For all of those who are wondering about using two left mountain bike cranks…
I came across two left 170 mountain bike cranks and attached them to my muni, despite all of the threads saying that it was a bad idea. At first I thought that I could tap out one of the threads and put a right pedal on one of them, but the cheaper option was to get another left pedal and see how that worked(the local bike shop happend to have an old pair identical to mine). All that I did was attach the cranks as normal and then use a whole lot of loctite on the right (actually a left) pedal.
With my two left cranks and two left pedals I have been on four, 1 hour rides with some pretty heavy drops and steep up and down hills and the pedal has not yet broken loose or given any hint that it will. I do not think that it will be long term solution, but if you are on a budget and are trying to piece together a muni…well it is working for me. I know some people will disagree with this method, but I thought that I would give you my opinion.
The uni I got on ebay had two left cranks. It didn’t show any signs of one loosening either. Visually one was newer than the other, which explained the oddity.
I spent a few dollars for a new set (this is a cottered crank uni) in the interests of consistancy, and knowing that if I took the wheel off, I would always be getting the orientation correct. It was awkward telling people how I knew “which way was front” besides the seat orientation.
As far as my limited experience went, it might have gone a long time without the odd pedal coming loose. But I went with the common wisdom.
Instead of using two left cranks you can get a right-hand crank from a tandem crankset. The crankset for the front rider (the captain) of a tandem has no spider on the RH side crank. So you split up the tandem crankset. Get the right tandem crank for the captain and a matching left crank for a normal one person bicycle. The bike shop should be able to order the cranks individually. I think the QBP (Quality Bicycle Products) catalog has the tandem cranks listed individually so you can buy just the RH crank.
I used Sugino tandem cranks on my Pashley muni. They worked well and weren’t too expensive (I think they were under $40 total for the LH and RH cranks). Getting tandem cranks is the most convenient option because you won’t have to deal with cutting off a spider or with getting a LH crank rethreaded with an insert to make it a RH crank. The tandem cranks are also cheaper once you consider the costs for machining the spider off or for rethreading the crank with a RH pedal thread insert.
>The uni I got on ebay had two left cranks. It didn’t show any signs of
>one loosening either. Visually one was newer than the other, which
>explained the oddity.
>I spent a few dollars for a new set (this is a cottered crank uni) in
>the interests of consistency, and knowing that if I took the wheel off,
>I would always be getting the orientation correct. It was awkward
>telling people how I knew “which way was front” besides the seat
>As far as my limited experience went, it might have gone a long time
>without the odd pedal coming loose. But I went with the common wisdom.
After learning to ride backwards, I experienced some problems with the
pedals coming loose. In my opinion, unicycle pedals must be tightened
almost to the point of stripping the threads to avoid the possibility of
the pedals unscrewing while riding backwards. Ever since, I have always
tightened pedals to the point of stripping the threads and having the
edge of the pedal spanner (wrench) surfaces put a circular gouge into
the crank arm centered at the pedal axle due to a few such severe
tightenings. Since using this severe tightening method, I’ve never had
a pedal come loose and never stripped the threads of a crank or pedal.
I have no doubt that the above described pedal tightening method would
work extremely well with left/left and right/right crank pairs or normal
crank sets put on the wrong sides.
>I agree that pedals should be put on pretty tight. However, a dollup or
>two of blue loctite on the threads makes a huge difference and makes the
>tightening force more reasonable.
Using my “severe tightening method”, I’ve never needed and thus never
thought to use any kind of loctite. Clearly, the blue loctite is one of
the “temporary” kinds that can be broken loose with enough force.
>Using an actual pedal wrench instead of a generic wrench ensures that
>tightening the pedal won’t tighten the wrench onto the crank arm.
Sorry, I didn’t clearly describe that it is the axle that is gouging my
cranks when using the “severe pedal tightening method”. It is the
edges of the spanner (wrench) surfaces of the axle that gouge my
cranks when severely tightening pedals. In some cases this may have to
do with the inexpensive cranks that I typically use where the pedal
hole may not be perfectly perpendicular to the crank surface surrounding
the hole on the side that the pedal is attached. This crank gouging is
the result of several severe tightenings, so if you remove your pedals
often, it may or may not cause more gouging. (I usually only remove
pedals for airplane trips and for crank removal or unicycle maintenance.)
My “severe pedal tightening method” requires the use of an actual pedal
spanner (wrench), otherwise most people wouldn’t be able to apply enough
torque (in my opinion) to the pedal axle while tightening it.