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Voofighters
| Posted on Tuesday, March 17, 2009 - 07:26 pm: |
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Ok.. please dont burn me at the stake, but I did post this in the knowledge vault area but I only got 1 response.. and it doesnt' seem to have helped. Here's my dilema.. I just replaced the OEM Pirelli's on my XB12Scg with some Michelin Road Pilot 2's. At speed, I'm starting to get some front end 'wobbles'. I had them mounted/balanced by Cycle gear and have about 100 miles on them so far. I'm noticing at speed (~85-90 MPH) that the front starts to wobble and the bike acts like it's having a mini-tank slapper. I went with the same tire size as the OEM Pirellis. I've checked/rechecked/re-torqued the axle bolts on the front and back, air pressure (front and rear are 32 PSI cold) but the bike still does this whenever i give it that much 'gas'. What's possibly causing this and how do i fix it?? |
Sifo
| Posted on Tuesday, March 17, 2009 - 07:37 pm: |
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Running RP2s on my Ss and they feel great. I would take a real good look at the tires and make sure that they run true. Also make sure that they are seated completely. Jack it up and spin the tires by hand looking for any irregularities. While it's jacked up it wouldn't hurt to check the steering head bearings. |
Teddagreek
| Posted on Tuesday, March 17, 2009 - 07:37 pm: |
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I would take everything you took off and start over... Don't forget your anti seize for the axles... |
Hexangler
| Posted on Tuesday, March 17, 2009 - 07:41 pm: |
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front and rear are 32 PSI cold My owners manual recommends 34psi front, 36psi rear. |
Gentleman_jon
| Posted on Tuesday, March 17, 2009 - 07:46 pm: |
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Well for a start, the tire pressures are wrong. Should be 36 front, 38 rear, according to the Buell Manual. However, I don't think that that is necessarily the cause of the problem but I certainly would correct it first. Since the guys at Cycle Gear didn't know what tire pressure to use, I can't help but wonder if they balanced the tires correctly. As it is easy to do wrong, I would recheck the balance. Those are really the only two things you changed. Normally however, wobbles result from loose steering bearings. A loose swing arm axle is a possible cause and one that is often over looked. That gives you a couple of things to think about. Let us know how it works out. |
Hexangler
| Posted on Tuesday, March 17, 2009 - 11:18 pm: |
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Granted its for an '07 XB12R with Pirellis. |
Old_man
| Posted on Tuesday, March 17, 2009 - 11:41 pm: |
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I would have them rebalanced. Further, The Buell pressure recommendations are for the original tires. But what you have seems a bit too low. See if the tire manufacturer gives a recommended pressure for your bike. I still think that it sounds like they are not in balance. |
Petebueller
| Posted on Wednesday, March 18, 2009 - 08:12 am: |
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You could run your front wheel to make sure it is spinning true. A friend developed problems after a tyre change. |
Fullcircle
| Posted on Wednesday, March 18, 2009 - 08:19 am: |
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Had the same thing a few years ago on a Yamaha. Had the tire rebalanced and problem was solved. |
Boliver
| Posted on Wednesday, March 18, 2009 - 08:21 am: |
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I just bought Pirelli's and could not be happier.I won't be buying anything else ever again.This is my second set of tires and I think if your bike started wobbling immediately after you got them I would go back and have the shop reinstall them correctly or replace with suitable tires.It would be different if that problem started 2,000 miles into your tread but from the start? Why waste time on here, go get your hard earned moneys worth from them. |
Wolfridgerider
| Posted on Wednesday, March 18, 2009 - 08:46 am: |
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Well for a start, the tire pressures are wrong. I was thinking the same thing.... I had to go look at the owners manuals on line to find out why 36/38 was in my head.... Dunlops -vs- Pirelli's So now I need to check my tires.... I've been running 36/38 on my Pirelli's Back on topic.... I'd get the tire re-mounted.... and.... http://www.youtube.com/watch?v=Yu_moia-oVI tiremounting |
Dentguy
| Posted on Wednesday, March 18, 2009 - 09:30 am: |
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The tire pressure at 32 may be lower than what Buell recommends, but it will not cause that. Look for another problem. |
Midknyte
| Posted on Wednesday, March 18, 2009 - 10:15 am: |
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Lower pressures will make the bike feel heavy in a turn. |
Voofighters
| Posted on Wednesday, March 18, 2009 - 10:57 am: |
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Sweet..thanks for the advice everyone.. I'll adjust the tire pressure, but I'm a little concerned that everyone says to run the bike at a particular PSI. The tires are NOT the OEM Pirelli's. I am running Michelin Road Pilot 2 on the bike. I thought that since the tire was no longer the same, the tire pressures in the service/owners manual were no longer valid? Regardless I'll check that first and see if it helps. If not, then I'm going to have cyclegear re-balance it for me. Hopefully that'll fix it. Thanks again for the help (and the youtube link.. ) |
Wolfridgerider
| Posted on Wednesday, March 18, 2009 - 03:08 pm: |
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the tire pressures in the service/owners manual were no longer valid? I believe you're right, but I can't find the recommended tire pressure for Michelins |
Old_man
| Posted on Wednesday, March 18, 2009 - 03:26 pm: |
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Someone here is running Michelins. They could tell you what's working for them. I'm sure it's not far from the original tire recommendations. |
Petebueller
| Posted on Thursday, March 19, 2009 - 05:36 am: |
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I've run through 2 sets of Pilot Power IIs and they are magic. Only thing I find is they are a bit slow to warm up on cold days. The road IIs should warm up faster. I can't see them giving wobbles. Low pressure may make the tyre a bit inclined to "walk" on the tread, but that is more at low speed than high speed. Low pressure affects your handling making turns harder and wider but not wobbles. My friend had a tyre change. He developed a shudder virtually straight away. When they tested the bike the dealer found that the front rim was buckled. It is a fairly new bike. He can't prove it was done with the tyre change, but that is what he suspects. You should run the tyre pressures for the bike always. The ratings that come with tyres are usually upper limits. |
Voofighters
| Posted on Thursday, March 19, 2009 - 10:13 pm: |
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OK.. So I cranked up the PSI to 38 front, 40 rear. I know it seems high but these are Michelin Pilot Road 2's- not the OEM Pirelli's. I checked online and with Cyclegear and the pressures are still within spec. Anyways, after giving it air, I took her out and gassed it hard up to about 95+ MPH.. Previously, this would make the bike shake viciously.. I did this a couple of times and while it did seem a tinyyyy bit squirrely, the wobble seems to be gone! All in all, a very good day. Thanks for the support everyone! |
Old_man
| Posted on Thursday, March 19, 2009 - 11:22 pm: |
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I would try 2psi less per tire and give it a ride. |
Gentleman_jon
| Posted on Friday, March 20, 2009 - 08:10 am: |
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All's well that ends well, but............... 1. Those tire pressures are a bit high, as mentioned above. 2. A properly set up Buell should not be even "a tinyyyy bit squirrely", at 95 mph, but that is a whole lot better than a major wobble. Perhaps the tire wasn't completely seated the first time, and the additional air pressure completed the seating. Still, something isn't just right. As mentioned above, improperly tightened steering bearings and swing arm axles are a possible cause. Believe it or not, the rider can also cause this, but wearing very loose jacket which flaps in the wind, when the rider holds on to the bars too tightly. In fact, holding on to the bars too tightly is more common than people think, and has several bad consequences. Firstly it can induce numb hands, and it can add inputs to the steering system that are not at all helpful. I used to be guilty of doing this, and I had to consciously relax my grip on the bars from time to time. After a while I realized that even in the middle of a corner, only a very light grip is required. Holding on to the bars too tightly can prevent the natural self steering that is caused by "trail" in the front wheel from working properly, and can thus increase instability. Let us know if you make more progress, ok? |
Corporatemonkey
| Posted on Saturday, March 21, 2009 - 07:01 am: |
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I run RP2's on my CityX. The stock recommended psi (34,36) works great for them. If you have any more wobbles I would look into the steering head bearing. I when through this last summer, once properly tightened all is well again. |
Iamarchangel
| Posted on Saturday, March 21, 2009 - 11:28 am: |
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That difference in psi is not going to cause that problem. Check your suspension settings. I found that I had to run my settings softer than the recommended to smooth out the front wheel. Set the setting to recommended. Copy or print the settings. Take the print, a pen, and the tools with you to the road that seems worst to you. Do runs until you feel comfortable. Worked for me. Made the bike a whole lot more comfortable (faster) and the only problem left was a near skating sensation in tight fast leaned over situations. That I blame on the Dunlops and why I'm putting Road Attacks on next week. Gentleman Jon's advice is right on, the tire will roll forever without you or the bike, that's just physics. There's some other input and you should chase that. |
Vdubfro
| Posted on Saturday, March 21, 2009 - 05:31 pm: |
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Michelin recommends 2.3 bars front and 2.5 bars rear. That converts to 33.35 psi front and 36.25 psi rear. I have Pilot Road 2 on my 03. I get alot of head shake at 95+ mph. I haven't checked my head bearing torque yet. I dropped a few psi in the front. 32 and it helped very little. |
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