Tyre side walls splitting

[NeilP]

I am now on my third rear tyre that has started coming apart on the side wall,
A crack develops near the bead just where the tyre gpes in to the rim, then if left long enough it eventually will become a hole and the inner tube will start pushing out

Three different brands of tyre, and run at around 50 to 60 psi which is where I have always run them on non electric bikes, Sometimes a bit softer if allmoff road riding, sometimes up at 80 on Maxis road slicks, but generally the e bike has been around the 50

Is this splitting a common thing on powerful e bikes or what ?

 

[The Mighty Volt]

I have been running rock-solid Maxxis Hookworm {front} and a Maxxis DHT {rear} to no demonstrable ill effects for the past 2 months.

I don't know the exact PSI but the tyres are always very hard. Front tube is some generic scrap, rear tube is a Maxxis Welter-Weight.

No ill effects to report yet. Surface ranges from concrete to trails and gravel.

My brother bought a Merida Hard-Tail and the tyres that were on it had sidewalls that wouldn't be found in any self-respecting packet of Durex.

 

[wineboyrider]

Cheap ass tires my friend.
I run walmart brand with over 2000 w continuous through mine and have over 800 miles on the first pair! About ready for a new front tire though!

 

[ZOMGVTEK]

I've always used the Bell 'Kevlar' tires from WalMart. They're inexpensive and work just dandy. I normally run about 60 PSI in them, and have several hundred miles on my current set, which looks like new.

I don't think power is the problem, I put 6-7kW into my rear tire all the time, and slam on my front brake often as well. The bike and spokes sure show signs of wear, but the tires don't care.

 

[cell_man]

I've had the same thing in the past and I think it is a combination of big tyres run at fairly high pressure on fairly narrow rims (type you'd normally get on a typical MTB, about 19mm inner width) plus tyres with quite stiff sidewalls. I've been using a set of 2.0" wide Bontaeger road tyres for the last few months which are much more expensive than the cheap stuff I was using. They have a very soft sidewall and they seem to be fine, also soak up the bumps a lot better than the stuff I used in the past. Big knobbly tyres I used didn't have this problem, it has only been big smooth road tyres and I've gone through at least 4 or 5 of them, all in the same way. I suspect wider rims would have helped and keeping the pressure a bit lower.

 

[Erogo]

I'd suggest looking at your rims, seeing they're the common element. - if you use metal tyre levers they can scar the rims, raising little burrs that would then damage the tyres.

 

[LI-ghtcycle]

If I understand correctly, you have been doing some off-road riding too? What does it look like when the side wall splits, are you sure it's not from rocks and such cutting them?

Never heard of this on a bicycle, but I have heard of rocks tearing up side walls on off-road 4x4 cars and such.

 

[Ykick]

Didn't you bend a rim a while back and I warned you about this possibility? 'thought you said you hammered it back to shape but I've learned the hard way it doesn't take much to cause this type of tyre damage.

 

[NeilP]

If I understand correctly, you have been doing some off-road riding too? What does it look like when the side wall splits, are you sure it's not from rocks and such cutting them?

Never heard of this on a bicycle, but I have heard of rocks tearing up side walls on off-road 4x4 cars and such.

No, off road, but not big rocky areas, these splits are right along the rim edge.

Didn't you bend a rim a while back and I warned you about this possibility? 'thought you said you hammered it back to shape but I've learned the hard way it doesn't take much to cause this type of tyre damage.

Shit...you are right...bloody hell...did not think of that ...totally forgot ...but along with this comment

I'd suggest looking at your rims, seeing they're the common element. - if you use metal tyre levers they can scar the rims, raising little burrs that would then damage the tyres.

But no, ...use plastic levers


That must be it. I did straighten the rim and did actually use very fine glass paper and then a polishing wheel on the inside to clean up the edges. and also ( have just been down to the bike to check) one big split is starting on one part of the rim that is not near the bit I straightened, it is around almost diametrically opposite , going aroudn a good 25% of the rim...but no where near the damage was

But anyway, that completely slipped my mind when I got to wondering about this again last night, and posted the initial question

I even a have a spare rim that arrived last week...I stuck it at the back in the store, since i managed to true the old rim back in to shape, and thought I would not be needing it unless I bend the rim again

Guess I got myself a job to day...swapping the rim...

Cheers guys for kicking my brain in to action

Oh the rim is a Mavic EX721...28 mm width according to
http://www.tech-mavic.com/tech-mavic/technical_manual/data/docs/products/2_102.pdf

 

[liveforphysics]

My race bikes that use bicycle tires see the sidewalls crack, and the tread-blocks on the edges of the tire rip away from the base tire carcass.

 

[NeilP]

what sort of power is that though? probably a lot more continious than my peaks of about 6.5kW and 3.5 to 4 than I can see for continious periods

It is probably a combination of all, a few possible rough edges, tyres and power

I will get my arse out of bed in a minute and get down the workshop and get this rim swapped
I have these Continental Vertical 26x 2.3 tyres, new, so if they will fit my frame I ll use those

 

[dogman dan]

You are just hammering em. It's everything, the weight, the power, the way you ride. It's bikes stuff. Built to handle at most, a sprinters brief 1000w You built a motorcycle. Only 4000w continous is not small power. It would be interesting to see a high speed shot of a 4k watt ebike taking off. I bet that tire distorts like mad.

On my commuters, I like the bell tires too, but I always beat the sidewall up before I can wear out the tread. I tend to get about 2000 miles form a set. it's the motor wheel that gets beat up every time. The damage is from potholes or an occasional curb hop.

 

[MadRhino]

The Kenda Nevegal Stick-E 2.7 X 26 is the tire I use mainly on FS bikes, lasting 2 or 3 month average for the last 10 years or so. They suffered many kind of damage, but I think they never lasted enough to show cracks in the sidewalls.

 

[NeilP]

Well I swapped the rim today and put the new Continental Vertical 26 x 2.3's on.

Previous tyres were Scott and the ones before were Kenda Komodo tyres.

Dogman is probably correct, though, on checking the tyre, the bead was separating at the base of the side wall, along most of the tyre, not just at the section where the rim had suffered damage in the past.

To swap the rims, I first got a handful of cable ties, and tied in all the spoke crosses, before I took the nipples off and removed the old rim
This made keeping all the spokes in check a lot easier when re lacing to the new rim.
I used the same rim type again (Mavix EX721) but this time I just enlarged the rim inserts, not removed them completely.
I did notice something that I had not noticed when I first built the wheel ...the spoke holes were left and right handed...and previously I had laced the old rim with out noticing this...and had got the spokes in the wrong way..the left angled spoke holes fitted with right spokes, and right to left

So I rotated the rim around one hole so the spokes were now going to the correct holes in the rim....but only after finishing the wheel did I realise that now the valve is not in a wide gap between spokes...not major but annoying...and I am not going to strip the wheel again to sort that little issue, I can still easily get the inflator on so not a real issue...but annoying just the same

I can't get the tyre seated square on the rim though, the rim is running true, to within less than a quarter mm, yet the tyre is running out by over an eighth of an inch at one place

 

[liveforphysics]

If you want to see how wrinkled a bicycle tire gets, watch this video at the 35sec point. That is a properly inflated 3" DH tire (which has since had all it's knobs ripped off and the carcass started delaminating.)

http://www.youtube.com/watch?v=FJsMDsT8siU

 

[dogman dan]

I keep getting distracted by the shoe flying off. 8)

About 20 laps on the Tuscon track was enough to break most of the cords on the tires I had at the death race. Cheap bike tires were good for about 40 miles max at that kind of use.

Definitely a problem for those trying to use high power Ebikes as a daily rider.

 

[knoxie]

Hi Neil

Funny as I was going to post the exact same thing, I have the same problem on all of my ebikes it doesn't matter the make or quality I have had expensive tyres go quicker than cheap ones, I have nice wide rims on my X5 wheel as well so don't think that's an issue, I think its as others have said its a combination on the weight, the high speed impacts and the rotational forces applied to the beading, they were just never designed for this kind of abuse.

On my BMX when I ran 72V @ 35A It would tear the bead in no time, this was caused by the wheel moving on the tyre under traction, doesn't take long for the beading to fray and the inner tube to pop out of the side so you could check if your tyre is doing that (mark the tyre and the rim).

Pretty much all of my rear tyres get binned well before the tread has gone they always hit the bin due to this issue, all my rides are between 1.6 and 2KW max, I am a big guy though 200 lbs and the bikes get abused, I can change a tyre in no time and I have started using the really cheap tyres from Chain Reaction Cycles bargain bin as they were lasting longer than the expensive ones (my armadillo tyres were 35 quid and they let go in no time)

Cheap tyres last me about 1500 miles or so, only ever have issues with the drive tyres the fronts as mine mostly are last forever.

I suppose when some of us are running about on mopeds we should really be using moped tyres

Knoxie

 

[NeilP]

Hi guys

that is all 'good ' to know..at least it is not just me

 

[Ykick]

Good stuff Neil, always enjoy your posts and experiences. Bottom line is you're pushing the envelope of bicycle tyre technology.

I remembered your bent rim 'cause it happened to me with a barely noticeable deformed rim. Apparently it allowed the tyre to move just enough that the friction wore through at the bead. Tube squeezed out and pop... And you've got much more going on than just that.

More I do this, 'more I realize that for rear hub speedster eBikes m/c rims/tyres are probably the only genuine solution. Say goodbye to rim brakes but if you can do discs and/or strong regen say hello to DOT rated performance.

 

[knoxie]

Hi guys

that is all 'good ' to know..at least it is not just me

Yes there is nothing wrong and at first I wondered if it was just my bad luck also, folding tyres seem to fair better for some reason? you would think it the other way around really, either way I think my last set were only like a fiver each and they are still lasting well, I did once have an issue that was my fault though a badly aligned brake block rubbed on the tyre and did the same thing, I didnt notice it rubbing till it was too late.

Crikey Autumn is really coming with a vengeance here in the UK today, time to break out the bike lights and the fleeces! so glad I have a little assistance on the way home from work tonight tail end of Hurricane Katia...

 

[NeilP]

Yea, lights...I have some really OTT 1200Lumen ones from Denoitte lights...expensive but worth it at night...I am planning to rig them to the main battery via a 84 volt to 12 volt convertor. it is not a actually a proper dc/dc convertor..it is a power supply from a computer screen...240 volt in 12 v dc out...but it works fine with 84 volts in too.

 

[NeilP]

These

http://www.dinottelighting.com/Products.htm

 

[NeilP]

Good stuff Neil, always enjoy your posts and experiences. Bottom line is you're pushing the envelope of bicycle tyre technology.

I remembered your bent rim 'cause it happened to me with a barely noticeable deformed rim. Apparently it allowed the tyre to move just enough that the friction wore through at the bead. Tube squeezed out and pop... And you've got much more going on than just that.

More I do this, 'more I realize that for rear hub speedster eBikes m/c rims/tyres are probably the only genuine solution. Say goodbye to rim brakes but if you can do discs and/or strong regen say hello to DOT rated performance.

Well I got a new rim on there now..and no one else is going to ride it...I want all the damage to be mine!!

Now I have a bike running ( well two now) I have more time to search for Motorbike or moped type rims.
I have also just acquired a Falcon Beach Cruiser

Wondering if I can do anything with this...but this is long term though...may not be this year ...I get my driving licence back this year...so i need to re build the Harley and stick new gearbox on the Landrover.....just too many projects