Question for the rocket scientists (it's cool if you know suspension too)

Can lack of rebound damping in the forks make a bike wheelie?

I'm asking because that SV650 I borrowed last weekend was diagnosed as having a severe damping deficiency. And it did loft the front rather generously in 5th gear as I hit the crest right before entering T4 at Summit Point. The first couple of times, I thought the suspension was just extending to the max. The third time, the bike's attitude clearly changed and the front wheel deflected way to the left. I'm pretty sure I did not imagine that one: it was a wheelie if I ever saw one! Now, I know a stock SV650 doesn't make the kind of power that will allow it to do that. At that point, I had about 4-5 laps on the bike and hadn't adopted the full, lay-flat-on-tank race tuck yet. So weight positioning was likely a factor. But it can't explain all of it. I've wiggled the front wheel on my 600 there, but never experienced a real wheelie.

So, can a lack of rebound damping make you wheelie?

 

What are you afraid of?

59views, not one single answer? Would this be the first time BBSers are afraid to sound stupid? I took the lead in admitting I don't know jack. C'mon, somebody must know something about suspension. Where's Max at?

 

Papa,

I'm not a suspension guru, but I can tell you this:
I couldn't ride my bike, the front end was fried. It was bouncing everywhere. Coming out of turns it was loose and bouncing. Going into turns, it felt like it was gonna tuck, and wouldn't hold a line. I let a couple people look at them, did the bouncing thing and got the same answer. Something doesn't feel right in there. These were from very reputable racers that know suspension.

Finally got fed up and took them to Jacob when Traxxion was at NPR. His exact words more or less were. These forks have no rebound. But I'll fix it for ya.

I ended up doing everything to the forks -the compression emulators and different springs, I hope that i said that right. Anyway, the rest will be done at TWS in September.

Anyway Papa, long story short. No more loose jittery front end. It feels great.

Maybe this is your problem too. I know after they were done, it felt like a different bike. You know, "The suspension gods(Max and Co.) have graced my suspension, etc. etc."

So, that is all I have to say about that........


Hope this helps ya a little papa

 

Lack of rebound could let a bike wheelie more easily but only when the suspension is "rebounding" from compression. The bike will bounce up easily with little resistance to hold the springs in the forks down.

Doesn't seem it could be the culprit though, your suspension should have settled long before you reached the crest. It's not steep enough "on line" to let the bottom drop out from under the front end and if that was the case lack of rebound would help. Off line is a different story, if your more than four feet from the left edge you can easily wheelie there on a 600, so it could be possible on an SV, I guess.

 

I believe one thing to take into consideration is the position of your body, the footpegs, and the clip on's. The weight bias may be completely diffeent from your 600. I know my vintage RZ350 wanted to pop wheelies on Road Atlanta's "wheelie hill" (turn eight, or the crest of the hill after turn seven) before I started to apply more force downward on the footpegs and forward on the bike.

There are ways to keeping a front end down. Here's one expert who seems to know what he is doing ... look at him hug that tank and apply force downward on the front end of the bike.

Photo from www.amaproracing.com web site.

 

Well, I can see why one of those would want to wheelie...

 

PT,

My stock SV didn't wheelie down the front straight at Putnam at the crest at the end of the straight. I've since put in the racetech doo-dads and the front will get light on the power out of a fast turn, but no wheeeeelie, really!