way124

I have a bike which cranks use 1/2" for them pedals. I have new 9/16" SPD pedals. How can I get them to fit? The only thing I could find were these adaptors, but I'm cheap and I don't want to pay $45 for a pair of metal stubs with fancy threads. I tried changing the crank (failed because none the LBS has was compatible) and I don't want to drill a bigger hole because the crank is not that thick to begin with. Get a new bike? Not an option either

sorebutt

you should be able to find them here www.loosescrews.com

dafydd

Pretty much the only other option is to convert to three-piece cranks w/ 9/16" threading, which will run you more unless you have spare parts around.

1oldRoadie

are you sure your not into metric? 1/2"=12.7mm 9/16"=14.3mm? a half-inch wrench feels loose and a 9/16s doesn't work.

DieselDan

The measurement he is referring to is the spindle size, not a wrench size.

rollwithme

I need this as well. I have a bike with a one piece crank and 1/2" pedals, but I'd like to use my clipless 9/16" pedals with it. I cannot find clipless 1/2" pedals so I am looking to get this

https://www.amazon.com/gp/product/B0037N6NCG/

Any thoughts or advice?

Bill Kapaun

Yes.
They will do nothing for you except move 9/16" pedals further out in 9/16" cranks.

rollwithme

There is one option that is for 1/2 to 9/16 in addition to the other extension options .

Bill Kapaun

I missed that.

dsaul

I have a set of those Knee Savers that I'll send you for $20. I bought them to adapt clipless pedals to an exercise bike that I no longer use. Send me a PM if you're interested.

andr0id

Make friends with a skilled machinist who has access to a rudimentary lathe.
Take the spindles out of your good pedals and ask him to make you spindles that are exactly the same, only with 1/2" threads. (Don't forget to point out the LH and RH threading)
Buy him a 6 pack when he's done.

IthaDan 

It's not exactly a rudimentary lathe that can single point a female 9/16"-20 tpi LEFT handed thread. I am a skilled machinist and I'd tell you to pound sand. Single pointing female threads is NOT a straight forward job, and pedal taps are about $50 for the pair. Sooooo...

First I'd recommend you buy an Ashtabula bottom bracket with a "euro" square taper spindle and I'd give you an old crankset.

OP: get something like this- https://www.danscomp.com/products-PA...Sealed_BB.html

and use whatever square taper cranks you can find.

DO NOT BUY THE CONVERTER WITH THE TWO PLATES WITH FEMALE ENGLISH THREADS AND THE THREE BOLTS TO HOLD THE HALVES TOGETHER. Those adapters are great in theory, but I've found most frames with Ashtabula/American bottom brackets have some kind of plate inside the shell which gets in the way of the bolts to hold the two plates together (free spirit, I'm looking at you). And they creak like crazy.

CroMo Mike 

The machinist would laugh you out of his shop.

IthaDan 

I see now you've said to make new spindles not adapters. Still, a PITA as not only will the custom spindles be not nearly as hard, and therefore much more wont to wear, but SPDs aren't exactly easy to take apartt- hey have that weird plastic splined nut on the crank arm side that takes a proprietary tool that isn't easy to improvise with damaging the nut.

fietsbob

You may have a smaller budget than your desires require, It happens ..

the machined adaptors have a male 1/2 " threaded end and a 9/16" female end to screw Into.

they sell for what they cost to make and distribute.

Here is one STATIONARY BIKES they're $45

If you can make them for less in your Machine shop, Do So..


Other than that, replace the BB with a conversion assembly, and once you have the Square Taper BB spindle installed ..

you can fit aluminum cranks which have 9/16 pedal threads NB: It will cost Much More than $45 to do so.

andr0id

The "rudimentary lathe" bit is a tongue in cheek reference from Galaxy Quest.

I figured I'd suggest the most impractical and expensive solution before somebody else beat me to it.

jyl

Am I missing something?. How about tapping out the 1/2" threads in the crank to 9/16" threading?

IthaDan 

Not enough meat on the crank arm to drill and retap. ..And pedal taps cost more than the adapters.

AlmostTrick

The TruVativ American-to-Euro Conversion kit fit fine in my Electroforged Schwinn frame. I did have to grind a small amount on the inside of the BB shell to get a completely flush fit. Have not had any creaking either.

It would only take a glance (after removing the one piece crank) to see if it would fit. Plus, with this adaptor you then have the benefit of sealed bearings. Those other units allow lots of water and grit into the bearings.

rollwithme

I think the adapters on the Amazon link I posted are similar to those Knee Savers ( 1/2" male, 9/16" female). I read a post elsewhere that described how to exchange spindles in the pedals or something, this seems a little more straight forward.

They arrive tomorrow, and I really hope the solution will work. This bike is on the cheaper side (my only option) and thus I don't think the crank can be modified.