Good ride gone bad

[tomv]

So yesterday I was going to do a long ride to measure full discharge of my batts and other stats. Everything was working great for the first 15 miles until I got a flat, on front wheel with the motor. Considering what a PITA it is to fix it, I didn't even cary spare tube/repair tools.

So there I was, 10 miles away from home. The usual bailout option of taking subway home also didn't look appealing with 100lbs bike (for that particular situation I had 6 flights of stairs to carry it through). So i tried riding it home flat, slowly... I now realise how stupid that idea was. I've learned the hard way that flat tire has no sideways traction. I've wiped out when turning at something like 5mph.

So now, the reason why this is in Technical section. Considering that flat tire is pretty much the worst thing that can happen to an e-bike short of bent dropouts, what tires/tubes/rim tape do you go guys use? How many miles between flats for you on average? What is your tire rated PSI and what do you inflate to?

My Stats:
e-bike: smooth 26"x1.9", 65 psi, inflate to 65 psi, slime tubes, 50 miles before flat
Commuting bike: 700Cx35mm, 90psi, Kenda, no flats in 500+ miles
road bike: 700Cx23, 120psi, flats on average every 300 miles in 3000 miles total, no flats after switch to michelin kevlar tires.

Also peculiar is my most frequent flat type: ripped out valve stem. Do you ever get it? What causes this? How can I avoid it? I've tried different tubes, using locking nut on the valve stem, not using it, same results. I've even got this failure on bikes i'm not riding, just keeping inflated!

 

[Ypedal]

Flats.. SUCK..... :x

I would carefully inspect the rim for sharp edges, take note when you take the tire/tube off to find out if the flat happened from the rim or from the road side of the tube.

I wrap the rim with multiple layers of electrical tape before i put the rim liner on .. ( makes installing the valve a PITA.. but the tape protects the valve somewhat )

If you have sharp edges on the rim, file/sand them down....

Inspect your rim very carefully if you rode the bike on a flat tire.. it could have cracked it...


A repair is possible without removing the wheel from the bike.. you just deflate the tire ( usually already done for you ! lol ) .. remove one side of the tire.. patch tube.. then reinstall tire !

 

[mvadventure]

Agreed, flats suck on any bike and more on an ebike, front or rear as, in my case, one has a motor with a zillion wires and the other has the batteries.

So, I carry two cans of compressed air with tire adhesive inside. These are small cans, fairly inexpensive and I have no idea if they will work. Both of my inner tubes are the "slime" kind with the green patch stuff already in them. I also carry a tube repair kit, wrenches and a extra inner tube. I have a small pump on my regular bike and I've been "tempted" to put it on the ebike but there is already so much stuff there that so far I'm been able to overcome the temptation.

The tool kit contains regular wrenches, electrical tape, nylon ties, screwdrivers and tire tools. To my way of figuring I already weigh 230 pounds, the batteries probably 50, the bike and motor are heavy so what is an extra couple of pounds for tools.

Like a boy scout, "be prepared" and it probably won't happen.
Mike

 

[tomv]

Well, yes, this particular flat was on the inside of the tube. So the tube was damaged by the rim. I'm really puzzled how that could happen, as the rim is smooth and rim tape is where it should be... I'll double tape it just in case. And slime is usless on inside of the rim punctures, as all the "slime" sits on the outside to to centrifugal momentum of the wheel.

Ypedal, what tires/tubes do you use on your megapower rig?

 

[patrick_mahoney]

I put kevlar belt strips in between the tube and tire, and use "slime tubes".

Kevlar belt strip insert:
http://aebike.com/page.cfm?action=details&PageID=30&SKU=RS4900

Slime tube:
http://aebike.com/page.cfm?PageID=30&action=details&sku=TU2623


I'm not sure how much protection this gives me - although I used to get flats from goathead thorn weeds at least once a month ( http://en.wikipedia.org/wiki/Goathead ), and now I don't. I don't know if this is due to erradication efforts by the city or all the tire protection, but definitely flats seem more rare with these two sets of protection.

 

[Mark_A_W]

I have a Schwalbe Marathon Plus tyre with inbuilt Kevlar lining, and a thick rubber section on the "apex" of the tyre - it's about 8mm thick.

And a thick and heavy thornproof tube.

And I always keep it inflated at maximum, to avoid pinch flats.


So far (fingers crossed) it's been bulletproof.


I've never heard of a slime tube before - interesting.

 

[safe]

I have a 140 lb bike. When the tire goes flat (and I've had it happen a few times) I can't lift the bike or even roll it without the rim destroying the tire. So what I've done is park the bike (I ride in the country or suburbs) someplace where it's hidden and then walk home.

My worst distance was only 2 miles from home so it wasn't so bad, but one day I'm sure I'll have a problem 7 miles out which is about my safe limit for distance to be sure the batteries will get me home.

 

[bobmcree]

i have had several flats from small punctures where slime tubes completely failed to help. i consider them almost useless. the same goes for their cold patches (scabs)-useless.

i use the ride-on product "bike-on" in my tubes now and have had much better luck. it does not eat up the rims like slime, either. this is the stuff truckers, the postal service, couriers, and the military use. it is only available direct as far as i know, 6.95 for a bottle that fills 2 bike tires. ride-on.com

 

[oatnet]

I've been using Xyster's recommendation of Maxxis Hookworm's and kevlar liners, and thick DH tubes. No flats yet, but I don't have a lot of hazards on my test loops. Nonetheless, I have been thinking about the very topic you mention and appreciate the thread.

Whups, actually I did have a tube blow on a x5, minutes after I filled it. Tracked it down to a burr on the rim at a spoke hole... I filed all the spoke holes down to be sure, no more problem.

-JD

 

[tomv]

Thanks for all the good information!

It looks like Maxxis now makes a tire with kevlar belt built in. In addition it has high PSI rating (75psi).
http://www.maxxis.com/products/bicycle/product_detail.asp?id=225

It's easy to find 700C kevlar belt tires, but pretty rare for 26". Also for what it's worth New York city pedicabs mostly use Maxxis hookworms. That's a pretty strong recommendation in my option. Those guys drive 400lbs bikes whole day long. Or maybe that's because nobody else makes 20" slick heavy duty tires :lol:

Nobody else ever get torn valve stem? I must be doing something wrong then. I had it happen to me like 10 times at least.

I've attached a picture showing the spot where it always fails for me. That's the spot where valve stem is welded/vulcanized into the tube.

 

[Ypedal]

Very important that the valve comes thru the rim at a 90 degree angle, and then partially inflate the tire .. bounce it on the ground a few times to settle things in.. if the valve is crooked it will slice itself into the rim...

 

[fechter]

It's also important that the base of the valve stem fits into the rim all the way. Some rims are so narrow around the stem hole that the stem can't come all the way out. The causes the rubber around the base of the stem to stretch excessively when you inflate it. Some inner tubes have a narrower collar around the base that tolerates this better.

I've managed to shear off a valve stem by having the tire slip with respect to the rim during hard braking. Increasing the tire pressure will reduce the chances of this happening.

 

[xyster]

I've had two failures of this type while in the process of inflating thin, cheap tubes. No problems with thick tubes yet -- even though I can't seem to get the valve stems absolutely straight. I put electrical tape over the hole, and bore it out such that the tape coats the edges of the hole as the stem is pushed through.