
I own a Specialized E-Bike and I had a tube failure. This was the closest fit that I found on BTD's website. I compared the tube to the failed original Specialized tube on the bike and it was very similar in build and weighed the same. The 700, 45-50 size is perfect for the 700, 47 sized tires on the bike. The threads on the Kenda tube Presta valve are 60 mm whereas the Specialized tire came with 40 mm long threads. It is a minor, visible difference.
The original tire failed I believe due to a faulty, removable Presta valve. The failure mode was explosion.
I intentionally sought a different brand of tube due to the failure even though I believe Specialized makes a great bike. The original tire was a 700, 32-50, 40 mm. Since Kenda's size was the narrow width band of 45-50 I'm hoping this may be helpful in avoiding another problem. So far, 2 months later no flats or problems.
I bought two tubes, and one came with a hole in it. But that's on me, I've bought enough tubes to know you should always buy more than two. To their credit, BikeTiresDirect gave me a quick refund.
had a couple of other Kenda's fail where the valve stem meets the rubber. They lasted 10 years, but both failed within a week. Hoping for better with these. Not a lot of choices in the tube market.
These tubes are nice and light, but I was pleasantly surprised at how compact they are (in comparison to other quality brands) - great for fitting my small saddle bag! And as always, a great price through biketiresdirect.com.
Discounted commodity purchase. Air loss at about 2%-3% daily. If using long stems on shallow rims, be sure that value stem is secure or some flats will occur at valve base. Have patched and the repair provided a lasting seal and a useful tube. Many punctures seem to happen near a seam, so patching is useless.