Well,...my new Cane Creek "Thudbuster LT" came in on saturday,.....pleasant surprise as it wasn't expected until monday according to the tracking.
I've made some neat changes to my Thudbuster LT to vastly improve it's bushing seals against dust and wear, (side strength also), that i think will drastically slow down the unwanted feature of side play creeping in over time. (time will tell)
I know you can get a rebuild kit for these,......but since this was a new install i thought i would do all i could NOW to prolong it's tight fitting quality feel and function.
But all that comes a bit later, so don't freak out and leave thinking there was nothing worthwhile!
I just wanted to start at the beginning and cover a problem i anticipated before i ordered the unit,....and how i handled it once it arrived.
Then we'll get into the good stuff!
Mine was not expected to be a quick install, as i wanted a direct fit without needing a spacer. My 1987 Schwinn Cimarron's original seatpost measured just 1.045" (about 26.43mm), and the nearest Thudbuster LT post was made in 26.8mm, so that's what arrived.
Looking inside the seat post tube, i could see there was a layer of paint, and also i expected to be able to open up the tube clamp area a little also, but didn't want to do anything until the Thudbuster arrived.
I used that huge antique flat screwdriver (1st pic) to lightly tap the clamp area slot of the tube a bit (a little added grease helps) , but it was obvious the tube itself would need a reaming. I had picked up a brake cylinder hone in anticipation of the job before me, and chucked it up into a 3/8" drill i had.
At a medium speed, and moving the drill up and down at a pretty even pace to keep the paint/metal removal even,......in about 5 minutes i had a snug fitting post (dry) that went down to the 1st bottle screw.
If you have a similiar need, be sure to take a little off and check the fit regularly as you go! I used my air compressor to blow out the tube, and added a little bit of wheel bearing grease to the inside of the tube with a wooden dowel, and also on the new seat post. Friction fit just about perfect with the lube on.
However, it was not obvious the Thudbuster post was too long to allow me to get the seat down to a usuable level, so when it was down as low as i could go (hitting the water cage screw and some sort of support inside the tube i could feel with a wooden dowel), i measured how much tube was remaining up top. That was to be my cut off amount....
Here's my original seatpost compared to the Thudbuster,....big difference:
.....And so out the TB came back out, and i wiped the grease off the tube and proceeded to saw off the required amount.
Here is where i ended up:
....and the Thudbuster LT at it's new length:
I was a little bummed out the manufacturer didn't put the size marking and patent number further up, in anticipation some folks would have to trim the posts?
....so i lost them:
A quick cleanup of the cut followed by added a slight bevel to the outer edge, and with a light coating of wheel bearing grease added, i now could "just" bottom out the new Thudbuster LT post within the confines of my bike's seat post tube.
OK,.....now we'll get into the changes i made.
I wanted this new Thudbuster to be as "bullet proof" as possible, and was willing to take on a few ounces of weight to get there,.....no free lunch as you all know.
I'll present my final version (for now!), but in the 3rd post of this thread i'll outline some simpler options if all you want to do is offer a bit of dustproofing to your bushings.
Right off i knew i would have to trim a few of the stainless steel part of the bushing area. Some were sticking out a bit, and others pretty flat and at a similiar level to the bronze bushing.
Here's one of the higher ones:
.....and one i wish all were from the beginning:
I carefully trimmed the high steel tube ends, until they were all pretty flush with the bronze bushing. I was a bench jeweler for 35 years, so i got pretty good at using my Foredom Flex-shaft machine with a 1" cutoff disc. A piloted facing bit would have been easier to trim the steel tubes flush with the bronze ones, but couldn't find one or even know where to look?
IF anyone knows where a tool bit like that is available, please pass it along. The center SS tube is 7mm diameter, (for the piloted plug to guide the cutter), and the outer diameter of the bronze bushing is about 12.065mm (measures .475 inch on my dial caliper when closely eyeballing it)
In this case, it's not critical as long as you're reasonably flat. Be sure to clean up all the grinding dust. I used my air compressor to get most of it, then several wipe downs with paper towels lightly coated with 93% denatured alcohol to make sure no abrasives worked into the bushing over time. (negating what i was attempting to prevent!) A few Q-tips in tighter areas also.
OK, we got down to all of the bushings having a similiar look to this, wherein the stainless center tube is fairly even with the outer bronze bushings:
That made it easier to get an effective dust seal , and on my 3rd incarnation i arrived at using a nylon washer to cover each bushing(coat with wheel bearing grease on the bushing facing side), followed by a stainless steel wash and nut. I used a stainless steel 1/4 X 20 X 2" hex bolt and lock nut (with the nylon locking material on one end) to keep it all together.
A 7mmX 1mm threaded bolt would have made a little tighter fit to the ss tubing of the bushings, but my local hardware store didn't have them in stainless steel and i didn't bother looking online.
I ended up filling most of the slack on the bolts by putting some 3/16" heat shrink tubing over the bolts. It had to be stretched a bit with needle nose plyers, and there was no need to heat it as it was still a snug fit. Added just a little wheel bearing grease on the outside of the tubing, as the bolt does spin slightly in use while the ss tubing does not. Doubt the bolt sides ever touche the inner stainless steel tube of the bushings though, so probably not necessary.
The 2 inch bolt length will need to be trimed after you've aquired your nylon and ss washers, as they vary a lot in width depending on where you get them. (you'll end up in the 1 3/4" range probably)
BTW, i did find it interesting the Thudbuster rebuild kits contain new bronze bushing and washers, among other items,....but no new stainless steel
tubing at the center.
I guess it should survive several of the softer bushing replacments, but wondered when the time comes if it's possible to just use a solid ss bolt of the proper outside dimention? We'll look into that should the need arise.
more to follow...............