Front Suspension Setup Question

[TampaDave]

2004 with 35K miles, Michelin 2CT tires, running 34 psi front, 36 rear.

My front end is a bit "squirrely," tends to "worry" in rain grooves, center stripes, defects in pavement. No big deal most of the time, but this sort of thing occasionally makes me pee a little in turns.

My question is, whether softening the front preload will help.

What I've done so far:

- Crank up the rear pre-load (helped a lot, I'm a heavy fellow, 220 in street clothes)

- Keeping weight low and forward in turns (now I see why the stock clipons are the way they are, but I'm keeping my Heli's anyway)

What I plan to do:

- It's due for new rubber

- Gonna replace the front bearings while I'm at it

But I'm still not totally sure I have my front suspension just right. In the front, my sag is 25mm from side stand to sitting on it, and in the rear it's 20mm. I'll go out and get some proper measurements today but the question is, let's say I dial the front back to 30 or 35, making it softer than the rear, would that improve handing or make it worse ya think?

[Switchblade]

Never had any luck with a softer front fork setting, the bike starts pogoing .

Get your bike measurements and the rider measurements.

There are several good to sites for info.

http://www.sportrider.com/suspension-tuning-guide-suspension-troubleshooting-symptoms

[deltaboxii]

I run more pressure myself on the street. 36 F and 41 R. If your tires are shot this won't help much but worth a try.

Replacing your steering head bearings is also a good idea.

[Cogswell]

These suspension threads went a long way toward helping me understand what I need to do to get my suspension set up properly.

http://www.vfrdiscussion.com/forum/index.php/topic/19943-transformed-wow/

http://www.vfrdiscussion.com/forum/index.php/topic/32986-cbr-f4-shock-in-place-of-vfr-shock/

[TampaDave]

OK here are the numbers. Did the best I could by myself because wifey is being all bitchy about helping me. ("It's 7am on Sunday!!")

Front fork: sticktion 9mm. preload sag 19, with rider an additional 16. Net of stickson, lets call it preload sag of 23 and total sag of 39.

Rear: siction 6mm, preload sag 10mm, with rider an additional 34. Net of stickson, lets call it preload 13, total 47.

I'm definitely gonna tighten up the rear a notch. Not sure what to think about those front measurements. Kinda scratching my head. Maybe... I think it needs a new spring?

@Deltaboxii: the stem bearings don't feel totally shot but I'm definitely keeping that in mind. If my list of things to do don't iron it out, that's next. Not exactly looking forward to it... so far, there's been no cursing or bleeding. Once I get into the stem bearings, that's a different matter.

ETA: eh I guess those numbers up front look OK, just not used to working on heavy bikes. Proportionally I guess the preload sag should be around 28, so we are in the ballpark. So yeah, I think I want to leave the front where it is and tighten up the rear, I guess that's what I'm feeling.

[JimGregory]

On another bike I had, just increasing tire pressure helped 100%. I run 36 and 41 on my vfr 5th gen. Feels great through the turns. I lowered the pressures to 34 38 for winter riding and it's definately a little unsettled. My preload is whatever it was when I got it last spring. Havent touched a thing and it handles real nice but it only had 3500 miles on it.

If your rear is squared off that will also screw up the front.

[TampaDave]

On another bike I had, just increasing tire pressure helped 100%. I run 36 and 41 on my vfr 5th gen. Feels great through the turns. I lowered the pressures to 34 38 for winter riding and it's definately a little unsettled. My preload is whatever it was when I got it last spring. Havent touched a thing and it handles real nice but it only had 3500 miles on it.

If your rear is squared off that will also screw up the front.

Interesting regarding the tire pressure thing, I'll definitely air em up next time, thanks!

OK, got the wheels off. The wheel bearings are fine.

The rear is a Michelin Power pure which is just a tad squared off, not bad at all. Wear bars are just now showing. Rubber still nice and soft. Not in bad shape but it's time to go.

The front tire is a Pilot Road 3, which looks and feels old. It's not so much that it's squared off. The middle third of the tire is standing proud. In section, kind of a trapezoidal shape. So all the wear is on the softer compound on the side, and very little wear down the middle. No wonder it feels so squirrely. It's like having a teeny 25mm tire up there.

Guess PO sent more time laid over than straight up.

[Terry]

Dave it sounds like you've already answered your own question! Tyre wear is almost certainly the cause of the bike wanting to wander around on longitudinal road defects, especially the rear if it is a bit squared off, but I would also take a close look at the steering head bearings. These can develop dents or notches in the races and stop the steering gliding from one side to the other. If you get the front wheel off the ground, it should move smoothly from side to side without any notchiness around dead centre. If it is notched, then you'll need to replace the bearing.

Regarding changing suspension settings, if you reduce the front preload you will steepen the steering angle and make the bike a little faster turning and less stable. Conversely increasing the preload will rake the front end out further and give slower, more stable steering. You can also affect the geometry by moving the forks through the clamps, changing rear preload or shimming the top shock mount.

I wear my tyres out the same way as your PO, the rear wears pretty evenly but the front ends up with flatter sections of the sides at my comfortable maximum lean angle. This makes the bike tip over onto that lean angle quickly and steadily, but leaning even further takes you over the edge of the flat section which can feel unpleasantly like a front end tuck...That's when I replace them (7000km out of Metzeler MeZ8 Roadtecs), although legally they could go much further.

[TampaDave]

Regarding changing suspension settings, if you reduce the front preload you will steepen the steering angle and make the bike a little faster turning and less stable.

Ah that totally makes sense. That's what they taught me in racing school, when you jam on the brakes and compress the forks you can hook into the turn more quickly.

I'm sure the rear suspension has the converse effect. You see the Harley boys slam the rear of their bikes, and then they wonder why they won't turn. I don't think I want my rear too soft relative to the front, but since the front is already in a reasonable range I better not mess with it.

[Terry]

Regarding changing suspension settings, if you reduce the front preload you will steepen the steering angle and make the bike a little faster turning and less stable.

Ah that totally makes sense. That's what they taught me in racing school, when you jam on the brakes and compress the forks you can hook into the turn more quickly.

I'm sure the rear suspension has the converse effect. You see the Harley boys slam the rear of their bikes, and then they wonder why they won't turn. I don't think I want my rear too soft relative to the front, but since the front is already in a reasonable range I better not mess with it.

You are right, softening the shock drops the back and rakes the front out for more stability, same as increasing front pre-load. Reducing sag to change the geometry can result in more bottoming out on bumps, so I think it is better to either move the fork tubes through the clamps or shim/lengthen the shock, and keep the suspension settings at the point where they are most effective.

[spud786]

2004 with 35K miles, Michelin 2CT tires, running 34 psi front, 36 rear.

My front end is a bit "squirrely," tends to "worry" in rain grooves, center stripes, defects in pavement. No big deal most of the time, but this sort of thing occasionally makes me pee a little in turns.

My question is, whether softening the front preload will help.

What I've done so far:

- Crank up the rear pre-load (helped a lot, I'm a heavy fellow, 220 in street clothes)

- Keeping weight low and forward in turns (now I see why the stock clipons are the way they are, but I'm keeping my Heli's anyway)

Best thing to do is install an original single grade Pilot power on the front(that is the bar on straight as an arrow front tire. If you still have issue, no tire will fix it. and you can move on to something else.

[TampaDave]

OK, got the new tires on. Problem solved.

OP said that Road Pilot on the front had like 20K miles on it. Shoot. Don't have to tell me twice, I put some new RP4's on it. Cool tire. I'll see how far I can grind them down on my trip out west; but dang 20K miles? I dunno if you could grind that wear strip down with a belt sander.

[deltaboxii]

On another bike I had, just increasing tire pressure helped 100%. I run 36 and 41 on my vfr 5th gen. Feels great through the turns. I lowered the pressures to 34 38 for winter riding and it's definately a little unsettled. My preload is whatever it was when I got it last spring. Havent touched a thing and it handles real nice but it only had 3500 miles on it.

If your rear is squared off that will also screw up the front.

Interesting regarding the tire pressure thing, I'll definitely air em up next time, thanks!

OK, got the wheels off. The wheel bearings are fine.

The rear is a Michelin Power pure which is just a tad squared off, not bad at all. Wear bars are just now showing. Rubber still nice and soft. Not in bad shape but it's time to go.

The front tire is a Pilot Road 3, which looks and feels old. It's not so much that it's squared off. The middle third of the tire is standing proud. In section, kind of a trapezoidal shape. So all the wear is on the softer compound on the side, and very little wear down the middle. No wonder it feels so squirrely. It's like having a teeny 25mm tire up there.

Guess PO sent more time laid over than straight up.

I had issues with my Michelin Pilot Pure's on my Speed Triple feeling the same way. Felt like it was wandering all over the place. When I was running 2CTs prior to that, I had no issues at all- and my suspension / tire pressures were spot on.

The Michelin Pilot Pures were only available for sale for one year. Michelin pulled them from the market and replaced it with the Power 3. They never said why but that was very unlike MIchelin to do that. You have to wonder if they knew they had some issues.

Honestly, I bet if you switched to a set of Power 3 or even a Power/ or 2CT, your wandering/ "squirelly" would probably go away. The Pures might not have been ideal for heavier sport bikes like the VFR and Speed Triple.

Sorry I would have pointed that out before but your first post said that you were running 2CTs, then I noticed in your last post you had mentioned the Pures.

[TampaDave]

Sorry for the misleading first post, didn't initially realize he had two different tires on there. The rear was labelled both "2CT" and "Power Pure." Which I believe is also a dual compound tire, although it had a much more "normal" looking wear pattern, a bit squared off but still soft and sticky all the way to the end (and I wore that thing down to a nub, no idea how many miles it had on it). My feeling is that both tires are very decent, just maybe slightly different applications, with the Pilot Road maybe being a good long-distance highway tire, which is what I want.

I've only sort of hijacked my own thread so let me see if I can close the circle.

I think the take-home message is that the Road Pilots can wear in such a way as to cause unusual handling issues, which might lead one to suspect suspension issues, when it's really a tire issue.

Although, after thinking about it, I don't think what I was describing was really consistent with a suspension issue. I guess "worrying" and tracking pavement defects is usually tire more than suspension or geometry.