Tire Balance Issues

[turtlecreek]

I looked through old posts, but didn't find anything specific on this:

I just used my static balancer and tire change rig to swap out 4 tires between my track bike and my vfr. I have not tried the track bike, but took the VFR for a shake down cruise as I also did the coolant and oil while I was at it.

The rear tire was a brand new metzeler m3 and it feels fine.

The front tire is a 120/70 AVON Viper tire that came off of the track bike. It appears to be about 50% tread.

On the static balancer, I did not find any particular heavy spot (only tire of the 4 that did not need any weight added)

When I took it out for a run my results were:

below 40mph smooth :thumbsup:

40 to around 60 handle bars oscillated :unsure:

60-95 smooth :thumbsup:

I may try to rebalance it, but thought I would ask for any thoughts on why the oscillation would occur at such a small range of mph's

[tinyminds]

That was my thought exactly, if its not out of balance, it could have everything to do with the design of the 2 different types of tires. Even going straight, its possible for them to create a wobble at certain speeds. Hope its just out of balance =P

[Stéphane]

I looked through old posts, but didn't find anything specific on this:

I just used my static balancer and tire change rig to swap out 4 tires between my track bike and my vfr. I have not tried the track bike, but took the VFR for a shake down cruise as I also did the coolant and oil while I was at it.

The rear tire was a brand new metzeler m3 and it feels fine.

The front tire is a 120/70 AVON Viper tire that came off of the track bike. It appears to be about 50% tread.

On the static balancer, I did not find any particular heavy spot (only tire of the 4 that did not need any weight added)

When I took it out for a run my results were:

below 40mph smooth :thumbsup:

40 to around 60 handle bars oscillated :pissed:

60-95 smooth :thumbsup:

I may try to rebalance it, but thought I would ask for any thoughts on why the oscillation would occur at such a small range of mph's

Try this: spin the tire on the rim 180 degrees. Rebalnce and gor for a ride.

I worked for a tire shop for years, and I can't tell you how many vibration problems we solved that way. Even with brand new tires.

[turtlecreek]

I looked through old posts, but didn't find anything specific on this:

I just used my static balancer and tire change rig to swap out 4 tires between my track bike and my vfr. I have not tried the track bike, but took the VFR for a shake down cruise as I also did the coolant and oil while I was at it.

The rear tire was a brand new metzeler m3 and it feels fine.

The front tire is a 120/70 AVON Viper tire that came off of the track bike. It appears to be about 50% tread.

On the static balancer, I did not find any particular heavy spot (only tire of the 4 that did not need any weight added)

When I took it out for a run my results were:

below 40mph smooth :thumbsup:

40 to around 60 handle bars oscillated :blink:

60-95 smooth :thumbsup:

I may try to rebalance it, but thought I would ask for any thoughts on why the oscillation would occur at such a small range of mph's

Try this: spin the tire on the rim 180 degrees. Rebalnce and gor for a ride.

I worked for a tire shop for years, and I can't tell you how many vibration problems we solved that way. Even with brand new tires.

well,

i practiced balancing a couple more times with other tires, rechecked the balance, tried rotating 180 degrees, rebalanced and still have the wobble.

I will be curious to see if a new avon w/ metzeler causes the issue too. please pm me when you try it either way.

I am going to order a m3 front and see if problem goes away. the only reason i mixed was to save a few $$'s as I had a used avon laying around.

will let you know if the problem doesn't go away.

[Stéphane]

well,

i practiced balancing a couple more times with other tires, rechecked the balance, tried rotating 180 degrees, rebalanced and still have the wobble.

Sorry it didn't work. What we did was rotate 180, then check(again) how it spins. Looking at the top, you can see if the tire moves up and down. If it does, then we roate it (say 90 degrees), and try again. If it still does it, then rotate gain 180 degrees (covering the majority of the possibilities). When looking at how it spins, there will be a time when you're getting closer to perfection. Move around that. The reasoning behind that is that inside of your rim(where the bead sits) has some imperfections, so does the bead of your tire. So you're moving them to avoid having them together.

Other things to consider:

1.Usually, the yellow (sometimes white or red) dot on the tire should be at the same location as the vavle stem.

2.Make sure the bead is sitting properly on the rim. You should put air in your tire without the springvalve: it helps to have more air in at once to have the bead setting in.

3. Check how it spins

[enzed_viffer]

My 'bike guy' specialises in Avons, and told me a few things. The Avons don't have markings on the outside for the heavy spot, because (apparently) they don't like the way that looks! Bad asthetics and that sort of thing.

Avons are balanced at the factory to within some mental tolerance like 0.05 of a gram or somesuch, so don't usually need balancing if the rim is already balanced. However, because yours isn't new, this probably doesn't apply. Maybe it has a flat spot or somesuch?

Some Avons suffer from "tread walk", where the tyre (particularly the front) will make the bike tend to track a wiggly path as the treads deform and/or steer the bike. This is most noticeble at slow speeds, especially on front-heavy bikes like VFRs and Blackbirds and may be responsible for the oscillations you noticed. Now mine are thoroughly scrubbed-in, I don't notice it, but if I don't keep the tyre pressure high (at least 38, but preferably 40psi) the bike tends to wander on coarse-chip seal and flop into corners. This is because the carcase (especially the sidewalls) of the SP front is softer than on many tyres.

[turtlecreek]

My 'bike guy' specialises in Avons, and told me a few things. The Avons don't have markings on the outside for the heavy spot, because (apparently) they don't like the way that looks! Bad asthetics and that sort of thing.

Avons are balanced at the factory to within some mental tolerance like 0.05 of a gram or somesuch, so don't usually need balancing if the rim is already balanced. However, because yours isn't new, this probably doesn't apply. Maybe it has a flat spot or somesuch?

Some Avons suffer from "tread walk", where the tyre (particularly the front) will make the bike tend to track a wiggly path as the treads deform and/or steer the bike. This is most noticeble at slow speeds, especially on front-heavy bikes like VFRs and Blackbirds and may be responsible for the oscillations you noticed. Now mine are thoroughly scrubbed-in, I don't notice it, but if I don't keep the tyre pressure high (at least 38, but preferably 40psi) the bike tends to wander on coarse-chip seal and flop into corners. This is because the carcase (especially the sidewalls) of the SP front is softer than on many tyres.

i am assuming it has something to do with the fact they are used tires from a track bike. but, i am 270lbs on top of the bike being heavy, so that might not help either. i did notice they went on real easy so i can believe the soft side wall statement

question: why would you want a soft sidewall? what advantage would this give you?

[enzed_viffer]

question: why would you want a soft sidewall? what advantage would this give you?

I guess it's so they flex more and give better grip/traction (only guessing here...) It also means they heat up faster (it is a sports tyre after all...)

I didn't actually realise the front tyre was like this until some time after they were fitted. I was talking to a technician at the bike shop and he asked me how I found the tyres. I said they were good, but I'd had trouble with the front one wandering. He then told me that's because of the soft carcase, showed me a tyre in the rack and how soft it was, and suggested I try putting more air in. Worked a treat.

[Guest joe7]

Question: Does it seem like the vibration is side-to-side, or up and down? Can you tell?

Clearly, up/down vibration...bouncing...is from an out of balance situation, and side-to-side would be more like the uneven wear or walking issue mentioned by our Kiwi brother enzed_viffer.

Although my knowledge is limited, using only logic, I would expect that an out of balance situation would get exponentially worse with speed, and not happen for only small range of speed.

I hope someone will correct me if I am on the wrong track.

Joe

[turtlecreek]

question: why would you want a soft sidewall? what advantage would this give you?

I guess it's so they flex more and give better grip/traction (only guessing here...) It also means they heat up faster (it is a sports tyre after all...)

I didn't actually realise the front tyre was like this until some time after they were fitted. I was talking to a technician at the bike shop and he asked me how I found the tyres. I said they were good, but I'd had trouble with the front one wandering. He then told me that's because of the soft carcase, showed me a tyre in the rack and how soft it was, and suggested I try putting more air in. Worked a treat.

you know, i am only running 36lbs. i'll try 40 lbs and see if anything changes. i did notice an odd sensation when i came into a pretty fast curve too. perhaps this was the 'flop' you mentioned. i dont want to throw them out after one try with a used tire, but i will say that the metzelers m1's on my vfr and the pilot powers on my track bike have both done so well, i am not sure why i should mess with anything else.

dsm

[enzed_viffer]

i will say that the metzelers m1's on my vfr and the pilot powers on my track bike have both done so well, i am not sure why i should mess with anything else.

Yeah, it's always a bit of a gamble swapping to something new. I've really enjoyed the Azaros, especially after running BT-020s, but they're getting on a bit, and I'm not sure whether to go with the new model Azaros that are out, or try something different like Pirellis. What makes the decision even harder is that the Azaros are very competitively priced, and my bike guy offers things like a free 1000km/one month trial with a free swap to something else if I don't like them, and free puncture repair for the lifetime of the tyres (which I've used twice now - once on the VTR1000, and once on the VFR - both times when the tyres were new! Must stop riding in gutters and lanesplitting...)

[turtlecreek]

I looked through old posts, but didn't find anything specific on this:

I just used my static balancer and tire change rig to swap out 4 tires between my track bike and my vfr. I have not tried the track bike, but took the VFR for a shake down cruise as I also did the coolant and oil while I was at it.

The rear tire was a brand new metzeler m3 and it feels fine.

The front tire is a 120/70 AVON Viper tire that came off of the track bike. It appears to be about 50% tread.

On the static balancer, I did not find any particular heavy spot (only tire of the 4 that did not need any weight added)

When I took it out for a run my results were:

below 40mph smooth :thumbsup:

40 to around 60 handle bars oscillated :goofy:

60-95 smooth :thumbsup:

I may try to rebalance it, but thought I would ask for any thoughts on why the oscillation would occur at such a small range of mph's

this is the exact combo I plan to run, hope it has nothing to do with running different type/brand tires???

just an fyi that I put a new m3 front on and ALL the issue went away. so either the avon was worn oddly from being run on the track or else the avon/m3 combo doesn't work. anyone had any luck with this combo?