1994 Serotta Colorado ATi - and a Lot of DIY Anodizing

[MuchAlohaNui]

Cantilever brake posts...in steel, can you BELIEVE this nonsense on a titanium fork for frick sake... I mean, look at that tiny spot of corrosion. Abhorrent! The 5mm bolt supplied with the headset and frame from the previous owner looks to be aluminum and light weight- so it can stay, but not before I clean off that DIY paint job on it with my wifes nail polish remover. Thanks in advance, wife.

 

[MuchAlohaNui]

A few weight previews since I had the scale out. Here is the full carbon no-name, questionable Chinese made seat with carbon rails. Honestly the comfort is not that bad, but really who is in the saddle anyways when they are doing full sends everywhere they go? Also I have this American Classic seat post, which is a bit piggish. Aluminum. Cool USA factor, but it's pretty heavy.

To recap on suggestions for parts and to add a few, I am looking for suggestions on:
-Wheels
-titanium stem around 110mm, flat to low rise
-titanium canti posts, colored or not
-titanium canti bosses (where the preload of the canti spring is set by sliding the spring into the hole and onto the brake posts)
-titanium (or dare I say carbon) seat post
-bottom bracket (FSA titanium square taper?)

 

[Dr Dremel]

The original Mag 21 SL booster is just 110g, so there would be potential for weight saving me thinks (yours looks a bit heavier, but way cooler).

For brake studs (or just the screws) you could ask Christian Jenny (ex Tune employee, also has Ti shafts).

http://kon-q-renz.de/
You may have stumbled upon his quite comprehensive ebay shop, at least that´s where I got to know him:

https://www.ebay.de/str/konqrenzpunktde?_ipg=72

 

[MuchAlohaNui]

Cool thank you. I had a few of his parts already bookmarked such as the Tune seatpost and bottom bracket. I will have a look at his ebay store today with a cup of coffee and do some window shopping. Mhm, the original booster is quite light and I think the one I have now is around 175 g IIRC, but man...looks so much nicer than the original. There needs to be some fashion before function too (and a bit of moving the goal post around to fit my world-view)

 

[MuchAlohaNui]

Weighed the front fork with the MD brake booster, Chris King lower race and the star nut. Let's be a little OCD...

1322 g total weight
-10 g star nut
-17 g King bearing race

Grand total:
1295 g

...but there is room for improvement?
View attachment 693877

Looking at this old Rock Shox catalog scan, the fork I have is much heavier than what is claimed in the catalog. My 1322 grams total vs. the catalog 1043 grams, a 21% difference. If the catalog claimed weight is accurate the brake booster and the billet crown stiffness come with a significant weight penalty (see catalog scan below). I pulled the stem shims off to see if that steerer tube is ferric in any way, like some kind of alloy mixture because there are people out there with SL forks who have steel steerer tubes

...aluminum. I used a strong magnet too. Though on the Weight Weenies website, the weight of the SL fork is listed as 1225 grams 'actual' (Al steerer w/ canti cable guides removed), a 7.5% weight difference. Do I press in a titanium steer tube? At first glance, no, titanium dollars to donuts is heavier than aluminum. However this doesn't consider wall thickness of the current aluminum steerer tube and what is available. I measured the wall thickness of the aluminum tube: about 3.5 mm. From a prior link posted above to a German Tune machinist, he sells a 1 1/8" titanium steerer at 170 mm long and claims 84 grams but does not mention wall thickness; my assumption is about 2x thinner maybe 2.5x.

What is the aluminum steer tube weight though? Using yet another link posted prior in this thread to another German-based website a thread starter has the same fork here along with the Ultimate Machine crown. His fork pre-upgrades weighs 1550 grams WITH a steel steerer tube at 180 mm.

My Rock Shox SL = 1322 grams with Ultimate Machine crown and MB brake booster and aluminum steerer tube
Other guys SL = 1550 grams stock with a steel steerer tube

He then goes on to post pictures of parts on a scale:

1) Ultimate Machine crown = 186 grams
2) Ultimate Machine crown and aluminum steerer tube 170 mm = 345 grams

By deduction I can then infer by his data that the stock aluminum steerer tube = 159 grams

Titanium 170 mm steerer tube = 86 grams
Stock aluminum steerer tube = 159 grams

Reduction of steerer tube = 73 grams
Steel allen head bolts = 10 grams
Steel canti bosses = 22 grams

Titanium allen had bolts = 3 grams
Titanium canti bosses = 11 grams

Reduction of bolts = 18 grams

So it looks like for a lot of money I can reduce about 90 - 95 grams total, simply by switching to a titanium steerer and titanium bolts. In a small pursuit of keeping the fork "blingy", adding a bit more "blinginess" and chasing a tiny bit of grams for the hell of it, this is a good side project for tinkering. I guess I'll order some hardware.

 

[Dr Dremel]

Titanium 170 mm steerer tube = 86 grams
Stock aluminum steerer tube = 159 grams

Been looking at the Ti steerer tubes myself (for a Tange Switchblade) and noticed that the length given on the ebay auction is of course overall length. As I understand it you have to add the part that is used to clamp your crown. With my fork I´d still save over 100g (24cm overall steel steerer), but coming from an aluminium tube it would be far less than your estimated 75g.

 

[MuchAlohaNui]

Dear lord 24 cm. You are right: I didn’t account for the length pressed into the crown, but the difference in weight doesn’t really change too much. In your case, do it and post results. Do you have access to a press? I have an old but good and straight bottle jack and will cautiously DIY the conversion from Al to Ti with sockets and a home made jig.

 

[Dr Dremel]

No press here, but I don´t need one for the Switchblade crown, it simultaneously clamps the fork legs and steerer, so with the bolts loosened the steerer just falls out. But it´s a project well down the line, the bike it is for is already built and I´ve 3 others waiting for attention before.

Bottlejack/jig/sockets seems like a solution I´d try, I´m a fan of improvising. Smaller presses are nothing else than bottlejacks in a frame, right?

 

[benjabbi]

These are two Rockshox steerers, one steel threaded, the other aluminium threadless in equivalent lengths. I thought it was quite interesting that going threadless and aluminium actually only saved weight on the headset and stem. The steerers themselves are more or less identical.

 

[MuchAlohaNui]

Hey! Thanks for posting those photos and weights! This goes to show you that a different material isn't always lighter, due to inherent properties of said material- i.e. the wall thickness of a steerer tube to make it safe to use. Out of curiosity can you measure the wall width of the steel steerer with calipers?