Public service announcement: 1991 Diamond Back Master TG seatpost size

Yep, it reads 27.0 mm on that Avenir 4130 steel seatpost.

 Per request from a reader, here are some images of the seat tube cluster on my 1991 Diamond Back Master TG. As these bikes age, there are likely still many usable frames out there in the wild. A critical element of putting one back together is to source the correct size of seatpost. As this type of info can be difficult to find elsewhere, I'm posting it here. For the record, the frame requires a 27.0 mm seatpost.

If you're here for the purpose of rebuilding an old Diamond Back road bike, you may be interested in learning more about my pepto-pink '91 Master TG, which I discovered nearly unused a few years ago. Good luck with your project!

Seat cluster from the back...

...the left side...

...and the right.

I'm still here.

My view for a vast majority of the time during the past month.

In the waning hour of the month, I realized it's been exactly 30 days since I was last around this lonely little blog. I have good reasons for my delinquency. Nearly all of them have to do with me finishing my dissertation. I'll hopefully be able to emerge from my cocoon and be a real person once again in the near future.

However, I can't let this go without some bike content. So, voila! Behold my incongruous Diamond Back collection.

My "salmon" colored 1991 Diamond Back Master TG with its little brother...

... a 1995 Diamond Back Assault. This is as it was when I got it.

I picked up a mid '90s fully chromed Diamond Back Assault BMX bike over the summer, from an era I have since learned is referred to as "mid school" as opposed to "old school." The bike is ostensibly for visiting nieces and nephews to use. It had been enjoyed and ridden over the years, but was in reasonably good shape. In typical fashion, while making some adjustments I ended up stripping it down, cleaning and rebuilding it.

Three or so decades back, as a kid, I always wanted, but never had, a chrome BMX. The DB Assault is not quite as alluring as a mag-wheeled, nickel plated '77 Roger De Coster or a loop tailed '79 Diamond Back Pro were for me in my halcyon days, but it'll do.

Perhaps after growing a few more inches, a little blonde girl that I know might give the bike a taste of some dirt. Until then, I have found that I am surprisingly not too tall to ride it. Who knows, I may see about getting to a pump track one of these days. Probably during my plentiful spare time.

Bike to Work Day

Pink. Old. Speedy. No, I still haven't wrapped the bars yet.

Today was the annually recurring day when biking to work gets the attention it deserves. It's always encouraging to see the trails and streets teeming with people of all shapes and sizes on bikes. A lot of people worked hard to bring to the public bicycle infrastructure improvements over the past year. A similarly large effort was behind the day's wide range of quality treats, goodies and entertainment. Having been involved with some of the underlying processes, it is rewarding to see Denver continue to blossom into a top-tier bike town.

I'm all for coaxing people to try riding to work or school or to coffee or really for any trip. However, it's too bad that biking for transportation doesn't receive more attention and acknowledgement throughout the rest of the year. Bike to work day, perhaps without so much fanfare, could easily occur monthly, or even weekly year around. I'm not suggesting as a city we should forgo the fun of the annual event, but to truly encourage people to bike more, the periodic frequency of Bike to Work Day may need to be greatly increased. Off my soapbox now.

Since the day involves uncharacteristic choices for many who don't ride regularly, I decided to follow suit by doing something uncharacteristic for me, and ride my road bike as a commuter. Those who know me, readily see me as a cargo and/or utilitarian bike rider, accustomed to platform BMX pedals, any type of shoes and whatever clothes are comfortable. Today I chose my least utilitarian bike and rode with cleats and, although I wasn't in full kit, I did incorporate some thought into my choice of apparel.

1991 Diamond Back Master TG

I've always liked this part of the Master TG, where the narrow angle of the seatstays meet the seat tube.

I was rewarded in my choice to ride a different steed with a much faster journey, at least in my terms. My Garmin 210 reported a summary of each mile to me while enroute, and there were several miles during which I averaged about 20 mph. That may not sound impressive to any racer types out there, but that is lightning fast compared to riding many of my other bikes.

The giant metallic dog sparkles in the sun.

I was going along my way quickly, and didn't pause often to take photos. I made an exception to take a shot of a new piece of public art along the Platte River Trail, and found out by way of the Culinary Hack that the dog sculpture is for the new Denver Animal Shelter. As someone who has a critical eye for art, I thought it to be quite good and am pleased that the work entitled Sun Spot is associated with the new facility.

The Master TG parked downtown outside the building where I had a meeting.

Later in the day we met friends visiting from Alabama in Wash Park for a relaxing evening. At least one of us is of the opinion that it's always good to have other kids around to play with.

That's the way she rolls.

Kids and mud; a perennial favorite.

I have something new, black and Surly that will be finding its way more substantially onto this blog at some point in the near future. A couple of teaser shots appear below. However, it is not quite as impressive as something else that is new, black and Surly rumored to have arrived recently. We'll have to wait for the owner to spill the beans.

Antlers?

Or something else?

New rubber and parts for my road bike

A bit of a refresh for my 1991 Diamond Back Master TG.

After being sick for much of the past week, I was finally feeling well enough to spend some time in the shop. It's fortunate that I was up for a little shop time, because my 1991 Diamond Back Master TG was in need of some work. You may remember my 20 year-old crazy pink road bike from an earlier post. Curiously, that post about my Master TG is one of the most visited pages on this site, possibly because not much relevant info exists anywhere else about these particular bikes. If you happen to be here looking for info on the short era of steel Diamond Back road bikes, I'll do my best to continue to expand the story as I'm able. For now though, on to a little shop work.

When I got the Master TG, although initially flat, the tires and tubes held air well when pumped. In fact, they've held air very well for several months now, and have carried me on several shortish rides totaling perhaps 80 to 100 miles. However, I knew the tires were dry and brittle and could become problematic any time, so new tires were in order.

The old Vittoria 22c clinchers crumbled when I removed them from the rims.

I hadn't yet taken the tires off the rims since I had owned the bike, but when I did, the casing near the bead disintegrated into dust and fragments. However, the tube inside was supple and in good condition. After a careful inspection of the tubes, they had no patches and served to support my hypothesis that this bike had only been minimally used. I decided to reuse the tubes with new tires. After all, the tubes appeared to be in at least as good of condition, if not better than tubes on many of my other bikes. I have a pile of tubes that have accumulated in my shop over the years, a few of which are at least 20 years old. Some of my older tubes have been patched many times, but seem to have more lasting power than newer tubes. Maybe they just made them better back in the old days. In any case, I have no qualms about reinstalling the original tubes on the Master TG. 

New Michelin 25c tire (left) versus old Vittoria 22c tire (right). Who knew an extra 3 mm of width would make the carcass look so fat?

I chose a pair of Michelin Lithion 2.0 25c folding bead tires as replacements, mostly because they seemed to be decent mid range standard road tires. I was tempted by some colored tires that would match and/or contrast interestingly with the frame color, but I couldn't quite pull the trigger. I decided to modestly up-size the carcass width of the new tires because I couldn't see any clear advantage of running such skinny tires on this bike, and thought I might appreciate a little more bounce.

There's not a lot of clearance between the new tire and the fork crown, 3 mm or so, but that's enough.

It's a good thing that I didn't decide on any fatter tires than I did, or else I might have had to file down the inner fork crown to fit. The rear triangle had plenty of clearance at the seat stay bridge and the chainstays, so probably 28c or even 30c tires would work on the back. The 25c tires are just fine for my purposes though.

I also decided to make some alterations to the cockpit, with a new bar and stem. I liked the original black anodized Tioga Prestige road stem, but I felt a bit stretched out along my torso when riding. This could be because I'm not recently accustomed to a traditional road bike riding posture, but I decided to install a somewhat shorter and taller stem. I swapped the original low rise 130 mm extension stem for a Nitto Technomic Deluxe 100 mm extension with a higher rise. I'm not sure that this stem will permanently stick on this bike, but I wanted to give it a try.

For the handlebar, I went with a Nitto Model 177, otherwise known as a "Noodle" bar, in 44 cm width. The original Centurion bar was 41 cm wide and felt a little narrow for me. I haven't owned a Noodle bar before, but based on the feedback of a lot of people who swear by this model, I'm now entering the test phase.

I like the shape of the Nitto Model 177 (top) better than the original Centurion bar (bottom), at least in theory. Only putting on some miles will let me know for sure.

Those who are familiar with Nitto products know that they come with a glowing satiny finish reminiscent of times gone by, when Japan and Europe exported components with buttery smooth metal surfaces. Modern components aim more for the technical wow factor of a plastic-like carbon fiber finish. I know carbon fiber parts are lighter, but for me they are diminished in aesthetic appeal by the way they feel. This is probably no small contributing factor in why I'm working on a bike that's almost old enough to buy beer. Well, that and the fact that I likely couldn't withstand the price tag of carbon fiber anything.

If the good weather holds and I continue to regain my health, I'll put my refurbished road bike to the test sooner than later.

Retina-vibrating, skinny-tired time capsule

Yes, that's me in spandex and clipless shoes, not a common sight

UPDATE 18 Sep 2014: I've added a post featuring seatpost size and images of the seat tube cluster, per a reader request. See it here.
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This post veers far away from Big Dummying or Daddying. In fact it's about a bike with no provision for fenders or cargo at all. Nevertheless, rest assured it is chock full of the bike nerd-ness you've come to expect.

You may remember my recent encounter with speed on two wheels. I was surprised to find that as non-competitive as I am, I enjoyed racing, at least against myself. I had fun as part of a team triathlon, even though my equipment was not well suited to all-out speed. While all-out speed for me remains a distant possibility, I now have a real road bike.

Enter a 1991 Diamond Back Master TG via Craigslist that I picked up for a mere $6.52 per pound. It has a 60cm center-to-top seat tube and a 58cm center-to-center top tube. The bike has been a garage ornament for the better part of the past two decades. It was obviously un-ridden, with grease having seeped out of every bearing assembly, collecting a translucent encasement of oily dust. 

1991 Diamond Back Master TG as it was when I got it

The Master TG has a full Shimano 105 7-speed group including Look compatible pedals. No unserviceable STI or finicky 9 or 10 speed parts, and it has a threaded headset; all big pluses for me. The tubing is Tange oversized chromium-molybdenum steel, TIG welded together. The bike maximizes use of quality steel with an Avenir 4130 heat treated seatpost and a Tioga Prestige stem. The rims are hard anodized Sun Mistrals, 36 hole front and 32 hole rear.

The previous owner bought it new from Pauli's Bicycle and Lawnmower in Metairie, Louisiana. He later equipped it time trial style, with a Profile aero bar, a Vetta C-10 cyclocomputer and a CO2 cartridge emergency pump. Other than these additions, the bike was stock catalog spec. The original bars were included, as were a pair of size 44.5 Lake shoes (unfortunately a bit too small for me) and a seat pack containing two new tubes with their receipt from a bike shop dated 9/10/91, a bottle of Motrin that expired 6/94 and a multi-tool.

The OEM 22mm Vittoria Zefir tires were flat but in good condition and held air confidently when I pumped them up. I've always liked the look of gumwall tires on dark gray hard anodized rims. I wonder why good gumwalls are so hard to find anymore?

Tange 100% OS CRMO tubing and a slightly askew dealer sticker

Dig the cool matching pink splattered black Paramount bottle cage

Other than old grease, dust and a few paint chips from leaning against things, the bike was immaculate. The photos don't do the intensity of the salmon pink color justice, which I have to admit I quite like. Although the color clashes with current ideals of a proper color for a bike, the paint itself is impressively high in quality, flecked and streaked with gloss black over top. The combo of garish 90s era paint, non-horizontal dropouts, lack of lugs and oversized tubing makes this bike unappealing both for hipsters looking for a fixie frame and collectors looking for a holy grail classic. These features contribute to a lack of respect culminating in low market value for what is really a great road bike, well suited for my purposes.

The frame is a descendant of the highly sought Centurion Dave Scott Ironman road bikes. It was made less than two years after Western States Imports (WSI), the owners of the Centurion brand, apparently decided to capitalize on the name recognition of their Diamond Back mountain bikes by re-branding their road bikes. As a remnant of this lineage, the bike has a decal on the left chainstay declaring it "Designed by Centurion." Sheldon Brown has some info about Centurion bikes, but there is very little info on the web about the short era of high quality steel Diamond Back branded road bikes, starting in 1990 and going to about '94 or '95. 

Furry with dust, prior to cleaning

WSI owned the Centurion and Diamond Back brands

The frameset was made in Taiwan, and appears to be of very similar quality and build characteristics as the two Surlys I own, which were also built in Taiwan. In this respect, it seems a bit like an antecedent to the Surly Pacer road frame. Overall, the welds are clean and the finish work is more than competent, though well short of custom. This is actually preferable to me; I am averse to owning a bike that is too expensive or pretty to ride. That propensity once kept me from buying a Rivendell Atlantis, and I'm glad to now know and acknowledge it.

I enjoy working on a bike as much as riding one, so as soon as I had the time I completely disassembled the bike and cleaned, adjusted and rebuilt everything from the bearings outward.

After cleaning and a coat of wax, it's almost factory fresh and completely rust free

The bike rides smoothly and quickly. After reassembly, I took it for a ride to Chatfield on the Platte River Trail and it performed well, with the resilient liveliness and subtle road surface feedback of a good steel frame. It's not the lightest or the quickest thing out there, but neither am I. At about 23 pounds, the Master TG feels like a svelte and nimble rocket after having ridden so many miles on a loaded Big Dummy.

1991 Diamond Back Master TG, resplendent in Pepto-Bismol colored glory

I've never been a fan of lycra-covered gel saddles, so the original Avenir saddle is off in favor of a vintage Flite from my parts box. I also temporarily swapped the Shimano 105 pedals for some SPD compatible units until I have the time to install Look cleats on my shoes. I returned the stock Centurion drop bar to its place, bringing the bike back close to original spec, with the exception of saddle and pedals. I haven't taped the bars yet, because I may exchange the stem with something that has a shorter extension than 130mm. I might go with a 110mm Salsa CroMoto to keep the TIG welded look, but a Nitto Technomic is also a possibility.

It's a little odd for me to ride a bike that doesn't have a utilitarian purpose, but I enjoy it anyway. I'll definitely be doing some more road riding, and who knows, maybe even some casual racing.