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Author Topic: Plus One Syndrome  (Read 10799 times)

Offline jspringator

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Re: Plus One Syndrome
« Reply #75 on: October 29, 2018, 06:37:23 AM »
What is your front tire pressure?  Try 40PSI. That will make the lean easier.
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Offline Larry Fine

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Re: Plus One Syndrome
« Reply #76 on: October 29, 2018, 08:08:14 AM »
Your results are fairly common.  You are transferring more weight to the front wheel, which is (among other things) making the front suspension more compliant (and settled), which helps with the turn in and overall steering (and braking).
Pants, thank you for your input.

I believe the change in steering geometry has more to do with the perceived steering improvement than the minimal change in weight distribution. I went to the Blue Ridge Parkway yesterday and the ride was great. The steering felt completely neutral and predictable.

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Other things to consider:

1.  Play around with the front tire air pressure.  Even a couple of PSI one way of the other (which way is a matter of debate - I think upping the pressure will make the bike steer better, but your corner tracking (and certainly traction) may not be a good.
Actually, I haven't checked or adjusted tire pressure since getting the bike. I guess I should.

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2.  How many miles on the front tire?  What does it look like?  I can tell you that on my bike, after a trip to the mountains, if I have been pushing the front tire for a couple thousand miles, it scallops a bit on both sides (right side slightly more - tighter radii I believe).  Even a smidge of scalloping will make it harder to countersteer.  Also, if I've spent a few thousand miles on very straight roads (Midwest or even out West), the front tire will square off a bit and that affects steering handling.
I don't know about the mileage, but the front tire is slightly squared in the middle, but there is no hint of the sudden contact-patch transfer I have experienced in the past.

There is no visible scalloping. After the trip to Back of the Dragon in '17, the rear tire on the Nighthawk was very visibly scalloped, with each tread block angled enough that the bike hums when leaned either to side.

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3.  Moving the forks up or down in the triple tree makes a HUGE difference.  Even a 1/4" one way or the other changes the track measurement considerably.
That make sense just as the rear adjustment does. If I were to raise the forks and shorten the rear by the same amount, the geometry would stay the same, but lower the bike. Since I am 6'3" and 240 lbs, I want to keep the height and ground clearance.

Thus, I want to keep the forks flush in the clamps. So I will use the rear suspension to alter the steering geometry as I deem necessary. If I do make any more adjustment, it will be to raise the rear a tad more, and see if I like the change in handling.

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When I first leave the house loaded (top box full, camping bag on the pillion, panniers full), it takes me about 20 minutes to get used to the added weight and the shift in the weight.
Interestingly, when I loaded the Nighthawk for the above-mentioned trip, I noticed little if any change in handling during the ride up. In the mountains, the trunk stayed in the cabin, but the saddlebags, loaded with tools and accessories, stayed on.


The bottom line is that the ST handled just about perfectly yesterday on the twisties. The resistance-to-lean feeling was gone, and the response to counter-steering was right on the money. The bike went exactly where I wanted it to go.

Offline Larry Fine

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Re: Plus One Syndrome
« Reply #77 on: October 29, 2018, 08:14:19 AM »
To adjust the front preload, you do have to cut new spacers. If you can't get enough preload that way, you'll need to get heavier springs. When I had Traxxion Dynamics rebuild the forks last winter (new straight rate springs, emulators, bushings and seals), they did it for my weight (185). Springs only run around $100.
Correct me if I'm wrong, but spacers, like rear "preload" adjustment, only affects loaded ride height, not sag distance per added weight; the latter requires a different spring rate. Isn't it correct that sag has to do with the change in height between loaded and unloaded?

Offline Larry Fine

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Re: Plus One Syndrome
« Reply #78 on: October 29, 2018, 08:19:51 AM »
When I had Traxxion Dynamics rebuild the forks last winter (new straight rate springs, emulators, bushings and seals), they did it for my weight (185). Springs only run around $100.
Robbie, do you know whether they keep your build info on file, so I could contact them, give them your name, and they know immediately what is in the forks now?

Offline Larry Fine

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Re: Plus One Syndrome
« Reply #79 on: October 29, 2018, 08:21:21 AM »
Larry - maybe try flushing the fork oil and changing the weight of the oil.  If you are looking for stiffer, go up one viscosity on the fork oil.  It's virtually free (except for your time), and if nothing else, it might tell you what you want.

Progressive also has springs for the ST1100.  Again, only about $100.00 for the pair.
I'm happy with the suspension stiffness as it is. I have no doubt that the Traxxion suspension is way better than the original in every way.

I will look into the springs, but don't know whether I really need to mess with it now.

Offline Larry Fine

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Re: Plus One Syndrome
« Reply #80 on: October 29, 2018, 08:27:09 AM »
What is your front tire pressure?  Try 40PSI. That will make the lean easier.
I will have to check the tire pressure, especially now that the weather is cooler. One concern I've always had with checking bike tire pressure is that, with the smaller volume as compared to car tires, each check of the pressure lowers it slightly.

I guess the best method would be to over-fill slightly and see how much drop there is with each check, and stop when you hit your target.

Offline RobbieAG

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Re: Plus One Syndrome
« Reply #81 on: October 29, 2018, 10:00:31 AM »
I don't know about the mileage, but the front tire is slightly squared in the middle, but there is no hint of the sudden contact-patch transfer I have experienced in the past.

The tires were replaced last winter. You should have the exact mileage in the maintenance history I gave you. I think it was at around 58k.

Correct me if I'm wrong, but spacers, like rear "preload" adjustment, only affects loaded ride height, not sag distance per added weight; the latter requires a different spring rate. Isn't it correct that sag has to do with the change in height between loaded and unloaded?

You do adjust sag by adjusting preload. There are limits however if the springs are not correct for your weight. Here's a link (http://www.promecha.com.au/sag_preload.htm) that discusses the relationship of sag and preload (I'm sure there are many others).

Robbie, do you know whether they keep your build info on file, so I could contact them, give them your name, and they know immediately what is in the forks now?

I gave you the receipt from the work done. They should have the work order on file. A complete rebuild was done along with new springs and a re-valve.
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Offline hppants

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Re: Plus One Syndrome
« Reply #82 on: October 29, 2018, 11:26:02 AM »
I'm glad that you want to keep the forks at the top of the triple clamp.

Play around with tire pressure.  Don't go stupid with it, but take a few 4-5 mile stints with a range of 10 psi, changing 2 -3 psi each time. Just so you can feel the difference and try to equate it to your previous (and future) concerns.

A day riding the BRP on an ST110 setup the way you want it qualifies for a good day, indeed!!

 

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