'96 RTS-3 Rehab

[SteveCar]

There will be many questions that I will ask. Let's start with the bottom bracket. The shell is the round hole the crank shaft fits in right? So that is 73mm. The measurement from one end of the tapered square shaft to the other is 114mm. The actual numbers I see on the BB case are BB-LP26. Then there is 73 above BC 137X24 What is the replacement for this?
The Shimano BB-ES300 says it is a 73x113, The BB300's are all over the place on shaft length. So. .5mm shorter per side (113mm) is better than +2mm (118mm) per side.... is that correct? I would think that the wider outboard the drive crank mounts that it would affect the geometry of the chain path. I'm probably way overthinking this so just tell what to get. lol.
Gonna paint soon so that is a plus.
BTW, there is nothing wrong with the unit except that the non drive cup cracked a little. It appears someone used an impact driver to install. No rust or loctite residue on the threads. Yes I know about the thread directions. Had to use a 2' pipe on the ratchet AFTER heating the outside, it sucked.

 

[ishaw]

Sounds like you have a nice project on your hands. I'm a big fan of the RTS, had many, still have 2, a mint team and another us built frame which I've had converted to disc. I know my way around the frames.

Your BB shell sounds like 73mm based on the existing BB and your measurement. However, the axle length will depend on the crank you are using, and as you've rightly deduced, too long will mess with the chain line, as will too short, but may also result in your chain rings eating the chain stay.

Speaking of stays, if you have alloy ones, check the rear pivot points for cracks as they often go there if not looked after. Worth checking the BB pivot point for cracks around the weld, my first RTS-2 went there.

Good luck with the project, if you need any help just ask.

 

[SteveCar]

So my thinking is that, using the org Alivio cranks, the -.5mm per side of the 113mm axel should be fine, not the +2mm of the 118's. When the frame and rear are stripped for new paint I'll look real hard at the welds, so far, just cleaned up, there are no cracks showing in the org paint.
I should also say I'm 65, this is my going to town rig, not something I'll be jumping lol. But yeah, check the integrity.

 

[mior]

Sounds like you have a nice project on your hands. I'm a big fan of the RTS, had many, still have 2, a mint team and another us built frame which I've had converted to disc. I know my way around the frames.

Your BB shell sounds like 73mm based on the existing BB and your measurement. However, the axle length will depend on the crank you are using, and as you've rightly deduced, too long will mess with the chain line, as will too short, but may also result in your chain rings eating the chain stay.

Speaking of stays, if you have alloy ones, check the rear pivot points for cracks as they often go there if not looked after. Worth checking the BB pivot point for cracks around the weld, my first RTS-2 went there.

Good luck with the project, if you need any help just ask.

unrelated but mine went. finally got around to replace it with steel, and it fully snapped once i took it off and set it down on the floor. scary stuff

 

[ishaw]

I do have a spare nos steel rear end should that happen to mine, though olive had an alloy one converted to disc. I hope that doesn't go.