Wednesday, January 27, 2010

Brooks B-17 Champion Special Titanium tension bolt re-seating / replacement

A little routine oiling of a Brooks B-17 saddle (a gift from Peter) found me disassembling the tension mechanism for a thorough cleaning.

Apart from the leather, all parts for the Brooks B-17 saddle may purchased as spares or replacements.

The regular steel, black enameled frame is available for US$20; the titanium version retails at US$260. Titanium is one of the few metals that is biocompatible; this means that if you get into a wreck and the saddle frame gets embedded into your ass, surgeons won't have to remove it. Buy it.

The replacement nose (titanium) is available for US$24; 'U' shaped tension shackle (titanium) for US$16; 60 mm zinc-plated steel bolt, with nut for US$14. (Image from Wallingford Bicycle Parts, New Orleans. All parts may be ordered from them.)

The Brooks B-17 Champion Special Titanium model uses a 60 mm zinc-plated bolt with a tapered collar nut (the importance of which will be apparent later).

Brooks also offers replacement of the leather at their factory in Birmingham, England:

From tomd (20th October 2009):

e-mail from brooks regarding re-hiding:

It is possible to fit a new leather top onto saddle, provided that the model concerned is still a current one.
The price for this repair would be £50.

Best Regards


Once I started putting it together again, that's when the fun really began:

Replacing the tension bolt on a Brooks saddle? - What's the trick?

I have a Brooks saddle and the tension bolt sheered in half. So I got my hands on a new one, but my problem is actually trying to squeeze the thing into place. The saddle has been without tension for many months. Is there some trick for actually getting this damn thing into it "seated" into both circular holes? It seems like there is no 'safe' way to spread the rail assembly away from the front brass notch-piece.

Has anyone done this before?

(SlowIsMe, Road Bike Review Forums)

An excerpt of an email from Bill Laine of Wallingford Bicycle Parts to Roger Sacilotto, 7 July, 2007:

The most frustrating part . . . might be re-assembling the saddle. Unless your saddle is really stretched it will be hard to get the end of the tension bolt into its cup in the nose piece. At the factory they have a hydraulic saddle stretcher. If you don't have one of those then it could be a real wrestling match trying to pry the nose out far enough to let the bolt drop in.

NIC [2:26 PM]: Tension's kinda high. Straaange. Might wanna reduce the tension a slight bit for storage
BEN [2:28 PM]: Must be gravity well of Dom nearby.
BEN [2:32 PM]: Okay, no tension now.
Pete insane.
Mad tension.
NIC [2:33 PM]: LOL

[much, much later...]

BEN [5:19 PM]: Fuck. Never back out the tension bolt of Brooks Ti saddles all the way.
NIC [5:20 PM]: Now its floppy?
BEN [5:20 PM]: Between the hours of 2:32 PM and 5:15 PM, I struggled to put it back.
'Just succeeded.
You need to get the collar of the nut and the head of the bolt JUST RIGHT to have both seated.
Oh, ya, add the natural springiness of Ti to fuck things up.
NIC [5:22 PM]: Helps if you put it on the ground and press it in with your body weight.
BEN [5:24 PM]: Us, starvies don't have no body weight :-P
NIC [5:24 PM]: LOL
BEN [5:27 PM]: Ya, so that's how you do it.
NIC [5:27 PM]: Body weight?
BEN [5:28 PM]: I used finesse. Heh!
Not by choice, mind you.
After 2 hours of wrestling with Ti and a piece of dead cow, I was exhausted.
NIC (5:31 PM): Ahaha!

The procedure that finally worked for me:

Apply a thin coating of anti-seize (or grease) on: the tapered end of the tension bolt nut; the edge of the hole on the tension shackle; around the head of the tension bolt.

Place tension shackle ('U' shaped piece) over the nose end of the saddle rails.

Thread the tension bolt nut until 2 threads are visible from the head of the tension bolt.

Insert tension bolt into tension shackle.

Press tension assembly down.

Push head of tension bolt toward the nose of saddle until it seats in the recess of the nose piece.

Move tension bolt nut toward tension shackle by either rotating tension bolt nut or turning the head of the tension bolt using an allen key — gently.

At some point, resistance will be felt. Stop.

Alternately reduce or increase tension while pressing and pulling on the tension assembly (on a vertical plane. I.e. 90 degrees to the tension mechanism assembly). Keep each rotation of the bolt or nut small.

The tension bolt nut has a tapered collar (stained brown/bronze by the anti-seize in the picture) which aids in it slipping into the hole of the tension shackle. The aim of this procedure is to leverage what little play there is to get the lip of the tension bolt nut collar to slip into the hole of the tension shackle with a minimum of force and galling — you're talking millimeters here.

The clunk! you hear when the tension bolt nut seats in, will be about the sweetest sound you'll hear all day.

Your mileage may vary for other models of the Brooks B17 as they do not have a hex head, but the procedure should be quite similar (albeit, slightly more difficult due to the inability to rotate the tension bolt).

Just remember, patience and finesse, not brute force. Save the last for the re-railing! :-P


veii said...

Hello, have you seen this "How it's made" feature?

-ben said...

Oww... very nice!

Thanks, veii!