Bobbd

Hello, I had a spill on my bike the other day, I am alright the front tire went flat at 25 miles an hour and separated from the rim I thought it was a blowout but there was no boom and when I checked the tire for any holes or nails there were none the valve was also good but the tube had 5 or 6 tiny pin holes on the side of the tube that lay against the rim tape but when I run my fingers over rim tape it is nice and smooth I don't feel anything that would have caused these holes I can't figure how this happened the only thing I can think of is if the 40mm tires are too wide for my rims the rim measures 5/8ths inch, I measured with a ruler I don't have a caliper I converted that to mms and got 15.875 but I did notice on the rim it states 700c and ETRTO 622 x 16 could the 16 mean the width of the inside of the rim is 16mms? Also, what is the max width tire can I safely install on this rim? thanks

easyupbug 

16 is a narrow rim, I would want a 20 or more for a 40mm tire.

Iride01 

Possibly the holes in the side of the tube were worn into it from your tube/tire not being inflated enough and the tube got caught between the tire bead and tread as you rolled along. Pretty similar to a pinch flat.

When you get to the extremes of the recommended tire width to rim width, you have to expect that some tires on some rims might not do as well as others. There's no requirement that tire makers build their tire to conform with the commonly accepted size range we often see on charts. And quite a few tire makers lately seem loathe to provide their own guidance for rim width.

Usually this is something you find out for yourself with your own experiences. If you've made certain you've kept the tire inflated enough and you still have this issue, then change the rim or the tire width. Same thing if you find the tire tends to roll under the rim from side to side making you feel unstable as you go down twisty turns.

And don't just go by the recommended tire pressure for your weight and size tire. Those are good for a first try, but you might need to go higher or lower. Again, you find this yourself by experimenting to see what works best for you.

Welcome to BF!

easyupbug 

Having had a front tire blow out at speed I definitely don't want another, if you are there as well Google search "bicycle tire width chart" and you will see several tire recommendations charts for your rim size.

Bobbd

Thanks for all replies I guess ill just buy 28mm tires and tubes since they are cheaper than rims. What do you think about front rim it has some scrapes on outside but does not look bent in any way should i just roll with it ?

Iride01 

Depends on how bad and where those scrapes and dings are. But generally not an issue. Of course deep gouges and nicks might be a place for cracks to start, those will generally be noticed before they are an issue if you just simply look and see and take notice of such areas when you clean your bike, air up the tires or most any other time you are admiring it.

If you aren't sure you can snap a pic and upload it to the Gallery here on BF and then let us know it's there.

28 mm tires will likely be fine for paved roads and packed dirt or packed gravel. Heck, most of us were riding 18 mm tires on the road long ago just after 700C's became popular in the USA. And 23 and 25mm tires for the road are also starting to be less common.

Tire width isn't the only thing to have a comfortable ride. Tire pressure as well as just better tires can make a big difference for ride comfort. The things that make a tire good for racing tend to also make them comfortable tires. Though tires for racing can also be a little less resistant to puncture. Though only a real issue if you live where goatheads and other thorns and hazards are present.

Our vintage bikes with 27x 1¼ tires were 32mm wide. So the move to wider tires is just a rebirth of what we once did.

If you ride gravel often, you might prefer wider than 28's. If you are off road entirely most of the time then you might want to stay closer to your 40's.

Bobbd

Thanks One last question I forgot to add that I am 300 lbs and I converted this Trek road bike into a electric bike which also adds another 30 to 40 lbs for battery and motor do you think it is safe to put all this weight on a 700c 16mm rim ?

soyabean

There are so many problems with this scenario, I can't even begin.

Best of luck to the OP.

I will now use my time to do some cycling

easyupbug 

I am most
sure there is no Trek made for anything over 300 lbs load, Mongoose Dolomite is rated for 350 lbs, good luck.

Iride01 

Just because one 700C rim and wheel will, doesn't mean that they all will be able to. So how can we answer your question of weight and e-bike motor?

You really need to get into the specifications of the components of your wheel to determine whether bike weight and your weight are any issue. Also, motors can put more torque into things than a person can, so things might simply wear out faster or present problems that the designers intending this to be for human powered use may not have considered.

It's partly why we see some things today that say they are for e-bikes.

alcjphil

What type of conversion? Does you bike have a motor in the hub, or is it a mid drive?

Bill Kapaun

I think a 32mm tire and probably aired up near the max?

From your statement above and reading the "other stuff", I surmise you allowed the air pressure to get too low.
Lean over going around your favorite corner and the rim is digging into the tube or hit enough pot holes, abrupt driveway edges etc. so the rim is bottoming out.
Enough repeats.......

Bobbd

Thanks it is a bafang mid drive motor. I am just really concerned about the 700c shimano rim failing due to weight issues. Tires was a year old no holes or dry rot , tube was also year old filled to max tire pressure 73lbs. Tube also had Stanleys sealant in it.

grumpus

I'd go for 32 or 35 mm on a 16 mm rim - I run 28 mm tyres on 13.5 mm rims and that's about the limit for road wheels. Historically we ran 2 inch tyres on 13.5 mm rims for off road use without a problem, but on road you can generate greater cornering forces so the tyre is more likely to roll off the rim, or feel like it's going to.
Polish any rough areas that will contact the tyre or brake with a fine abrasive and a flat block - you don't have to remove the marks, just soften the edges so they don't snag as you run a fingernail over them.

Lombard

Nowadays, 16mm is considered on the narrow side for 40mm tires, but it certainly won't cause any safety issues. This is not why you got the flat. Heck, some mountain bikes with 53mm tires used to come fitted with 17mm rims.

Hmmm. Is that the max pressure rating for the tire? The rims also have a max pressure rating which you may have exceeded. And if you are 300lbs, you definitely should not go to a narrower tire.

Also, what is the spoke count on your wheel? This is key for heavier riders. Get the highest spoke count possible.