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Pedals coring out mounts

Posted: Jun 08 2019 8:29pm
by markz
I've been having this problem now for the last half dozen cranks, but now its a brand new crank and brand new pedals.
Normal 3 pc, $30cdn Shimano Tourney triple crank, Square Taper
I can see how, since I am 375lbs, and using the pedals for curbs, ruts, roots and such that this will happen to cheap components.

What do I do?

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Re: Pedals coring out mounts

Posted: Jun 08 2019 10:20pm
by RunForTheHills
I don't know the answer for that. I am average size haven't run into that problem. Perhaps a better crankset like the Deore XT would last longer. You would have to replace the bottom bracket too though. Lennard Zinn makes bikes for larger riders and I ran across this article by him a couple of years ago on the subject that I thought was interesting.

https://www.velonews.com/2013/10/techni ... ers_306560

Re: Pedals coring out mounts

Posted: Jun 08 2019 10:41pm
by Ozzzz
Is it loose in the thread? (hard to see)

Iv'e just been through this on my mid drive bafang.. the RHS crank thread flogged out after 35klm and the pedal fell off :shock:


The majority consensus was that you really need to check the torque, especially after the first rides and keep them tight.I must admit iv'e even (only) hand screwed pedals on and some bikes in the past with no issues (so the bafang in particular must be pretty soft). I'v'e ordered a new one but i'll be using torque + loctite (blue)

Re: Pedals coring out mounts

Posted: Jun 09 2019 12:47am
by Chalo
Get any tubular chromoly BMX crank. It's probably easier to use one with a 19mm single than any other size. Get a 19mm "Euro" bottom bracket for it. Get a chainring of your preferred size (if you want a chain on it) or of any size at all if you aren't going to fit a chain.

Here is an example of the kind of crank I'm talking about. This one doesn't have the right bottom bracket bearings, so you'd have to add those.

Image
https://www.ebay.ca/itm/Bicycle-3PC-CR- ... 2857149945

You can probably salvage a crank like this from some punk-ass little puke's bike.

At your size, you should have been using something strong like this all along. I earned my fancy gold teeth by snapping off a top quality square taper spindle under heavy pedaling forces, back when I weighed about 100 pounds less than I do now.

Re: Pedals coring out mounts

Posted: Jun 09 2019 1:04pm
by markz
Chalo wrote:
Jun 09 2019 12:47am
Get any tubular chromoly BMX crank. It's probably easier to use one with a 19mm single than any other size. Get a 19mm "Euro" bottom bracket for it.
Thanks mate, will do!

Get a chainring of your preferred size (if you want a chain on it) or of any size at all if you aren't going to fit a chain.
:wink:

Here is an example of the kind of crank I'm talking about. This one doesn't have the right bottom bracket bearings, so you'd have to add those.


Image
https://www.ebay.ca/itm/Bicycle-3PC-CR- ... 2857149945

You can probably salvage a crank like this from some punk-ass little puke's bike.
Too funny :lol:

At your size, you should have been using something strong like this all along. I earned my fancy gold teeth by snapping off a top quality square taper spindle under heavy pedaling forces, back when I weighed about 100 pounds less than I do now.
Now I know I Shoulda Woulda Coulda
Thanks
Steel arms, with what looks like a decent amount of threads for the pedals. You seen any pedals with longer threads on it, width wise that is, more threads is the correct term.

Re: Pedals coring out mounts

Posted: Jun 09 2019 1:23pm
by Chalo
Pedal threads all tend to be pretty short, because the thread length in cranks tends to be pretty short.

Threaded interfaces between like materials (e.g. steel pedal spindle in a steel crank) carry pretty much the entire thread tension on the first three turns of full thread. That changes when one of the materials is stiffer than the other (steel is 3X as stiff as aluminum).

Grease the pedal thread, get it good and tight, and you won't have any problems with it.

The next thing that fails will be the pedal spindle. It will bend or even break off when you push it to the limit.

Re: Pedals coring out mounts

Posted: Jun 09 2019 2:55pm
by markz
flat tire wrote:
Jun 09 2019 2:40pm
Second, make sure your pedals are being installed correctly and tightened.
They were installed correctly, as for tightened to the proper ft-lbs well I do not have a torque wrench.

Re: Pedals coring out mounts

Posted: Jun 09 2019 5:53pm
by Chalo
flat tire wrote:
Jun 09 2019 2:40pm
First, lose some weight. You are way too fat. It's easy, eat fewer calories than you expend while meeting bare nutritional requirements.
How about, don't be a dick? He's 6'5" or something and he lives in a frozen cesspit. There would be something wrong with him if he weren't "too fat".

Re: Pedals coring out mounts

Posted: Jun 09 2019 11:24pm
by markz
Excuse me, that frozen Cesspool shite is Vancouver and area along with Toronto and area. No offense to members currently residing in such abodes.
The fat is to keep me warm in the frozen artic (its only logical ;) ) of Alberta from the 49th parallel to 60th parallel, basically where all your "dirty" oil comes from! :D


Chalo wrote:
Jun 09 2019 5:53pm
flat tire wrote:
Jun 09 2019 2:40pm
First, lose some weight. You are way too fat. It's easy, eat fewer calories than you expend while meeting bare nutritional requirements.
How about, don't be a dick? He's 6'5" or something and he lives in a frozen cesspit. There would be something wrong with him if he weren't "too fat".

Re: Pedals coring out mounts

Posted: Jun 09 2019 11:27pm
by markz
Here are some pictures....


Looks good
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Looks not good
Clipboard02.jpg
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Looks not good
Clipboard03.jpg
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Re: Pedals coring out mounts

Posted: Jun 09 2019 11:40pm
by Chalo
markz wrote:
Jun 09 2019 11:24pm
Excuse me, that frozen Cesspool shite is Vancouver and area along with Toronto and area. No offense to members currently residing in such abodes.
Hey, Vancouver and Victoria are the only Canuckian cities with survivable climates. Not that I'd move there or anything.

I only exceeded 400 American pounds while living in Seattle. It wasn't out of order for 40 degrees F and drizzling. But let me tell you: sweat keeps you honest. 97F/36C in Austin today.

Re: Pedals coring out mounts

Posted: Jun 10 2019 2:33pm
by thundercamel
My bike came with steel (or at least not aluminum) cranks. They must have stronger threads than aluminum.

Image

Re: Pedals coring out mounts

Posted: Jun 10 2019 8:36pm
by Ozzzz
Something's gotta give.. I'm hesitant to disagree.. but his crank arm didn't flog out because it's alloy. The pedal was clearly loose allowing movement in the shaft. That said, a steel crank arm would allow you to get away with loose pedals.

Re: Pedals coring out mounts

Posted: Jun 11 2019 7:02am
by dogman dan
Well, sure, less weight might help. But more realistic to just get into some kind of steel crank arms.

At his size, saving weight on the bike itself won't matter like it would for a 110 pound rider. So go with something steel, whatever it costs, it must be cheaper than blowing out cranks designed for 250 pound max riders.


Don't know what you need exactly, but really cheap MTBs can come with steel square taper cranks. Terrible chain rings on them though. Might work temporarily, till you figure out a better steel crank.

Re: Pedals coring out mounts

Posted: Jun 11 2019 11:14am
by HK1200
flat tire wrote:
Jun 09 2019 2:40pm
First, lose some weight. You are way too fat. It's easy, eat fewer calories than you expend while meeting bare nutritional requirements.
Someone should force feed you a frame pump.

Re: Pedals coring out mounts

Posted: Jun 11 2019 12:27pm
by Chalo
dogman dan wrote:
Jun 11 2019 7:02am
Don't know what you need exactly, but really cheap MTBs can come with steel square taper cranks. Terrible chain rings on them though. Might work temporarily, till you figure out a better steel crank.
I have gotten cranks like that (plastic clad steel) to see if they're good for anything. (They were so cheap they may as well have been free.) I twisted both sides along the length of the arm, just pedaling. On the other hand, I've used vintage-style chromed three-piece and one-piece steel cranks without problems. Most recently it was a pair of steel unicycle cranks for my BBS02.

Re: Pedals coring out mounts

Posted: Jul 21 2019 1:54pm
by markz
Why should they be tubular Chalo?
Sunlite Steel Triple Crank Arms & Sets - Mtn - 170X48-38-28 - 120 Sqr Jis - Blk would order in from LBS!

I found this one on Ebay (Euro BB, 19mm, tubular, cro-mo) Perhaps the LBS could order something like that in.

Its a long shot but I figure I'd ask:
Is there a simple and easy way to put 2 gears, or better yet 3 gears on them 3 piece bmx cranks?
I see how the bmx cranks gears are attached. but maybe get a longer axle to stuff 3 gears in there.
If not then options would be:
- New double road or triple mtb cranks that are steel (if at all possible)

- Vintage steel cranks like these which would come up for sale on kijiji every now and then.

- Not an option: One piece crankset requires an American style bb with the bearing race inside the bikes bb.

- Find new products that mimicks the old skool design that are steel (which I'm sure is pricy)

Unicycle, so no way to put
https://www.ebay.com/itm/Sunlite-Steel- ... Swf05bJkdj



Chromoly
Cromo
19mm
single (means gear?)
Euro bottom bracket bb
Chalo wrote:
Jun 09 2019 12:47am
Get any tubular chromoly BMX crank. It's probably easier to use one with a 19mm single than any other size. Get a 19mm "Euro" bottom bracket for it. Get a chainring of your preferred size (if you want a chain on it) or of any size at all if you aren't going to fit a chain.

Here is an example of the kind of crank I'm talking about. This one doesn't have the right bottom bracket bearings, so you'd have to add those.

https://www.ebay.ca/itm/Bicycle-3PC-CR- ... 2857149945

At your size, you should have been using something strong like this all along.

Re: Pedals coring out mounts

Posted: Jul 21 2019 4:45pm
by Voltron
Cheap steel cranks are just solid mild steel, are heavy and bending prone. Tubular chromoly welded bmx cranks are a whole different thing... Still heavy, but basically indestructible at any g loads a human can survive 😉

Re: Pedals coring out mounts

Posted: Jul 21 2019 10:37pm
by markz
Voltron wrote:
Jul 21 2019 4:45pm
Cheap steel cranks are just solid mild steel, are heavy and bending prone. Tubular chromoly welded bmx cranks are a whole different thing... Still heavy, but basically indestructible at any g loads a human can survive 😉
Makes sense to me
:thumb:

So grab that ebay crank! Expensive but should last a long long time. I did go to a large bicycle shop in town today, on a 30km cruise, and again I stumped yet another LBS. I dont even know why I bother. Its all the new fangledshit they care about. Maybe I gotta go back deep into the hood/slums to https://bpcycle.com/ someone said they are the BMX go to. Of course give em a ring a ding ding first huh.
https://www.ebay.ca/itm/New-Bike-Bicycl ... 0752.m1982

Re: Pedals coring out mounts

Posted: Jul 21 2019 11:17pm
by markz
I see how the euro bb on mtb/cruisers really throws a curve ball on them bmx cranks.

Re: Pedals coring out mounts

Posted: Jul 22 2019 6:00pm
by MadRhino
You are the in the rockies? Buy a used DH crank 50$. Ugly but: Light and strong, no matter your weight. Street riding, it will last a lifetime.

Re: Pedals coring out mounts

Posted: Sep 22 2019 7:44pm
by markz
These pedals lasted 3 days, 2 of those days were 15km of casual riding.

The first thing to go wrong with this Norco bike.
The second, is the chain on the 1x7 sometimes will slip off the crank gear.



Norco Pedals.jpg
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Re: Pedals coring out mounts

Posted: Sep 23 2019 11:35am
by HK12K
It may be your riding style or bike setup. AFAIK on most pedal bikes your weight should ideally be spread across the pedals, saddle and bars while riding, unless you're standing to pedal. I suspect that standing to pedal is when this is happening, unless you're just standing on the pedals at all times and bombing over everything you see.

I believe what may be causing this is using too low of a gear, too much standing and mashing, resulting in too much torque for the parts to handle. Assuming that's the case you can either gear up and spin faster, which would probably be the preferred method for most cyclist types though It's probably going to be hell on your cardio (what doesn't kill us makes us stronger), or build it to be bombproof and keep on mashing.

Perhaps a little of both. I'm heavy too (265 or so) and despite the fact it kills me to do, the increased cardio would probably do us good. (Says the guy with a 14kw raptor, I know, but I have an analog CX bike too. Not that I've ridden it since buying the Raptor, but I digress, spinning is winning. Or something.)

Re: Pedals coring out mounts

Posted: Sep 23 2019 12:24pm
by markz
There is no motor on the bike. The bike is basically brand new, bought used. I have not stood up to pedal on this bike. The pedals are cheap, there was no tread on the flats of the pedal for grip. Shoes were regular style Keen shoes with normal ankle height. My 375lb's broke the pedals. But like some have said, I need the BMX style cranks with the tubular arms. I prefer large steel pedals with lots of grip.

Re: Pedals coring out mounts

Posted: Sep 23 2019 2:22pm
by HK12K
Well, I guess it is standing on them that's killing them, though just not whilst pedaling.

Crank and pedal upgrade sound like money well spent. I'm sure you'll be able to get it to a place of comfort and reliability.