ASK MBA: HOW DO I REPAIR PUNCTURES AT THE TIRE BEAD AND SIDEWALL?
A few solutions to common spots for damage on mountain bike tires.
A Pinch and a Compromise
Q: Hi, I’ve been reading the magazine for eight years now and love it! I just had a puncture at the bead/rim interface of my Maxxis 27.5 Aggressor 2.3-width, dual-compound, double-down tire (tubeless) at 28 psi with a DT Swiss EX511 rim in a heavy rock garden with potentially sharp, jagged rocks. I weigh 200 pounds loaded. The rim was not dinged, as I was able to install another tire temporarily and no leaks.
I called Fanatik, where I bought this wheel, and they told me the only things I can do with this tire is to use a tire boot from Park, for example, but that’s apparently a temporary solution, and/or install a tube, which I don’t want to do for a variety of reasons. Is it a bad idea to try Stan’s DART for this type of puncture repair?
He recommended going to DH casing potentially or installing CushCore or other insert, which as I’ve heard/seen is a major pain. But, both of these add additional weight, and I’d like to avoid this if possible. I ride mostly enduro ST trails in L.A. and O.C. in SoCal and bike parks.
I know enduro riders run aluminum rims, like EX511 with DH casing (e.g., Jack Moir), or also with inserts (e.g., Richie Rude) and MaxxGrip compound, but they’re very strong riders.
What do you recommend should/could be done with a tire with a puncture at the bead like this one? Basically, throw it away (and better to trash it or recycle)? And, why don’t rim manufacturers give us the option of a pre-installed (glued?) insert to make installation easier?
A: Hey, Arbi, thanks for the continued support. We’re stoked to have you as a reader! As to your issue, bead/rim interface punctures can be an absolute nightmare and often end with no choice but to throw out the tire. We’ve had multiple cases where there was no saving the tire from the dumpster relatively recently and had to cut our losses. Tire boots are specifically designed to only be used with inner tubes, so tubeless applications will likely be iffy at best. Plugs and Stan’s DARTS are typically only effective in the tread area where there isn’t any contact with the rim, but since the DART chemically bonds to the tire with the sealant, it could be an option, though we’re not sure how constant contact with the rim would affect it. We’ve tried and failed to use traditional tire plugs many times and normally end up just throwing a tube in.
There is a non-bike-specific solution to this problem that may or may not work along the beaded edge. Some people will actually take a needle and tough wear-resistant thread or fishing line to stitch the hole up so it doesn’t grow. They will then take an old inner tube and create and glue a patch of it on the inside of the tire to help strengthen and bring a little water tightness for the tubeless application. The last thing they’ll end up doing is to spread a generous amount of shoe glue on the outside of the cut to fill in the gaps, add a bit more waterproofing, and hold it together for longer. This likely won’t last forever, but it may provide you enough use to continue using the tire for a good time yet. All of this on the bead of the tire is very iffy. Since the interface of the tire and the rim sees so much interaction, any patchwork done on that part of the tire is going to have to be extra strong compared to a patch anywhere else on the tire.
Our best advice is that you just toss away this tire and accept the weight penalty of some inserts or DH-cased tires.
Most bike shops will take old tires, but they generally end up in the trash. In reality, if you’re riding mostly enduro/DH stuff anyway, that little weight isn’t going to affect you as much as you might expect. It just so happens that CushCore came out with a new trail version of their inserts that is much lighter than the normal version and supplies a good amount of sidewall support as well. It’s not foolproof, but it may help you keep from having this same problem repeatedly.
In reference to your pre-glued tire idea, we think that wouldn’t work simply because it would be incredibly messy and make it very hard to change tires once they’re worn down, plus it wouldn’t exactly help with the issue you just experienced. We hope this helps you make a decision in the future, and if you do end up trying to sew up and patch it, let us know how it goes!