Charger GX - Alexrims MD40 spoke, wheel rim issue

Tbone

Member
Approaching 12000km and over three years of use on my R&M Charger GX and while giving it a good clean the other day I noticed these hair-line cracks in the Alexrims. Obviously I need new wheels and am now facing the reality, after initial search of what/where/which wheels to buy... how the heck do I pick the right wheels? I'm not gonna put a lot of blame on Alexrims for this. I'm pretty sure these cracks happened after riding on some rough terrain at not so slow a pace a few weeks back. Plus the rear rack was laden with an extra 500w battery and a bag full of other equipment. Anywho. I felt some pretty jarring bumps here and there ricocheting through the frame that day. After that I noticed the wheel not spinning true anymore.

Any advice/experience on changing/replacing wheels is welcome.

Ride safe, baby.


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JayVee

Well-Known Member
This has happened to me too. it can be challenging.

I'm assuming it's the rear wheel. I've bought two rear wheels so far. It's no fun...

What type of fastening mechanism is that on your wheel? If it's traditional QR, it will be 10x135mm for the rear axle. 10mm is the diameter of the axle at the point where it slots into the frame. You can measure that to be sure (you'll have to remove the wheel). The rod that slips into QR is 5mm in diameter. Hopefully you have a slide calliper somewhere.

Other remarks:

- If your bike has 6 bolt to fasten the disk, you'll need either a 6 bolt wheel or a center lock wheel which has an adaptor for 6 bolt. But if you buy anything with Centerlock, you'll need a special tool to fasten it. If possible, try to stick with 6 bolt if that's what came on the original wheel.
- You will need tools to put on/remove the cassette.
- Pay attention to which size, type, and brand cassettes are supported for a given wheel. Mine supports both 10 & 11 speed cassettes, but needs a special ring for 10 speed.
- Pay attention to rim width. You want your tire to fit on the new wheel!
- You may need to realign your rear disk brakes with a new wheel.
- You may need to reindex the gears.

The easiest would be if you had the full specs of the original wheel. That includes wheel size, rim height and rim width.
 

Tbone

Member
This has happened to me too. it can be challenging.

I'm assuming it's the rear wheel. I've bought two rear wheels so far. It's no fun...

What type of fastening mechanism is that on your wheel? If it's traditional QR, it will be 10x135mm for the rear axle. 10mm is the diameter of the axle at the point where it slots into the frame. You can measure that to be sure (you'll have to remove the wheel). The rod that slips into QR is 5mm in diameter. Hopefully you have a slide calliper somewhere.

Other remarks:

- If your bike has 6 bolt to fasten the disk, you'll need either a 6 bolt wheel or a center lock wheel which has an adaptor for 6 bolt. But if you buy anything with Centerlock, you'll need a special tool to fasten it. If possible, try to stick with 6 bolt if that's what came on the original wheel.
- You will need tools to put on/remove the cassette.
- Pay attention to which size, type, and brand cassettes are supported for a given wheel. Mine supports both 10 & 11 speed cassettes, but needs a special ring for 10 speed.
- Pay attention to rim width. You want your tire to fit on the new wheel!
- You may need to realign your rear disk brakes with a new wheel.
- You may need to reindex the gears.

The easiest would be if you had the full specs of the original wheel. That includes wheel size, rim height and rim width.
Great info JayVee! Just what I need.
Yes, it's the rear wheel.
Also includes traditional QR. Disks are 6 bolt.
Cassette is 11 speed Shimano.
Have tools to change cassette, although I've never done it before. More bike repair fun and learning ahead.
Realign brake callipers no problem, can handle that.
Where exactly do I find the wheel spec info? The only info on outside of wheel rim is "ETRTO 584x40 6061H Taiwan Rim For Disk Use Only". The wheels are Alexrims MB40.
When I look at online German bike shops and search for 27,5 wheels (which is the only info I know about wheels since buying new tires), I'm awash in wheels and brands and sizes, including prices that blow my mind. What a mess. I've been to three local bikes shops and no one has any 27.5 wheels in stock.
Even though I hate indexing the gears, I'll manage that somehow.

Maybe. Maybe. Maybe. Buy a new e-bike? The only problem with that thought is I don't really like any of the new R&M models.

Thanks again for any help.

-T
 
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JayVee

Well-Known Member
Great info JayVee! Just what I need.
Yes, it's the rear wheel.
Also includes traditional QR. Disks are 6 bolt.
Cassette is 11 speed Shimano.
Have tools to change cassette, although I've never done it before. More bike repair fun and learning ahead.
Realign brake callipers no problem, can handle that.
Where exactly do I find the wheel spec info? The only info on outside of wheel rim is "ETRTO 584x40 6061H Taiwan Rim For Disk Use Only". The wheels are Alexrims MB40.
When I look at online German bike shops and search for 27,5 wheels (which is the only info I know about wheels since buying new tires), I'm awash in wheels and brands and sizes, including prices that blow my mind. What a mess. I've been to three local bikes shops and no one has any 27.5 wheels in stock.
Even though I hate indexing the gears, I'll manage that somehow.

Thanks again for any help.

-T
To get through the mess, you need to determine:

- type of axle (QR 10x135, 12x142, etc.)
- type of disc mounts (6 bolt, centerlock, etc.)
- your cassette size (10, 11 speed)
- wheel size (27.5 in your case)
- the ETRTO is useful as it gives the rim width, but you might want to measure. Measure the inner and outer widths, as many shops refer these.

Essentially, once you have that, you're good to go. Be it will be a big search, requiring lots of Googling. It's much more complicated than it looks at first. I'm sure you'll find something reasonable in terms of price. If you find a wheel, but the axle type isn't right, some brands have conversion kits. My DT Swiss rear wheel can be made to fit 12x142 or 10x135. There's a conversion kit which requires no tools. But for each wheel, you'll need to enquire.

Good luck.