Oxygen Scross MTB ongoing review

[Deleted member 4366]

I have had no end of problems with spoke tension on my Oxydrive kit. I think they must make them out of pasta.

The problem is that your motor's spoke flanges not symmetrical from the centreline, so the rim has to be offset, which means low tension in the disc side spokes and high tension in the drive side.

 

[Andy Bluenoes]

The problem is that your motor's spoke flanges not symmetrical from the centreline, so the rim has to be offset, which means low tension in the disc side spokes and high tension in the drive side.

Is that the same for the oxygen wheel d8veh?
Will that cause any problems for a local bike shop?

Sent from my Moto E (4) using Tapatalk

 

[Deleted member 4366]

It won't cause any problem for the bike shop. nearly all hub-motors need at least a slight off-set of the rim.

I true the wheel by using a cable-tie fixed to the chain-stay as a point. No need to take the wheel off. Just turn the bike upside down and sit behind it. I would say about 20 minutes to true it.

That's how a practical guy would do it. A jobsworth would want to take the wheel off and put it in his fancy jig, which it will most likely not fit.

One time, a guy bought a massive DD hub-motor (3KW) into the shop for truing. It wouldn't fit in the jig and he didn't bring the bike, so I needed a pointer. I screwed a couple of U-brackets to the ends of a pair of 2 x 2 lengths of wood to hold the axle, put them in a vice and banged a big nail through as a pointer. the only problem was that I had no idea whether there needed to be an off-set, so I set it to the average of where it was. After he took the wheel, he never came back, but that doesn't necessarily mean that he was happy.

 

[Andy Bluenoes]

Thanks D8veh, thats a useful tip. I might take a quick look at that tonight. I think I may have over tightened most f the spokes now, so probably need to slacken them all off a little bit first, and then try your method. It cant get any worse than it is now....it has about 3 or 4 buckles in it!

 

[RobF]

Spokes on motor hub wheels is another reason why there's no single answer to the hub or crank drive question.

A commuting bike needs to be bombproof reliable and easily fixable if it does go wrong.

Crank drives take standard wheels, which means you could spec something suitable and any competent wheel builder could service the wheel.

 

[Andy Bluenoes]

Spokes on motor hub wheels is another reason why there's no single answer to the hub or crank drive question.

A commuting bike needs to be bombproof reliable and easily fixable if it does go wrong.

Crank drives take standard wheels, which means you could spec something suitable and any competent wheel builder could service the wheel.

I dropped the wheel into a bike shop near work, picking it up tomorrow...they seemed to know what they were doing, and specialise in wheel rebuilds so hopefully there won't be any issues

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[Andy Bluenoes]

Just had news back on my rear wheel, the rim itself is beyond repair...I'm guessing that peice of metal did hit it.

The bike shop has given me two options....they can provide a new rim, but they would need to replace the spokes as they dont have the exact rim, so it will cost just over £100

But, if i can source the outer rim, they can rebuild the wheel on the existing spokes for £35

Im hoping that Oxygen can help out with a replacement rim

 

[Deleted member 4366]

Im hoping that Oxygen can help out with a replacement rim

Ask them if they have a used one on a scrap motor. You would't need to rebuild the wheel then, just take out the motor core and swap it to the hub and wheel from the scrap one, or you could just take the spokes and rim off it.

 

[Woosh]

.they can provide a new rim, but they would need to replace the spokes as they dont have the exact rim, so it will cost just over £100

it's usually not worth recovering old spokes when replacing the rim.
Over time, the thread on the old spokes are caked with a little oxidation, making it very time consuming to undo their nipples one by one.
I think d8veh suggested to use 14G spokes, most bikeshops can cut and roll them for you from stock 14G spokes so that's what I would recommend.

 

[Andy Bluenoes]

Thanks both...never thought of that about replacing all spokes, didn’t see your message until now Tony...

I popped up to oxygen today...what a nasty journey that is over the Pennines...

Anyway, really helpful as always.

Picked up a new rim for 17 quid, and 10 replacement spokes...hopefully that should cover any that get damaged on removal.

Got loads of tips and advice from Scott (I think)

Spoke to the bike shop...unfortunately they can’t start it until Tuesday due to holidays.


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[DBye]

Looks like my S-Cross CB needs a new rim too. Tempted to find one with eyelets for extra strength!

 

[Deleted member 4366]

Looks like my S-Cross CB needs a new rim too. Tempted to find one with eyelets for extra strength!

How did that happen? It looks like somebody took a lump-hammer to it.

 

[DBye]

I promise I've not taken a lump hammer to it! I'm not sure, but it has had some serious stick as I commute 25 miles round daily on it for the last 2 years and the roads here are more hole than anything else. I can't say there was a single "bang", I only noticed it because I'd got a puncture elsewhere on the tire and only spotted the crack as it is next to the valve.

 

[Deleted member 4366]

The rim is all dented from the side, though.

 

[DBye]

That's my photography skills and that'd I've not cleaned the rim before photographing. I'll get a better image later, but any image of a dent is an illusion. Likewise, looking at the picture there appears to be a fork in the crack leading to the spoke, but that isn't there either. It is just a straight crack and the profile of the rim is otherwise normal.

 

[RobF]

Both the bikes needing new rims have done a fair bit of work.

But the problems do illustrate one of the benefits of a crank drive bike.

The wheels last longer than a motor wheel, and if a wheel does fail replacement is straightforward and can be as cheap or as expensive as you want to make it.

 

[Deleted member 4366]

That's my photography skills and that'd I've not cleaned the rim before photographing. I'll get a better image later, but any image of a dent is an illusion. Likewise, looking at the picture there appears to be a fork in the crack leading to the spoke, but that isn't there either. It is just a straight crack and the profile of the rim is otherwise normal.

If you look at the line where the tyre meets the rim, the tyre is in a uniform arc, like you'd expect, but you can see shadows where the rim is waving up and down.

 

[Deleted member 4366]

But the problems do illustrate one of the benefits of a crank drive bike.

The wheels last longer than a motor wheel

It's nothing to do with crank-drives or hub-motors. Andy said that he bashed his rim and bent it. This one also looks damaged, but even if that's an illusion, the damage is nothing to do with the type of motor. The forces on the rim are the same, as the spokes are being turned from the other end, and the rim doesn't see any difference whether a hub or crank motor. The torque from a crank-motor in a low gear is likely to be higher, which would do more damage.

Try not to let your prejudices colour your opinions of how physics works.

 

[Woosh]

a bit of extra dishing may tip the scales in favour of crank drive versus hub drive but I don't think there is much in it. Most rim damages are Murphy's law.

 

[DBye]

Cleaner photo taken. Going to take it to lbs for them to rebuild with new rim.