2008 Specialized Globe Centrum Singlespeed

I don’t know why, but the first time I saw this bike in Specialized’s catalog, I wanted one. I thought it’s be a cool “city” bike for commuting or whatnot.

I don’t think they sold very many of them, as they killed the design/model after just one year. I think it was Specialized’s reaction to the success of Cannondale’s Bad Boy series of urban bikes.

I got this one off of craigslist a few years ago, and proceeded to swap out the parts as I do with all of my bikes it seems.

Now, the only stock parts left are the headset and brakes! Also, it was originally a 26er…turns out 29″/700c wheels fit just fine with lower-volume tires..

I would say this bike (like the Bad Boy) was actually designed to handle both wheel sizes, as the geometry seems largely unaffected by the increase in wheel size.

  • Chris King 29er ISO disc wheelset, with Stans 355 rims and Specialized 25c Rouxbaix rubber
  • Specialized low-riser bar and seatpost, with Format SL saddle
  • Ritchey WCS stem
  • Truvativ FireX crankset
  • 21.2lbs with pedals

Lastest updates:

  • Shimano hydraulic disc brakeset/levers
  • DiamondBack OEM 29er wheelset (sold the Chris Kings)
  • KS Supernatural Dropper Post with Joplin remote (the 29er wheels make it a bit too tall to put my feet on the ground when stopped; the dropper is a sweet solution!)
  • Kickstand!

Future updates?:

  • I’d like to find an internally geared hub and turn it into a 7 or 8-spd bike. Or maybe find a compatible derailleur hanger, but I don’t think one exists for this frame.

Latest build 06/17:

The Centrum has become my ‘city’ bike and sits in my office for occasional lunchtime runs, etc. The LEV was pretty unreliable, so I got rid of it and put on a Specialized Command Post instead. I’ve had a couple of those posts and they have never given me any issues.

The bars were swapped out with some FSA Metropolis mustache bars. And for grips I used some old bar tape.

Seems I lost a part of this post with a recent server migration, but I ended up selling the CK wheelset and setting it up with a set of Shimano 650b wheels, which lowers the bike back down a bit.

Update 07/23/2018:

Latest build/changes:

  • new rubber! Panaracer Parimoto 650b x 42c tires w/ Gravel King casing (made in Japan!) – Waaay wider and makes it feel more like a cruiser than a hybrid.
  • Origin8 Bat Wing bars
  • Fox Transfer Performance 125mm dropper w/Specialized SRL lever
  • XTR 180/160mm Freeza centerlock rotors (spares from my MTB)
  • Thomson seatpost collar
  • Spurcycle bell
  • Looks Legit!

Even Moar updates! 05/05/2019:

  • Changed grips to ODI Vans waffle lock-ons
  • Swapped the Fox Transfer external dropper for an INTERNALLY-routed Reverb Stealth 150mm! I ordered some frame plugs off of eBay and decided to go for it. Not the best work I’ve done, but it works and looks trick! Hardest part was getting the plugs into the holes as I undersized them to make sure they would fit tightly. Pretty sure my Centrum is unique with the internal routing! Lovin’ it!

In retrospect, I think I should have put the routing holes on the non-drive side as the housing could potentially rub the chainring/front derailleur if I had a multi-ring crankset (which I’m not really planning on adding, but you never know!). I originally wanted to route the holes in the center of the tubes, so just beneath the water bottle cage and back into the seattube where the sticker is. But the problem with that is I wouldn’t be able to fit my drill in such a tight space. I’m glad I thought about that before I started drilling!

Latest updates! 10/12/2019

The frame plugs from eBay (China) were total shite. They were too brittle and cracked into pieces. I decided to order some rubber frame plugs made by Giant. They were only $1.50 each and I needed 3 of them.

I had to dremel/file the holes to be larger, but the plugs are soo much nicer. They are flexible and fit snugly and the cable housing is held securely.

I also changed out the Reverb for a OneUp 150mm dropper. Oneup is my new favorite dropper post. It’s super smooth and much easier to deal with than the Reverb. The lever action is also considerably lighter to depress than the Reverb remote.

One change that isn’t in these photos is a fork swap to a 2009 RockShox SID Race. Although it was a 26″ fork, it fit my 650b wheels just fine with plenty of clearance. It’s also very easy to reduce the travel in those forks, so I dropped it down to 60mm. I rode it this way for a few months, but ultimately sold off the fork since it was relatively rare with it’s v-brake lowers. It was sort of an interesting experiment, and it made the bike feel more like a proper gravel bike, akin to having a Fox AX gravel fork but with 60mm of travel on it. Another small fitting change was to swap out the 90mm Specialized stem for a Syntace 60mm one.

Join the Conversation


  1. I have been thinking about converting mine to a hub gear and have seen an Alfine 8 wheel which appears to be the same size. Would it just be a change of the wheel or would I need to add a chain tensioner, new chain.

    1. If it’s the same wheel size, it will be a simple swap. Tension can be adjusted by adjusting the position of the dropouts if needed, and the existing chain will work although I think it’s a little clunky.

  2. Is the headset fully integrated or semi-integrated I’ve got old caged bearings in mine which I can’t get for love nor money, got any ideas?

    Cheers John

    1. I believe it’s an integrated headset with caged balls. If the races are ok, you should be able to swap in loose balls or get new caged bearing sets. I took these photos some time ago. Looks like the model is a VP-A18AK.


      Some digging around seems to say you can press out the integrated cups and replace the headset with a Cane Creek IS-2, etc.:


      Would love to hear what you end up doing and what works! Thanks and be safe out there!

      1. Hi
        Thanks for the reply, I bought some sealed bearings and had a go at knocking the races out but having had the frame powder coated they just wouldn’t shift due to the frame being baked I’m guessing, took the caged bearings out and replaced them with loose 1/8th bearings, much better and smoother than a dolphins back. The name of the headset Specialized used on it is a Mindset (mindf??k more like)

        1. That’s really interesting. We’ve just picked up a Centrum and the only thing wrong was the Headset was way over tightened via the top cap. Pulling apart showed the bearing race was all bent, and the bearings look a bit ground down. Luckily the cups look fine. Has zero grease.

          I also come to the conclusion that there is no off the peg solution, reckon a IS42 could fit, but would probably need some fettling, and could be an expensive mistake.

          Was thinking to try some 1/8 loose balls? The race is 23 balls. I guess it will be a couple more when fitted loose.

          Having read this seems the way to go, this bike is in the office, and no stand… going to be a fiddly little job to do top and bottom!

  3. Heya,

    I’m interested in the SID Race experiment, do you have pictures of the tyre clearance?

    1. Hmm, I can’t seem to find any photos, which is weird since I usually always take photos of any mods/upgrades I do. If I find some, I will update my post. I would say there is quite a bit of clearance. The tires I was running were 42mm wide. I think you could probably go up to even 50 or perhaps even a 2.0/2.1 MTB tire. The issue would be the rear clearance. I think you can go wider, but the height of the tire would become an issue as you go up. I think there is about 10mm clearance with the 42mm parimoto’s on there now.

      The other issue is finding a SID with a long enough steerer tube. The headtube on the Centrum is very long. I think the SID I used had a 9+ inch steerer. Good luck and please let me know if you end up making this upgrade!

      1. I stayed with the fork that came with it. But changed the wheels to 27,5″ (Alfine8 + deore ), I ride a Michelin Country Rock tyre, which fits nicely in the rear. I can send some pics if you’re interested.


  4. Do you have any pics with 700c/29 wheels that show tire clearance? I am converting one to gravel and have 38mm tires but not sure if i even want to try if its to tight.

    1. I don’t unfortunately. I think it will clear, but it may be tight on the rear. I would suggest borrowing a 700c/29″ wheel from someone to eye it first. If it works, please let me know! Good luck!

    1. Hi Eric! I used a kickstand that mounts to the rear set and chainstays, instead of the normal position by the bottom bracket. This looks exactly like the one I used: https://amz.run/5ZEV

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