I just spent 4 days getting a seized Al seatpost out of a steel frame. It’s a winter/rain bike sometimes, so it’s seen some weather. I could have been better about keeping it clean, but alas, I’m not the anal retentive clean freak type. New pedals/stack change required a seat height adjustment, which I obviously couldn’t do. I probably hadn’t moved the seat in ~1 year, though it was last ridden in May.
So for my replacement seatpost, what’s the best option? I’m trying to limit the amount of carbon on this bike, but will go that route if it is the best option for a lazy post-ride clean-up guy like myself. (and it anyone has that option in a 27.2 to sell cheap, I’m all ears).
The inside of the seat tube was pretty gunky (some certainly all the crap I put down there to unseize it, but some certainly rust colored). I used some cleaner on a shirt and shoved it down there as far as I could, and now the top foot or so is clean, but the rest still has a reddish/dusty hue. Should I be worried?
generally if you remove the thing after riding in the rain and wipe it off, dump the water out and let the whole thing dry, then grease and put it back together when dry you will be fine with another aluminum post. It’s one of those things you have to do with a steel frame
A lot of steel frames have problems with the inside of the seat tube being deformed from welding/brazing at the top tube and seat stay intersections so the fit of the seatpost is poor. Throw in a few years of rust and it gets worse. If the fit of the seatpost is too tight, when you grease it and insert it, the grease just gets scraped off going in and not much actually makes it inside.
Best fix is to clean it out with an adjustable ream so it’s a nice and smooth inside so the seatpost fits properly. Then just smear it with grease and you’re good to go.
I think any good shop that has been around for 10 years or so should have an adjustable ream.
A lot of steel frames have problems with the inside of the seat tube being deformed from welding/brazing at the top tube and seat stay intersections so the fit of the seatpost is poor. Throw in a few years of rust and it gets worse. If the fit of the seatpost is too tight, when you grease it and insert it, the grease just gets scraped off going in and not much actually makes it inside.
Best fix is to clean it out with an adjustable ream so it’s a nice and smooth inside so the seatpost fits properly. Then just smear it with grease and you’re good to go.
I think any good shop that has been around for 10 years or so should have an adjustable ream.
+1. If you don’t have access to an adjustable reamer, then the first thing to do is to clean up the burr that’s sometimes left in the tube where the seatpost binder slot is. Use a fine half-round (or round) file to smooth the inside of the slot; then apply grease or antiseize compound to the inside of the seat tube as well as to the outside of the seat post, put the seatpost in, and tighten the seatpost binder just enough that the seat doesn’t move when you ride it. Resist the urge to clamp that sucker down just 'cause it’s a steel frame…
Same treatment goes for aluminum frames. You shouldn’t have galvanic corrosion, but you can get galling from a burr at the bottom of the binder slot, especially when the binder has been tightened too much and someone attempts to undo the seat post by vigorously swiveling the seat back and forth without first undoing the binder enough. Seen it, and had to deal with it.
my steel bike was an ebay buy, turned out the frame was a little rusty inside… took a bit of effort get the seatpost out too. Cleaned as best I could, used rust stabilizer, then added a couple of ounces of motor oil inside the frame, which gets spread around as the bike is hung from the ceiling hooks. Greased the inside of the seatpost tube as well as the seatpost itself. so far ten years without any problems or further sticking…
No burr issues here. One big issue is I need like 20 nm to reach the point where the post doesn’t slip. The binder bolt itself is fine and tightens without resistance (so the threads aren’t all jacked up and causing excessive torque to spin).
use a assembly grease or similar lubricant or anitseize.
I’ve had aluminum posts in my 15 year old road bike. I can loosed the pinch bolt and adjust it right now. I’ve gone 5 years without touching it before and I had no problem adjusting it. I’ve ridden it in wet conditions many, many, many times. Even ridden on salty roads too. I rarely even clean or rinse it off either.
