death trap - front wheel falls off

[Zachary Skrivanek]

I recently bought two Sur-Ron X bikes from Luna. My friend was riding one and all of the sudden his front wheel fell off and he flew over the handle bars, barely avoiding serious injury. I inspected his bike and the front axle/bolt fell out (and the brake line got damaged from the crash). I inspected my bike and saw that the front axle bolt was about to slip out too! When facing the bike from the front, the axle "bolt" that enters the wheel has a screw in cap on both sides, the right of which slipped off. I re-read the instructions and looked on YouTube and don't see anything I did wrong regarding the installation. The installation was quite simple. I'm not sure why it even can "unscrew" on the right hand side since you slip the bolt in from that side. I'm surprised that the bolt is not solid. There might be a good engineering reason for this, but regardless the bolt slipped out because the right hand screw cap fell off and consequently the wheel fell off while my friend was riding the bike. This is a serious design flaw and I am now worried about the safety of anyone else riding these bikes. Has anyone else had their front wheel fall off while riding it?

[BikeBike69]

The design isn’t flawed or a death trap. Both axle head bolts need to be tightened then tighten the four axle clamping bolts on the fork legs. This design has been used for ages within the motorbike and cycling industry. It honestly sounds like improper assembly....not slamming you in any way. But it’s not the design.

[Zachary Skrivanek]

Thanks for your reply. I hope it is an issue due to assembly and I can figure out how to assemble it correctly, because I really like these bikes. I just don't want the front wheel to fall off while I am riding them. Attached are the instructions for installing the front wheel. They don't use terms like "head bolts" or "axle clamping bolts". All they say is to tighten the axle using the #8 wrench. You seem to imply that there are 6 things to tighten (2 axle head bolts and 4 axle clamping bolts). In the instructions attached it just says to "Use the Hexwrench (#8) to tighten up the front tire axle". In the YouTube instructions (https://www.youtube.com/watch?v=LCp_qQ_LFf8) the person just tightens two bolts; one on each side of the axle. (Are these "axle head bolts"? If they are, then I did tighten them. But I didn't tighten anything else so the missing link could be the 4 axle clamping bolts that you mention.) Would you please clarify what the 2 axle head bolts and the 4 axle clamping bolts are on this machine? Can you give a reference to instructions that use these terms or video where the person is tightening these 6 bolts on the Sur-ron?

[BikeBike69]

You have the DNM USD8 fork according to your pics. The description in the manual is for the RST Killah. Your axle is one open ended hollow axle, threaded on both ends for the axle head bolts/caps. Install the wheel then insert the hollow axle. Then install both axle head bolts/cap, tighten. Then tighten the four (two each side) axle clamping bolts on each leg. Total 6 bolts.

[BikeBike69]

Thanks for your reply. I hope it is an issue due to assembly and I can figure out how to assemble it correctly, because I really like these bikes. I just don't want the front wheel to fall off while I am riding them. Attached are the instructions for installing the front wheel. They don't use terms like "head bolts" or "axle clamping bolts". All they say is to tighten the axle using the #8 wrench. You seem to imply that there are 6 things to tighten (2 axle head bolts and 4 axle clamping bolts). In the instructions attached it just says to "Use the Hexwrench (#8) to tighten up the front tire axle". In the YouTube instructions (https://www.youtube.com/watch?v=LCp_qQ_LFf8) the person just tightens two bolts; one on each side of the axle. (Are these "axle head bolts"? If they are, then I did tighten them. But I didn't tighten anything else so the missing link could be the 4 axle clamping bolts that you mention.) Would you please clarify what the 2 axle head bolts and the 4 axle clamping bolts are on this machine? Can you give a reference to instructions that use these terms or video where the person is tightening these 6 bolts on the Sur-ron?

[BikeBike69]

Yeah it sounds like you left the axle clamping bolts loose. The two silver ones on the bottom of each leg facing upwards. Those are what stop the axle from rotating and coming out even if you lose a cap. If they are left loose the axle is free to move and rotate easier.

[ncmired]

Yeah it sounds like you left the axle clamping bolts loose. The two silver ones on the bottom of each leg facing upwards.

These:

... and blue loctite.

[Ryanh924]

I recently noticed my end caps were missing. I contacted Luna about this issue and this is basically what they told me:

a lot of people are experiencing this issue

they are sold out of the piece and don’t know when it will be in stock

some people are using car bolts of the same diameter and that is working for them

not advised to ride with missing end caps.

!! THIS INFORMATION CLEARLY POINTS TO IMPROPER ASSEMBLY INFORMATION !!

The agent wouldn’t tell me if this has happened to 10 people or 1000. This information could save someone’s life. I’m glad I noticed but some people won’t be so lucky. Hopefully this information gets addressed by Luna before too many accidents.

The assembly guide I followed did not say to tighten the axel clamp bolts.

[DaHose]

If you look at the Luna site, in the Sur Ron documentation thread, the first post mentions those extra pinch bolts.

https://electricbike.com/forum/forum...-initial-setup

That post dates back to 1/5/2018. What assembly documentation were you working from?

You know folks, this thread highlights a very important issue with buying something like an EV. It's pretty easy to be lulled into a sense of confidence when retailers make really complicated things like an EV into a purchase you can complete from home with minimal vendor interaction. This is not a hostile indictment of the OP, just an observation by a hobbyist who is into a lot of pretty complex "stuff".

When we buy a motorcycle or a car, we tend to be very careful about asking questions related to maintenance and long term ownership, but because a dealer is selling us the vehicle in drive-away condition, we don't worry about whether or not the wheel lug nuts, the motor mounts, door hinges, etc. are all torqued. We assume the ready-to-drive condition includes all that.

Something like the Sur Ron is also a vehicle, but we receive it partially assembled. That makes it imperative that we as consumers read all we can, and learn all there is to know about making that vehicle road safe. In the motorcycle world we run pre-flight checks before major rides, and SHOULD do regular fastener inspections of critical components like wheels, brake calipers and hub/axle fasteners. Again, since the Sur Ron lives in a space between motorcycle and bicycle it can be easy to forget that we must treat it like the high speed vehicle it is. I would add that even with bicycles, a high end mountain bike will come from a store where a trained technician has gone through and road prepped the vehicle for us. We SHOULD reasonable expect that vehicle to be ready to go when we get it. If we buy a Schwinn from Walmart, we accept a certain level of responsibility to safety check the bike, because we KNOW a trained technician did not perform the assembly.

In my opinion, because a Sur Ron is mot just a simple turn-key "toy" (it's a high-end hobbyist level vehicle) we really need to have a broad scope of understanding what that means, and how to properly assemble, use, and maintain these kinds of vehicles. That means we need to go through all the available information, and ask lots of questions. I certainly went hog wild asking anyone and everyone about how they built up a Cyclone kit. I would attempt to be just as thorough if I was buying a Sur Ron. Granted, I am a mechanic with a fairly serious workshop, and that does color my perspective.

I'll finish back on topic. The Sur Ron information thread seems pretty comprehensive. I think the OP (and any new Sur Ron owner) should really dig into all the threads in the Sur Ron forum area, before completing assembly and taking them out on the first ride.

Jose

[Kauaiguy]

Maybe we should change the title:Check your instructions,Rst forks and Dnm look nothing alike,don’t assume,this is a Chinese made bike.My Surron had a Rst manual included,but even if it hadn’t,I would double check everything.

[superslimjim]

The new 2020 LBX seems to be shipping with a manual that still pictures the old RST forks with the 2x axle nuts and no pinch bolts, anyone following the included build instructions to the letter and not checking those pinch bolts is going to have the same problem. They stick out like a sore thumb to me, but they may not for others.

The reason for my post is there doesn't seem to be torque settings anywhere for the 2x front axle end caps or the 4x M5 pinch bolts. I'm not very mechanically experienced so I tend to use torque tables to the letter. 2 of my 4 pinch bolts snapped when I tried to take them out which was a complete nightmare, the dealer must have tightened them up too much. I've fixed that now and replaced them, torquing them up to around 10NM. One of the axle caps is also starting to round off, they are made out of such a soft material so again I think this has been done up too tight by the dealer.

If anyone knows how tight these all have to be done up i'd really appreciate it. I'm definitely going to have to replace one of those axle caps, annoyingly it looks like you can only buy them with a new axle and not on their own.

[SUR-gary]

Printed thing on post #8 by Jose says: 8Nm on the caps and 5Nm on the pinch bolts.
That seems so light to me. Anybody else?

[MikeinVegas]

You can find replacement axle bolts here on Ebay: https://www.ebay.com/itm/254720089267

[Dave K]

Today I noticed the front axle was sticking out to the right as I was about to descend a steep hill.
It was out at least 3/4". Left side axle bolt was gone. My bad as I do not recall tightening the pinch bolts when assembling the bike back in June, 275 miles ago.
Got lucky and rode her gingerly home.
Just ordered a new bolt from the link in the above post. Thank you MIkeinVegas!
Tighten those pinch bolts!

[SUR-gary]

Found my axle caps loose today. DNM 8 forks. 98 miles total.
Jose's # 8 post above clearly shows documentation : 8Nm for axle caps and 5Nm for pinch bolts.
Seems a little light to me? Anybody else?

[Kauaiguy]

Are you using blue loc-tight?

[SUR-gary]

I am now with Same torque.

[Pappa K]

My kids front wheel just fell off, thankfully he didn't. This looks like an issue as the bike has only travelled 60 miles. Thank you everyone for your posts, very useful information :-) Off to the store to do my angry Dad bit as they put the wheel on.