| Author | Message | ||
     Gobadgers |
I had a Pirelli Angle GT mounted on a rear PM rim for my S1. In having the tire mounted I asked for the mounter to let me know how much weight and where it would be put on the rim. (I was intending to use dyna-beads.) He mounted the two red dots on the sidewall aligned with the valve stem, and then in the balance said it would take 1 oz of weight at the valve stem (right at the red dots). I have never had more than 1/4 oz. on the wheel before to balance. Two questions: 1. It would seem that if weight is being added at the lightest point of the tire--at the red dots--that the tire should be rotated around 180 degrees. Is the reasonable? 2. I am not sure I should be concerned about 1 oz of balance weight, yet in turning the tire 180 degrees, how much might this reduce the weight needed to balance? i.e. would a tire on its own be out of balance by close to 1 oz. and turning around only shows weight needing to be added to the other side? I have never done a balance on just the rim as up to now I thought it was pretty close to being in balance without weight. | ||
| Williamscottrobertson |
I may be remembering wrong (as I always just let a metric shop mount/balance my tires) but the tire should have a dot at the heaviest point and that should be lined up with the valve stem (the lightest point of the wheel). Then balance, statically or dynamic. Static wheel balancer from harbor freight is cheap. | ||
| Gobadgers |
I am pretty sure the Pirelli two red dots mark the lightest spot on the tire. | ||
| Hootowl |
Just put some armor all on the side wall. It works twice as well as dyna beads.  | ||
| Gobadgers |
Simply put, should wheel weights ever be mounted at the red dots (lightest spot)on the tire? I would theorize only on a rim that is perfectly balanced without a tire. And then the question becomes how much out of tolerance is acceptable on a tire? 1/2 oz, 1 oz, 2 oz.? | ||
| X1tuber |
Truthfully my policy has always been to have as little weight as possible, mostly to lessen the chance of a weight falling off and definitely becoming unbalanced. Usually if I need that much weight on that size rim, I would be inclined to rotate the tire a bit and see if the weight moves/lessens then re-seat the bead at the most ideal spot. That being said, my PM took (1) 7g stick on weight with a Shinko Raven, which is one heavy assed tire. Entirely plausible that the tire you put on is just 1oz heavy in that spot. Last but not least, the last motorcycle shop I worked at we still used the old fashioned balancer which was just a road between two posts riding on roller bearings. Same for track days, which is what just about everyone else I know uses. Anyhoo, that balancer can be had or less than $50 from certain places, given that cost I am unlikely to pay a shop by me the same to mount and balance 1 tire. | ||
| 1313 |
And then the question becomes how much out of tolerance is acceptable on a tire? 1/2 oz, 1 oz, 2 oz.? I would suspect that kind of info would be in the manual for your bike. However...back in the tuber days...if my memory isn't failing me...the limits in production were 1 ounce for the front and 2 ounces for the rear. | ||
| Gobadgers |
Your memory is right Brankin. Back in the day, had the factory received a rear tire let's say from the manufacturer that was 2 oz. out of true would they return that tire to the manufacturer? Or was the factory's tolerance lower? | ||
| X1tuber |
Ditto on the 1oz/2oz rule. It's not that it's a set in stone thing but at .75 Oz I start to look for a different way to balance. .75 at high RPM is quite a bit of weight, a few pounds I believe at as little as 500 rpms. So that would be my basis I think, how fast do I normally ride, how much is the imbalance, and what is the force exerted as a result. | ||
| Two_seasons |
I've got a $1600 Magna-Matic mower blade grinder with a vertical seven ball-bearing balancer and an adjustable run-out (true) guide. Bits from my old landscaper days. You'd not believe how most new mower blades are not even close to balanced! That said, I'd like to set up a fixture, with a vertical seven ball-bearing balancer just for motorcycle wheel balancing. Maybe a Tootal and me project  I think, in retirement, I'm going to buy a Nomar tire changer. And with the above wheel balancer setup, maybe be riding two wheels well into my retirement years! As for right now, I'm in physical therapy from a 4,300+ ride recently  (Message edited by two_seasons on July 31, 2017) | ||
| Gobadgers |
Thank you for your responses. When X1Tuber indicated that the weight of force would be in the pounds, it blew my mind a bit. So I went to do some calculations and that is what I come up with. 1 oz weight at 60 mph is a force of about 5.8 lbs. and at 90 mph about 13.2 lbs. if I calculated correctly. It shows how extreme just 1 oz of balance/out of balance can be. This experience demonstrates to me how important to know the light/heavy spots on the rims and mount tires accordingly. Not to leave it to chance. My XB rims show this, but I have never had the PM rims gauged for balance. Two Seasons, hope you are back to good health soon! | ||
| Two_seasons |
I would think that checking a raw wheel for balance would be ideal. Then, add bearings and inner spacer and check again for balance and runout. Then, check sprocket/pulley/rotor for balance and runout. Then, check the axle for runout. With all of these variables, how would you compensate and balance a wheel "properly", meaning minimizing each variable to zero to get as close to a perfect balance as possible. After all of that, which is the better valve stem, all rubber, or rubber/steel. Another thought, are angled valve stems going to give you more problems. I'd think not unless that angled valve stem flexes during high speed rotation. And what then is considered high speed. I thought I read somewhere where under 60mph isn't worth consideration for "absolute" balance. Thanks Gobadgers. The TV show Roseanne is starting to make sense to me  | ||
| 89rs1200 |
Valve stem? Use short metal with rubber gaskets if available. Would never recommend angled! Think of the force hanging over pulling on that angled bit. Valve stem covers; Recommend sheet metal ones with the rubber o-ring in the end. Provides little weight, but more importantly, if the Shrader valve fails the metal cover will keep the tire inflated. When I club raced, AFM mandated these as one rider had crashed because of a failed Shrader valve. Rubber? AS SHORT AS POSSIBLE! Had a shop put a long rubber valve stem on my front tire once. After an 85MPH run for 20 miles, the valve stem bent over and tore. Fortunately the centripetal force kept the tire working well enough until slowing to about 40 MPH. That is when the wobble happened and I was stranded. | ||
| Ceejay |
This will sound like sacrilege in this discussion but I just spooned a different set of tires on my 1125, along with new bearings pressed in. I didn't even check the balance, and after a brief scrub in had the bike up over 120...didn't notice anything out of the ordinary. | ||
| Ceejay |
The tires, Avon storms, did not have any dots which may be part of the reason. I did find it somewhat difficult to believe that they were in complete balance out of the box but I'm not going to complain either... | ||
| Upthemaiden |
When I had my old supermoto, which rarely got over 60mph, I never even used to balance the tires. It was pretty common for guys with those bikes, and honestly I couldn't even tell a difference. Even on the Tuber, last time I mounted a rear tire I just never got around to balancing the rear wheel. I always do, but with a newborn in the house... I forgot to balance it and haven't had the time to pull the wheel off to do it. Really haven't noticed on this one either. I only use it to commute, so my standard speeds are between 0-60, but on the random chance I get up to 80-100, it still feels fine. As far as the angled valve stems, luckily the Marchesini style rims are too thick to even use angled valve stems how they come. I did dig around a bit, and found a way to modify them and add an extension to the part that goes through the rim, so next time I change my tires I'm going to mess with them and put them on my wheels. I figure any potential forces they deal with from being angled over are significantly small compared to how nice it'll be to easily fit a compressor fitting to the valve without worrying about the pulley or rear rotor. I think low tire pressure has way more affect on these wheels than a perfect balance does so anything I can do to make it more likely that I'll check my pressure, the better. Regardless, a ton of bikes way faster than ours have angled valves, they're not going to break. A lot of cars have rubber valves that are angled out towards the side of the car and they're fine as well. Random fact: Back when I used to ride bicycles more the ongoing rumor as to why bicycles started to get those threaded presta valves instead of Schrader valves, was because some people rode too fast, which caused the plunger inside the valve to press in due to the centripetal force, letting all the air out, so they had to change the valve. Considering motorcycles use these valves up to 200mph on wheels that are half the diameter as road bikes, which really aren't ever going to see speeds over 40mph(and significantly lower if you're just a normal person who isn't in the tour de france...), that obviously wasn't even close to true. | ||
| X1tuber |
Ditto on no balance at all. As big of a proponent I am for balancing, I'm currently running used shinkos, no longer balanced, 160 section rear...with a plug in the center. lol, the definition of sacrilege. The last pair were Q2's balanced perfectly with nitro fill, difference...meh, slower turn in at the front, a little sketchy in the rear. | ||
| Gobadgers |
The Angel GT I took off I had put Ride On balancer/sealant in. It road very smooth throughout its entire life of just about 4000 miles, but as you can see from the pictures below did not wear evenly. The shots taken are from 180 degree opposite sides of the tire. I do not know if the Ride On is the problem here or something else. It was the first time I used it, though,I do also have it in my other bike and the wear there is more consistent. The tire never felt out of balance even up to 90. Initially I became acquainted with Ride On as extra protection as I picked up a small staple at about 150 miles on a new tire on another bike. Had about 1000 miles experience on that tire when I put the Ride On in this tire. The roads I ride are back country roads and there is a lot more junk on them from farmers etc. My thinking has been that it gives just a bit extra protection. The takeaway from this: The balance and possibly balance point dramatically changed over the life of the tire. Now there is quite a bit extra weight on one side of the tire versus the other. In true scientific fashion I need to better control all my variables from here on out.   | ||
| X1tuber |
I'd say that looks fairly normal. Less than 1/32 difference from left to right is certainly fine. I bet the difference is from making more left turns than right, or just cornering harder on that side. Either way you're just down to the wear bars so if it passes inspection I'd ride another season on that. | ||
| Gobadgers |
Thanks X1tuber. Yes there is a difference from left to right too. What I am trying to show in the pictures, the top of the picture shows one side of the tire and the bottom the opposite (180 degrees)side. The 2nd picture is a closeup of the 1st picture. Notice, there is quite a difference. In the top half of the first picture, the last time I rode you can see the cords started to show there in the center. The tire is toast. | ||
| Upthemaiden |
Never considered balancing a tire between tire changes, but reading this makes me feel like it'd be worth throwing a wheel on the balancing stand any time I have it off for regular maintenance, just to see how it's doing. | ||
| X1tuber |
Has anyone gone to the "darkside" on a buell? (Car tire on rear) You seem to be in the straights a lot, I met another person today that switched over and he says it corners just fine, same as everyone else. | ||
| Upthemaiden |
I've only ever seen that one on a Boss Hoss in person. I'm sure it would work, some car tires even have a slightly curved profile on the outside. What size are those little donut wheels they put in car trunks? Those things seem pretty round. I'm not sure about this bike though, it really likes to lean so I'm not sure how a car tire would do. I typically have always had at least half an inch of chicken strip on my tires, and the centers wear flat much quicker, even when I was younger on 600s when I was dumb and always going unnecessarily fast on back roads and trying to lean the bike as far as I could to get to the edge of the tire. Now that I'm older, only commute and make a point to not go crazy on back roads for the sake of not being reckless... I have less than 1/4" strips on both sides of my tires. Clearly the bike is doing the work because it's not me. | ||
| Natexlh1000 |
Those donuts are rated for 50 miles per hour though. I think they pump them up like 60 pounds too. | ||
| Upthemaiden |
Forgot about the speed rating. I started to google "car tire on motorcycle" just because I was curious to see pictures. The list of pre-populated results were: Car tire on motorcycle Car tire on motorcycle accident Car tire on motorcycle crash Car tire on motorcycle darkside Car tire on motorcycle rim Car tire on motorcycle video Car tire on motorcycle insurance Probably not the best sign.... I laughed when I say "darkside" in the list though after X1tuber mentioned it haha | ||
| X1tuber |
So far I know three people first hand that use them and a dozen or so second hand. The three I know of for sure have been through the dragon and the bikes are a Valkyrie, a VTX 1800, and most recently a Honda ST. All have in excess of 30k and report that they wish they had done it sooner and corner better than before. Also, much more stable when braking hard in the straights and while traveling over rough/uneven/unfinished roads. If I can figure out the size I'm going to try it just to be able to say it can be done on a sport bike. | ||
| Upthemaiden |
The only thing I saw online that made it look a little iffy was the difference in the tire and rim profiles. They're shaped differently and appear to not exactly match up the same way they should. If people do it and it works, then it's probably not a real problem. If you look in google images you should be able to see the pictures I'm referring to. One other thing to consider on the opposite end.... of all of the streetfighter builds I've seen, a ton of guys with single sided swingarms put car wheels on the back of their bike with bike tires on them. I guess the only difference there is the motorcycle tires were the ones with the smaller and shorter lip, so they wouldn't have as much of a problem still sitting flush on the lip of the rim, while the car tires seemed to be the ones that are jammed in there and don't seat as well. | ||
| Upthemaiden |
These are the pictures. I'm not sure if the measurements are standard for all cars and bikes, but I assume they'd have to be close.   | ||
| X1tuber |
The evidence and experience belie the pictures. For the record, every darkside discussion starts out like this and ends in misery. I promise to never mention it again, and will forever forget the tire setup which shall not be named. Not really, I will put a car tire on the back of my X1 this winter when it gets stripped down and take thorough pictures the whole way. | ||
| Gobadgers |
Final report on my tire: some Buell guys took a look at the tire this week and said they never saw uneven wear as on that tire. They suspect that maybe it had not been seated evenly. As it never felt out of balance, the Ride-On may have continued to dynamically balance through this uneven wear. I will chalk it up to a one off and see how the replacement wears. |
