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Front Metzler cupping-why?

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  #51  
Old 09-12-2008 | 01:01 AM
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MidnitEvil
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From: Joliet, Illinois
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Originally Posted by kered
also when going low speeds and using the front brake with the handlebars turned it will cause you to drop it...ive seen it happen alot...dont believe me? try it...
Tried it. Do it all the time. I don't fall down. What am I doing wrong?

i also disagree with using front brake in a regular speed turn...of course set your speed before the turn but if you absolutely need to scrub off speed use your rear...using your front will cause the bike to stand up and want to go straight...using the rear mid corner is common and called trail braking
Trail braking works great. How does it do at bringing you to a complete or almost complete stop when you round a blind curve and encounter a stopped vehicle or some other hazard? For that, I'm jammin' on both brakes as hard as possible, just short of lock... and not falling down.
 
  #52  
Old 09-12-2008 | 01:09 AM
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Originally Posted by GT_RoadGlide
MidnitEvil - Stopping too quickly with the front brake and the wheel turned will put some strange loads on the front end. When the load is removed (bike is stopped) the unexpected springback can be enough that the rider can not overcome it and the bike goes down. Even though I know better I dropped my Sporty trying to avoid a cage from hitting me head on. I could not hold it up and just stepped away.
Practice. If you had released the front brake just prior to your complete stop, finishing up with just the rear, or using both when you straightened up the front end, you'd have stayed upright.

One of the hardest lessons to teach riders is when to *quit* stopping (or slowing down). Most people want to just grab and stomp on all the brake they can get. They get a death grip on that lever and can't let go. Some times it's better to jam on the brakes, then let them go so you can maneuver and keep going (or put yourself in a better situation to come to a complete stop)

Also... not in your case, but with others, I get the impression they think the front brake lever is a on off switch, rather than something which can be controlled to varying degrees of application.
 
  #53  
Old 09-12-2008 | 04:22 AM
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kkrommm
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From: Las Vegas NV
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bubba,, Metzlers suck, I put 8k on a set at 45 psi . the rear tire had 25 of the points ( if you will ) coming up and a 3in x 3in chunk gone in the middle of the tire. Down to the cords. warrantee you say??? NOOOO .... according to the manufacture they were underinflated so no warrante. they want no less than 50 psi in the tire. Mine was made in Brazil and the side wall said 42 psi cold. I will never buy or reccomend metz again. Also never use Best cycle parts inLas Vegas either hes an a** too. good luck with yours kkrommm
 
  #54  
Old 09-12-2008 | 05:30 AM
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Originally Posted by GT_RoadGlide
I've heard more than one MSF Instructor say that your primary brake is the rear one. One instructor even said he told his students to forget they had a front brake.
I agree with most of your post, but this part is really a shame. It is contrary to the msf's official teaching. You can't pass the msf without doing the panic stop, and you can't do that without getting most of your braking from the front brake. If you just use the rear brake the tire will just slide and you won't stop.

The weight shift puts most of the traction onto the front tire. That's why even cages have bigger brakes on the front.

When I see someone who gets only about 5k miles out of a rear tire, I always wonder about his braking habits. I know this isn't about cupping, sorry for off-topic.

$.02
 
  #55  
Old 09-12-2008 | 05:33 AM
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JBaker421
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Originally Posted by Big Cholla
I lost this thread for a spell. Back to it now. I will answer for JB if that's OK. Front tire cupping probable causes: under inflation, bad spring in one front fork, internal fork shock valving problem, unequal fork oil quantities, unequal quality of fork oil (one is contaminated-one isn't....quite common), bad wheel bearing on one side, loose spokes, break in frame close to rear swing arm, bad bushing on one side of swing arm, bad front tire OR a combination of two or more of any of those factors.

In short a motorcycle that is cupping a front tire probably needs some TLC maintenance. .............

BC
Thank you Big Cholla, I lost track of this thread for a long time and never saw the questions to me. Good post.

May I add, possible out of balance?

Thanks again,

JB
 
  #56  
Old 09-12-2008 | 07:16 PM
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av8r
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Originally Posted by GT_RoadGlide
AV8R - Pick up a small, but accurate tire pressure gage. If not every day you ride check at least once a week. I have an 07 RG and check tire pressue every week or so. Every couple weeks I add air to the front tire and every 3-4 weeks I add to the rear. Never have cupping and get 20K + miles on my RG tires. Could probably run 25-27K on front. The service manager was amazed with my tire life. I'm getting close to double the life of what other riders in my area get (10-12K).
Thanks for the advice. I've been carrying a gauge in my pocket for some time now, but I still forget to check as often as I'd like to. I do plan on checking much more often than I used to though after shelling out almost $400 (installed) for the new tires. I don't expect I'll get your RG kind of mileage the way I ride the Custom, but I'm hoping to improve it over the first set. Thanks for the reminder.
 
  #57  
Old 09-12-2008 | 07:25 PM
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I don't think it's a good idea to try to simplify proper braking procedure by saying you should use more front or more rear. It's a complicated, dynamic thing that is different in every situation. I've been riding a long time and use both brakes all the time but in different amounts in different situations. I won't even try to say how much and when, it's just automatic to me now. It takes experience to learn how best to use the brakes. Beginners should take it easy and use common sense as they build that experience.
 
  #58  
Old 09-12-2008 | 07:42 PM
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SportsterBob
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Originally Posted by 55Bubba
New front and rear Metz on 95 Ultra.&nbsp\\; 4k miles on tires and the front one is cupping badly.&nbsp\\; It was balanced when put on.&nbsp\\; Local indy shop asked if I used the front brake alot and when I said oh yeah,,&nbsp\\; he nodded wisely and made a noise to himslef.&nbsp\\; Hell the msf teaches the front brake provides 70% of braking.&nbsp\\; Should I not be using the brake now to keep the Metz from cupping? Any idea what is causing this cupping.&nbsp\\; I mean you can feel it when rolling the bike backwards into a&nbsp\\;parking space.&nbsp\\; Help
&nbsp\\;
Bubba
Had the same cupping issue with my front 21" AVON Venom AM41 MH-90 56H tire....While going along at 50mph, I let go of the front grips and allowed the bike to decelerate on its own...A wobble occured at 35-mph...It also had a serious up/down vibration at 95+mph. Replaced front tire when it wore out and had it balanced by an old friend....Did the same 50mph test and no wobble; repeated test from 85mph and no wobble....still haven't got the space to do the test at above 85mph due to traffic. Front steering cup bearings/races are fine, lower fork leg bushings are fine, wheel bearings/races are fine, tire pressure at 30-32psi.

Never checked the balance with the old tire but the wobble is definitely gone at 35mph. I'll get back with you when I get the space to go 95+.
 
  #59  
Old 09-12-2008 | 08:48 PM
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themensh
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balance and/or tire pressure.
Front braking (if you happen to lock-up the front brakes.)
 
  #60  
Old 09-13-2008 | 03:09 AM
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LDUltra
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before i rode to Sturgis i had my 15000 mile service done, I had new brakes and a new back tire put on. when i got out there my neck bolt was so loose the front of the bike had a really bad wobble and it ruined the front tire and also, as i was to find out later, the back tire, so be sure to check that area for loose bearings or neck bolt. all i can figure is my wrench loosened something and forgot to tighten it back up
 


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