ... but not as slow as before :drink: