CF base question

I recently bought a used Miyata/Gemcrest cf saddle base, and it just arrived. I came undrilled and I have all the hardware to start drilling, but when I placed a seatpost bracket on the underside to mark the holes, I noticed that there is a pretty sizeable gap between the seatpost bracket and the base.

Question is, what can I use to fill that gap? Also, I dry fit my death grip handle and the fit is good, but there is some space that allows it to move a bit fore & aft. I’m not sure if it should be mounted all the way up against the front of the base, or the other way to allow for the foam and saddle cover? Would appreciate any help on this.

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I went ahead and hot glued foam pieces to the sides of the seatpost bracket, each cut to the shape of the saddle curve, then simply filled it in with bondo. When it’s totally cured I’ll smooth it out and then drill baby drill!

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Good thinking! Hope it works! Let us know how it holds up! Can I ask what you are going to do to put foam on the Miyata style base I’m considering doing the same thing?

Your seat post solution looks pretty neat. If you weren’t already going to, may I highly recommend using T-nuts in the seatbase instead of bolts sticking through? It is just better in every way. I mounted the handle somewhere in a middle position, enough space for the seatcover on the inside, enough for foam + seatcover on the outside.

As with my original Scott Wallis saddle setup, I used foam and cover from an extra fusion free ride, and it works great, and the shape of the foam gives it a nice semi-flat profile.

Yes, I used T nuts and snipped off all but one of the points,(extra insurance against spinning) which were anchored into small holes plus I used marine epoxy to secure them and they’e solid as a rock. I used a dremel with round cutter to cut down the sleeves of each of the 10 T nuts so they wouldn’t protrude and be flush with the underside. The pics below show the t nuts, (before epoxy) death grip, seatpost and bumper test fitted, and the last pic shows the finished saddle. I applied a clear rubber coating (plasti-dip) to the front of the death grip to help prevent damage from impacts.

And the best part is, the total cost of both the death grip and CF base was just $75! I was very lucky to have won and ebay auction for the DG about a week ago ($50 winning bid!) and picked up the gemcrest (Miyata type) CF base for $25. Both are exceedingly rare to find, especially in new condition! (The DG will not fit a KH/Nimbus base properly, which is why I needed the cf Miyata base.)

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Here’s the riser/seatpost shim I cast from Bondo. Today I covered it with a layer of fiberglass just for some added strength. I maybe could’ve also made it from a piece of hardwood, but cutting it evenly and getting the curve just right wouldn’t have been doable with my limited shop tools. I think the bondo version should hold up fine. Took it out for a 4 mile MUni this morning with no issues.

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