Unresolved Front Wheel Bounce

I have a BT45 with maybe 500 miles on the front. I've real many posts concerning the 35 mph front wheel bounce due to axle fork misalignment and have tried the methods listed in the forms to alleviate this problem. I found the following excellent explanation and followed the attached instructions and illustration multiple times, yet I still have wheel hop at 35 mph.

Any suggestions? What am I missing?

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(Note:Axle pinch bolts are finger loose at this point)

1. Tighten the left axle pinch bolts to 22 N-m (2.2 kgf-m, 16 lbf-ft)
   Note: Indication of “Left” is if you were sitting on bike
2. Tighten Axle Bolt to 79 N-m (8.1 kgf-m, 58 lbf-ft)
3. Tighten the right axle pinch bolts to 22 N-m (2.2 kgf-m, 16 lbf-ft)
4. Now loosen the left axle pinch bolts
5. Note: During the assembly process, this is where you would be installing the brake calipers.
6. Set the bike down where the bike's weight is on the wheels. Lock the front brake and push the suspension up and down several times.
7. Tighten the left axle pinch bolts to 22 N-m (2.2 kgf-m, 16 lbf-ft)
   
   
   

If there is no mechanical defect then:-

Have you checked the tyre fit lines along the bead/rim interface?

If you prop the front of the bike and spin the front wheel while looking across the tyre, does it have any high spots at the tread crown?

I wouldn't let it run any longer if you suspect it is not fitted correctly?

Zonker said:

yet I still have wheel hop at 35 mph.

Click to expand...

Can you describe what you call "wheel hop"? Most folks have a different definition of wheel hop.

Sounds like you have an out of round tire.

Zonker said:

I have a BT45 with maybe 500 miles on the front. I've real many posts concerning the 35 mph front wheel bounce due to axle fork misalignment and have tried the methods listed in the forms to alleviate this problem. I found the following excellent explanation and followed the attached instructions and illustration multiple times, yet I still have wheel hop at 35 mph.

Any suggestions? What am I missing?

-------------------------------
(Note:Axle pinch bolts are finger loose at this point)

1. Tighten the left axle pinch bolts to 22 N-m (2.2 kgf-m, 16 lbf-ft)
   Note: Indication of ?Left? is if you were sitting on bike
2. Tighten Axle Bolt to 79 N-m (8.1 kgf-m, 58 lbf-ft)
3. Tighten the right axle pinch bolts to 22 N-m (2.2 kgf-m, 16 lbf-ft)
4. Now loosen the left axle pinch bolts
5. Note: During the assembly process, this is where you would be installing the brake calipers.
6. Set the bike down where the bike's weight is on the wheels. Lock the front brake and push the suspension up and down several times.
7. Tighten the left axle pinch bolts to 22 N-m (2.2 kgf-m, 16 lbf-ft)
   
   
   

Click to expand...

Delete the steps in RED. Tightening the axle nut will pull the axle against the right fork leg and set the bearing and spacer tension then you can tighten the right pinch bolts. After you bounce the front and check the left end of the axle is flush with the flat machined surface of the left fork you can tighten the left pinch bolts. This should have nothing to do with bounce, just proper wheel mounting.

If the tire is out of round or not seated properly on the rim, has an unseen defect in the carcase of the tire, or the balance is out then you would get a bounce.

I always torque the axle bolt first, then pinch bolts, then caliper(s).
I'd check tire balance First, then roundness. Both can be done a balancer. Take it off the rim and insure there isn't anything inside. Remount and balance. Couldn't hurt to inspect and spin the rim without the tire to ensure it hasn't been damaged.

The BT45 is stiff sidewall bias ply tire and isn't made in a size that fits the ST1300 front rim correctly. Aside from possible problems with the tire mounting or excessive runout from an out of round tire or bent rim why even put a BT45 on the ST1300?

The installation of the wheel procedure above typically only results in eliminating the pull-to-the-left issue, or was it right.

Anyway, the 1st time I had a front tire 'hop' on me it was a Road(smart?) tire and it only had a couple hundred miles on it.

I would try balancing the tire first as maybe it just has an unusual heavy spot and the tire install maybe also happened to get that in the same spot as the heavy spot on the wheel. A lot of the times, you don't eve have to balance a tire at all. If the balance doesn't fix it, it's a bad tire, they are not all perfect and bad one will show up once in a while.

dduelin said:

The BT45 is stiff sidewall bias ply tire and isn't made in a size that fits the ST1300 front rim correctly. Aside from possible problems with the tire mounting or excessive runout from an out of round tire or bent rim why even put a BT45 on the ST1300?

Click to expand...

+1
"Correctly" being the key word.

Fits the ST1300 front rim correctly???
Mine mounted up just fine and most have no problems at all with the tire. Are you trying to say the bead is different between a front and rear MC tire, If so where are you getting your info? I would most likely vote it is a bad tire or they didn't seat the bead when mounting the tire.

The Dan said:

Fits the ST1300 front rim correctly???
Mine mounted up just fine and most have no problems at all with the tire. Are you trying to say the bead is different between a front and rear MC tire, If so where are you getting your info? I would most likely vote it is a bad tire or they didn't seat the bead when mounting the tire.

Click to expand...

Poor choice of phrasing on my part.

My source is the DOT placard on the headstock, the owners and service manuals, and from Bridgestone's 2014 Tire Data Booklet.

Bridgestone does not make a BT45 front (or rear) tire in the recommended fitment size and construction for a ST1300. Other tires may fit and mount at the rider's discretion.

First off. Thank you guys for your suggestions, even the tongue-in-cheek ones.

Byron said:

Delete the steps in RED. Tightening the axle nut will pull the axle against the right fork leg and set the bearing and spacer tension then you can tighten the right pinch bolts. After you bounce the front and check the left end of the axle is flush with the flat machined surface of the left fork you can tighten the left pinch bolts. This should have nothing to do with bounce, just proper wheel mounting

Click to expand...

Byron, I'll try that way in a few minutes. I have her up in the shop and I'll re-torque before I go for a ride, I'll post later.

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Firstpeke said:

Have you checked the tyre fit lines along the bead/rim interface?
If you prop the front of the bike and spin the front wheel while looking across the tyre, does it have any high spots at the tread crown?
I wouldn't let it run any longer if you suspect it is not fitted correctly?

Click to expand...

Firstpeke, I've done this in a cursory fashion twice, however I'll check in detail while I'm redoing the tightening pattern as Byron suggests.

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caldercay said:

Can you describe what you call "wheel hop"? Most folks have a different definition of wheel hop.

Click to expand...

Caldercay, Between indicated speed of 32mph and 38mph my front forks develop what feels like a cyclic vertical vibration that appears strongest at 35mph.

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kperham said:

I always torque the axle bolt first, then pinch bolts, then caliper(s).
I'd check tire balance First, then roundness. Both can be done a balancer. Take it off the rim and insure there isn't anything inside. Remount and balance. Couldn't hurt to inspect and spin the rim without the tire to ensure it hasn't been damaged.

Click to expand...

Kperham, Good suggestions. I took the wheels to a local shop which may be the last real motorcycle shop, slightly greasy floor, bike parts, projects laying about, and the owner has greasy hands and talks old bikes! The rim is without defect, and I was at the tire machine through the process so I feel comfortable ruling out damage or debris. (see below)

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So I guess I'll re-torque the axle/pinch bolts, check for out of round and defects, as well as bead alignment. If nothing is found I'll drag the wheel off to the tire a MC shop and see if they can verify the balance. My history with Bridgestone Truck tires would indicate that the tire is not out of round or lumpy and most likely free from defect. I had mused in passing if anyone in my neck of the woods shaved tires this small.

Once again THANKS!

dduelin said:

Poor choice of phrasing on my part.

My source is the DOT placard on the headstock, the owners and service manuals, and from Bridgestone's 2014 Tire Data Booklet.
Bridgestone does not make a BT45 front (or rear) tire in the recommended fitment size and construction for a ST1300. Other tires may fit and mount at the rider's discretion.

Click to expand...

Dduelin,

Noted. Yes, I color out of the lines and run with scissors when my wife isn't looking.

Haven't had any problems with BT45's on either the ST1300 or the Wing. I'm also thinking the bead might need reseating.

John

Zonker said:

Dduelin,

Noted. Yes, I color out of the lines and run with scissors when my wife isn't looking.

Click to expand...

One other thought....having a directional tire mounted backwards on the wrong end may have induced a problem with a slipped belt in the carcass. I had a BT45 replaced under shop warranty years ago when the shop mounted the tire backwards on my Nighthawk 750. A knot or bump on the tread surface coupled with a indentation in the sidewall was the visible sign and the tire vibrated the bike. Of course by now you have probably ruled that out when you checked for out of round run-out.

An indentation in the sidewall of a tyre is normally the indication of a product join in the casing materials.... being stronger at a join does not allow the casing to be pushed out as far as the rest of the sidewall......

Bumps or high areas can be the result of air infiltration to the casing or damaged casing structure, which makes it the opposite of a product join.....

I spooned on a rear BT45 Saturday on my front rim and didn't have any issues. Did you mount the tire the same direction as recommended or backwards? Mine is mounted same as recommended by the manufacturer.

Mine is mounted counter rotational as suggested by the guy who mounted the tire. I did jack her up and used the archaic switchblade point method and found an area of approximately 3" - 4" that appears to be 3/16" less in diameter than the rest of the tire.

1. it may be a faulty tire (being a bridgstone I doubt it)
2. it may be an error mounting the tire (see below)
3. axle/fork mis-aligned (adjusted ad nauseam)
4. cosmic wrath for daring to tread where angles fear (darkside)

I'll pull the wheel off tomorrow and have it remounted and see if the will remove the 'flat' spot. Please note, I purchased the tire from Rocky Mountain ATV, who issued a return UPS postage label immediately and promised to ship a new BT45 my was upon my faulty tire's arrival. I'm more than pleased with their customer service. If I can avoid using this method, I will.
.Ahh to be an outlaw once again! =)


I swear this really happened, I didn't make it up or spice it at all.

playinatwork said:

I spooned on a rear BT45 Saturday on my front rim and didn't have any issues. Did you mount the tire the same direction as recommended or backwards? Mine is mounted same as recommended by the manufacturer.

Click to expand...

Another example of me over thinking a problem. I believe you are on to something! Since the tire is already mounted, I'll just pop the beads, lube all affected areas and see about re-seating the tire.

Now the question is if I turn the tire around will I wad the cords up? The only time I've ever seen it is when someone reverses the rotational direction. Hmmmmm?

Zonker said:

Another example of me over thinking a problem. I believe you are on to something! Since the tire is already mounted, I'll just pop the beads, lube all affected areas and see about re-seating the tire.

Now the question is if I turn the tire around will I wad the cords up? The only time I've ever seen it is when someone reverses the rotational direction. Hmmmmm?

Click to expand...

Get rid of that tire. Put a set of quality, radial, motorcycle tires on the bike in the size 120/70/18 Front and 170/60/17 Rear. Be sure they are mounted in the correct rotation and balanced with a static balancer. While the wheels are off, check the bearings in the wheels, the driven flange and the steering head. Install the front wheel according to the steps Honda says.