Wednesday, June 26, 2013

1990 Doug Bradbury Manitou

This is the last of the three DBMs that I've had the pleasure on work on. As far as the evolution of the design this frame (in my somewhat limited experience) represents close to the pinnacle of the design. There were a few more changes in later years, but as far as I can tell they were limited to the frame accepting a 31.8mm seat post vs the 27.2 in this frame (26.8 in earlier years).


Although I am very much partial to my 89 "Big Blue", something about this bike just screams "Go FAST!". I really like the look and am very happy with how it turned out. Maybe some Grafton brakes or Cook Cranks might spice it up a bit more, but all in all I think the balance here is great!


Although each of the three DBMs presented here came with the first generation of the Manitou suspension fork I only built this one using the fork. It was a bit of a challenge, but in the end I was able to make some custom elastomers from a Manitou 4 and got it work pretty well.


This fork represents the genesis of the widely known line of Manitou suspension forks. This is Doug's first design (identifiable by the diagonal dropouts) and features a whopping 1.25", maybe 1.5" of travel. Perhaps the travel is limited in this fork by my choice of elastomers, but I don't think so. Since this fork is made to go with this fram it's spaced out to accomodate the 115mm modified Hi-E hub, I imagine the forks that Doug made for Tomac and other racers back in the day were available and regular spacing as well.


Like my 89 bike this frame uses the machined 3/8" Aluminum stock to connect the chainstay box section to the 90mm bottom bracket shell. A Cook Bros bottom bracket with a 135mm spindle neatly tucks into shell.


The shape of the top tube to head tube reinforcing gusset changed from the 88 to 89/90 frames. In the earlier frames the gusset was taller to accomodate the longer extension of the head tube above the top tube. In the later frames the gusset grew longer along the top tube, but the overlap with the head tube was reduced. I'm not exactly sure as to how this change came about, all I can suggest is that Doug made some subtle changes to the geometry over the years which resulted in less overhang of the head tube above the top tube, and so a shorter gusset was sufficient to reinforce the joint.





The rear end on this bike is the same as the 88 and 89, 0.75" box section for the seat stay and 1.0" box section for the chainstay connecting to a vertical dropout machined out of 3/8" aluminum plate.


Definitely my favorite style / font used on the MANITOU decals.






Well, not much more to say here. This is a killer bike that's once again ready to hit the trails!!

3 comments:

  1. Absolutely stunning!!! OMW! What an awesome bike! I am totally in love with the real mountain bikes, those being 1992-1995.

    What a bike! What a job.

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  2. Do anyone know where to get elastomers for this fork?
    I've a Manitou fork on my vintage 90's Ritchey, but elastomers are gone!!!

    thank you!!

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  3. I cut a set of Manitou 1 elastomers down to size to fit this fork. You can get new elastomers from http://www.suspensionforkparts.net/

    ReplyDelete