oldster

Looking at a Sunrace 13-28 7sp f/w, It appears that the end cog is threaded on like the older f/w's. I would like to buy a 13-24 7sp Sunrace and between the two make one that is geared the way I want it...The sunrace folks say"we dont recommend it" . I assume some lawyer told em to say that, because they would not even tell me if it would come apart. Can I do this********** I dont have the strength anymore to just "wing it" when the ratios are not close enough...I have a chain whip and an old chain and vise to take it apart..
Bud

Sheldon Brown

It is probably doable, depending on what exactly you want to make up. Note that customizing freewheels is MUCH harder than customizing cassettes, because freewheels are generally stepped, usually with at least three different spline sizes for different gear positions.

If SunRace's rejection was not just knee-jerk rejection of any customization, it might have to do with interrupting the "Hyperglide-like" ramp/gate positioning, resulting in one shift that would be slightly noisier than the standard shift positions.

Sheldon "Should Work" Brown

p4nh4ndle

"Ignore the killjoys who tell you this is a bad idea."

SB
(https://sheldonbrown.com/tandem-build.html)

oldster

Thanks Sheldon, I really probably only need one cog from the other one..My flat ground, gear optimum these days is about 83"which is 17 teeth at 52 crank ring. So I probably will just replace the 15 with a 16. If the threads/sizes are ok I will try a 14 from another f/w for the screw on cog...(probably won't be able to do that however).
The bike is a Gianni Motta I built in the mid 80's

By the way, your site is really great...And the thing about your father on 75M mobile was great. I have been a Ham for about 40 years. Those were heady days in the hobby..
73's Bud