T14 Thill...2X within one foot of the other

[stangmx13]

Originally Posted by Holeshot

I think there are a few things that either got misinterpreted;

1. At max lean, I want off the lever when it's time to go to the throttle. T14 is a flat(ish) corner and I make most of time on the side of the tire for my entries. Holding more lever in T14 would be the same problem only earlier in the corner, IMO.

2. 2 links = 35mm. One is about 16mm. using only the axle position as the measurement, the wheel was moved rearward about 35 mm or so from the previous measure we had on it. 43-46 too is 3 teeth, for whatever that is worth.

I still have nothing more. Rode the last race weekend with the original WB and bike was good, but twitchy as hell, which I don't remember from previous time we had it setup that way. Put it more on it's nose and I started to get front end feel back. I still think I might go back to a longer wheelbase for mid corner stability for the last AFM round and see how that works. Or do one link added and run with that.

Thanks for the thoughts Rob.

holding more lever will prevent u from trying to carry too much pace, too much lean angle. front crashes in between brake and gas at our pace are usually caused by some combination of excessive lean angle and too little grip. ive crashed like that too many times . u can fix both of those by holding some brake longer. it doesnt just "move" the problem because your speed is constantly decreasing.

lets switch to using chain length instead. the only way you can get ~32mm of axle movement is 14/43-110 to 15/46-116. thats a 6 link change which is nuts. I dont even think a 110 chain fits with those sprocket. the slot only has ~45mm of adjustment. if it does fit, you'd def be within a few mm of the very front. im shocked anyone would ever run the axle there. any less of a chain length change is less axle movement of course.

15/46-116 is within a few mm of both 15/42-114 and 15/43-114. I run those 2 combos a lot and like them. every setup ive seen in MA is there too. so you arent out of range. but 16mm is def a big change from what you were running previously.

Originally Posted by Holeshot

Update: measured shock and discovered the bike sits high in the back as is. We settled on the geometry being affected as the issue. Didn't get a chance to walk T14 apex, but another of my close competitors went down in the same spot over the weekend. Suspect the combination of geometry, more weight on the front end and excessive lean angle as the prime contributors...least that's what I'm telling myself.

one side effect of more swingarm length is less rake and trail in the front end. because the swingarm spends almost all of its time angled down, moving the axle back also moves it downward. so the bike is pitched forward a little bit. if you already have the shock long, your real trail number might be small. bikes with less rake and less trail are known to tuck unexpectedly. they have plenty of grip, but when the tire lets go, it goes fast.

this is just a guess without knowing the height of your front end.

[stangmx13]

Originally Posted by afm199

It's an interesting place. We want to get as much speed as possible for T15, which is SO IMPORTANT, but at the same time don't want to overwhelm the front with lean angle. We all want as much drive as possible on the exit of T15, on the little bikes we need all the roll speed as well. On the bigger bikes I am comfortable trail braking right to the apex and then rolling on, my crashes both were on the SV, where I was desperately (the correct word) looking for lean angle and roll speed. I gave up the brake a bit early and that's what got me. Of all the corners at Thill, this is the only one that I just don't like on the SV. The front feels wooden and vague and I have no idea what's going on.

I'd agree about the surface but even at my perceived apex and Berto's, there's probably five feet of track both ways between us.

ive done that too many times. the most recent one was Sept '18 in Alabama. I let off the brakes early in an attempt to keep my roll speed up through one of the faster corners and the front just let go. later in the weekend, i used the "opposite" technique to go faster - I braked later. that helped a lot

[Holeshot]

Originally Posted by stangmx13

if it does fit, you'd def be within a few mm of the very front. im shocked anyone would ever run the axle there. any less of a chain length change is less axle movement of course.

one side effect of more swingarm length is less rake and trail in the front end. because the swingarm spends almost all of its time angled down, moving the axle back also moves it downward. so the bike is pitched forward a little bit. if you already have the shock long, your real trail number might be small. bikes with less rake and less trail are known to tuck unexpectedly. they have plenty of grip, but when the tire lets go, it goes fast.

this is just a guess without knowing the height of your front end.

Good point on the thing tucking with less trail. I run the rear wheel packed up in the swingarm; the tire warmers always rub putting them on. No one seems to run it that way (so I'm told), but then again, it's worked for me for now and gives me a bike that flicks quickly and rips through T3 at Thill. I'm kinda ready to try something different though cause the thing can probably be better...but not at turning under people, etc. I should take a pic of where the rear wheel is...you'd probably chastise me for sure.

[afm199]

Originally Posted by stangmx13

ive done that too many times. the most recent one was Sept '18 in Alabama. I let off the brakes early in an attempt to keep my roll speed up through one of the faster corners and the front just let go. later in the weekend, i used the "opposite" technique to go faster - I braked later. that helped a lot

Amen. As soon as the front tucked I was kicking myself in the ass, knowing that sliding across the track is definitely not faster than riding around the corner. I suspect if I had kept on the last two ounces of brake for another five feet, I would have had no problems at all. The poor front tire just didn't have the contact patch to handle my demands.

And that was a fucked up crash! I got hit by a buddy and broke my C5, still sore as hell and waiting for full nerve function to return. Getting better every day, but still about 70% of full function.

[stangmx13]

Originally Posted by Holeshot

Good point on the thing tucking with less trail. I run the rear wheel packed up in the swingarm; the tire warmers always rub putting them on. No one seems to run it that way (so I'm told), but then again, it's worked for me for now and gives me a bike that flicks quickly and rips through T3 at Thill. I'm kinda ready to try something different though cause the thing can probably be better...but not at turning under people, etc. I should take a pic of where the rear wheel is...you'd probably chastise me for sure.

I have plenty of bias when doing my own setup. Ive always had my front end tall and was attached to it. The last time I raised it, it worked better, so why would I shorten it now? Ive always liked soft shock springs and was attached to those because going softer worked better too. But the shock hasn't gripped well in over a year and the front end now seems to work better with lighter springs. Of course, I should have tried stiffer rear springs and lowering the front a year ago. but I didnt because of my bias.

last time out in Alabama, I started working with Ken Hall (SBSuspension, Ohlins, Bryce Prince's technician) and he suggested all the changes that I wouldn't make myself. They worked and I went a lot faster. He actually told me exactly what I needed to hear too - something like "that old setup does work well to a point. but if you want to go faster, we gotta go in a diff direction".

we all know that setups are good for specific tracks, tires, and riders. as we get faster, we become different riders. so its silly to assume some setup will always work as we improve. your short wheelbase might be the same as my super-tall front end. might not though.

[Holeshot]

Agee...it seems it's time to turn the page on it and as it turns out, that'll happen. I'm retiring my trusty 2010 R6. Got her as a little baby R6 and she really can't do any better than she did in her last season. She'll wear the #15 and her earned #6 plate (1st overall points in club) in perpetuity...and her super short, super weird wheelbase! My 17' already has a standard wheelbase, which I liked when I rode him.

[afm199]

I'm saving this page for being a great read. Also decided to never ride another SV on the track. I feel safer on a 1000

[Holeshot]

Just sell the SV...

[afm199]

Originally Posted by Holeshot

Just sell the SV...

Indeed. It's done. Room for a more modern bike now.

Congrats on a super year with the AFM. You and Rue really put on some shows for the rest of us backmarkers.

[dtrides]

Thanks for sharing that Ernie.
You just vocalized my current experience.
I was truly bummed I took myself out on the Carter's 5 mile on Sunday and missed the school on Monday . I was looking forward to working with an instructor on that section and T-3.
DT

[Mechanikrazy]

Add another one to the T14 group. Second session on Saturday for the last round of AFM, I lost the front and went for a slide on the very first lap. I was taking it easy (real easy relative to everyone else, considering my best is only a 2:08 on a 450) and going maybe 80%. I was almost at the apex and just off trail braking when the front let go. I didn't sense any warning slide or anything. I will say though, about 1/2 way to the apex from turn in point, I did think that I felt a bump but then it smoothed out before where I lost the front.

One thing I am learning from this thread though is I need to be better about braking later and carrying that trail all the way to apex. Next year.