Shimano TZ replacement/adapter

[MountainBeach]

       
   

Hi All:
I have been using Shimano and VGsports freewheels on my ebike to get a 34t low gear. The gearing is cool but these hubs suck for beach work, one little splash of salt water and they are cooked. I want to replace the freewheel threaded hub with something that can be serviced. Have tried to get these apart but they turn into scrap, I even made a special high torque pin wrench but it didn't help. Any advice for adapters or other magic?

[Jesper]

(08-01-2024, 09:24 PM)MountainBeach Wrote:  Hi All:
I have been using Shimano and VGsports freewheels on my ebike to get a 34t low gear. The gearing is cool but these hubs suck for beach work, one little splash of salt water and they are cooked. I want to replace the freewheel threaded hub with something that can be serviced. Have tried to get these apart but they turn into scrap, I even made a special high torque pin wrench but it didn't help. Any advice for adapters or other magic?

My only suggestion is PB Blaster or Kroil penetrant. WD 40 next. You might have to soak it in a bath for hours (I recommend overnight). Hit the area with a heat gun on low, or hair dryer on high. If you think that the heat might cause damage then do not do that. Regardless, apply as much heat as you feel and allow to cool down. Apply an ice pack to cool more. Usually with the heating and cooling it will allow the oil to better penetrate via capillary action due to the expansion and contraction helping to break the corrosive "weld". This technique woks well for me in many different "stuck" component situations. Sometimes the heating and cooling phases must be done 2 or 3 times, but generally it works well without damaging anything. The best results come from steel to aluminium issues since the coefficient between the expansion of the 2 different metals is greater. Using your tool with an impact driver might help, but be careful since torque could possibly cause damage. If adjustable torque, start at lowest setting.
You might want to consult a bike shop, if you have not already done so, before trying anything beyond what you have already done.
Good luck!

[MountainBeach]

thanks for the feedback Jes

I have separated a new one, these things are actually just specially shaped roller bearings without a seal. The entire body is a hardened shell. The clearance is set with shims. I think they must be assembled with a torquing bench that applies force in the Y axis as well as the Z axis because the "pin" recess' are stupid shallow. Repeated disassembly for service will be limited thanks to the pin recess's. I may drill a hole in the outer body under the sprocket/flower through the splines, so I can force some grease into it without complete disassembly. Maybe a tungsten carbide mill will penetrate this hardened shell, if not I will have to use an electrical discharge drilling thingy. This should be -done at the factory but I surmise they are more interested in selling new ones rather than providing methods to service. If you drive your off road bike on the coffee table, they will last forever.

[Talha]

Brands like DT Swiss, Hope and Chris King make some real tough parts made for the toughest of environments. Look for models like the Shimano XT or XTR, which have serviceable freehub bodies that are easier to maintain and clean. And if you want the reliability of a freehub body but with your existing freewheel, then investigate this adapter to use an old-school freewheel on a modern cassette

[meamoantonio]

I don't think any part old or new(threaded or cassette type) can withstand salt water damage, closest I can imagine to getting the job done is what @Jesper mentioned. He's one of the best mechanics in this forum who has experience with old and new models