Jump to content
Stroker

How Do You " Read " Tire Wear?

Recommended Posts

Hi Eric,

 

I'll give you my academic speculation here - The rebound on the rear is too fast and the compression looks slow.There might also be a preload issue. The rebound on the front is slow and compression is fast.Again, might be a preload issue.

 

The wear pattern on the rear looks ok...good throttle habits.The very edge looks a little ragged to me.Perhaps you got on the gas a little hard when leaned over?

 

You have not used the front tire fully, and the area that served as the " Edge " with respect to the amount you used looks ragged. If i am correct, the slow rebound meant the suspension collapsed early but did not recover in time, leading to punishment on the front tire. Was the bike understeering?

 

I think you're right on the money. The bike does tend to understeer, especially if the throttle is only lightly rolled on. If I get greedy with the gas or apply the "hook turn" technique (depending on the type of corner) it feels like my line tightens significantly. Next time I'm in the curves, but definitely at my CSS class, I'll pull the screwdriver and notepad out while listening to what their mechanics say. I ran a zip tie on the fork leg and they are nowhere near bottoming, but too slow rebound is definitely a possibility.

 

I think the rear is about as good as I'm going to get for stock. I may try 1/8 turn increments, but I am used to how it feels. I don't necessarily love it, but it's set where it will pack down the least. I have an Elka unit on order; no word on shipping yet. The front hasn't been adjusted since I installed the valving and bounced it for a few minutes trying to get it to "sit" at the top of the stroke at the same speed as the rear.

 

Realistically, it's an F4i...I can't expect perfection...I have to keep telling myself that. :)

 

 

Thanks for the insight!

Share this post


Link to post
Share on other sites

Could you put up pics of the lovely F4?

 

You could try the " Bouncing the bike " technique to see if the compression and rebound are off and get them to a good starting place.Mark a reference point on the forks noting the amount of travel available when the bike is held upright.Have a friend hold up the bike and push down on the seat.The suspension should -

 

1. Go down when you press down on the bike , but not collapse rapidly. If it does you need more compression damping. If it is too slow and difficult to push down you need less damping. Applicable for both front and rear.

 

2. When it returns , it should not go up past the reference point and down for another stroke or two. This means you need more rebound damping.If it slows down on the way to the reference point and does not cross it, you need less damping. Applicable for the forks.

 

3. When you have set the rebound, have your friend press down again.The front and rear of the bike should come back up as one. If rebound is off whack, then one side will rise faster than the other.

 

4. Make sure you set the preload before doing the above, and also ride around for a bit so the fork oil has gotten to temperature.

 

I trust you know how to adjust the settings on your bike? Fine tune on track.

 

How heavy are you in full kit?

Share this post


Link to post
Share on other sites

Sure, this is the only picture I have handy on the PC. I'm sure some of you can identify where this was taken. B) OK, starting to drift off topic.

 

post-25831-0-83075500-1428455198_thumb.jpg

 

I'm pushing 215 in gear. Thanks for the instructions, and yes, I am familiar with how my suspension adjustments work. I only have low-speed compression/rebound adjustment on the stock shock. Large suspension inputs bypass the adjuster amost entirely. I'm hoping to fix this with the aftermarket unit.

 

 

 

Share this post


Link to post
Share on other sites

AAh....i have heard talk that these Jap bikes are usually tested by fairly light riders in the 120-140 pound range in full kit. The suspension is dialed in for this weight range. Add another 100 pounds and the spring is punching wayy above it's weight. Add to this the valving etc, and you need a full suspension tune before the stock suspension can handle your weight.

 

Aftermarket is the way to go, and if you are holding on to this bike for a bit, invest money in good suspension front and rear.

Share this post


Link to post
Share on other sites

gosh... I am so late.

 

Here are some fun and easy ones.

 

wvyaac.jpg
fzc8jb.jpg
I rode on these tires at JenningsGP doing some 1 on 1 coaching and a little bit of playing around in A group, for the new to me bike's first outting to the track. The rear should be an easy diag.

Share this post


Link to post
Share on other sites

I found a really helpful guide on tire wear through the BMW groups. Figured I would share.

 

http://biketrackdayshub.com/motorcycle-tyre-wear-guide/

 

Learned a lesson about under inflating tires. Here's the tires on my nearly perfectly setup RR that were under inflated. This is one pretty slow session.

 

IMG_1052.JPG

Share this post


Link to post
Share on other sites

Hmm....looks like there wasnt enough weight on the front and the bike was understeering? That seems to have torn up the front tire a bit.

 

Looks like you got on the gas hard as you were picking up the bike.The throttle control is good, as there is a clean area on either side of the worn area.

 

Which bike was this? Were the tires warmed properly?

Share this post


Link to post
Share on other sites

Robert, how did the under inflated tire feel like on track?

 

Not bad really. The bike had lots of grip that I was not really using all of. Felt well planted. When I say under inflated they were 26psi when I should have been running 28psi for because of ambient conditions.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...