Best tire + rim combination for a heavy E-bike

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Mar 29, 2016
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383
Hi,
I have a touring bicycle, that has front+rear panniers, and H3525 motor powering the front wheel as assistance (and regen on descents).
I bought a 24mm wide alexrims from Grin (622x24) for the front motor, and mounted Schwalbe marathon touring tire, which is 700x45.
On the first pump, I was inflating to the max allowed pressure, and after just 1 minute after inflation I heard the tire coming out of the rim clincher (at one point, not the entire rim), and then there was explosion. The tube got torn at that point.
I am curious what was the cause?
The tube is rated for around 1.75inch wide, which could have been the reason? (combining a very wide rim).
Or is it the tire that failed to hold that pressure because of the very wide rim and the tube collapsed following it?
One of my assumptions is that if the tube failed first, then the huge pressure upon the tire, which is not tubeless (and way above tubeless pressures even if so), caused it to come out of the rim at the weak point and release the air as explosion. Makes sense?

Is 622x24 rim too wide for a 622x45 tire?
I replaced that tube with MTB tube of 1.9-2.3 and it looks fine, although it seems that at one point the tire is "bulging" out of the rim by few mm, and it could be normal. Or is it not ok? Should the tire be completely concentric with the rim, if I were to check if it's radial distance is changing during the rotation?

If you think that tire is too narrow, what tire would you recommend for long distance touring, that can allow a bit of off-road grip in case you go a little of the pavement?
 
I'm using Schwalbe Marathon Supreme 622-42 on an Alex DM24 for about 2500km so far on my ebike, no problems. sounds like the tyre is not seated right to me. After I inflate a tyre enough for the tube to fill the tyre, I go around the wheel and make sure that the tyre is even all the way around, the bead fully engaged etc. then inflate to whatever I'm going to ride it at.
 
It could be as simple as you got the bead just slightly crooked as you inflated. Was it just really loose, unusually easy to mount on the rim by hand?

I've had some issues with bottranger brand cruiser size tires being large at the bead diameter, then with less rubber touching the rim, they creep till valves cut off. Those also have to be very carefully inflated to keep the bead on the rim or the tube will squirt out and pop.
 
+1 with above; I've "blown" too many tubes that way and a$$ume the tube was between the tire and the rim when it was inflated. True some tire-rim combinations need to be inflated more carefully than others. Ultimately it's never been a problem once the tire was installed properly, but keep an eye on it.
 
I have the DM19 and DM24 Alex rims and they work fine. I really like the Schwalbe Marathon Plus tires... available up to 2" in 559... looks like you may have a different size. But YES a bulge is a problem. I had a bit of a problem with the DM19... just couldn't seat the tire properly. So it could be your rim. Another problem which can cause blow outs is a pinched tube while mounting. It's pretty easy to do.

When I put on a new tire I always inflate to a very low pressure and work my thumbs around both sides of the rim slowly to make sure no part of the tube is being pinched under the tire bead between the rim and the tire. Before you mount the tube/tire also make sure you run your finger along the rim sealing tape to make sure there are no sharp edges. I love Schwalbe Marathon Plus tires for my ebikes. I also run the Big Apple (3,000 miles and still has tread).

If your tire is hard to mount on your tire with just your hands consider getting a Kool Stop Tire Bead Jack. http://www.koolstop.com/images/Accessories/KS-TBJ%20IMAGE.jpg

You can get them online from many sources. They make mounting difficult tires pretty easy. To learn how to use them just check out Youtube. Youtue is a great what to learn bike repair tips (Although some videos do it wrong, watch enough and you'll get the idea).
 
Hey guys,
I haven't been here for quite a long time.
Thanks for all the advices!
It makes sense that probably the tube got pinched between the bead and the rim, which caused the explosion and the tire coming out.

The Kool Stop Tire Bead Jack looks great, and I will certainly buy one. I have another bicycle with a combination of Schwable 27.5 2.4inch tyres on a Asym 29mm WTB rim. These two were nearly IMPOSSIBLE to fit! I broke several tire spoons attempting to mount it, and eventually could succeed only with a screwdriver..... (which is very bad, but I had no option)
Do you think that tool would have helped in that case?
 
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