Total Motorcycle Community Forums

Alright guys, I have a really quick question for ya. I'm new to motorcycles and racing in general. My uncle's the one that actually rides, while I have to sit on the sidelines and watch (Can't really afford it at the moment, lol). But anyways, we were talking to some guys at Summit Point at our last race, and they were talking about the suspension setup on the bike. We've got Ohlins on the front and an Ohlins rear. Keep in mind I'm trying to learn more about all this. But they had said the front tire wasn't wearing the way that it should. The rear tires are being chewed to hell and back all the way to the edge (Which is a good thing, lol). Although the front tire is wearing to about a 1/4" from the edge. So they were saying that maybe we should try dropping the front end down a little bit more to help remedy the problem. There's no headshake at high speeds, the bike is handling fine in the corners, it's just the wear that seems to be the problem. I checked today and the front forks are already 15mm above the triple clamps, and I was wondering if it would be a good or bad idea to drop them another 5mm or so (Or however much). Anyways, do y'all have any input on that idea? Any reply would be greatly apprectiated!!!

Thanks guys.

-T

Droping them more shouldn't be too bad. Though do it in increments. Drop 5mm, run it a little to see how it feels, and repeat. Eventually, you'll get headshake. You can either deal with the headshake if it's not that bad, get a steering dampener to help prevent shaking, or raise it back up 5mm so it stops shaking.

Yeah, it's got the stock dampener already on it. And as of right now there isn't any headshake. But I know the rear end of the bike is loose as hell goin' into turns (w/ hard braking). It's like, unintentional MotoGP style braking. haha you can see the rear wantin to dance around a little when he's goin from the front/back straights into a hard turn. But I know that the front forks are designed like the Ducati's. I'm not sure of the teminology used for it, but you can actually change the angle that the forks make from the tire, up into the triple clamp. Basically extending or shortening the wheelbase if need be. I'm just not sure what kind of handling it would produce either way. Idk. I'm still in the learning stage with all this, and I'm actually picking up on it pretty fast. I've been around cars my entire life (Cars that were built for the strip), so I know the basics of race setups, but I'm still developing some skills with bikes. I got the drive to learn, but even though John's the racer and he knows more about bikes than I can imagine, he's still too busy to sit down and really break this stuff down for me. So I'm kinda left on my own in that regard. But anyways, thanks for that. But you got any more ideas? lol, I'm up for tryin' to pick up on anything. So y'all go for it....


Thanks again.

::Edit::
Just fyi, we're runnin' 1:27's at Summit Point Raceway. Which is OK, but definetley not all that fast. That was from his first race at the track (Went from 1:35's to 1:27's in 2 days, so I was actually impressed) a few weeks back. Since he knows the track better now, and we've been really studying it. I'm wonderin' if tweakin the suspension just a tad might help get him down another second. So for the end of the month, we're shootin' for 1:26. Got a track day Friday, and races on Sat/Sun. So it's gonna make it easier to set the bike up for the races. Sooo yeahhh....

I think you're talking about the trail... Basically the rule of thumb is that if you have a shorter trail (less wheelbase), then the sharper the cornering is. The longer, the higher speeds you can handle, but you lose performance...
Wrider

Man, this forum is so dead. i can't believe it, but HEY you have a little question... Funny how "quick questions" can lead to so much more...

With chassis stuff I always start at the beginning, approach it linearly to begin with and keep notes and measurements, then loop back through the settings, changing one thing at a time and make sure the bike is being ridden consistently.

Looking at this bit of info,

MullenRacing35 wrote: Although the front tire is wearing to about a 1/4" from the edge.

and the fact that you've dropped the front-end 15mm and we can touch on a couple things. Really we would need info on the tires, and without knowing if the stock tires are taller than the tires you've got on the bike the change of 15mm may not be a change at all.

It helps if these things are measured before starting, but such is life, you have to work with what ya got. The tires you put on the bike are the unknown in comparison with the stockers and possibly (likely) a different height even if the numbers on the tires are IDENTICAL.

Caveat: The manufacturers have a very large amount of leeway in there labelling specifications, so a 180/55ZR17 can be a lot more like a 170/55ZR17 (or 170/60ZR17) or even close to a 190/55ZR17, etc.. The 10mm taller in overall diameter and the 15mm drop in front end (say approx 10mm vertical) would make the front end a very close height to the stock setup. Or conversely they may be 10mm shorter and thus you have something like 20mm lower front end. Like NinjaGeoff said, dropping in smaller increments is the best approach to start, just be aware of front tire clearance between the radiator and fairing bits when the suspension is compressed.

You should keep info on the tires. Model, mileage or sessions, hot and cold pressures and the weather conditions, as you may spot something in the future to assist in tuning some other problem. You didn't mention the brand and model etc, but really measuring the difference between stock and whatever is on it is the way to do this. Measure circumference and calculate the height, or measure the height.

The tire *profile* is very critical and can affect bikes a lot when at speed, especially important with the issue you describe. Even at speeds 10 seconds under the lap record, you should be able to get edge-to-edge wear. I've seen many cases of misfitted tires, AND it may be the rear tire that is too wide and thus not allowing the front contact patch to achieve adequate lean to spread out.

Are you using zip-ties around the fork tubes to measure fork travel?? It's a cheap, simple way measure fork travel. Poor man's telemetry kit! (this info may help you resolve/reduce the tail wagging issue you mention too). If the front-end doesn't compress fully or it compresses too slowly (depending primarily upon spring rate, oil, and the compression damping setting) then that force is transfered into lifting the rear wheel off the pavement - waggle waggle. Also if the pavement is bumpy and rippled it's possible that the fork is not recovering from bumps, and lightening the rebound may be required to give the fork the opportunity to recover from bumps.

Also, as far as starting with the basics: Do you know how to set the "static sag" for a base-line ride height? If not google for info, or pick up a book or magazine article.

You didnt mention if your Ohlins rear shock has adjustment for ride-height, you can always raise the rear if it does. This is an alternate way to put more rake (and the weight) on the front end.

The TL1000R never had much of a following for race use, and thus info is tougher to come by, but I'd look for specific articles or web-sites on it, because it is a much more unique bike than most. Too bad Yoshimura only used them briefly in AMASBK and Steve Crevier doesn't appear to be offering free info on that puppy at this second, but if you ever see him at a race, I'd ask him for quick advice.

Note: being that you are "new to racing and motorcycles in general" there is a steep learning curve and Jewel Hendricks wrote a great book on chassis setup...i loaned my copy to someone, and have not seen it in may years now. But if you're getting into it, then it's best to have real info. I know so many people who after years of racing still cannot setup there bike in the least. A huge loss to them, because as you hope, you can gain seconds with proper chassis "tweaking", or you can lose them with improper tweaking just as easily

anyhooo, it all can get very involved, so grab some books for basic chassis setup and scour the web for base-line suspension settings specific to your TLR1000.

//monkey