1983 Trek

[p nut]

Had an 83 Trek 400 a couple years ago and sold it to a fellow PL member.

Happened on another one today and picked it up. But it’s a 520 this time.

I had the 400 set up as a SS/FG. I’m going to retain the drivetrain on this one. However, I am going to 650b it. I have a wheelset already OP built for me. Uses 130 hub but will work fine in the 126 spacing.

It came with Suntour ARX derailers. 6-speed rear. The 650b wheelset has an 8-speed cassette. Any reason why this wouldn’t work? I’m hoping there is enough throw and the RD won’t be maxed out with the 30t cassette.

I like the kooky crankset. It’s a triple. 50/45/24. Not sure why they spaced the bigger ones so close. But it’ll work for me.

I’m also going to try my hand at dimpling the CS so I can fit 650bx42.

[bikinchris]

Originally Posted by p nut

Had an 83 Trek 400 a couple years ago and sold it to a fellow PL member.

Happened on another one today and picked it up. But it’s a 520 this time.

I had the 400 set up as a SS/FG. I’m going to retain the drivetrain on this one. However, I am going to 650b it. I have a wheelset already OP built for me. Uses 130 hub but will work fine in the 126 spacing.

It came with Suntour ARX derailers. 6-speed rear. The 650b wheelset has an 8-speed cassette. Any reason why this wouldn’t work? I’m hoping there is enough throw and the RD won’t be maxed out with the 30t cassette.

I like the kooky crankset. It’s a triple. 50/45/24. Not sure why they spaced the bigger ones so close. But it’ll work for me.

I’m also going to try my hand at dimpling the CS so I can fit 650bx42.

That's almost a half step gear setup plus granny.

[ColonelJLloyd]

Should be fine on the RD throw. Unsure about the 30t cog, but I'd think you'd be fine if you set it all up well.

4-6 tooth difference between big rings with a smallest ring of 26-30t seemed to be pretty common in the 80s. 21 tooth gap with that cute little 24t will require some focused shifting so as not to drop the chain.

There were a few different ARX RDs (long cage, short, 3-pulley). Which do you have?

[fiamme red]

Originally Posted by p nut

I like the kooky crankset. It’s a triple. 50/45/24. Not sure why they spaced the bigger ones so close. But it’ll work for me.

The idea is not to have any duplicated gears on the big and middle chainrings. The small ring is used for steep climbs. I have a 50/46/30 crankset on two of my vintage bikes, and it works well with a 14-28 5-speed freewheel or 14-30 6-speed freewheel.

https://www.sheldonbrown.com/gear-theory.html#halfstep

[p nut]

Thanks.

Looks like it’s a short cage rear (ARX-GT). The current cassette is a 13-28 so I’m guessing 30t will work. If not, I’ll go down to a 28T cassette.

[ColonelJLloyd]

You'll be gold. SRAM PC-8xx and Robert's your father's brother.

[ultraman6970]

Probably nobody care but those suntour RD;s you dont need to open the chain to remove the RD, the cage is kind'a open so if by any reason the RD goes bad or you need to remove it just release the chain from the jockey wheels and good to go.

[nesteel]

Originally Posted by p nut

Thanks.

Looks like it’s a short cage rear (ARX-GT). The current cassette is a 13-28 so I’m guessing 30t will work. If not, I’ll go down to a 28T cassette.

That is actually a long cage. I've never had any issue getting a "GT" sub series Suntour to shift a 30 big cog. Typically they're good for 34.

[p nut]

Thanks gents! Looks like it’ll work.