Tusk Wheels - Issues?

JB 19
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JB 19 12/29/2015 5:33pm
12/29/2015 5:33pm
Guys saying, "where did the bolts go?" .......Maybe they broke?

I'm not going to try to figure out what happened with the rest of it.
Justin345
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Justin345 12/29/2015 5:34pm
12/29/2015 5:34pm
colintrax wrote:
I repeat, when was the torque wrench last calibrated?
One ride day together, we torqued them down using my Snap on torque wrench which was checked by my snap on rep 6 months prior. Within 2 20 minute sessions on the track, the sprocket was loose. I couldn't believe it.
JerseyFresh
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JerseyFresh 12/29/2015 5:38pm
12/29/2015 5:38pm
Oh so NOW it's YOUR bike..... ps torque wrench shmork wrench, I was working on bikes at 14 and never had a sprocket bolt come loose then. As my old man would say, "I got a torque wrench right here."

colintrax
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colintrax 12/29/2015 5:43pm
12/29/2015 5:43pm
colintrax wrote:
I repeat, when was the torque wrench last calibrated?
Justin345 wrote:
One ride day together, we torqued them down using my Snap on torque wrench which was checked by my snap on rep 6 months prior. Within...
One ride day together, we torqued them down using my Snap on torque wrench which was checked by my snap on rep 6 months prior. Within 2 20 minute sessions on the track, the sprocket was loose. I couldn't believe it.
Thank you, your buddy seems to think it's not possible for 2 torque wrenches to be off.

How tight was the chain both times?

I don't think it's a Tusk problem, but ya never know. Bigger/faster guy, riding in sand, with a 450 spinning a 120 tire.... gonna put some stress on the hub

The Shop

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MXVet261
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MXVet261 12/29/2015 5:43pm
12/29/2015 5:43pm
I would look more at the sprocket bolts as the culprit. Typically the issue is not the bolts coming loose, but stretching. Therefore putting loctite on them really doesn't help and it also explains how this happens after a couple months of use.

I would use either OEM sprocket bolts, TAG, or titanium. Those are the 3 kinds I've never had any issue with.
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Team Ideal
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Team Ideal 12/29/2015 5:44pm
12/29/2015 5:44pm Edited Date/Time 12/29/2015 5:45pm
So checking the bolts before each ride is a bit much? I've had this happen before and I've prevented it from happening again by going from checking them at the beginning of each ride day and switching to checking them before each ride. Guess your fine with it eventually having it happen again. Every time the bike comes off the track I put it on the stand lube the chain and check the bolts, takes less than two minutes and cost a lot less than a new hub and spokes
scagle3
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scagle3 12/29/2015 5:44pm
12/29/2015 5:44pm
JerseyFresh, don't be ignorant. He posted it, and then I replied with pictures explaining what happened to MY bike. We ride together, thus he torqued them using his wrench.
cslacker
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cslacker 12/29/2015 5:44pm
12/29/2015 5:44pm
scagle3 wrote:
This is what a neglected bike looks like...? The second time this happened, a certified mechanic installed all the components and used loctite at my request...
This is what a neglected bike looks like...?

The second time this happened, a certified mechanic installed all the components and used loctite at my request. The bike had 5 rides on a new chain, sprocket, chain guide, and rear wheel and hub. Each time the bolts were checked before riding based on what happened beforehand. And let's not get crazy, people don't, and should not have to check sprocket bolts every ride.

There was no oblong wear pattern to the sprocket or the hub once this broke. I used a different sprocket, chain, chain guide, and sprocket bolts this time. The only thing that was the same was the hub and rear wheel.





As mentioned before, it's this style of sprocket that can lead to this type of failure. I've seen it before with yamaha oem hubs and the old style of ironman sprockets. Go with one where all of the bolt holes are directly connected and therefore take the individual stress off each hole. Ironman changed their design due to failures just like this.
Brad460
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Brad460 12/29/2015 5:46pm
12/29/2015 5:46pm Edited Date/Time 12/29/2015 5:48pm
Where are the missing bolts? Did they fall out? Fail by tension..shear??

I can see the hub bolt holes are eggs shaped in the pictures...The anodizing is wore off the area on the hub where the sprocket bolts up.

Is there fretting on the hub and back of the sprocket?

A lot points to loose bolts or perhaps as mentioned above the sprocket was flexing causing the wear/loosening of the bolts and eventual failure.

Use a little common sense root cause analysis here..
Justin345
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Justin345 12/29/2015 5:46pm
12/29/2015 5:46pm
JerseyFresh wrote:
Oh so NOW it's YOUR bike..... ps torque wrench shmork wrench, I was working on bikes at 14 and never had a sprocket bolt come loose...
Oh so NOW it's YOUR bike..... ps torque wrench shmork wrench, I was working on bikes at 14 and never had a sprocket bolt come loose then. As my old man would say, "I got a torque wrench right here."

No, it's not my bike, as I said in my original post. Its my friends bike. It doesn't take many brain cells to figure out which member in this thread the bike belongs to.

And as calibrated as your elbow is, torque specs are there for a reason. So when you've already had an issue with a sprocket coming loose and busting a hub, you eliminate the variables that you can control. In this case, using a quality torque wrench and not your trusty calibrated elbow.
scagle3
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scagle3 12/29/2015 5:46pm
12/29/2015 5:46pm
colintrax wrote:
I repeat, when was the torque wrench last calibrated?
Justin345 wrote:
One ride day together, we torqued them down using my Snap on torque wrench which was checked by my snap on rep 6 months prior. Within...
One ride day together, we torqued them down using my Snap on torque wrench which was checked by my snap on rep 6 months prior. Within 2 20 minute sessions on the track, the sprocket was loose. I couldn't believe it.
colintrax wrote:
Thank you, your buddy seems to think it's not possible for 2 torque wrenches to be off. How tight was the chain both times? I don't...
Thank you, your buddy seems to think it's not possible for 2 torque wrenches to be off.

How tight was the chain both times?

I don't think it's a Tusk problem, but ya never know. Bigger/faster guy, riding in sand, with a 450 spinning a 120 tire.... gonna put some stress on the hub
So look at the picture of the bike on the stand and you can see the chain. It's where it's supposed to be each ride.
scagle3
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scagle3 12/29/2015 5:49pm
12/29/2015 5:49pm
Brad460 wrote:
Where are the missing bolts? Did they fall out? Fail by tension..shear?? I can see the hub bolt holes are eggs shaped in the pictures...The anodizing...
Where are the missing bolts? Did they fall out? Fail by tension..shear??

I can see the hub bolt holes are eggs shaped in the pictures...The anodizing is wore off the area on the hub where the sprocket bolts up.

Is there fretting on the hub and back of the sprocket?

A lot points to loose bolts or perhaps as mentioned above the sprocket was flexing causing the wear/loosening of the bolts and eventual failure.

Use a little common sense root cause analysis here..
This happened twice. The first time I can say that they were oblong and probably led to that happening. The second time after 5 rides, the holes are perfectly circular and not oblong.
Justin345
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Justin345 12/29/2015 5:49pm
12/29/2015 5:49pm
MXVet261 wrote:
I would look more at the sprocket bolts as the culprit. Typically the issue is not the bolts coming loose, but stretching. Therefore putting loctite on...
I would look more at the sprocket bolts as the culprit. Typically the issue is not the bolts coming loose, but stretching. Therefore putting loctite on them really doesn't help and it also explains how this happens after a couple months of use.

I would use either OEM sprocket bolts, TAG, or titanium. Those are the 3 kinds I've never had any issue with.
That's a really good point. I hadn't thought about the bolts stretching.
Markopolo400
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Markopolo400 12/29/2015 5:51pm
12/29/2015 5:51pm
Off topic...But A kit suspension on cheapie wheels?
scagle3
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scagle3 12/29/2015 5:55pm
12/29/2015 5:55pm
Markopolo400 wrote:
Off topic...But A kit suspension on cheapie wheels?
Yeah, it's an A-Kit. I read all the reviews of the Tusk wheel set and figured it would work well. Not so much
Darryl916
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Darryl916 12/29/2015 6:04pm
12/29/2015 6:04pm
To further add to this conundrum ...

I am a professional mechanic and have worked on tons of my own bikes, other people's bikes, boats, cars, airplanes, helicopters, you name it... my entire life. Im the one that installed the first chain and sprockets on the bike in question the same as I have hundreds of times before without a single failure and his came loose just a couple hours after I installed it the first go round. I couldn't believe it. Everything was new and it's not rocket science. Something tolerance wise is off. No question....
chuckie108
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chuckie108 12/29/2015 6:08pm
12/29/2015 6:08pm
cslacker wrote:
As mentioned before, it's this style of sprocket that can lead to this type of failure. I've seen it before with yamaha oem hubs and the...
As mentioned before, it's this style of sprocket that can lead to this type of failure. I've seen it before with yamaha oem hubs and the old style of ironman sprockets. Go with one where all of the bolt holes are directly connected and therefore take the individual stress off each hole. Ironman changed their design due to failures just like this.
Best piece of info in this thread- every time I've seen this type of failure, it's with sprockets that don't have a continuous center ring area. But I will also say, I've seen it more commonly on the Chinese hubs too. Also the sprocket bolt input is valid- not all fasteners are equal quality. I always use OE bolts on sprockets and rotors. If you're not going OE, then get bolts that are marked grade 8 or higher(or the metric equivalent).
wwoberg
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wwoberg 12/29/2015 6:18pm
12/29/2015 6:18pm
I did the same with a stock 06 CRF450 wheel.....twice. Orginal wheel started experiencing loose sprocket bolts on second sprocket change. Tried everything, locktite, New bolts, proper tourque, they would be loose after a moto. Finally did like your picture landing from a double. Didn't crash but hurt my wrist.

A number of parts later (including swing arm) I didn't learn my lesson and the stock wheel I got off eBay did the same thing after bolts starting giving me fits again.

Got a pair of DNAs and it never happened again.

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IE22
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IE22 12/29/2015 6:28pm
12/29/2015 6:28pm
No offense, but your bike clearly has more time on it in the first photo that it does in the last. The first photo shows a rim with a good amount of wear around the outside from poor tire iron changes. The rim must have had a good amount of ride time before the failure. The later photo looks like the bike was new at that point.
mattyhamz2 12/29/2015 6:43pm
12/29/2015 6:43pm Edited Date/Time 12/29/2015 6:44pm
Im gunna stick with my tusk wheels, renthal sprockets and my elbow torque wrench when it comes to rotor and sprocket bolts. Most other bolts on the bike I will tighten to spec per my manual but when it comes to sprockets and rotors I am going to crank as tight as I can. Hasn't failed me in 23 years of riding/racing not had it failed my dad in his 40 years of riding and racing.
Jake_Pischke
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Jake_Pischke 12/29/2015 6:49pm
12/29/2015 6:49pm
IE22 wrote:
No offense, but your bike clearly has more time on it in the first photo that it does in the last. The first photo shows a...
No offense, but your bike clearly has more time on it in the first photo that it does in the last. The first photo shows a rim with a good amount of wear around the outside from poor tire iron changes. The rim must have had a good amount of ride time before the failure. The later photo looks like the bike was new at that point.
Not sure if you read he whole post, just ignored half of it, or just couldn't take it all in. 1st wheel did have more time on it, and the hub had went out. He gat a brand new complete rear wheel, therefore it looks like it has less wear. Lol bike only had 5-6 rides on it with complete new wheel, different chain/sprocket. Later on we put the neon yellow plastic kit, new graphics etc. His bike is professionally maintained. I am thinking it is something to do with the sprocket flexing from not having the complete circle.
fulltime wrench 12/29/2015 7:00pm
12/29/2015 7:00pm
Sometimes the taper of the sprocket bolt heads and sprocket are mismatched. This leads to the sprocket "walking" causing the bolts to come loose quicker than normal. A friend/mentor and former Yamaha tech pointed this out to me some years ago. He told me he has even used blue layout fluid to verify the bolt was seated fully into the sprocket. If it wasn't he would use different bolts or sprocket and sometimes both. On occasion he would lap the bolt to the sprocket with lapping compound to achieve a perfect fit. He would do this with his personal road racing bikes.

Also, it is possible for the sprocket bolt holes in the hub to be slightly oversized. This would allow the same "walking" of the sprocket. The bolts are shouldered to align the sprocket to the hub. If the tolerance is too wide, a problem could be rooted here.

I agree with using a sprocket that has a fully connected bolt holes. Much stronger design. This is very important especially for a 450 ridden by an aggressive rider who lands jumps throttle on.

And finally, not saying the installer did or did not, the nut should always be tightened holding the bolt stationary rather than the bolt tightened holding the nut.
alien
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alien 12/29/2015 7:20pm
12/29/2015 7:20pm
I'm with full time wrench , you must tighten the nut only. Hold the bolt with an allen until it starts to get tight and the taper should hold the bolt at that point , allen wrench no longer needed. The same way the taper on the flywheel works.
I have never been able to get a torque wrench on the sprocket nut , spokes get in the way. Are you guys using a crows foot adaptor or something? If the taper never holds you have a mismatch and it will never be as strong.
wwoberg
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wwoberg 12/29/2015 7:26pm
12/29/2015 7:26pm
fulltime wrench wrote:
Sometimes the taper of the sprocket bolt heads and sprocket are mismatched. This leads to the sprocket "walking" causing the bolts to come loose quicker than...
Sometimes the taper of the sprocket bolt heads and sprocket are mismatched. This leads to the sprocket "walking" causing the bolts to come loose quicker than normal. A friend/mentor and former Yamaha tech pointed this out to me some years ago. He told me he has even used blue layout fluid to verify the bolt was seated fully into the sprocket. If it wasn't he would use different bolts or sprocket and sometimes both. On occasion he would lap the bolt to the sprocket with lapping compound to achieve a perfect fit. He would do this with his personal road racing bikes.

Also, it is possible for the sprocket bolt holes in the hub to be slightly oversized. This would allow the same "walking" of the sprocket. The bolts are shouldered to align the sprocket to the hub. If the tolerance is too wide, a problem could be rooted here.

I agree with using a sprocket that has a fully connected bolt holes. Much stronger design. This is very important especially for a 450 ridden by an aggressive rider who lands jumps throttle on.

And finally, not saying the installer did or did not, the nut should always be tightened holding the bolt stationary rather than the bolt tightened holding the nut.
I really like that lapping idea. Thanks
GeorgiePorgie 12/29/2015 8:07pm
12/29/2015 8:07pm Edited Date/Time 12/29/2015 8:08pm
Hmm. After reading this I'm glad I Just laced up tusks to oem powder coated Yamaha hubs. Gonna have use oem sprocket and bolts now.


Cancerman
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Cancerman 12/29/2015 8:17pm
12/29/2015 8:17pm
IE22 wrote:
No offense, but your bike clearly has more time on it in the first photo that it does in the last. The first photo shows a...
No offense, but your bike clearly has more time on it in the first photo that it does in the last. The first photo shows a rim with a good amount of wear around the outside from poor tire iron changes. The rim must have had a good amount of ride time before the failure. The later photo looks like the bike was new at that point.
If you are looking at the bright wear all the way around the outside of the rim itself, that's call "Rim Scrub". The bigger the bright line, ie (wider), the lower your tire pressure is (was). Your tire sidewall flexes, or "rolls over". You can measure your roll over and adjust your tire pressure for better tire performance, mainly in cornering.
GeorgiePorgie 12/29/2015 8:21pm
12/29/2015 8:21pm Edited Date/Time 12/29/2015 8:23pm
Also so those vortex sprockets are putting more stress on the bolt holes because there is no central center hole? So does this make more stress On the bolt holes. Leading to egging....which leads to hub failure From "walking"? This is what I'm gathering from the thread. Just wanna make sure I don't ruin my new wheel setup. Right?



Trav138
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Trav138 12/29/2015 8:25pm
12/29/2015 8:25pm
any opinions on the Spec-bolt sprocket bolts? I just got a new RAD hub on an excel rim and i used sprocket bolts from my spec-bolt kit to mount my new Renthal sprocket.
I have never used any other sprocket bolts other than oem before this. I will keep an eye on them, they seem like decent quality when i used on different parts of my bikes.
Lucky13FIST
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Lucky13FIST 12/29/2015 8:31pm
12/29/2015 8:31pm
100%, for sure, a loose sprocket bolt caused this. The sprocket bolts were loosening because of the sprocket not the hub.
Cancerman
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Cancerman 12/29/2015 8:37pm
12/29/2015 8:37pm
As Fulltime Wrench stated, the bolts need to be checked in both the hub and the sprocket. If either are not snug, then things are going to "Walk", so to speak. In the photos provided, I'm seeing some distortion in the hub holes. I would think that came from riding it with the bolts loose. Also, check the taper on the shoulder of the bolt and the sprocket to see if they are a matching angle. A difference would mean any torque value is meaningless. It's the little things that can get you. The new modern 450's are running hubs that are run on 250's, and sometimes the same is used on 125's, to save money. If the design is from a 125/250 and then used on a 450, maybe that is the line that is being crossed. MXA beats the shite with dozens of riders do laps. And since we all know that since it's not each of the test riders bikes, they are beating the crap out of them. And each bike and product goes through a durability testing as well as just performance. If Tusk has a durability problem, I think MAX would have called them out. Just my .02 cents, anyway. I would send Tusk the wheel, sprocket and bolts for an analyses. I've had good luck with their products.
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