[How Much Pressure On 'bars To Initiate A Turn?]

Before the quick flick drill I was careful to push 90 degrees (or so) to the bar, and parallel to the track. With my attention on the press and release (which I have to focus on pretty closely as it's a new and strange move) I'm not thinking about those other things. I guess I could be not getting the best leverage on the bars now.

 

So I shouldn't be working that hard, then, eh?

[How Much Pressure On 'bars To Initiate A Turn?]

I had always gently let the bike take me into corners with a little prodding at the bar. During the quick flick lesson during Level 1 we were told that more pressure on the bar, rather than a quicker application, would initiate the turn quicker. When we went out on track to try it my turn-ins got MUCH faster, but I am now working much harder than I ever have, getting off track with tired arms. I really feel like I'm wrestling the bike and I watch other riders and don't see the same force. I really have to PUSH the bar to turn the bike in. My bike, btw, is an EX500 set up for racing with steep rake than stock.

 

Should I be fighting the bike like this? Is it normal to feel arm fatigue?

[Did My Preload Adjustment Cause My Crash At Sears?]

Maybe I should have included more info. My forks are from a CBR F3, so I don't have compression damping adjustments, just rebound. The forks were revalved and sprung for my weight by a local suspension shop. My front sag, prior to the preload adjustment, was 35mm.

 

As you point out, I did raise the ride height with the preload adjustment, which is exactly whey I compensated by lowering the triples on the tubes the same amount. A racer told me that this was a huge no no later on.

 

Also no expert, but sounds like the tyres could be part of the problem. Second hand slicks - who can know what conditions they had been stored in and for how long, whether they had done too many cycles, and especially no tyre warmers......no point having slicks if you don't have tyre warmers - I reckon you'll just get cold tear when trying to warm them up if you're going fast enough, if your not going fast enough you'll never get them to proper operating temperature, so its catch 22.

Of course that's IMHO.

Regarding preload adjustment as a cure to fork dive under brakes - this would be a stop gap measure at best. Has your body weight suddenly changed? Correct stiffness springs would be a better cure. By adjusting the preload only, you'd be raising the ride height of the front of bike in the process of taking out the springs compliance. This could have been a contributing factor. Unless your compression damping was maxed out already, I think that should have been the adjustment to make to reduce the dive, of course with rebound damping adjustments to suit. If your damping was maxed out, then the problem would have to be the spring rates.

Suspension adjustment is a tricky thing, my advice would be to go and get your spring rates set for your weight, with proper static sag adjustments , and with appropriate valving changes for the different rate of spring, and then experiment with rebound and compression damping settings, one variable at a time, to learn what each variable does FROM YOUR IMPRESSIONS and then attempt to set your bike up from there. Getting a good base setting from a suspension expert is vital, and recording what changes you make religiously so you can return to your base setting is crucial also.

 

regards

 

db

[Did My Preload Adjustment Cause My Crash At Sears?]

I ran the Saturday Sears Point AFM practice and was doing very well, especially after the CSS Level 1 I took on Monday. I had my lap times down to 2:13 (I'm on an ex500), which is the fastest I've gone at Sears. I had some serious brake dive on corner entries so I asked my suspension guy for some input and he recommended adding preload to my F3 forks. I added 8 mm at the beginning of Sunday practice and the dive was significantly reduced. I was slowly working my pace up that morning due to the cold track and cold tires and my first lap was 2:30, my second 2:19. On my third lap I lost the bike on the entrance to T7. I was going pretty fast on the dragstrip to get heat in my tires so I braked pretty hard for the turn. I was still more or less up and down - maybe I was 5 degrees leaned - when the bike just went. It felt as though I hit a patch of oil or something. The cornerworkers said there was nothing on the track there, and nobody else had the same problem. The strange part is that the bike and I both went down on our LEFT sides.

 

I hadn't grabbed the brakes, but was easing them on.

my tires, when the bike finally made it back to my pit, were at 23 psi front and rear, which is where they should have been according to the Bridgestone tire guy.

I can't identify any mistake I made in riding that would have contributed to the crash.

My rear tire had only the CSS day and the Saturday practice on it. The front had an additional 10 laps from a 600 supersport before I bought it.

Apparently the Bridgestone slicks take the longest to warm up an any slick, but the Bridgestone guy said 3 laps should have been fine. Also, I don't have tire warmers.

 

The only thing that seems to have possibly played a part is the preload. I tested the front end when the bike came back by pushing down on it and it was awfully stiff. Since the bike sustained minor damage (peg, bar, engine case, slider) I don't thing the forks are twisted or sticking so the stiffness is probably a result of the preload adjustment. Before the adjustment I had 37 mm of rider sag. The tires also looked a little funny. Cold tearing and just general raggedness - I don't really know what else to call it.

 

I am truly in the dark here and want to at least come away with some idea of what happened and what I can do in the future to keep it from happening again.

 

Does anybody have any idea?

[Best Places To Pass At Sears Point?]

I did Level 1 at Sears yesterday and someone (Keith?) mentioned - while outlining the 6 ft passing rule at the morning meeting - he could show us some good passing places on that particular track. I got caught up in the drills etc., and forgot to ask. I've got a race at Sears this weekend and knowing where good places to pass are would be a help.

 

Thanks,

David.