tapping bicycle crank arms (to shorten) in Chiang Mai?

[JimShortz]

Pedal Taps, or at least access to some wanted. I want to drill and tap the crank arms on a bike for my son, so that he can properly ride it now ( he's tall enough to sit on it, but pedal stroke is too long really).

I can buy the taps (one left hand thread one right) off eBay for 1500 Baht, then another 800 for a handle! Do any local shops do this? Anyone have a pair of 9/16" taps? A long shot I know....

Any help very gratefully received.

[toybits]

Why not just pad the pedals?

[JimShortz]

Why not just pad the pedals?

It sounds like a good idea, and would shorten the stroke at the bottom, BUT, would have the knee even higher at the top of the stroke... It doesn't actually reduce the size of the stroke at all, just makes it higher up!

Thanks for the thought though. ?

[NeverSure]

None of my business really, but I collect bicycles. If you haven't already, be sure those pedals are 9/16 inch and not 1/2 inch. There are both. In both cases the taps should show "20" or "20 tpi" as your picture does and not "NF". NF has too fine of a thread pitch - too many threads per inch and I've never seen that on a bicycle.

I'm sure you also know that there is an exact size drill bit for that which will leave just enough metal for threads without being too tight and binding.

Labor is pretty cheap in Thailand. Is there no bicycle shop with those taps?

[JimShortz]

Thank you Neversure, yes it's 9/16" 20 thread that I need, the 1/2" is not really used anymore. I believe they were mostly on BMX type bikes.

I hope a bike shop, or engineering place has those taps. I'm hoping that someone can tell me where!

[MrBrad]

This might be an option, though not sure. I bought a bicycle at Chaitawat Bike Shop for my neighbor boy who was 7 at the time. It's a Trek bike with an adjustable pedal crank.

For the first year or so we had the pedals in the shorter-distance position, but then moved them to the regular position. This is exactly what you're after, and the cranks are (most likely) available by special order. That said, who knows if cranks are interchangeable?

[MaeJoMTB]

I think you're fussing needlessly.

Most kids can fit themselves to any bike they can mount.

[CNXBKKMAN]

Thank you Neversure, yes it's 9/16" 20 thread that I need, the 1/2" is not really used anymore. I believe they were mostly on BMX type bikes.

I hope a bike shop, or engineering place has those taps. I'm hoping that someone can tell me where!

The half inch pedals normally fit onto the old one piece cranks found on BMX but can be found on other bikes too.

TopGear bike shop on the right hand side of the one way road going down to Kad Luang from the moat where Mike Burger used to be(forget the name of the road!). This shop has in the past been considered to have the most comprehensive workshop in CM. I believe the original owner was an american and he brought over a lot of tools from the states. They might be worth a try.

I dont rate thai bike shops generally as very good for repairs. I had a bearing crack on a shimano coaster hub. No big deal go to a bike shop with one of the old bearings and get a replacement or a whole set. How wrong i was. I ended up touring nearly all the bike shops in CM. TCA dont have any loose bearings of any kind! Velocity had a jar with a couple sealed units in it. Not a loose ball bearing in the shop. This was the same all over town. Finally i went into the little shack type shop on the southern moat road across from the chinese consulate, going in the direction of chiang mai gate, 100m before the fire station. This guy has the odd second hand bike outside and doesnt seem to sell any new stuff, just repairs. I go in with my bearing the guy straight away picks a ruler type thing with holes in it. Pushes the bearing through the right size hole to get the size and promptly sells me a replacement for 2 baht. Brilliant.

Nuts and bolts, bearings, washers, pedal bearing cones etc should be a standard thing for a bike shop but not in Thailand. I needed a pair of handlebar plugs a while back. Easy no problem i thought. Same thing shops didnt have any only a sets of new handlebar tape with plugs included. Tommo Bikes on the right side of the canal road going south out of the city, past the Royal Flora junction, just keep on going for another KM or so. Tommo bikes demonstrated to be a superior shop IMO. I asked for plugs, Tommo just handed me a box full of different ones. I found a pair that fitted well. How much? Nothing they were just happy to help. Tommo knows what he is doing. He had a file in his hand when i visited, working on something , making it fit, fixing a problem. No big deal you may think but in the CM bike shop world that puts you at the top!

[MaeJoMTB]

Chiang Mai Mountain Biking (just down the road from the shop you got the bearing) are also very good at repairs.

They don't sell bikes, just maintain their hire bikes from the downhill runs.

[JimShortz]

Great help everyone, thank you so much! I will start with TopGear bike shop I think. They have also just been recommended to me via Facebook as having these taps. I hope they do.

I really don't want to mess up his little legs.... I know kids are adaptable, but I don't want odd leg adaptations due to long rides with oversized cranks. He's done well over 30km with me several times already; I want to give him the right length crank arms...

[sticklee]

I have a box of taps, dies and applicable handles. I havn't dug them out so no guarantee of having the size and thread you're after. PM me if you can't find what you are looking for. I'm in Mae Hia area.

[JimShortz]

I've been down to see the people at Mong (ex. Top Gear) and found an incredibly helpful guy who has the taps and is happy to do it - a real bike shop! Taking the bike tomorrow - thanks all :-)

[JimShortz]

..and the final outcome:

Just got it back today. They did a great job at Mong, including installing a new bottom bracket (old one was getting a bit crunchy!). I highly recommend them for their super service and great communication - a real rarity!